[12/12] v4l2-compat-ioctl32.c: refactor, fix security bug in compat ioctl32

Commit Message

Hans Verkuil Jan. 26, 2018, 12:43 p.m. UTC

From: Daniel Mentz <[e-mail]>

The 32-bit compat v4l2 ioctl is implemented based on its 64-bit
equivalent. It converts 32-bit data structures into its 64-bit
equivalents and needs to provide the data to the 64-bit ioctl in user
space memory which is commonly allocated using
compat_alloc_user_space(). However, due to how that function is
implemented, it can only be called a single time for every syscall
invocation.  Supposedly to avoid this limitation, the existing code uses
a mix of memory from the kernel stack and memory allocated through
compat_alloc_user_space(). Under normal circumstances, this would not
work, because the 64-bit ioctl expects all pointers to point to user
space memory. As a workaround, set_fs(KERNEL_DS) is called to
temporarily disable this extra safety check and allow kernel pointers.
However, this might introduce a security vulnerability: The
result of the 32-bit to 64-bit conversion is writeable by user space
because the output buffer has been allocated via
compat_alloc_user_space(). A malicious user space process could then
manipulate pointers inside this output buffer, and due to the previous
set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer
prevent kernel memory access.

The new approach is to pre-calculate the total amount of user space
memory that is needed, allocate it using compat_alloc_user_space() and
then divide up the allocated memory to accommodate all data structures
that need to be converted.

An alternative approach would have been to retain the union type karg
that they allocated on the kernel stack in do_video_ioctl(), copy all
data from user space into karg and then back to user space. However,
we decided against this approach because it does not align with other
compat syscall implementations. Instead, we tried to replicate the
get_user/put_user pairs as found in other places in the kernel:

if (get_user(clipcount, &up->clipcount) ||
    put_user(clipcount, &kp->clipcount)) return -EFAULT;

Notes from [e-mail]:

This patch was taken from
https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7

Clearly nobody could be bothered to upstream this patch or at minimum
tell us :-( We only heard about this a week ago.

This patch was rebased and cleaned up. Compared to the original I
also swapped the order of the convert_in_user arguments so that they
matched copy_in_user. It was hard to review otherwise. I also replaced
the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.

Signed-off-by: Daniel Mentz <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 700 ++++++++++++++++----------
 1 file changed, 448 insertions(+), 252 deletions(-)

Comments

Sakari Ailus Jan. 29, 2018, 5:06 p.m. UTC | #1

Hi Hans,

Thanks for your efforts on this patch and the patchset. Please see my comments below.

On Fri, Jan 26, 2018 at 01:43:27PM +0100, Hans Verkuil wrote:
> From: Daniel Mentz <[e-mail]>
> 
> The 32-bit compat v4l2 ioctl is implemented based on its 64-bit

s/v4l2 ioctl/V4L2 IOCTL handling/

?

> equivalent. It converts 32-bit data structures into its 64-bit
> equivalents and needs to provide the data to the 64-bit ioctl in user
> space memory which is commonly allocated using
> compat_alloc_user_space(). However, due to how that function is
> implemented, it can only be called a single time for every syscall
> invocation.  Supposedly to avoid this limitation, the existing code uses
> a mix of memory from the kernel stack and memory allocated through
> compat_alloc_user_space(). Under normal circumstances, this would not
> work, because the 64-bit ioctl expects all pointers to point to user
> space memory. As a workaround, set_fs(KERNEL_DS) is called to
> temporarily disable this extra safety check and allow kernel pointers.
> However, this might introduce a security vulnerability: The
> result of the 32-bit to 64-bit conversion is writeable by user space
> because the output buffer has been allocated via
> compat_alloc_user_space(). A malicious user space process could then
> manipulate pointers inside this output buffer, and due to the previous
> set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer
> prevent kernel memory access.
> 
> The new approach is to pre-calculate the total amount of user space
> memory that is needed, allocate it using compat_alloc_user_space() and
> then divide up the allocated memory to accommodate all data structures
> that need to be converted.
> 
> An alternative approach would have been to retain the union type karg
> that they allocated on the kernel stack in do_video_ioctl(), copy all
> data from user space into karg and then back to user space. However,
> we decided against this approach because it does not align with other
> compat syscall implementations. Instead, we tried to replicate the
> get_user/put_user pairs as found in other places in the kernel:
> 
> if (get_user(clipcount, &up->clipcount) ||
>     put_user(clipcount, &kp->clipcount)) return -EFAULT;
> 
> Notes from [e-mail]:
> 
> This patch was taken from
> https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7
> 
> Clearly nobody could be bothered to upstream this patch or at minimum
> tell us :-( We only heard about this a week ago.

This is very sad indeed. I would really hope that we'll never run into
something this again!

> 
> This patch was rebased and cleaned up. Compared to the original I
> also swapped the order of the convert_in_user arguments so that they
> matched copy_in_user. It was hard to review otherwise. I also replaced
> the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.

The result looks more complicated than it should be.

I wonder if the result could be made cleaner by separating the argument
checking and copying from / to user space in video_usercopy. That
separation almost completely exists already. Rather than mangling the
compat argument struct to look like a user-provided 64-bit argument struct,
copying the arguments from and to the user space would be separately done
to 32-bit compat IOCTL arguments.

I suppose that wouldn't be a trivial change either, so for now I'd maintain
the approach and later consider how to make this more maintainable in the
future. Still, that approach is quite different and it'd be easier to
switch from status quo rather than this last patch, suggesting to start
with a revert, should we embark into this direction.

What do you think?

> 
> Signed-off-by: Daniel Mentz <[e-mail]>
> Signed-off-by: Hans Verkuil <[e-mail]>
> ---
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 700 ++++++++++++++++----------
>  1 file changed, 448 insertions(+), 252 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> index 2aa9b43daf60..27a5a0961cbd 100644
> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> @@ -22,6 +22,14 @@
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-ioctl.h>
>  
> +/* Use the same argument order as copy_in_user */
> +#define convert_in_user(to, from)			\

This doesn't really convert anything. How about calling it assign_in_user,
for example?

> +({							\
> +	typeof(*from) val;				\

"val" is very short, easily leading to hard-to-find namespace collisions.
At least the versions of GCC I've used happily get this wrong without a
warning.

How about __convert_in_user_tmp instead?

> +							\
> +	get_user(val, from) || put_user(val, to);	\
> +})
> +
>  static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  {
>  	long ret = -ENOIOCTLCMD;
> @@ -48,37 +56,41 @@ struct v4l2_window32 {
>  	__u8                    global_alpha;
>  };
>  
> -static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
> +static int get_v4l2_window32(struct v4l2_window __user *kp,
> +			     struct v4l2_window32 __user *up,
> +			     void __user *aux_buf, int aux_space)
>  {
>  	struct v4l2_clip32 __user *uclips;
>  	struct v4l2_clip __user *kclips;
>  	compat_caddr_t p;
> -	u32 n;
> +	u32 clipcount;
>  
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
> -	    get_user(kp->field, &up->field) ||
> -	    get_user(kp->chromakey, &up->chromakey) ||
> -	    get_user(kp->clipcount, &up->clipcount) ||
> -	    get_user(kp->global_alpha, &up->global_alpha))
> +	    copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
> +	    convert_in_user(&kp->field, &up->field) ||
> +	    convert_in_user(&kp->chromakey, &up->chromakey) ||
> +	    convert_in_user(&kp->global_alpha, &up->global_alpha) ||
> +	    get_user(clipcount, &up->clipcount) ||
> +	    put_user(clipcount, &kp->clipcount))
>  		return -EFAULT;
> -	if (kp->clipcount > 2048)
> +	if (clipcount > 2048)
>  		return -EINVAL;
> -	if (!kp->clipcount) {
> -		kp->clips = NULL;
> -		return 0;
> -	}
> +	if (!clipcount)
> +		return put_user(NULL, &kp->clips) ? -EFAULT : 0;

Isn't this what put_user would return anyway?

>  
> -	n = kp->clipcount;
>  	if (get_user(p, &up->clips))
>  		return -EFAULT;
>  	uclips = compat_ptr(p);
> -	kclips = compat_alloc_user_space(n * sizeof(*kclips));
> -	kp->clips = kclips;
> -	while (n--) {
> +	if (aux_space < clipcount * sizeof(*kclips))
> +		return -EFAULT;
> +	kclips = aux_buf;
> +	if (put_user(kclips, &kp->clips))
> +		return -EFAULT;
> +
> +	while (clipcount--) {
>  		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
>  			return -EFAULT;
> -		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
> +		if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
>  			return -EFAULT;
>  		uclips++;
>  		kclips++;
> @@ -86,26 +98,28 @@ static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
>  	return 0;
>  }
>  
> -static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
> +static int put_v4l2_window32(struct v4l2_window __user *kp,
> +			     struct v4l2_window32 __user *up)
>  {
>  	struct v4l2_clip __user *kclips = kp->clips;
>  	struct v4l2_clip32 __user *uclips;
> -	int n = kp->clipcount;
>  	compat_caddr_t p;
> -
> -	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
> -	    put_user(kp->field, &up->field) ||
> -	    put_user(kp->chromakey, &up->chromakey) ||
> -	    put_user(kp->clipcount, &up->clipcount) ||
> -	    put_user(kp->global_alpha, &up->global_alpha))
> +	u32 clipcount;
> +
> +	if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
> +	    convert_in_user(&up->field, &kp->field) ||
> +	    convert_in_user(&up->chromakey, &kp->chromakey) ||
> +	    convert_in_user(&up->global_alpha, &kp->global_alpha) ||
> +	    get_user(clipcount, &kp->clipcount) ||
> +	    put_user(clipcount, &up->clipcount))
>  		return -EFAULT;
> -	if (!kp->clipcount)
> +	if (!clipcount)
>  		return 0;
>  
>  	if (get_user(p, &up->clips))
>  		return -EFAULT;
>  	uclips = compat_ptr(p);
> -	while (n--) {
> +	while (clipcount--) {
>  		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
>  			return -EFAULT;
>  		uclips++;
> @@ -145,107 +159,161 @@ struct v4l2_create_buffers32 {
>  	__u32			reserved[8];
>  };
>  
> -static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> +static int __bufsize_v4l2_format32(struct v4l2_format32 __user *up)

This is effectively returning the size of the non-compat struct, or just
the part of which is variable. How about calling it __bufsize_v4l2_format
instead? The same for other such functions.

I'd also separate the size calculated by the function and the return value.

>  {
> -	if (get_user(kp->type, &up->type))
> +	u32 type;
> +
> +	if (get_user(type, &up->type))
>  		return -EFAULT;
>  
> -	switch (kp->type) {
> +	switch (type) {
> +	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
> +		u32 clipcount;
> +
> +		if (get_user(clipcount, &up->fmt.win.clipcount))
> +			return -EFAULT;
> +		if (clipcount > 2048)
> +			return -EINVAL;
> +		return clipcount * sizeof(struct v4l2_clip);
> +	}
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static int bufsize_v4l2_format32(struct v4l2_format32 __user *up)
> +{
> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
> +		return -EFAULT;

Newline?

> +	return __bufsize_v4l2_format32(up);
> +}
> +
> +static int __get_v4l2_format32(struct v4l2_format __user *kp,
> +			       struct v4l2_format32 __user *up,
> +			       void __user *aux_buf, int aux_space)
> +{
> +	u32 type;
> +
> +	if (get_user(type, &up->type) || put_user(type, &kp->type))
> +		return -EFAULT;
> +
> +	switch (type) {
>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> -		return copy_from_user(&kp->fmt.pix, &up->fmt.pix,
> -				      sizeof(kp->fmt.pix)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> -		return copy_from_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
> -				      sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> -		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win);
> +		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
> +					 aux_buf, aux_space);
>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
> -		return copy_from_user(&kp->fmt.vbi, &up->fmt.vbi,
> -				      sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
> -		return copy_from_user(&kp->fmt.sliced, &up->fmt.sliced,
> -				      sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
> -		return copy_from_user(&kp->fmt.sdr, &up->fmt.sdr,
> -				      sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_META_CAPTURE:
> -		return copy_from_user(&kp->fmt.meta, &up->fmt.meta,
> -				      sizeof(kp->fmt.meta)) ? -EFAULT : 0;
> +		return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>  	default:
>  		return -EINVAL;
>  	}
>  }
>  
> -static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> +static int get_v4l2_format32(struct v4l2_format __user *kp,
> +			     struct v4l2_format32 __user *up,
> +			     void __user *aux_buf, int aux_space)
> +{
> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
> +		return -EFAULT;
> +	return __get_v4l2_format32(kp, up, aux_buf, aux_space);
> +}
> +
> +static int bufsize_v4l2_create32(struct v4l2_create_buffers32 __user *up)
>  {
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>  		return -EFAULT;
> -	return __get_v4l2_format32(kp, up);
> +	return __bufsize_v4l2_format32(&up->format);
>  }
>  
> -static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
> +static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
> +			     struct v4l2_create_buffers32 __user *up,
> +			     void __user *aux_buf, int aux_space)
>  {
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
> +	    copy_in_user(kp, up,
> +			 offsetof(struct v4l2_create_buffers32, format)))
>  		return -EFAULT;
> -	return __get_v4l2_format32(&kp->format, &up->format);
> +	return __get_v4l2_format32(&kp->format, &up->format,
> +				   aux_buf, aux_space);
>  }
>  
> -static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> +static int __put_v4l2_format32(struct v4l2_format __user *kp,
> +			       struct v4l2_format32 __user *up)
>  {
> -	if (put_user(kp->type, &up->type))
> +	u32 type;
> +
> +	if (get_user(type, &kp->type))
>  		return -EFAULT;
>  
> -	switch (kp->type) {
> +	switch (type) {
>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> -		return copy_to_user(&up->fmt.pix, &kp->fmt.pix,
> -				    sizeof(kp->fmt.pix)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> -		return copy_to_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
> -				    sizeof(kp->fmt.pix_mp)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
>  		return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
> -		return copy_to_user(&up->fmt.vbi, &kp->fmt.vbi,
> -				    sizeof(kp->fmt.vbi)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
> -		return copy_to_user(&up->fmt.sliced, &kp->fmt.sliced,
> -				    sizeof(kp->fmt.sliced)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
> -		return copy_to_user(&up->fmt.sdr, &kp->fmt.sdr,
> -				    sizeof(kp->fmt.sdr)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>  	case V4L2_BUF_TYPE_META_CAPTURE:
> -		return copy_to_user(&up->fmt.meta, &kp->fmt.meta,
> -				    sizeof(kp->fmt.meta)) ?  -EFAULT : 0;
> +		return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>  	default:
>  		return -EINVAL;
>  	}
>  }
>  
> -static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> +static int put_v4l2_format32(struct v4l2_format __user *kp,
> +			     struct v4l2_format32 __user *up)
>  {
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))

For some pointers we do perform such checks, for others we don't. While
this patch doesn't change this, it'd be good to align this by either
introducing it everywhere or removing it everywhere.

I guess that can be done separately.

>  		return -EFAULT;
>  	return __put_v4l2_format32(kp, up);
>  }
>  
> -static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
> +static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
> +			     struct v4l2_create_buffers32 __user *up)
>  {
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format)) ||
> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> +	    copy_in_user(up, kp,
> +			 offsetof(struct v4l2_create_buffers32, format)) ||
> +	    copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>  		return -EFAULT;
>  	return __put_v4l2_format32(&kp->format, &up->format);
>  }
> @@ -259,25 +327,27 @@ struct v4l2_standard32 {
>  	__u32		     reserved[4];
>  };
>  
> -static int get_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
> +static int get_v4l2_standard32(struct v4l2_standard __user *kp,
> +			       struct v4l2_standard32 __user *up)
>  {
>  	/* other fields are not set by the user, nor used by the driver */
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    get_user(kp->index, &up->index))
> +	    convert_in_user(&kp->index, &up->index))
>  		return -EFAULT;
>  	return 0;
>  }
>  
> -static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
> +static int put_v4l2_standard32(struct v4l2_standard __user *kp,
> +			       struct v4l2_standard32 __user *up)
>  {
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(kp->index, &up->index) ||
> -	    put_user(kp->id, &up->id) ||
> -	    copy_to_user(up->name, kp->name, 24) ||
> -	    copy_to_user(&up->frameperiod, &kp->frameperiod,
> -			 sizeof(kp->frameperiod)) ||
> -	    put_user(kp->framelines, &up->framelines) ||
> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> +	    convert_in_user(&up->index, &kp->index) ||
> +	    copy_in_user(&up->id, &kp->id, sizeof(up->id)) ||

Why not convert_in_user()?

> +	    copy_in_user(up->name, kp->name, 24) ||
> +	    copy_in_user(&up->frameperiod, &kp->frameperiod,
> +			 sizeof(up->frameperiod)) ||
> +	    convert_in_user(&up->framelines, &kp->framelines) ||
> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>  		return -EFAULT;
>  	return 0;
>  }
> @@ -317,10 +387,10 @@ struct v4l2_buffer32 {
>  	__u32			reserved;
>  };
>  
> -static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
> +static int get_v4l2_plane32(struct v4l2_plane __user *up,
> +			    struct v4l2_plane32 __user *up32,
>  			    enum v4l2_memory memory)
>  {
> -	void __user *up_pln;
>  	compat_long_t p;

Shouldn't this be compat_ulong_t?

>  
>  	if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
> @@ -336,10 +406,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>  			return -EFAULT;
>  		break;
>  	case V4L2_MEMORY_USERPTR:
> -		if (get_user(p, &up32->m.userptr))
> -			return -EFAULT;
> -		up_pln = compat_ptr(p);
> -		if (put_user((unsigned long)up_pln, &up->m.userptr))
> +		if (get_user(p, &up32->m.userptr) ||
> +		    put_user((unsigned long)compat_ptr(p), &up->m.userptr))
>  			return -EFAULT;
>  		break;
>  	case V4L2_MEMORY_DMABUF:
> @@ -351,7 +419,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>  	return 0;
>  }
>  
> -static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
> +static int put_v4l2_plane32(struct v4l2_plane __user *up,
> +			    struct v4l2_plane32 __user *up32,
>  			    enum v4l2_memory memory)
>  {
>  	unsigned long p;
> @@ -375,8 +444,7 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>  			return -EFAULT;
>  		break;
>  	case V4L2_MEMORY_DMABUF:
> -		if (copy_in_user(&up32->m.fd, &up->m.fd,
> -				 sizeof(up->m.fd)))
> +		if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
>  			return -EFAULT;
>  		break;
>  	}
> @@ -384,37 +452,68 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>  	return 0;
>  }
>  
> -static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
> +static int bufsize_v4l2_buffer32(struct v4l2_buffer32 __user *up)
> +{
> +	u32 type;
> +	u32 length;
> +
> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> +	    get_user(type, &up->type) ||
> +	    get_user(length, &up->length))
> +		return -EFAULT;
> +
> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> +		if (length > VIDEO_MAX_PLANES)
> +			return -EINVAL;
> +
> +		/* We don't really care if userspace decides to kill itself

/*
 * ...

> +		 * by passing a very big length value
> +		 */
> +		return length * sizeof(struct v4l2_plane);
> +	}
> +	return 0;
> +}
> +
> +static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
> +			     struct v4l2_buffer32 __user *up,
> +			     void __user *aux_buf, int aux_space)
>  {
> +	u32 type;
> +	u32 length;
> +	enum v4l2_memory memory;
>  	struct v4l2_plane32 __user *uplane32;
>  	struct v4l2_plane __user *uplane;
>  	compat_caddr_t p;
> +	int num_planes;

u32?

>  	int ret;
>  
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    get_user(kp->index, &up->index) ||
> -	    get_user(kp->type, &up->type) ||
> -	    get_user(kp->flags, &up->flags) ||
> -	    get_user(kp->memory, &up->memory) ||
> -	    get_user(kp->length, &up->length))
> +	    convert_in_user(&kp->index, &up->index) ||
> +	    get_user(type, &up->type) ||
> +	    put_user(type, &kp->type) ||
> +	    convert_in_user(&kp->flags, &up->flags) ||
> +	    get_user(memory, &up->memory) ||
> +	    put_user(memory, &kp->memory) ||
> +	    get_user(length, &up->length) ||
> +	    put_user(length, &kp->length))
>  		return -EFAULT;
>  
> -	if (V4L2_TYPE_IS_OUTPUT(kp->type))
> -		if (get_user(kp->bytesused, &up->bytesused) ||
> -		    get_user(kp->field, &up->field) ||
> -		    get_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> -		    get_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec))
> +	if (V4L2_TYPE_IS_OUTPUT(type))
> +		if (convert_in_user(&kp->bytesused, &up->bytesused) ||
> +		    convert_in_user(&kp->field, &up->field) ||
> +		    convert_in_user(&kp->timestamp.tv_sec,
> +				    &up->timestamp.tv_sec) ||
> +		    convert_in_user(&kp->timestamp.tv_usec,
> +				    &up->timestamp.tv_usec))
>  			return -EFAULT;
>  
> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
> -		unsigned int num_planes;
> -
> -		if (kp->length == 0) {
> -			kp->m.planes = NULL;
> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> +		num_planes = length;

Do you need a local variable for just that?

> +		if (num_planes == 0) {
>  			/* num_planes == 0 is legal, e.g. when userspace doesn't
>  			 * need planes array on DQBUF*/
> -			return 0;
> -		} else if (kp->length > VIDEO_MAX_PLANES) {
> +			return put_user(NULL, &kp->m.planes);
> +		} else if (num_planes > VIDEO_MAX_PLANES) {
>  			return -EINVAL;
>  		}
>  
> @@ -423,40 +522,47 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>  
>  		uplane32 = compat_ptr(p);
>  		if (!access_ok(VERIFY_READ, uplane32,
> -			       kp->length * sizeof(*uplane32)))
> +				num_planes * sizeof(*uplane32)))

Alignment.

>  			return -EFAULT;
>  
>  		/* We don't really care if userspace decides to kill itself
>  		 * by passing a very big num_planes value */
> -		uplane = compat_alloc_user_space(kp->length * sizeof(*uplane));
> -		kp->m.planes = (__force struct v4l2_plane *)uplane;
> +		if (aux_space < num_planes * sizeof(*uplane))
> +			return -EFAULT;
> +
> +		uplane = aux_buf;
> +		if (put_user((__force struct v4l2_plane *)uplane,
> +					&kp->m.planes))
> +			return -EFAULT;
>  
> -		for (num_planes = 0; num_planes < kp->length; num_planes++) {
> -			ret = get_v4l2_plane32(uplane, uplane32, kp->memory);
> +		while (--num_planes >= 0) {

while (num_planes--) {

?

> +			ret = get_v4l2_plane32(uplane, uplane32, memory);
>  			if (ret)
>  				return ret;
> -			++uplane;
> -			++uplane32;
> +			uplane++;
> +			uplane32++;
>  		}
>  	} else {
> -		switch (kp->memory) {
> +		switch (memory) {
>  		case V4L2_MEMORY_MMAP:
> -		case V4L2_MEMORY_OVERLAY:
> -			if (get_user(kp->m.offset, &up->m.offset))
> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
>  				return -EFAULT;
>  			break;
> -		case V4L2_MEMORY_USERPTR:
> -			{
> -				compat_long_t tmp;
> -
> -				if (get_user(tmp, &up->m.userptr))
> -					return -EFAULT;
> +		case V4L2_MEMORY_USERPTR: {
> +			compat_long_t tmp;

compat_ulong_t, I'd call it "userptr". The latter is entirely up to you.

>  
> -				kp->m.userptr = (unsigned long)compat_ptr(tmp);
> -			}
> +			if (get_user(tmp, &up->m.userptr) ||
> +			    put_user((unsigned long)compat_ptr(tmp),
> +				     &kp->m.userptr))
> +				return -EFAULT;
> +			break;
> +		}
> +		case V4L2_MEMORY_OVERLAY:
> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
> +				return -EFAULT;

Is there a reason to split this off from MMAP handling? The code is the
same.

>  			break;
>  		case V4L2_MEMORY_DMABUF:
> -			if (get_user(kp->m.fd, &up->m.fd))
> +			if (convert_in_user(&kp->m.fd, &up->m.fd))
>  				return -EFAULT;
>  			break;
>  		}
> @@ -465,8 +571,12 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>  	return 0;
>  }
>  
> -static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
> +static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
> +			     struct v4l2_buffer32 __user *up)
>  {
> +	u32 type;
> +	u32 length;
> +	enum v4l2_memory memory;
>  	struct v4l2_plane32 __user *uplane32;
>  	struct v4l2_plane __user *uplane;
>  	compat_caddr_t p;
> @@ -474,53 +584,60 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>  	int ret;
>  
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(kp->index, &up->index) ||
> -	    put_user(kp->type, &up->type) ||
> -	    put_user(kp->flags, &up->flags) ||
> -	    put_user(kp->memory, &up->memory))
> +	    convert_in_user(&up->index, &kp->index) ||
> +	    get_user(type, &kp->type) ||
> +	    put_user(type, &up->type) ||
> +	    convert_in_user(&up->flags, &kp->flags) ||
> +	    get_user(memory, &kp->memory) ||
> +	    put_user(memory, &up->memory))
>  		return -EFAULT;
>  
> -	if (put_user(kp->bytesused, &up->bytesused) ||
> -	    put_user(kp->field, &up->field) ||
> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> -	    put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
> -	    copy_to_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
> -	    put_user(kp->sequence, &up->sequence) ||
> -	    put_user(kp->reserved2, &up->reserved2) ||
> -	    put_user(kp->reserved, &up->reserved) ||
> -	    put_user(kp->length, &up->length))
> +	if (convert_in_user(&up->bytesused, &kp->bytesused) ||
> +	    convert_in_user(&up->field, &kp->field) ||
> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
> +	    convert_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
> +	    copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
> +	    convert_in_user(&up->sequence, &kp->sequence) ||
> +	    convert_in_user(&up->reserved2, &kp->reserved2) ||
> +	    convert_in_user(&up->reserved, &kp->reserved) ||
> +	    get_user(length, &kp->length) ||
> +	    put_user(length, &up->length))
>  		return -EFAULT;
>  
> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
> -		num_planes = kp->length;
> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> +		num_planes = length;
>  		if (num_planes == 0)
>  			return 0;
>  
> -		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
> +		if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
> +			return -EFAULT;
>  		if (get_user(p, &up->m.planes))
>  			return -EFAULT;
>  		uplane32 = compat_ptr(p);
>  
>  		while (--num_planes >= 0) {


while (num_planes--) {

Or rather: s/num_planes/length/

Then you can remove num_planes.

> -			ret = put_v4l2_plane32(uplane, uplane32, kp->memory);
> +			ret = put_v4l2_plane32(uplane, uplane32, memory);
>  			if (ret)
>  				return ret;
>  			++uplane;
>  			++uplane32;
>  		}
>  	} else {
> -		switch (kp->memory) {
> +		switch (memory) {
>  		case V4L2_MEMORY_MMAP:
> -		case V4L2_MEMORY_OVERLAY:
> -			if (put_user(kp->m.offset, &up->m.offset))
> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
>  				return -EFAULT;
>  			break;
>  		case V4L2_MEMORY_USERPTR:
> -			if (put_user(kp->m.userptr, &up->m.userptr))
> +			if (convert_in_user(&up->m.userptr, &kp->m.userptr))
> +				return -EFAULT;
> +			break;
> +		case V4L2_MEMORY_OVERLAY:
> +			if (convert_in_user(&up->m.offset, &kp->m.offset))

Combine with MMAP case?

>  				return -EFAULT;
>  			break;
>  		case V4L2_MEMORY_DMABUF:
> -			if (put_user(kp->m.fd, &up->m.fd))
> +			if (convert_in_user(&up->m.fd, &kp->m.fd))
>  				return -EFAULT;
>  			break;
>  		}
> @@ -545,29 +662,32 @@ struct v4l2_framebuffer32 {
>  	} fmt;
>  };
>  
> -static int get_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
> +static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> +				  struct v4l2_framebuffer32 __user *up)
>  {
> -	u32 tmp;
> +	compat_caddr_t tmp;
>  
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>  	    get_user(tmp, &up->base) ||
> -	    get_user(kp->capability, &up->capability) ||
> -	    get_user(kp->flags, &up->flags) ||
> -	    copy_from_user(&kp->fmt, &up->fmt, sizeof(up->fmt)))
> +	    put_user((__force void *)compat_ptr(tmp), &kp->base) ||
> +	    convert_in_user(&kp->capability, &up->capability) ||
> +	    convert_in_user(&kp->flags, &up->flags) ||
> +	    copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
>  		return -EFAULT;
> -	kp->base = (__force void *)compat_ptr(tmp);
>  	return 0;
>  }
>  
> -static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
> +static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> +				  struct v4l2_framebuffer32 __user *up)
>  {
> -	u32 tmp = (u32)((unsigned long)kp->base);
> +	void *base;
>  
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(tmp, &up->base) ||
> -	    put_user(kp->capability, &up->capability) ||
> -	    put_user(kp->flags, &up->flags) ||
> -	    copy_to_user(&up->fmt, &kp->fmt, sizeof(up->fmt)))
> +	    get_user(base, &kp->base) ||
> +	    put_user(ptr_to_compat(base), &up->base) ||
> +	    convert_in_user(&up->capability, &kp->capability) ||
> +	    convert_in_user(&up->flags, &kp->flags) ||
> +	    copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
>  		return -EFAULT;
>  	return 0;
>  }
> @@ -586,16 +706,18 @@ struct v4l2_input32 {
>  
>  /* The 64-bit v4l2_input struct has extra padding at the end of the struct.
>     Otherwise it is identical to the 32-bit version. */
> -static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
> +static inline int get_v4l2_input32(struct v4l2_input __user *kp,
> +				   struct v4l2_input32 __user *up)
>  {
> -	if (copy_from_user(kp, up, sizeof(*up)))
> +	if (copy_in_user(kp, up, sizeof(*up)))
>  		return -EFAULT;
>  	return 0;
>  }
>  
> -static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
> +static inline int put_v4l2_input32(struct v4l2_input __user *kp,
> +				   struct v4l2_input32 __user *up)
>  {
> -	if (copy_to_user(up, kp, sizeof(*up)))
> +	if (copy_in_user(up, kp, sizeof(*up)))
>  		return -EFAULT;
>  	return 0;
>  }
> @@ -648,39 +770,58 @@ static inline bool ctrl_is_pointer(struct file *file, u32 id)
>  	return !ret && (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
>  }
>  
> +static int bufsize_v4l2_ext_controls32(struct v4l2_ext_controls32 __user *up)
> +{
> +	u32 count;
> +
> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> +	    get_user(count, &up->count))
> +		return -EFAULT;
> +	if (count > V4L2_CID_MAX_CTRLS)
> +		return -EINVAL;
> +	return count * sizeof(struct v4l2_ext_control);
> +}
> +
>  static int get_v4l2_ext_controls32(struct file *file,
> -				   struct v4l2_ext_controls *kp,
> -				   struct v4l2_ext_controls32 __user *up)
> +				   struct v4l2_ext_controls __user *kp,
> +				   struct v4l2_ext_controls32 __user *up,
> +				   void __user *aux_buf, int aux_space)
>  {
>  	struct v4l2_ext_control32 __user *ucontrols;
>  	struct v4l2_ext_control __user *kcontrols;
> +	u32 count;
>  	unsigned int n;

u32 n

>  	compat_caddr_t p;
>  
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    get_user(kp->which, &up->which) ||
> -	    get_user(kp->count, &up->count) ||
> -	    get_user(kp->error_idx, &up->error_idx) ||
> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> +	    convert_in_user(&kp->which, &up->which) ||
> +	    get_user(count, &up->count) ||
> +	    put_user(count, &kp->count) ||
> +	    convert_in_user(&kp->error_idx, &up->error_idx) ||
> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>  		return -EFAULT;
> -	if (kp->count == 0) {
> -		kp->controls = NULL;
> -		return 0;
> -	} else if (kp->count > V4L2_CID_MAX_CTRLS) {
> +	if (count == 0)
> +		return put_user(NULL, &kp->controls);
> +	else if (kp->count > V4L2_CID_MAX_CTRLS)

count

>  		return -EINVAL;
> -	}
>  	if (get_user(p, &up->controls))
>  		return -EFAULT;
>  	ucontrols = compat_ptr(p);
> -	if (!access_ok(VERIFY_READ, ucontrols, kp->count * sizeof(*ucontrols)))
> +	if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))
> +		return -EFAULT;
> +	if (aux_space < count * sizeof(*kcontrols))
>  		return -EFAULT;
> -	kcontrols = compat_alloc_user_space(kp->count * sizeof(*kcontrols));
> -	kp->controls = (__force struct v4l2_ext_control *)kcontrols;
> -	for (n = 0; n < kp->count; n++) {
> +	kcontrols = aux_buf;
> +	if (put_user((__force struct v4l2_ext_control *)kcontrols,
> +		     &kp->controls))
> +		return -EFAULT;
> +
> +	for (n = 0; n < count; n++) {
>  		u32 id;
>  
>  		if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
>  			return -EFAULT;
> +
>  		if (get_user(id, &kcontrols->id))
>  			return -EFAULT;

Newline here, too? Not really a problem with this patch though.

>  		if (ctrl_is_pointer(file, id)) {
> @@ -699,36 +840,47 @@ static int get_v4l2_ext_controls32(struct file *file,
>  }
>  
>  static int put_v4l2_ext_controls32(struct file *file,
> -				   struct v4l2_ext_controls *kp,
> +				   struct v4l2_ext_controls __user *kp,
>  				   struct v4l2_ext_controls32 __user *up)
>  {
>  	struct v4l2_ext_control32 __user *ucontrols;
> -	struct v4l2_ext_control __user *kcontrols =
> -		(__force struct v4l2_ext_control __user *)kp->controls;
> -	int n = kp->count;
> +	struct v4l2_ext_control __user *kcontrols;
> +	u32 count;
> +	unsigned int n;

u32 n

>  	compat_caddr_t p;
>  
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(kp->which, &up->which) ||
> -	    put_user(kp->count, &up->count) ||
> -	    put_user(kp->error_idx, &up->error_idx) ||
> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> +	    get_user(kcontrols, &kp->controls) ||

How about doing this as last? "controls" is the last member of the struct.

> +	    convert_in_user(&up->which, &kp->which) ||
> +	    get_user(count, &kp->count) ||
> +	    put_user(count, &up->count) ||
> +	    convert_in_user(&up->error_idx, &kp->error_idx) ||
> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>  		return -EFAULT;
> -	if (!kp->count)
> +	if (!count)
>  		return 0;
>  
>  	if (get_user(p, &up->controls))
>  		return -EFAULT;
>  	ucontrols = compat_ptr(p);
> -	if (!access_ok(VERIFY_WRITE, ucontrols, n * sizeof(*ucontrols)))
> +	if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
>  		return -EFAULT;
>  
> -	while (--n >= 0) {
> -		unsigned size = sizeof(*ucontrols);
> +	for (n = 0; n < count; n++) {
> +		unsigned int size = sizeof(*ucontrols);
>  		u32 id;
>  
> +		if (copy_in_user(&ucontrols->id, &kcontrols->id,
> +				 sizeof(ucontrols->id)) ||

get_user(id, &kcontrols->id) ||
put_user(id, &ucontrols->id) ||

> +		    copy_in_user(&ucontrols->size, &kcontrols->size,
> +				 sizeof(ucontrols->size)) ||

convert_in_user() ?

> +		    copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
> +				 sizeof(ucontrols->reserved2)))
> +			return -EFAULT;
> +
>  		if (get_user(id, &kcontrols->id))
>  			return -EFAULT;

...and the above if () can be removed.

> +
>  		/* Do not modify the pointer when copying a pointer control.
>  		   The contents of the pointer was changed, not the pointer
>  		   itself. */
> @@ -736,6 +888,7 @@ static int put_v4l2_ext_controls32(struct file *file,
>  			size -= sizeof(ucontrols->value64);

This chunk is yearning for newlines. Not a fault of this patch though.

>  		if (copy_in_user(ucontrols, kcontrols, size))
>  			return -EFAULT;
> +
>  		ucontrols++;
>  		kcontrols++;
>  	}
> @@ -755,17 +908,18 @@ struct v4l2_event32 {
>  	__u32				reserved[8];
>  };
>  
> -static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *up)
> +static int put_v4l2_event32(struct v4l2_event __user *kp,
> +			    struct v4l2_event32 __user *up)
>  {
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(kp->type, &up->type) ||
> -	    copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
> -	    put_user(kp->pending, &up->pending) ||
> -	    put_user(kp->sequence, &up->sequence) ||
> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> -	    put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
> -	    put_user(kp->id, &up->id) ||
> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> +	    convert_in_user(&up->type, &kp->type) ||
> +	    copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
> +	    convert_in_user(&up->pending, &kp->pending) ||
> +	    convert_in_user(&up->sequence, &kp->sequence) ||
> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
> +	    convert_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
> +	    convert_in_user(&up->id, &kp->id) ||
> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>  		return -EFAULT;
>  	return 0;
>  }
> @@ -778,31 +932,34 @@ struct v4l2_edid32 {
>  	compat_caddr_t edid;
>  };
>  
> -static int get_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
> +static int get_v4l2_edid32(struct v4l2_edid __user *kp,
> +			   struct v4l2_edid32 __user *up)
>  {
> -	u32 tmp;
> +	compat_uptr_t tmp;
>  
>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> -	    get_user(kp->pad, &up->pad) ||
> -	    get_user(kp->start_block, &up->start_block) ||
> -	    get_user(kp->blocks, &up->blocks) ||
> +	    convert_in_user(&kp->pad, &up->pad) ||
> +	    convert_in_user(&kp->start_block, &up->start_block) ||
> +	    convert_in_user(&kp->blocks, &up->blocks) ||
>  	    get_user(tmp, &up->edid) ||
> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> +	    put_user(compat_ptr(tmp), &kp->edid) ||
> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>  		return -EFAULT;
> -	kp->edid = (__force u8 *)compat_ptr(tmp);
>  	return 0;
>  }
>  
> -static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
> +static int put_v4l2_edid32(struct v4l2_edid __user *kp,
> +			   struct v4l2_edid32 __user *up)
>  {
> -	u32 tmp = (u32)((unsigned long)kp->edid);
> +	void *edid;
>  
>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> -	    put_user(kp->pad, &up->pad) ||
> -	    put_user(kp->start_block, &up->start_block) ||
> -	    put_user(kp->blocks, &up->blocks) ||
> -	    put_user(tmp, &up->edid) ||
> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> +	    convert_in_user(&up->pad, &kp->pad) ||
> +	    convert_in_user(&up->start_block, &kp->start_block) ||
> +	    convert_in_user(&up->blocks, &kp->blocks) ||
> +	    get_user(edid, &kp->edid) ||
> +	    put_user(ptr_to_compat(edid), &up->edid) ||
> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>  		return -EFAULT;
>  	return 0;
>  }
> @@ -835,22 +992,30 @@ static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>  #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
>  #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
>  
> +static void __user *alloc_userspace(unsigned int size, int aux_space, long *err)

This one is weird. Rather than following the pattern and returning an error
and assigning the result to a pointer passed to it, it does exactly the
opposite. I'd change that. I guess this is a matter of opinion to some
degree at least, though.

> +{
> +	void __user *up_native;
> +
> +	if (aux_space < 0) {
> +		*err = aux_space;
> +		return NULL;
> +	}
> +	up_native = compat_alloc_user_space(size + aux_space);
> +	if (!up_native)
> +		*err = -ENOMEM;
> +	else if (clear_user(up_native, size))
> +		*err = -EFAULT;
> +	else
> +		return up_native;
> +	return NULL;
> +}
> +
>  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  {
> -	union {
> -		struct v4l2_format v2f;
> -		struct v4l2_buffer v2b;
> -		struct v4l2_framebuffer v2fb;
> -		struct v4l2_input v2i;
> -		struct v4l2_standard v2s;
> -		struct v4l2_ext_controls v2ecs;
> -		struct v4l2_event v2ev;
> -		struct v4l2_create_buffers v2crt;
> -		struct v4l2_edid v2edid;
> -		unsigned long vx;
> -		int vi;
> -	} karg;
>  	void __user *up = compat_ptr(arg);
> +	void __user *up_native = NULL;
> +	void __user *aux_buf;
> +	int aux_space;

size_t?

>  	int compatible_arg = 1;
>  	long err = 0;
>  
> @@ -889,30 +1054,47 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  	case VIDIOC_STREAMOFF:
>  	case VIDIOC_S_INPUT:
>  	case VIDIOC_S_OUTPUT:
> -		err = get_user(karg.vi, (s32 __user *)up);
> +		up_native = alloc_userspace(sizeof(unsigned int __user),
> +					    0, &err);
> +		if (!err && convert_in_user((unsigned int __user *)up_native,
> +					    (compat_uint_t __user *)up))
> +			return -EFAULT;
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_G_INPUT:
>  	case VIDIOC_G_OUTPUT:
> +		up_native = alloc_userspace(sizeof(unsigned int __user),
> +					    0, &err);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_G_EDID:
>  	case VIDIOC_S_EDID:
> -		err = get_v4l2_edid32(&karg.v2edid, up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_edid), 0, &err);
> +		err = err ? : get_v4l2_edid32(up_native, up);

I'd write this as:

		if (!err)
			err = get_v4l2_edid32(native_up, up);

Same below.

>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_G_FMT:
>  	case VIDIOC_S_FMT:
>  	case VIDIOC_TRY_FMT:
> -		err = get_v4l2_format32(&karg.v2f, up);
> +		aux_space = bufsize_v4l2_format32(up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_format),
> +					    aux_space, &err);
> +		aux_buf = up_native + sizeof(struct v4l2_format);
> +		err = err ? : get_v4l2_format32(up_native, up,
> +						aux_buf, aux_space);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_CREATE_BUFS:
> -		err = get_v4l2_create32(&karg.v2crt, up);
> +		aux_space = bufsize_v4l2_create32(up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_create_buffers),
> +					    aux_space, &err);
> +		aux_buf = up_native + sizeof(struct v4l2_create_buffers);
> +		err = err ? : get_v4l2_create32(up_native, up,
> +						aux_buf, aux_space);
>  		compatible_arg = 0;
>  		break;
>  
> @@ -920,36 +1102,54 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  	case VIDIOC_QUERYBUF:
>  	case VIDIOC_QBUF:
>  	case VIDIOC_DQBUF:
> -		err = get_v4l2_buffer32(&karg.v2b, up);
> +		aux_space = bufsize_v4l2_buffer32(up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_buffer),
> +					    aux_space, &err);
> +		aux_buf = up_native + sizeof(struct v4l2_buffer);
> +		err = err ? : get_v4l2_buffer32(up_native, up,
> +						aux_buf, aux_space);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_S_FBUF:
> -		err = get_v4l2_framebuffer32(&karg.v2fb, up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
> +					    0, &err);
> +		err = err ? : get_v4l2_framebuffer32(up_native, up);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_G_FBUF:
> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
> +					    0, &err);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_ENUMSTD:
> -		err = get_v4l2_standard32(&karg.v2s, up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_standard),
> +					    0, &err);
> +		err = err ? : get_v4l2_standard32(up_native, up);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_ENUMINPUT:
> -		err = get_v4l2_input32(&karg.v2i, up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_input), 0, &err);
> +		err = err ? : get_v4l2_input32(up_native, up);
>  		compatible_arg = 0;
>  		break;
>  
>  	case VIDIOC_G_EXT_CTRLS:
>  	case VIDIOC_S_EXT_CTRLS:
>  	case VIDIOC_TRY_EXT_CTRLS:
> -		err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
> +		aux_space = bufsize_v4l2_ext_controls32(up);
> +		up_native = alloc_userspace(sizeof(struct v4l2_ext_controls),
> +					    aux_space, &err);
> +		aux_buf = up_native + sizeof(struct v4l2_ext_controls);
> +		err = err ? : get_v4l2_ext_controls32(file, up_native, up,
> +						      aux_buf, aux_space);
>  		compatible_arg = 0;
>  		break;
>  	case VIDIOC_DQEVENT:
> +		up_native = alloc_userspace(sizeof(struct v4l2_event), 0, &err);
>  		compatible_arg = 0;
>  		break;
>  	}
> @@ -958,13 +1158,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  
>  	if (compatible_arg)
>  		err = native_ioctl(file, cmd, (unsigned long)up);
> -	else {
> -		mm_segment_t old_fs = get_fs();
> -
> -		set_fs(KERNEL_DS);
> -		err = native_ioctl(file, cmd, (unsigned long)&karg);
> -		set_fs(old_fs);
> -	}
> +	else
> +		err = native_ioctl(file, cmd, (unsigned long)up_native);
>  
>  	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
>  		return err;
> @@ -976,11 +1171,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  	case VIDIOC_G_EXT_CTRLS:
>  	case VIDIOC_S_EXT_CTRLS:
>  	case VIDIOC_TRY_EXT_CTRLS:
> -		if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
> +		if (put_v4l2_ext_controls32(file, up_native, up))
>  			err = -EFAULT;
>  		break;
>  	case VIDIOC_S_EDID:
> -		if (put_v4l2_edid32(&karg.v2edid, up))
> +		if (put_v4l2_edid32(up_native, up))
>  			err = -EFAULT;
>  		break;
>  	}
> @@ -992,44 +1187,45 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  	case VIDIOC_S_OUTPUT:
>  	case VIDIOC_G_INPUT:
>  	case VIDIOC_G_OUTPUT:
> -		err = put_user(((s32)karg.vi), (s32 __user *)up);
> +		err = convert_in_user((compat_uint_t __user *)up,
> +				      ((unsigned int __user *)up_native));

Do note that convert_in_user() returns Boolean. This will effectively yield
1 in case of an error here. How about changing convert_in_user() to return
whatever get_user / put_user do, to avoid errors in the future?

>  		break;
>  
>  	case VIDIOC_G_FBUF:
> -		err = put_v4l2_framebuffer32(&karg.v2fb, up);
> +		err = put_v4l2_framebuffer32(up_native, up);
>  		break;
>  
>  	case VIDIOC_DQEVENT:
> -		err = put_v4l2_event32(&karg.v2ev, up);
> +		err = put_v4l2_event32(up_native, up);
>  		break;
>  
>  	case VIDIOC_G_EDID:
> -		err = put_v4l2_edid32(&karg.v2edid, up);
> +		err = put_v4l2_edid32(up_native, up);
>  		break;
>  
>  	case VIDIOC_G_FMT:
>  	case VIDIOC_S_FMT:
>  	case VIDIOC_TRY_FMT:
> -		err = put_v4l2_format32(&karg.v2f, up);
> +		err = put_v4l2_format32(up_native, up);
>  		break;
>  
>  	case VIDIOC_CREATE_BUFS:
> -		err = put_v4l2_create32(&karg.v2crt, up);
> +		err = put_v4l2_create32(up_native, up);
>  		break;
>  
>  	case VIDIOC_PREPARE_BUF:
>  	case VIDIOC_QUERYBUF:
>  	case VIDIOC_QBUF:
>  	case VIDIOC_DQBUF:
> -		err = put_v4l2_buffer32(&karg.v2b, up);
> +		err = put_v4l2_buffer32(up_native, up);
>  		break;
>  
>  	case VIDIOC_ENUMSTD:
> -		err = put_v4l2_standard32(&karg.v2s, up);
> +		err = put_v4l2_standard32(up_native, up);
>  		break;
>  
>  	case VIDIOC_ENUMINPUT:
> -		err = put_v4l2_input32(&karg.v2i, up);
> +		err = put_v4l2_input32(up_native, up);
>  		break;
>  	}
>  	return err;

Hans Verkuil Jan. 29, 2018, 5:41 p.m. UTC | #2

On 01/29/2018 06:06 PM, Sakari Ailus wrote:
> Hi Hans,
> 
> Thanks for your efforts on this patch and the patchset. Please see my comments below.
> 
> On Fri, Jan 26, 2018 at 01:43:27PM +0100, Hans Verkuil wrote:
>> From: Daniel Mentz <[e-mail]>
>>
>> The 32-bit compat v4l2 ioctl is implemented based on its 64-bit
> 
> s/v4l2 ioctl/V4L2 IOCTL handling/
> 
> ?
> 
>> equivalent. It converts 32-bit data structures into its 64-bit
>> equivalents and needs to provide the data to the 64-bit ioctl in user
>> space memory which is commonly allocated using
>> compat_alloc_user_space(). However, due to how that function is
>> implemented, it can only be called a single time for every syscall
>> invocation.  Supposedly to avoid this limitation, the existing code uses
>> a mix of memory from the kernel stack and memory allocated through
>> compat_alloc_user_space(). Under normal circumstances, this would not
>> work, because the 64-bit ioctl expects all pointers to point to user
>> space memory. As a workaround, set_fs(KERNEL_DS) is called to
>> temporarily disable this extra safety check and allow kernel pointers.
>> However, this might introduce a security vulnerability: The
>> result of the 32-bit to 64-bit conversion is writeable by user space
>> because the output buffer has been allocated via
>> compat_alloc_user_space(). A malicious user space process could then
>> manipulate pointers inside this output buffer, and due to the previous
>> set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer
>> prevent kernel memory access.
>>
>> The new approach is to pre-calculate the total amount of user space
>> memory that is needed, allocate it using compat_alloc_user_space() and
>> then divide up the allocated memory to accommodate all data structures
>> that need to be converted.
>>
>> An alternative approach would have been to retain the union type karg
>> that they allocated on the kernel stack in do_video_ioctl(), copy all
>> data from user space into karg and then back to user space. However,
>> we decided against this approach because it does not align with other
>> compat syscall implementations. Instead, we tried to replicate the
>> get_user/put_user pairs as found in other places in the kernel:
>>
>> if (get_user(clipcount, &up->clipcount) ||
>>     put_user(clipcount, &kp->clipcount)) return -EFAULT;
>>
>> Notes from [e-mail]:
>>
>> This patch was taken from
>> https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7
>>
>> Clearly nobody could be bothered to upstream this patch or at minimum
>> tell us :-( We only heard about this a week ago.
> 
> This is very sad indeed. I would really hope that we'll never run into
> something this again!
> 
>>
>> This patch was rebased and cleaned up. Compared to the original I
>> also swapped the order of the convert_in_user arguments so that they
>> matched copy_in_user. It was hard to review otherwise. I also replaced
>> the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.
> 
> The result looks more complicated than it should be.
> 
> I wonder if the result could be made cleaner by separating the argument
> checking and copying from / to user space in video_usercopy. That
> separation almost completely exists already. Rather than mangling the
> compat argument struct to look like a user-provided 64-bit argument struct,
> copying the arguments from and to the user space would be separately done
> to 32-bit compat IOCTL arguments.
> 
> I suppose that wouldn't be a trivial change either, so for now I'd maintain
> the approach and later consider how to make this more maintainable in the
> future. Still, that approach is quite different and it'd be easier to
> switch from status quo rather than this last patch, suggesting to start
> with a revert, should we embark into this direction.
> 
> What do you think?

To be honest, I don't really know. Things will get even more complicated
once we have to deal with the year 2038 problem since that impacts this
code as well. I'm waiting for the fence code and request API code to
land before continuing working on that. Perhaps that might be a good
time to take a step back and see if we can do something smarter.

> 
>>
>> Signed-off-by: Daniel Mentz <[e-mail]>
>> Signed-off-by: Hans Verkuil <[e-mail]>
>> ---
>>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 700 ++++++++++++++++----------
>>  1 file changed, 448 insertions(+), 252 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> index 2aa9b43daf60..27a5a0961cbd 100644
>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> @@ -22,6 +22,14 @@
>>  #include <media/v4l2-ctrls.h>
>>  #include <media/v4l2-ioctl.h>
>>  
>> +/* Use the same argument order as copy_in_user */
>> +#define convert_in_user(to, from)			\
> 
> This doesn't really convert anything. How about calling it assign_in_user,
> for example?

Sounds reasonable.

> 
>> +({							\
>> +	typeof(*from) val;				\
> 
> "val" is very short, easily leading to hard-to-find namespace collisions.
> At least the versions of GCC I've used happily get this wrong without a
> warning.
> 
> How about __convert_in_user_tmp instead?

Hmm. What about __assign_tmp?

> 
>> +							\
>> +	get_user(val, from) || put_user(val, to);	\
>> +})
>> +
>>  static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>  {
>>  	long ret = -ENOIOCTLCMD;
>> @@ -48,37 +56,41 @@ struct v4l2_window32 {
>>  	__u8                    global_alpha;
>>  };
>>  
>> -static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
>> +static int get_v4l2_window32(struct v4l2_window __user *kp,
>> +			     struct v4l2_window32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>>  	struct v4l2_clip32 __user *uclips;
>>  	struct v4l2_clip __user *kclips;
>>  	compat_caddr_t p;
>> -	u32 n;
>> +	u32 clipcount;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
>> -	    get_user(kp->field, &up->field) ||
>> -	    get_user(kp->chromakey, &up->chromakey) ||
>> -	    get_user(kp->clipcount, &up->clipcount) ||
>> -	    get_user(kp->global_alpha, &up->global_alpha))
>> +	    copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
>> +	    convert_in_user(&kp->field, &up->field) ||
>> +	    convert_in_user(&kp->chromakey, &up->chromakey) ||
>> +	    convert_in_user(&kp->global_alpha, &up->global_alpha) ||
>> +	    get_user(clipcount, &up->clipcount) ||
>> +	    put_user(clipcount, &kp->clipcount))
>>  		return -EFAULT;
>> -	if (kp->clipcount > 2048)
>> +	if (clipcount > 2048)
>>  		return -EINVAL;
>> -	if (!kp->clipcount) {
>> -		kp->clips = NULL;
>> -		return 0;
>> -	}
>> +	if (!clipcount)
>> +		return put_user(NULL, &kp->clips) ? -EFAULT : 0;
> 
> Isn't this what put_user would return anyway?

True, I'll simplify this.

>>  
>> -	n = kp->clipcount;
>>  	if (get_user(p, &up->clips))
>>  		return -EFAULT;
>>  	uclips = compat_ptr(p);
>> -	kclips = compat_alloc_user_space(n * sizeof(*kclips));
>> -	kp->clips = kclips;
>> -	while (n--) {
>> +	if (aux_space < clipcount * sizeof(*kclips))
>> +		return -EFAULT;
>> +	kclips = aux_buf;
>> +	if (put_user(kclips, &kp->clips))
>> +		return -EFAULT;
>> +
>> +	while (clipcount--) {
>>  		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
>>  			return -EFAULT;
>> -		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
>> +		if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
>>  			return -EFAULT;
>>  		uclips++;
>>  		kclips++;
>> @@ -86,26 +98,28 @@ static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
>> +static int put_v4l2_window32(struct v4l2_window __user *kp,
>> +			     struct v4l2_window32 __user *up)
>>  {
>>  	struct v4l2_clip __user *kclips = kp->clips;
>>  	struct v4l2_clip32 __user *uclips;
>> -	int n = kp->clipcount;
>>  	compat_caddr_t p;
>> -
>> -	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
>> -	    put_user(kp->field, &up->field) ||
>> -	    put_user(kp->chromakey, &up->chromakey) ||
>> -	    put_user(kp->clipcount, &up->clipcount) ||
>> -	    put_user(kp->global_alpha, &up->global_alpha))
>> +	u32 clipcount;
>> +
>> +	if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
>> +	    convert_in_user(&up->field, &kp->field) ||
>> +	    convert_in_user(&up->chromakey, &kp->chromakey) ||
>> +	    convert_in_user(&up->global_alpha, &kp->global_alpha) ||
>> +	    get_user(clipcount, &kp->clipcount) ||
>> +	    put_user(clipcount, &up->clipcount))
>>  		return -EFAULT;
>> -	if (!kp->clipcount)
>> +	if (!clipcount)
>>  		return 0;
>>  
>>  	if (get_user(p, &up->clips))
>>  		return -EFAULT;
>>  	uclips = compat_ptr(p);
>> -	while (n--) {
>> +	while (clipcount--) {
>>  		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
>>  			return -EFAULT;
>>  		uclips++;
>> @@ -145,107 +159,161 @@ struct v4l2_create_buffers32 {
>>  	__u32			reserved[8];
>>  };
>>  
>> -static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int __bufsize_v4l2_format32(struct v4l2_format32 __user *up)
> 
> This is effectively returning the size of the non-compat struct, or just
> the part of which is variable. How about calling it __bufsize_v4l2_format
> instead? The same for other such functions.

Ack.

> I'd also separate the size calculated by the function and the return value.

That's cleaner, yes.

> 
>>  {
>> -	if (get_user(kp->type, &up->type))
>> +	u32 type;
>> +
>> +	if (get_user(type, &up->type))
>>  		return -EFAULT;
>>  
>> -	switch (kp->type) {
>> +	switch (type) {
>> +	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
>> +		u32 clipcount;
>> +
>> +		if (get_user(clipcount, &up->fmt.win.clipcount))
>> +			return -EFAULT;
>> +		if (clipcount > 2048)
>> +			return -EINVAL;
>> +		return clipcount * sizeof(struct v4l2_clip);
>> +	}
>> +	default:
>> +		return 0;
>> +	}
>> +}
>> +
>> +static int bufsize_v4l2_format32(struct v4l2_format32 __user *up)
>> +{
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>> +		return -EFAULT;
> 
> Newline?
> 
>> +	return __bufsize_v4l2_format32(up);
>> +}
>> +
>> +static int __get_v4l2_format32(struct v4l2_format __user *kp,
>> +			       struct v4l2_format32 __user *up,
>> +			       void __user *aux_buf, int aux_space)
>> +{
>> +	u32 type;
>> +
>> +	if (get_user(type, &up->type) || put_user(type, &kp->type))
>> +		return -EFAULT;
>> +
>> +	switch (type) {
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>> -		return copy_from_user(&kp->fmt.pix, &up->fmt.pix,
>> -				      sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
>> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
>> -		return copy_from_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
>> -				      sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
>> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
>> -		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win);
>> +		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
>> +					 aux_buf, aux_space);
>>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
>> -		return copy_from_user(&kp->fmt.vbi, &up->fmt.vbi,
>> -				      sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
>> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
>> -		return copy_from_user(&kp->fmt.sliced, &up->fmt.sliced,
>> -				      sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
>> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
>> -		return copy_from_user(&kp->fmt.sdr, &up->fmt.sdr,
>> -				      sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
>> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_META_CAPTURE:
>> -		return copy_from_user(&kp->fmt.meta, &up->fmt.meta,
>> -				      sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
>> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>>  }
>>  
>> -static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int get_v4l2_format32(struct v4l2_format __user *kp,
>> +			     struct v4l2_format32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>> +{
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>> +		return -EFAULT;
>> +	return __get_v4l2_format32(kp, up, aux_buf, aux_space);
>> +}
>> +
>> +static int bufsize_v4l2_create32(struct v4l2_create_buffers32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>>  		return -EFAULT;
>> -	return __get_v4l2_format32(kp, up);
>> +	return __bufsize_v4l2_format32(&up->format);
>>  }
>>  
>> -static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
>> +static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
>> +			     struct v4l2_create_buffers32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
>> +	    copy_in_user(kp, up,
>> +			 offsetof(struct v4l2_create_buffers32, format)))
>>  		return -EFAULT;
>> -	return __get_v4l2_format32(&kp->format, &up->format);
>> +	return __get_v4l2_format32(&kp->format, &up->format,
>> +				   aux_buf, aux_space);
>>  }
>>  
>> -static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int __put_v4l2_format32(struct v4l2_format __user *kp,
>> +			       struct v4l2_format32 __user *up)
>>  {
>> -	if (put_user(kp->type, &up->type))
>> +	u32 type;
>> +
>> +	if (get_user(type, &kp->type))
>>  		return -EFAULT;
>>  
>> -	switch (kp->type) {
>> +	switch (type) {
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>> -		return copy_to_user(&up->fmt.pix, &kp->fmt.pix,
>> -				    sizeof(kp->fmt.pix)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
>> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
>> -		return copy_to_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
>> -				    sizeof(kp->fmt.pix_mp)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
>> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
>>  		return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
>>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
>> -		return copy_to_user(&up->fmt.vbi, &kp->fmt.vbi,
>> -				    sizeof(kp->fmt.vbi)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
>> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
>> -		return copy_to_user(&up->fmt.sliced, &kp->fmt.sliced,
>> -				    sizeof(kp->fmt.sliced)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
>> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
>> -		return copy_to_user(&up->fmt.sdr, &kp->fmt.sdr,
>> -				    sizeof(kp->fmt.sdr)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
>> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_META_CAPTURE:
>> -		return copy_to_user(&up->fmt.meta, &kp->fmt.meta,
>> -				    sizeof(kp->fmt.meta)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
>> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>>  }
>>  
>> -static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int put_v4l2_format32(struct v4l2_format __user *kp,
>> +			     struct v4l2_format32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))
> 
> For some pointers we do perform such checks, for others we don't. While
> this patch doesn't change this, it'd be good to align this by either
> introducing it everywhere or removing it everywhere.
> 
> I guess that can be done separately.
> 
>>  		return -EFAULT;
>>  	return __put_v4l2_format32(kp, up);
>>  }
>>  
>> -static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
>> +static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
>> +			     struct v4l2_create_buffers32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format)) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    copy_in_user(up, kp,
>> +			 offsetof(struct v4l2_create_buffers32, format)) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>>  	return __put_v4l2_format32(&kp->format, &up->format);
>>  }
>> @@ -259,25 +327,27 @@ struct v4l2_standard32 {
>>  	__u32		     reserved[4];
>>  };
>>  
>> -static int get_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
>> +static int get_v4l2_standard32(struct v4l2_standard __user *kp,
>> +			       struct v4l2_standard32 __user *up)
>>  {
>>  	/* other fields are not set by the user, nor used by the driver */
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->index, &up->index))
>> +	    convert_in_user(&kp->index, &up->index))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
>> +static int put_v4l2_standard32(struct v4l2_standard __user *kp,
>> +			       struct v4l2_standard32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->index, &up->index) ||
>> -	    put_user(kp->id, &up->id) ||
>> -	    copy_to_user(up->name, kp->name, 24) ||
>> -	    copy_to_user(&up->frameperiod, &kp->frameperiod,
>> -			 sizeof(kp->frameperiod)) ||
>> -	    put_user(kp->framelines, &up->framelines) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&up->index, &kp->index) ||
>> +	    copy_in_user(&up->id, &kp->id, sizeof(up->id)) ||
> 
> Why not convert_in_user()?

Will change.

> 
>> +	    copy_in_user(up->name, kp->name, 24) ||

Urg. I missed this, this has a fixed number as the last argument instead of
sizeof(kp->name).

>> +	    copy_in_user(&up->frameperiod, &kp->frameperiod,
>> +			 sizeof(up->frameperiod)) ||
>> +	    convert_in_user(&up->framelines, &kp->framelines) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -317,10 +387,10 @@ struct v4l2_buffer32 {
>>  	__u32			reserved;
>>  };
>>  
>> -static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
>> +static int get_v4l2_plane32(struct v4l2_plane __user *up,
>> +			    struct v4l2_plane32 __user *up32,
>>  			    enum v4l2_memory memory)
>>  {
>> -	void __user *up_pln;
>>  	compat_long_t p;
> 
> Shouldn't this be compat_ulong_t?

That's better, yes.

> 
>>  
>>  	if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
>> @@ -336,10 +406,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_USERPTR:
>> -		if (get_user(p, &up32->m.userptr))
>> -			return -EFAULT;
>> -		up_pln = compat_ptr(p);
>> -		if (put_user((unsigned long)up_pln, &up->m.userptr))
>> +		if (get_user(p, &up32->m.userptr) ||
>> +		    put_user((unsigned long)compat_ptr(p), &up->m.userptr))
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_DMABUF:
>> @@ -351,7 +419,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
>> +static int put_v4l2_plane32(struct v4l2_plane __user *up,
>> +			    struct v4l2_plane32 __user *up32,
>>  			    enum v4l2_memory memory)
>>  {
>>  	unsigned long p;
>> @@ -375,8 +444,7 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_DMABUF:
>> -		if (copy_in_user(&up32->m.fd, &up->m.fd,
>> -				 sizeof(up->m.fd)))
>> +		if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
>>  			return -EFAULT;
>>  		break;
>>  	}
>> @@ -384,37 +452,68 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  	return 0;
>>  }
>>  
>> -static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
>> +static int bufsize_v4l2_buffer32(struct v4l2_buffer32 __user *up)
>> +{
>> +	u32 type;
>> +	u32 length;
>> +
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> +	    get_user(type, &up->type) ||
>> +	    get_user(length, &up->length))
>> +		return -EFAULT;
>> +
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		if (length > VIDEO_MAX_PLANES)
>> +			return -EINVAL;
>> +
>> +		/* We don't really care if userspace decides to kill itself
> 
> /*
>  * ...
> 
>> +		 * by passing a very big length value
>> +		 */
>> +		return length * sizeof(struct v4l2_plane);
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
>> +			     struct v4l2_buffer32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>> +	u32 type;
>> +	u32 length;
>> +	enum v4l2_memory memory;
>>  	struct v4l2_plane32 __user *uplane32;
>>  	struct v4l2_plane __user *uplane;
>>  	compat_caddr_t p;
>> +	int num_planes;
> 
> u32?
> 
>>  	int ret;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->index, &up->index) ||
>> -	    get_user(kp->type, &up->type) ||
>> -	    get_user(kp->flags, &up->flags) ||
>> -	    get_user(kp->memory, &up->memory) ||
>> -	    get_user(kp->length, &up->length))
>> +	    convert_in_user(&kp->index, &up->index) ||
>> +	    get_user(type, &up->type) ||
>> +	    put_user(type, &kp->type) ||
>> +	    convert_in_user(&kp->flags, &up->flags) ||
>> +	    get_user(memory, &up->memory) ||
>> +	    put_user(memory, &kp->memory) ||
>> +	    get_user(length, &up->length) ||
>> +	    put_user(length, &kp->length))
>>  		return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_OUTPUT(kp->type))
>> -		if (get_user(kp->bytesused, &up->bytesused) ||
>> -		    get_user(kp->field, &up->field) ||
>> -		    get_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -		    get_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec))
>> +	if (V4L2_TYPE_IS_OUTPUT(type))
>> +		if (convert_in_user(&kp->bytesused, &up->bytesused) ||
>> +		    convert_in_user(&kp->field, &up->field) ||
>> +		    convert_in_user(&kp->timestamp.tv_sec,
>> +				    &up->timestamp.tv_sec) ||
>> +		    convert_in_user(&kp->timestamp.tv_usec,
>> +				    &up->timestamp.tv_usec))
>>  			return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>> -		unsigned int num_planes;
>> -
>> -		if (kp->length == 0) {
>> -			kp->m.planes = NULL;
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		num_planes = length;
> 
> Do you need a local variable for just that?
> 
>> +		if (num_planes == 0) {
>>  			/* num_planes == 0 is legal, e.g. when userspace doesn't
>>  			 * need planes array on DQBUF*/
>> -			return 0;
>> -		} else if (kp->length > VIDEO_MAX_PLANES) {
>> +			return put_user(NULL, &kp->m.planes);
>> +		} else if (num_planes > VIDEO_MAX_PLANES) {
>>  			return -EINVAL;
>>  		}
>>  
>> @@ -423,40 +522,47 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  
>>  		uplane32 = compat_ptr(p);
>>  		if (!access_ok(VERIFY_READ, uplane32,
>> -			       kp->length * sizeof(*uplane32)))
>> +				num_planes * sizeof(*uplane32)))
> 
> Alignment.
> 
>>  			return -EFAULT;
>>  
>>  		/* We don't really care if userspace decides to kill itself
>>  		 * by passing a very big num_planes value */
>> -		uplane = compat_alloc_user_space(kp->length * sizeof(*uplane));
>> -		kp->m.planes = (__force struct v4l2_plane *)uplane;
>> +		if (aux_space < num_planes * sizeof(*uplane))
>> +			return -EFAULT;
>> +
>> +		uplane = aux_buf;
>> +		if (put_user((__force struct v4l2_plane *)uplane,
>> +					&kp->m.planes))
>> +			return -EFAULT;
>>  
>> -		for (num_planes = 0; num_planes < kp->length; num_planes++) {
>> -			ret = get_v4l2_plane32(uplane, uplane32, kp->memory);
>> +		while (--num_planes >= 0) {
> 
> while (num_planes--) {
> 
> ?

Yes. I missed this one :-)

> 
>> +			ret = get_v4l2_plane32(uplane, uplane32, memory);
>>  			if (ret)
>>  				return ret;
>> -			++uplane;
>> -			++uplane32;
>> +			uplane++;
>> +			uplane32++;
>>  		}
>>  	} else {
>> -		switch (kp->memory) {
>> +		switch (memory) {
>>  		case V4L2_MEMORY_MMAP:
>> -		case V4L2_MEMORY_OVERLAY:
>> -			if (get_user(kp->m.offset, &up->m.offset))
>> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
>>  				return -EFAULT;
>>  			break;
>> -		case V4L2_MEMORY_USERPTR:
>> -			{
>> -				compat_long_t tmp;
>> -
>> -				if (get_user(tmp, &up->m.userptr))
>> -					return -EFAULT;
>> +		case V4L2_MEMORY_USERPTR: {
>> +			compat_long_t tmp;
> 
> compat_ulong_t, I'd call it "userptr". The latter is entirely up to you.
> 
>>  
>> -				kp->m.userptr = (unsigned long)compat_ptr(tmp);
>> -			}
>> +			if (get_user(tmp, &up->m.userptr) ||
>> +			    put_user((unsigned long)compat_ptr(tmp),
>> +				     &kp->m.userptr))
>> +				return -EFAULT;
>> +			break;
>> +		}
>> +		case V4L2_MEMORY_OVERLAY:
>> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
>> +				return -EFAULT;
> 
> Is there a reason to split this off from MMAP handling? The code is the
> same.

Huh, I missed this as well. I merged MMAP and OVERLAY elsewhere.

> 
>>  			break;
>>  		case V4L2_MEMORY_DMABUF:
>> -			if (get_user(kp->m.fd, &up->m.fd))
>> +			if (convert_in_user(&kp->m.fd, &up->m.fd))
>>  				return -EFAULT;
>>  			break;
>>  		}
>> @@ -465,8 +571,12 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
>> +static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
>> +			     struct v4l2_buffer32 __user *up)
>>  {
>> +	u32 type;
>> +	u32 length;
>> +	enum v4l2_memory memory;
>>  	struct v4l2_plane32 __user *uplane32;
>>  	struct v4l2_plane __user *uplane;
>>  	compat_caddr_t p;
>> @@ -474,53 +584,60 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  	int ret;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->index, &up->index) ||
>> -	    put_user(kp->type, &up->type) ||
>> -	    put_user(kp->flags, &up->flags) ||
>> -	    put_user(kp->memory, &up->memory))
>> +	    convert_in_user(&up->index, &kp->index) ||
>> +	    get_user(type, &kp->type) ||
>> +	    put_user(type, &up->type) ||
>> +	    convert_in_user(&up->flags, &kp->flags) ||
>> +	    get_user(memory, &kp->memory) ||
>> +	    put_user(memory, &up->memory))
>>  		return -EFAULT;
>>  
>> -	if (put_user(kp->bytesused, &up->bytesused) ||
>> -	    put_user(kp->field, &up->field) ||
>> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -	    put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
>> -	    copy_to_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
>> -	    put_user(kp->sequence, &up->sequence) ||
>> -	    put_user(kp->reserved2, &up->reserved2) ||
>> -	    put_user(kp->reserved, &up->reserved) ||
>> -	    put_user(kp->length, &up->length))
>> +	if (convert_in_user(&up->bytesused, &kp->bytesused) ||
>> +	    convert_in_user(&up->field, &kp->field) ||
>> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
>> +	    convert_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
>> +	    copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
>> +	    convert_in_user(&up->sequence, &kp->sequence) ||
>> +	    convert_in_user(&up->reserved2, &kp->reserved2) ||
>> +	    convert_in_user(&up->reserved, &kp->reserved) ||
>> +	    get_user(length, &kp->length) ||
>> +	    put_user(length, &up->length))
>>  		return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>> -		num_planes = kp->length;
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		num_planes = length;
>>  		if (num_planes == 0)
>>  			return 0;
>>  
>> -		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
>> +		if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
>> +			return -EFAULT;
>>  		if (get_user(p, &up->m.planes))
>>  			return -EFAULT;
>>  		uplane32 = compat_ptr(p);
>>  
>>  		while (--num_planes >= 0) {
> 
> 
> while (num_planes--) {
> 
> Or rather: s/num_planes/length/
> 
> Then you can remove num_planes.

I will probably keep num_planes. It's more descriptive than 'length'.

> 
>> -			ret = put_v4l2_plane32(uplane, uplane32, kp->memory);
>> +			ret = put_v4l2_plane32(uplane, uplane32, memory);
>>  			if (ret)
>>  				return ret;
>>  			++uplane;
>>  			++uplane32;
>>  		}
>>  	} else {
>> -		switch (kp->memory) {
>> +		switch (memory) {
>>  		case V4L2_MEMORY_MMAP:
>> -		case V4L2_MEMORY_OVERLAY:
>> -			if (put_user(kp->m.offset, &up->m.offset))
>> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
>>  				return -EFAULT;
>>  			break;
>>  		case V4L2_MEMORY_USERPTR:
>> -			if (put_user(kp->m.userptr, &up->m.userptr))
>> +			if (convert_in_user(&up->m.userptr, &kp->m.userptr))
>> +				return -EFAULT;
>> +			break;
>> +		case V4L2_MEMORY_OVERLAY:
>> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
> 
> Combine with MMAP case?

Hmm. I did combine this, but I probably lost that change after some later
patch modifications. Thanks for noticing.

> 
>>  				return -EFAULT;
>>  			break;
>>  		case V4L2_MEMORY_DMABUF:
>> -			if (put_user(kp->m.fd, &up->m.fd))
>> +			if (convert_in_user(&up->m.fd, &kp->m.fd))
>>  				return -EFAULT;
>>  			break;
>>  		}
>> @@ -545,29 +662,32 @@ struct v4l2_framebuffer32 {
>>  	} fmt;
>>  };
>>  
>> -static int get_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
>> +static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
>> +				  struct v4l2_framebuffer32 __user *up)
>>  {
>> -	u32 tmp;
>> +	compat_caddr_t tmp;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>>  	    get_user(tmp, &up->base) ||
>> -	    get_user(kp->capability, &up->capability) ||
>> -	    get_user(kp->flags, &up->flags) ||
>> -	    copy_from_user(&kp->fmt, &up->fmt, sizeof(up->fmt)))
>> +	    put_user((__force void *)compat_ptr(tmp), &kp->base) ||
>> +	    convert_in_user(&kp->capability, &up->capability) ||
>> +	    convert_in_user(&kp->flags, &up->flags) ||
>> +	    copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
>>  		return -EFAULT;
>> -	kp->base = (__force void *)compat_ptr(tmp);
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
>> +static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
>> +				  struct v4l2_framebuffer32 __user *up)
>>  {
>> -	u32 tmp = (u32)((unsigned long)kp->base);
>> +	void *base;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(tmp, &up->base) ||
>> -	    put_user(kp->capability, &up->capability) ||
>> -	    put_user(kp->flags, &up->flags) ||
>> -	    copy_to_user(&up->fmt, &kp->fmt, sizeof(up->fmt)))
>> +	    get_user(base, &kp->base) ||
>> +	    put_user(ptr_to_compat(base), &up->base) ||
>> +	    convert_in_user(&up->capability, &kp->capability) ||
>> +	    convert_in_user(&up->flags, &kp->flags) ||
>> +	    copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -586,16 +706,18 @@ struct v4l2_input32 {
>>  
>>  /* The 64-bit v4l2_input struct has extra padding at the end of the struct.
>>     Otherwise it is identical to the 32-bit version. */
>> -static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
>> +static inline int get_v4l2_input32(struct v4l2_input __user *kp,
>> +				   struct v4l2_input32 __user *up)
>>  {
>> -	if (copy_from_user(kp, up, sizeof(*up)))
>> +	if (copy_in_user(kp, up, sizeof(*up)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>>  
>> -static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
>> +static inline int put_v4l2_input32(struct v4l2_input __user *kp,
>> +				   struct v4l2_input32 __user *up)
>>  {
>> -	if (copy_to_user(up, kp, sizeof(*up)))
>> +	if (copy_in_user(up, kp, sizeof(*up)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -648,39 +770,58 @@ static inline bool ctrl_is_pointer(struct file *file, u32 id)
>>  	return !ret && (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
>>  }
>>  
>> +static int bufsize_v4l2_ext_controls32(struct v4l2_ext_controls32 __user *up)
>> +{
>> +	u32 count;
>> +
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> +	    get_user(count, &up->count))
>> +		return -EFAULT;
>> +	if (count > V4L2_CID_MAX_CTRLS)
>> +		return -EINVAL;
>> +	return count * sizeof(struct v4l2_ext_control);
>> +}
>> +
>>  static int get_v4l2_ext_controls32(struct file *file,
>> -				   struct v4l2_ext_controls *kp,
>> -				   struct v4l2_ext_controls32 __user *up)
>> +				   struct v4l2_ext_controls __user *kp,
>> +				   struct v4l2_ext_controls32 __user *up,
>> +				   void __user *aux_buf, int aux_space)
>>  {
>>  	struct v4l2_ext_control32 __user *ucontrols;
>>  	struct v4l2_ext_control __user *kcontrols;
>> +	u32 count;
>>  	unsigned int n;
> 
> u32 n
> 
>>  	compat_caddr_t p;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->which, &up->which) ||
>> -	    get_user(kp->count, &up->count) ||
>> -	    get_user(kp->error_idx, &up->error_idx) ||
>> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&kp->which, &up->which) ||
>> +	    get_user(count, &up->count) ||
>> +	    put_user(count, &kp->count) ||
>> +	    convert_in_user(&kp->error_idx, &up->error_idx) ||
>> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>> -	if (kp->count == 0) {
>> -		kp->controls = NULL;
>> -		return 0;
>> -	} else if (kp->count > V4L2_CID_MAX_CTRLS) {
>> +	if (count == 0)
>> +		return put_user(NULL, &kp->controls);
>> +	else if (kp->count > V4L2_CID_MAX_CTRLS)
> 
> count
> 
>>  		return -EINVAL;
>> -	}
>>  	if (get_user(p, &up->controls))
>>  		return -EFAULT;
>>  	ucontrols = compat_ptr(p);
>> -	if (!access_ok(VERIFY_READ, ucontrols, kp->count * sizeof(*ucontrols)))
>> +	if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))
>> +		return -EFAULT;
>> +	if (aux_space < count * sizeof(*kcontrols))
>>  		return -EFAULT;
>> -	kcontrols = compat_alloc_user_space(kp->count * sizeof(*kcontrols));
>> -	kp->controls = (__force struct v4l2_ext_control *)kcontrols;
>> -	for (n = 0; n < kp->count; n++) {
>> +	kcontrols = aux_buf;
>> +	if (put_user((__force struct v4l2_ext_control *)kcontrols,
>> +		     &kp->controls))
>> +		return -EFAULT;
>> +
>> +	for (n = 0; n < count; n++) {
>>  		u32 id;
>>  
>>  		if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
>>  			return -EFAULT;
>> +
>>  		if (get_user(id, &kcontrols->id))
>>  			return -EFAULT;
> 
> Newline here, too? Not really a problem with this patch though.
> 
>>  		if (ctrl_is_pointer(file, id)) {
>> @@ -699,36 +840,47 @@ static int get_v4l2_ext_controls32(struct file *file,
>>  }
>>  
>>  static int put_v4l2_ext_controls32(struct file *file,
>> -				   struct v4l2_ext_controls *kp,
>> +				   struct v4l2_ext_controls __user *kp,
>>  				   struct v4l2_ext_controls32 __user *up)
>>  {
>>  	struct v4l2_ext_control32 __user *ucontrols;
>> -	struct v4l2_ext_control __user *kcontrols =
>> -		(__force struct v4l2_ext_control __user *)kp->controls;
>> -	int n = kp->count;
>> +	struct v4l2_ext_control __user *kcontrols;
>> +	u32 count;
>> +	unsigned int n;
> 
> u32 n
> 
>>  	compat_caddr_t p;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->which, &up->which) ||
>> -	    put_user(kp->count, &up->count) ||
>> -	    put_user(kp->error_idx, &up->error_idx) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>> +	    get_user(kcontrols, &kp->controls) ||
> 
> How about doing this as last? "controls" is the last member of the struct.
> 
>> +	    convert_in_user(&up->which, &kp->which) ||
>> +	    get_user(count, &kp->count) ||
>> +	    put_user(count, &up->count) ||
>> +	    convert_in_user(&up->error_idx, &kp->error_idx) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>> -	if (!kp->count)
>> +	if (!count)
>>  		return 0;
>>  
>>  	if (get_user(p, &up->controls))
>>  		return -EFAULT;
>>  	ucontrols = compat_ptr(p);
>> -	if (!access_ok(VERIFY_WRITE, ucontrols, n * sizeof(*ucontrols)))
>> +	if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
>>  		return -EFAULT;
>>  
>> -	while (--n >= 0) {
>> -		unsigned size = sizeof(*ucontrols);
>> +	for (n = 0; n < count; n++) {
>> +		unsigned int size = sizeof(*ucontrols);
>>  		u32 id;
>>  
>> +		if (copy_in_user(&ucontrols->id, &kcontrols->id,
>> +				 sizeof(ucontrols->id)) ||
> 
> get_user(id, &kcontrols->id) ||
> put_user(id, &ucontrols->id) ||
> 
>> +		    copy_in_user(&ucontrols->size, &kcontrols->size,
>> +				 sizeof(ucontrols->size)) ||
> 
> convert_in_user() ?
> 
>> +		    copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
>> +				 sizeof(ucontrols->reserved2)))
>> +			return -EFAULT;
>> +
>>  		if (get_user(id, &kcontrols->id))
>>  			return -EFAULT;
> 
> ...and the above if () can be removed.
> 
>> +
>>  		/* Do not modify the pointer when copying a pointer control.
>>  		   The contents of the pointer was changed, not the pointer
>>  		   itself. */
>> @@ -736,6 +888,7 @@ static int put_v4l2_ext_controls32(struct file *file,
>>  			size -= sizeof(ucontrols->value64);
> 
> This chunk is yearning for newlines. Not a fault of this patch though.
> 
>>  		if (copy_in_user(ucontrols, kcontrols, size))
>>  			return -EFAULT;
>> +
>>  		ucontrols++;
>>  		kcontrols++;
>>  	}
>> @@ -755,17 +908,18 @@ struct v4l2_event32 {
>>  	__u32				reserved[8];
>>  };
>>  
>> -static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *up)
>> +static int put_v4l2_event32(struct v4l2_event __user *kp,
>> +			    struct v4l2_event32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->type, &up->type) ||
>> -	    copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
>> -	    put_user(kp->pending, &up->pending) ||
>> -	    put_user(kp->sequence, &up->sequence) ||
>> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -	    put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
>> -	    put_user(kp->id, &up->id) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&up->type, &kp->type) ||
>> +	    copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
>> +	    convert_in_user(&up->pending, &kp->pending) ||
>> +	    convert_in_user(&up->sequence, &kp->sequence) ||
>> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
>> +	    convert_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
>> +	    convert_in_user(&up->id, &kp->id) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -778,31 +932,34 @@ struct v4l2_edid32 {
>>  	compat_caddr_t edid;
>>  };
>>  
>> -static int get_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>> +static int get_v4l2_edid32(struct v4l2_edid __user *kp,
>> +			   struct v4l2_edid32 __user *up)
>>  {
>> -	u32 tmp;
>> +	compat_uptr_t tmp;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->pad, &up->pad) ||
>> -	    get_user(kp->start_block, &up->start_block) ||
>> -	    get_user(kp->blocks, &up->blocks) ||
>> +	    convert_in_user(&kp->pad, &up->pad) ||
>> +	    convert_in_user(&kp->start_block, &up->start_block) ||
>> +	    convert_in_user(&kp->blocks, &up->blocks) ||
>>  	    get_user(tmp, &up->edid) ||
>> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>> +	    put_user(compat_ptr(tmp), &kp->edid) ||
>> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>> -	kp->edid = (__force u8 *)compat_ptr(tmp);
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>> +static int put_v4l2_edid32(struct v4l2_edid __user *kp,
>> +			   struct v4l2_edid32 __user *up)
>>  {
>> -	u32 tmp = (u32)((unsigned long)kp->edid);
>> +	void *edid;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->pad, &up->pad) ||
>> -	    put_user(kp->start_block, &up->start_block) ||
>> -	    put_user(kp->blocks, &up->blocks) ||
>> -	    put_user(tmp, &up->edid) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>> +	    convert_in_user(&up->pad, &kp->pad) ||
>> +	    convert_in_user(&up->start_block, &kp->start_block) ||
>> +	    convert_in_user(&up->blocks, &kp->blocks) ||
>> +	    get_user(edid, &kp->edid) ||
>> +	    put_user(ptr_to_compat(edid), &up->edid) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -835,22 +992,30 @@ static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>>  #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
>>  #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
>>  
>> +static void __user *alloc_userspace(unsigned int size, int aux_space, long *err)
> 
> This one is weird. Rather than following the pattern and returning an error
> and assigning the result to a pointer passed to it, it does exactly the
> opposite. I'd change that. I guess this is a matter of opinion to some
> degree at least, though.

I agree, I'll change that.

> 
>> +{
>> +	void __user *up_native;
>> +
>> +	if (aux_space < 0) {
>> +		*err = aux_space;
>> +		return NULL;
>> +	}
>> +	up_native = compat_alloc_user_space(size + aux_space);
>> +	if (!up_native)
>> +		*err = -ENOMEM;
>> +	else if (clear_user(up_native, size))
>> +		*err = -EFAULT;
>> +	else
>> +		return up_native;
>> +	return NULL;
>> +}
>> +
>>  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>  {
>> -	union {
>> -		struct v4l2_format v2f;
>> -		struct v4l2_buffer v2b;
>> -		struct v4l2_framebuffer v2fb;
>> -		struct v4l2_input v2i;
>> -		struct v4l2_standard v2s;
>> -		struct v4l2_ext_controls v2ecs;
>> -		struct v4l2_event v2ev;
>> -		struct v4l2_create_buffers v2crt;
>> -		struct v4l2_edid v2edid;
>> -		unsigned long vx;
>> -		int vi;
>> -	} karg;
>>  	void __user *up = compat_ptr(arg);
>> +	void __user *up_native = NULL;
>> +	void __user *aux_buf;
>> +	int aux_space;
> 
> size_t?
> 
>>  	int compatible_arg = 1;
>>  	long err = 0;
>>  
>> @@ -889,30 +1054,47 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_STREAMOFF:
>>  	case VIDIOC_S_INPUT:
>>  	case VIDIOC_S_OUTPUT:
>> -		err = get_user(karg.vi, (s32 __user *)up);
>> +		up_native = alloc_userspace(sizeof(unsigned int __user),
>> +					    0, &err);
>> +		if (!err && convert_in_user((unsigned int __user *)up_native,
>> +					    (compat_uint_t __user *)up))
>> +			return -EFAULT;
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_INPUT:
>>  	case VIDIOC_G_OUTPUT:
>> +		up_native = alloc_userspace(sizeof(unsigned int __user),
>> +					    0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_EDID:
>>  	case VIDIOC_S_EDID:
>> -		err = get_v4l2_edid32(&karg.v2edid, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_edid), 0, &err);
>> +		err = err ? : get_v4l2_edid32(up_native, up);
> 
> I'd write this as:
> 
> 		if (!err)
> 			err = get_v4l2_edid32(native_up, up);
> 
> Same below.
> 
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_FMT:
>>  	case VIDIOC_S_FMT:
>>  	case VIDIOC_TRY_FMT:
>> -		err = get_v4l2_format32(&karg.v2f, up);
>> +		aux_space = bufsize_v4l2_format32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_format),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_format);
>> +		err = err ? : get_v4l2_format32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_CREATE_BUFS:
>> -		err = get_v4l2_create32(&karg.v2crt, up);
>> +		aux_space = bufsize_v4l2_create32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_create_buffers),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_create_buffers);
>> +		err = err ? : get_v4l2_create32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>> @@ -920,36 +1102,54 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_QUERYBUF:
>>  	case VIDIOC_QBUF:
>>  	case VIDIOC_DQBUF:
>> -		err = get_v4l2_buffer32(&karg.v2b, up);
>> +		aux_space = bufsize_v4l2_buffer32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_buffer),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_buffer);
>> +		err = err ? : get_v4l2_buffer32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_S_FBUF:
>> -		err = get_v4l2_framebuffer32(&karg.v2fb, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
>> +					    0, &err);
>> +		err = err ? : get_v4l2_framebuffer32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_FBUF:
>> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
>> +					    0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_ENUMSTD:
>> -		err = get_v4l2_standard32(&karg.v2s, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_standard),
>> +					    0, &err);
>> +		err = err ? : get_v4l2_standard32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_ENUMINPUT:
>> -		err = get_v4l2_input32(&karg.v2i, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_input), 0, &err);
>> +		err = err ? : get_v4l2_input32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_EXT_CTRLS:
>>  	case VIDIOC_S_EXT_CTRLS:
>>  	case VIDIOC_TRY_EXT_CTRLS:
>> -		err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
>> +		aux_space = bufsize_v4l2_ext_controls32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_ext_controls),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_ext_controls);
>> +		err = err ? : get_v4l2_ext_controls32(file, up_native, up,
>> +						      aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  	case VIDIOC_DQEVENT:
>> +		up_native = alloc_userspace(sizeof(struct v4l2_event), 0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  	}
>> @@ -958,13 +1158,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  
>>  	if (compatible_arg)
>>  		err = native_ioctl(file, cmd, (unsigned long)up);
>> -	else {
>> -		mm_segment_t old_fs = get_fs();
>> -
>> -		set_fs(KERNEL_DS);
>> -		err = native_ioctl(file, cmd, (unsigned long)&karg);
>> -		set_fs(old_fs);
>> -	}
>> +	else
>> +		err = native_ioctl(file, cmd, (unsigned long)up_native);
>>  
>>  	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
>>  		return err;
>> @@ -976,11 +1171,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_G_EXT_CTRLS:
>>  	case VIDIOC_S_EXT_CTRLS:
>>  	case VIDIOC_TRY_EXT_CTRLS:
>> -		if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
>> +		if (put_v4l2_ext_controls32(file, up_native, up))
>>  			err = -EFAULT;
>>  		break;
>>  	case VIDIOC_S_EDID:
>> -		if (put_v4l2_edid32(&karg.v2edid, up))
>> +		if (put_v4l2_edid32(up_native, up))
>>  			err = -EFAULT;
>>  		break;
>>  	}
>> @@ -992,44 +1187,45 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_S_OUTPUT:
>>  	case VIDIOC_G_INPUT:
>>  	case VIDIOC_G_OUTPUT:
>> -		err = put_user(((s32)karg.vi), (s32 __user *)up);
>> +		err = convert_in_user((compat_uint_t __user *)up,
>> +				      ((unsigned int __user *)up_native));
> 
> Do note that convert_in_user() returns Boolean. This will effectively yield
> 1 in case of an error here. How about changing convert_in_user() to return
> whatever get_user / put_user do, to avoid errors in the future?

That's better indeed. Good catch.

> 
>>  		break;
>>  
>>  	case VIDIOC_G_FBUF:
>> -		err = put_v4l2_framebuffer32(&karg.v2fb, up);
>> +		err = put_v4l2_framebuffer32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_DQEVENT:
>> -		err = put_v4l2_event32(&karg.v2ev, up);
>> +		err = put_v4l2_event32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_G_EDID:
>> -		err = put_v4l2_edid32(&karg.v2edid, up);
>> +		err = put_v4l2_edid32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_G_FMT:
>>  	case VIDIOC_S_FMT:
>>  	case VIDIOC_TRY_FMT:
>> -		err = put_v4l2_format32(&karg.v2f, up);
>> +		err = put_v4l2_format32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_CREATE_BUFS:
>> -		err = put_v4l2_create32(&karg.v2crt, up);
>> +		err = put_v4l2_create32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_PREPARE_BUF:
>>  	case VIDIOC_QUERYBUF:
>>  	case VIDIOC_QBUF:
>>  	case VIDIOC_DQBUF:
>> -		err = put_v4l2_buffer32(&karg.v2b, up);
>> +		err = put_v4l2_buffer32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_ENUMSTD:
>> -		err = put_v4l2_standard32(&karg.v2s, up);
>> +		err = put_v4l2_standard32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_ENUMINPUT:
>> -		err = put_v4l2_input32(&karg.v2i, up);
>> +		err = put_v4l2_input32(up_native, up);
>>  		break;
>>  	}
>>  	return err;
> 

Thanks for the thorough review! Much appreciated.

Regards,

	Hans

Sakari Ailus Jan. 29, 2018, 9:14 p.m. UTC | #3

Hi Hans,

On Mon, Jan 29, 2018 at 06:41:20PM +0100, Hans Verkuil wrote:
> On 01/29/2018 06:06 PM, Sakari Ailus wrote:
> > Hi Hans,
> > 
> > Thanks for your efforts on this patch and the patchset. Please see my comments below.
> > 
> > On Fri, Jan 26, 2018 at 01:43:27PM +0100, Hans Verkuil wrote:
> >> From: Daniel Mentz <[e-mail]>
> >>
> >> The 32-bit compat v4l2 ioctl is implemented based on its 64-bit
> > 
> > s/v4l2 ioctl/V4L2 IOCTL handling/
> > 
> > ?
> > 
> >> equivalent. It converts 32-bit data structures into its 64-bit
> >> equivalents and needs to provide the data to the 64-bit ioctl in user
> >> space memory which is commonly allocated using
> >> compat_alloc_user_space(). However, due to how that function is
> >> implemented, it can only be called a single time for every syscall
> >> invocation.  Supposedly to avoid this limitation, the existing code uses
> >> a mix of memory from the kernel stack and memory allocated through
> >> compat_alloc_user_space(). Under normal circumstances, this would not
> >> work, because the 64-bit ioctl expects all pointers to point to user
> >> space memory. As a workaround, set_fs(KERNEL_DS) is called to
> >> temporarily disable this extra safety check and allow kernel pointers.
> >> However, this might introduce a security vulnerability: The
> >> result of the 32-bit to 64-bit conversion is writeable by user space
> >> because the output buffer has been allocated via
> >> compat_alloc_user_space(). A malicious user space process could then
> >> manipulate pointers inside this output buffer, and due to the previous
> >> set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer
> >> prevent kernel memory access.
> >>
> >> The new approach is to pre-calculate the total amount of user space
> >> memory that is needed, allocate it using compat_alloc_user_space() and
> >> then divide up the allocated memory to accommodate all data structures
> >> that need to be converted.
> >>
> >> An alternative approach would have been to retain the union type karg
> >> that they allocated on the kernel stack in do_video_ioctl(), copy all
> >> data from user space into karg and then back to user space. However,
> >> we decided against this approach because it does not align with other
> >> compat syscall implementations. Instead, we tried to replicate the
> >> get_user/put_user pairs as found in other places in the kernel:
> >>
> >> if (get_user(clipcount, &up->clipcount) ||
> >>     put_user(clipcount, &kp->clipcount)) return -EFAULT;
> >>
> >> Notes from [e-mail]:
> >>
> >> This patch was taken from
> >> https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7
> >>
> >> Clearly nobody could be bothered to upstream this patch or at minimum
> >> tell us :-( We only heard about this a week ago.
> > 
> > This is very sad indeed. I would really hope that we'll never run into
> > something this again!
> > 
> >>
> >> This patch was rebased and cleaned up. Compared to the original I
> >> also swapped the order of the convert_in_user arguments so that they
> >> matched copy_in_user. It was hard to review otherwise. I also replaced
> >> the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.
> > 
> > The result looks more complicated than it should be.
> > 
> > I wonder if the result could be made cleaner by separating the argument
> > checking and copying from / to user space in video_usercopy. That
> > separation almost completely exists already. Rather than mangling the
> > compat argument struct to look like a user-provided 64-bit argument struct,
> > copying the arguments from and to the user space would be separately done
> > to 32-bit compat IOCTL arguments.
> > 
> > I suppose that wouldn't be a trivial change either, so for now I'd maintain
> > the approach and later consider how to make this more maintainable in the
> > future. Still, that approach is quite different and it'd be easier to
> > switch from status quo rather than this last patch, suggesting to start
> > with a revert, should we embark into this direction.
> > 
> > What do you think?
> 
> To be honest, I don't really know. Things will get even more complicated
> once we have to deal with the year 2038 problem since that impacts this
> code as well. I'm waiting for the fence code and request API code to
> land before continuing working on that. Perhaps that might be a good
> time to take a step back and see if we can do something smarter.

Sounds good to me.

> 
> > 
> >>
> >> Signed-off-by: Daniel Mentz <[e-mail]>
> >> Signed-off-by: Hans Verkuil <[e-mail]>
> >> ---
> >>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 700 ++++++++++++++++----------
> >>  1 file changed, 448 insertions(+), 252 deletions(-)
> >>
> >> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >> index 2aa9b43daf60..27a5a0961cbd 100644
> >> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >> @@ -22,6 +22,14 @@
> >>  #include <media/v4l2-ctrls.h>
> >>  #include <media/v4l2-ioctl.h>
> >>  
> >> +/* Use the same argument order as copy_in_user */
> >> +#define convert_in_user(to, from)			\
> > 
> > This doesn't really convert anything. How about calling it assign_in_user,
> > for example?
> 
> Sounds reasonable.
> 
> > 
> >> +({							\
> >> +	typeof(*from) val;				\
> > 
> > "val" is very short, easily leading to hard-to-find namespace collisions.
> > At least the versions of GCC I've used happily get this wrong without a
> > warning.
> > 
> > How about __convert_in_user_tmp instead?
> 
> Hmm. What about __assign_tmp?

That seems a little risky still. Perhaps unlikely; I'd use a longer,
unconceivable name to be safe.

> 
> > 
> >> +							\
> >> +	get_user(val, from) || put_user(val, to);	\
> >> +})
> >> +
> >>  static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> >>  {
> >>  	long ret = -ENOIOCTLCMD;
> >> @@ -48,37 +56,41 @@ struct v4l2_window32 {
> >>  	__u8                    global_alpha;
> >>  };
> >>  
> >> -static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
> >> +static int get_v4l2_window32(struct v4l2_window __user *kp,
> >> +			     struct v4l2_window32 __user *up,
> >> +			     void __user *aux_buf, int aux_space)
> >>  {
> >>  	struct v4l2_clip32 __user *uclips;
> >>  	struct v4l2_clip __user *kclips;
> >>  	compat_caddr_t p;
> >> -	u32 n;
> >> +	u32 clipcount;
> >>  
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
> >> -	    get_user(kp->field, &up->field) ||
> >> -	    get_user(kp->chromakey, &up->chromakey) ||
> >> -	    get_user(kp->clipcount, &up->clipcount) ||
> >> -	    get_user(kp->global_alpha, &up->global_alpha))
> >> +	    copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
> >> +	    convert_in_user(&kp->field, &up->field) ||
> >> +	    convert_in_user(&kp->chromakey, &up->chromakey) ||
> >> +	    convert_in_user(&kp->global_alpha, &up->global_alpha) ||
> >> +	    get_user(clipcount, &up->clipcount) ||
> >> +	    put_user(clipcount, &kp->clipcount))
> >>  		return -EFAULT;
> >> -	if (kp->clipcount > 2048)
> >> +	if (clipcount > 2048)
> >>  		return -EINVAL;
> >> -	if (!kp->clipcount) {
> >> -		kp->clips = NULL;
> >> -		return 0;
> >> -	}
> >> +	if (!clipcount)
> >> +		return put_user(NULL, &kp->clips) ? -EFAULT : 0;
> > 
> > Isn't this what put_user would return anyway?
> 
> True, I'll simplify this.
> 
> >>  
> >> -	n = kp->clipcount;
> >>  	if (get_user(p, &up->clips))
> >>  		return -EFAULT;
> >>  	uclips = compat_ptr(p);
> >> -	kclips = compat_alloc_user_space(n * sizeof(*kclips));
> >> -	kp->clips = kclips;
> >> -	while (n--) {
> >> +	if (aux_space < clipcount * sizeof(*kclips))
> >> +		return -EFAULT;
> >> +	kclips = aux_buf;
> >> +	if (put_user(kclips, &kp->clips))
> >> +		return -EFAULT;
> >> +
> >> +	while (clipcount--) {
> >>  		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
> >>  			return -EFAULT;
> >> -		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
> >> +		if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
> >>  			return -EFAULT;
> >>  		uclips++;
> >>  		kclips++;
> >> @@ -86,26 +98,28 @@ static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
> >> +static int put_v4l2_window32(struct v4l2_window __user *kp,
> >> +			     struct v4l2_window32 __user *up)
> >>  {
> >>  	struct v4l2_clip __user *kclips = kp->clips;
> >>  	struct v4l2_clip32 __user *uclips;
> >> -	int n = kp->clipcount;
> >>  	compat_caddr_t p;
> >> -
> >> -	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
> >> -	    put_user(kp->field, &up->field) ||
> >> -	    put_user(kp->chromakey, &up->chromakey) ||
> >> -	    put_user(kp->clipcount, &up->clipcount) ||
> >> -	    put_user(kp->global_alpha, &up->global_alpha))
> >> +	u32 clipcount;
> >> +
> >> +	if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
> >> +	    convert_in_user(&up->field, &kp->field) ||
> >> +	    convert_in_user(&up->chromakey, &kp->chromakey) ||
> >> +	    convert_in_user(&up->global_alpha, &kp->global_alpha) ||
> >> +	    get_user(clipcount, &kp->clipcount) ||
> >> +	    put_user(clipcount, &up->clipcount))
> >>  		return -EFAULT;
> >> -	if (!kp->clipcount)
> >> +	if (!clipcount)
> >>  		return 0;
> >>  
> >>  	if (get_user(p, &up->clips))
> >>  		return -EFAULT;
> >>  	uclips = compat_ptr(p);
> >> -	while (n--) {
> >> +	while (clipcount--) {
> >>  		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
> >>  			return -EFAULT;
> >>  		uclips++;
> >> @@ -145,107 +159,161 @@ struct v4l2_create_buffers32 {
> >>  	__u32			reserved[8];
> >>  };
> >>  
> >> -static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> >> +static int __bufsize_v4l2_format32(struct v4l2_format32 __user *up)
> > 
> > This is effectively returning the size of the non-compat struct, or just
> > the part of which is variable. How about calling it __bufsize_v4l2_format
> > instead? The same for other such functions.
> 
> Ack.
> 
> > I'd also separate the size calculated by the function and the return value.
> 
> That's cleaner, yes.
> 
> > 
> >>  {
> >> -	if (get_user(kp->type, &up->type))
> >> +	u32 type;
> >> +
> >> +	if (get_user(type, &up->type))
> >>  		return -EFAULT;
> >>  
> >> -	switch (kp->type) {
> >> +	switch (type) {
> >> +	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
> >> +		u32 clipcount;
> >> +
> >> +		if (get_user(clipcount, &up->fmt.win.clipcount))
> >> +			return -EFAULT;
> >> +		if (clipcount > 2048)
> >> +			return -EINVAL;
> >> +		return clipcount * sizeof(struct v4l2_clip);
> >> +	}
> >> +	default:
> >> +		return 0;
> >> +	}
> >> +}
> >> +
> >> +static int bufsize_v4l2_format32(struct v4l2_format32 __user *up)
> >> +{
> >> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
> >> +		return -EFAULT;
> > 
> > Newline?
> > 
> >> +	return __bufsize_v4l2_format32(up);
> >> +}
> >> +
> >> +static int __get_v4l2_format32(struct v4l2_format __user *kp,
> >> +			       struct v4l2_format32 __user *up,
> >> +			       void __user *aux_buf, int aux_space)
> >> +{
> >> +	u32 type;
> >> +
> >> +	if (get_user(type, &up->type) || put_user(type, &kp->type))
> >> +		return -EFAULT;
> >> +
> >> +	switch (type) {
> >>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >> -		return copy_from_user(&kp->fmt.pix, &up->fmt.pix,
> >> -				      sizeof(kp->fmt.pix)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
> >> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >> -		return copy_from_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
> >> -				      sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
> >> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >> -		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win);
> >> +		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
> >> +					 aux_buf, aux_space);
> >>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
> >>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
> >> -		return copy_from_user(&kp->fmt.vbi, &up->fmt.vbi,
> >> -				      sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
> >> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
> >>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
> >> -		return copy_from_user(&kp->fmt.sliced, &up->fmt.sliced,
> >> -				      sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
> >> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
> >>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
> >> -		return copy_from_user(&kp->fmt.sdr, &up->fmt.sdr,
> >> -				      sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
> >> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_META_CAPTURE:
> >> -		return copy_from_user(&kp->fmt.meta, &up->fmt.meta,
> >> -				      sizeof(kp->fmt.meta)) ? -EFAULT : 0;
> >> +		return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
> >> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
> >>  	default:
> >>  		return -EINVAL;
> >>  	}
> >>  }
> >>  
> >> -static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> >> +static int get_v4l2_format32(struct v4l2_format __user *kp,
> >> +			     struct v4l2_format32 __user *up,
> >> +			     void __user *aux_buf, int aux_space)
> >> +{
> >> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
> >> +		return -EFAULT;
> >> +	return __get_v4l2_format32(kp, up, aux_buf, aux_space);
> >> +}
> >> +
> >> +static int bufsize_v4l2_create32(struct v4l2_create_buffers32 __user *up)
> >>  {
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
> >>  		return -EFAULT;
> >> -	return __get_v4l2_format32(kp, up);
> >> +	return __bufsize_v4l2_format32(&up->format);
> >>  }
> >>  
> >> -static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
> >> +static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
> >> +			     struct v4l2_create_buffers32 __user *up,
> >> +			     void __user *aux_buf, int aux_space)
> >>  {
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
> >> +	    copy_in_user(kp, up,
> >> +			 offsetof(struct v4l2_create_buffers32, format)))
> >>  		return -EFAULT;
> >> -	return __get_v4l2_format32(&kp->format, &up->format);
> >> +	return __get_v4l2_format32(&kp->format, &up->format,
> >> +				   aux_buf, aux_space);
> >>  }
> >>  
> >> -static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> >> +static int __put_v4l2_format32(struct v4l2_format __user *kp,
> >> +			       struct v4l2_format32 __user *up)
> >>  {
> >> -	if (put_user(kp->type, &up->type))
> >> +	u32 type;
> >> +
> >> +	if (get_user(type, &kp->type))
> >>  		return -EFAULT;
> >>  
> >> -	switch (kp->type) {
> >> +	switch (type) {
> >>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >> -		return copy_to_user(&up->fmt.pix, &kp->fmt.pix,
> >> -				    sizeof(kp->fmt.pix)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
> >> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >> -		return copy_to_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
> >> -				    sizeof(kp->fmt.pix_mp)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
> >> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >>  		return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
> >>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
> >>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
> >> -		return copy_to_user(&up->fmt.vbi, &kp->fmt.vbi,
> >> -				    sizeof(kp->fmt.vbi)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
> >> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
> >>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
> >> -		return copy_to_user(&up->fmt.sliced, &kp->fmt.sliced,
> >> -				    sizeof(kp->fmt.sliced)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
> >> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
> >>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
> >> -		return copy_to_user(&up->fmt.sdr, &kp->fmt.sdr,
> >> -				    sizeof(kp->fmt.sdr)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
> >> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
> >>  	case V4L2_BUF_TYPE_META_CAPTURE:
> >> -		return copy_to_user(&up->fmt.meta, &kp->fmt.meta,
> >> -				    sizeof(kp->fmt.meta)) ?  -EFAULT : 0;
> >> +		return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
> >> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
> >>  	default:
> >>  		return -EINVAL;
> >>  	}
> >>  }
> >>  
> >> -static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
> >> +static int put_v4l2_format32(struct v4l2_format __user *kp,
> >> +			     struct v4l2_format32 __user *up)
> >>  {
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))
> > 
> > For some pointers we do perform such checks, for others we don't. While
> > this patch doesn't change this, it'd be good to align this by either
> > introducing it everywhere or removing it everywhere.
> > 
> > I guess that can be done separately.
> > 
> >>  		return -EFAULT;
> >>  	return __put_v4l2_format32(kp, up);
> >>  }
> >>  
> >> -static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
> >> +static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
> >> +			     struct v4l2_create_buffers32 __user *up)
> >>  {
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format)) ||
> >> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> >> +	    copy_in_user(up, kp,
> >> +			 offsetof(struct v4l2_create_buffers32, format)) ||
> >> +	    copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> >>  		return -EFAULT;
> >>  	return __put_v4l2_format32(&kp->format, &up->format);
> >>  }
> >> @@ -259,25 +327,27 @@ struct v4l2_standard32 {
> >>  	__u32		     reserved[4];
> >>  };
> >>  
> >> -static int get_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
> >> +static int get_v4l2_standard32(struct v4l2_standard __user *kp,
> >> +			       struct v4l2_standard32 __user *up)
> >>  {
> >>  	/* other fields are not set by the user, nor used by the driver */
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    get_user(kp->index, &up->index))
> >> +	    convert_in_user(&kp->index, &up->index))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
> >> +static int put_v4l2_standard32(struct v4l2_standard __user *kp,
> >> +			       struct v4l2_standard32 __user *up)
> >>  {
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(kp->index, &up->index) ||
> >> -	    put_user(kp->id, &up->id) ||
> >> -	    copy_to_user(up->name, kp->name, 24) ||
> >> -	    copy_to_user(&up->frameperiod, &kp->frameperiod,
> >> -			 sizeof(kp->frameperiod)) ||
> >> -	    put_user(kp->framelines, &up->framelines) ||
> >> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> >> +	    convert_in_user(&up->index, &kp->index) ||
> >> +	    copy_in_user(&up->id, &kp->id, sizeof(up->id)) ||
> > 
> > Why not convert_in_user()?
> 
> Will change.
> 
> > 
> >> +	    copy_in_user(up->name, kp->name, 24) ||
> 
> Urg. I missed this, this has a fixed number as the last argument instead of
> sizeof(kp->name).

Right; I didn't comment on this as it's not a property of this patch. I'd
actually fix this separately. Up to you. It's a very risky habit,
especially with reserved fields.

> 
> >> +	    copy_in_user(&up->frameperiod, &kp->frameperiod,
> >> +			 sizeof(up->frameperiod)) ||
> >> +	    convert_in_user(&up->framelines, &kp->framelines) ||
> >> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >> @@ -317,10 +387,10 @@ struct v4l2_buffer32 {
> >>  	__u32			reserved;
> >>  };
> >>  
> >> -static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
> >> +static int get_v4l2_plane32(struct v4l2_plane __user *up,
> >> +			    struct v4l2_plane32 __user *up32,
> >>  			    enum v4l2_memory memory)
> >>  {
> >> -	void __user *up_pln;
> >>  	compat_long_t p;
> > 
> > Shouldn't this be compat_ulong_t?
> 
> That's better, yes.
> 
> > 
> >>  
> >>  	if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
> >> @@ -336,10 +406,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
> >>  			return -EFAULT;
> >>  		break;
> >>  	case V4L2_MEMORY_USERPTR:
> >> -		if (get_user(p, &up32->m.userptr))
> >> -			return -EFAULT;
> >> -		up_pln = compat_ptr(p);
> >> -		if (put_user((unsigned long)up_pln, &up->m.userptr))
> >> +		if (get_user(p, &up32->m.userptr) ||
> >> +		    put_user((unsigned long)compat_ptr(p), &up->m.userptr))
> >>  			return -EFAULT;
> >>  		break;
> >>  	case V4L2_MEMORY_DMABUF:
> >> @@ -351,7 +419,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
> >> +static int put_v4l2_plane32(struct v4l2_plane __user *up,
> >> +			    struct v4l2_plane32 __user *up32,
> >>  			    enum v4l2_memory memory)
> >>  {
> >>  	unsigned long p;
> >> @@ -375,8 +444,7 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
> >>  			return -EFAULT;
> >>  		break;
> >>  	case V4L2_MEMORY_DMABUF:
> >> -		if (copy_in_user(&up32->m.fd, &up->m.fd,
> >> -				 sizeof(up->m.fd)))
> >> +		if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
> >>  			return -EFAULT;
> >>  		break;
> >>  	}
> >> @@ -384,37 +452,68 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
> >>  	return 0;
> >>  }
> >>  
> >> -static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
> >> +static int bufsize_v4l2_buffer32(struct v4l2_buffer32 __user *up)
> >> +{
> >> +	u32 type;
> >> +	u32 length;
> >> +
> >> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> +	    get_user(type, &up->type) ||
> >> +	    get_user(length, &up->length))
> >> +		return -EFAULT;
> >> +
> >> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> >> +		if (length > VIDEO_MAX_PLANES)
> >> +			return -EINVAL;
> >> +
> >> +		/* We don't really care if userspace decides to kill itself
> > 
> > /*
> >  * ...
> > 
> >> +		 * by passing a very big length value
> >> +		 */
> >> +		return length * sizeof(struct v4l2_plane);
> >> +	}
> >> +	return 0;
> >> +}
> >> +
> >> +static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
> >> +			     struct v4l2_buffer32 __user *up,
> >> +			     void __user *aux_buf, int aux_space)
> >>  {
> >> +	u32 type;
> >> +	u32 length;
> >> +	enum v4l2_memory memory;
> >>  	struct v4l2_plane32 __user *uplane32;
> >>  	struct v4l2_plane __user *uplane;
> >>  	compat_caddr_t p;
> >> +	int num_planes;
> > 
> > u32?
> > 
> >>  	int ret;
> >>  
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    get_user(kp->index, &up->index) ||
> >> -	    get_user(kp->type, &up->type) ||
> >> -	    get_user(kp->flags, &up->flags) ||
> >> -	    get_user(kp->memory, &up->memory) ||
> >> -	    get_user(kp->length, &up->length))
> >> +	    convert_in_user(&kp->index, &up->index) ||
> >> +	    get_user(type, &up->type) ||
> >> +	    put_user(type, &kp->type) ||
> >> +	    convert_in_user(&kp->flags, &up->flags) ||
> >> +	    get_user(memory, &up->memory) ||
> >> +	    put_user(memory, &kp->memory) ||
> >> +	    get_user(length, &up->length) ||
> >> +	    put_user(length, &kp->length))
> >>  		return -EFAULT;
> >>  
> >> -	if (V4L2_TYPE_IS_OUTPUT(kp->type))
> >> -		if (get_user(kp->bytesused, &up->bytesused) ||
> >> -		    get_user(kp->field, &up->field) ||
> >> -		    get_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> >> -		    get_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec))
> >> +	if (V4L2_TYPE_IS_OUTPUT(type))
> >> +		if (convert_in_user(&kp->bytesused, &up->bytesused) ||
> >> +		    convert_in_user(&kp->field, &up->field) ||
> >> +		    convert_in_user(&kp->timestamp.tv_sec,
> >> +				    &up->timestamp.tv_sec) ||
> >> +		    convert_in_user(&kp->timestamp.tv_usec,
> >> +				    &up->timestamp.tv_usec))
> >>  			return -EFAULT;
> >>  
> >> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
> >> -		unsigned int num_planes;
> >> -
> >> -		if (kp->length == 0) {
> >> -			kp->m.planes = NULL;
> >> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> >> +		num_planes = length;
> > 
> > Do you need a local variable for just that?
> > 
> >> +		if (num_planes == 0) {
> >>  			/* num_planes == 0 is legal, e.g. when userspace doesn't
> >>  			 * need planes array on DQBUF*/
> >> -			return 0;
> >> -		} else if (kp->length > VIDEO_MAX_PLANES) {
> >> +			return put_user(NULL, &kp->m.planes);
> >> +		} else if (num_planes > VIDEO_MAX_PLANES) {
> >>  			return -EINVAL;
> >>  		}
> >>  
> >> @@ -423,40 +522,47 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
> >>  
> >>  		uplane32 = compat_ptr(p);
> >>  		if (!access_ok(VERIFY_READ, uplane32,
> >> -			       kp->length * sizeof(*uplane32)))
> >> +				num_planes * sizeof(*uplane32)))
> > 
> > Alignment.
> > 
> >>  			return -EFAULT;
> >>  
> >>  		/* We don't really care if userspace decides to kill itself
> >>  		 * by passing a very big num_planes value */
> >> -		uplane = compat_alloc_user_space(kp->length * sizeof(*uplane));
> >> -		kp->m.planes = (__force struct v4l2_plane *)uplane;
> >> +		if (aux_space < num_planes * sizeof(*uplane))
> >> +			return -EFAULT;
> >> +
> >> +		uplane = aux_buf;
> >> +		if (put_user((__force struct v4l2_plane *)uplane,
> >> +					&kp->m.planes))
> >> +			return -EFAULT;
> >>  
> >> -		for (num_planes = 0; num_planes < kp->length; num_planes++) {
> >> -			ret = get_v4l2_plane32(uplane, uplane32, kp->memory);
> >> +		while (--num_planes >= 0) {
> > 
> > while (num_planes--) {
> > 
> > ?
> 
> Yes. I missed this one :-)
> 
> > 
> >> +			ret = get_v4l2_plane32(uplane, uplane32, memory);
> >>  			if (ret)
> >>  				return ret;
> >> -			++uplane;
> >> -			++uplane32;
> >> +			uplane++;
> >> +			uplane32++;
> >>  		}
> >>  	} else {
> >> -		switch (kp->memory) {
> >> +		switch (memory) {
> >>  		case V4L2_MEMORY_MMAP:
> >> -		case V4L2_MEMORY_OVERLAY:
> >> -			if (get_user(kp->m.offset, &up->m.offset))
> >> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
> >>  				return -EFAULT;
> >>  			break;
> >> -		case V4L2_MEMORY_USERPTR:
> >> -			{
> >> -				compat_long_t tmp;
> >> -
> >> -				if (get_user(tmp, &up->m.userptr))
> >> -					return -EFAULT;
> >> +		case V4L2_MEMORY_USERPTR: {
> >> +			compat_long_t tmp;
> > 
> > compat_ulong_t, I'd call it "userptr". The latter is entirely up to you.
> > 
> >>  
> >> -				kp->m.userptr = (unsigned long)compat_ptr(tmp);
> >> -			}
> >> +			if (get_user(tmp, &up->m.userptr) ||
> >> +			    put_user((unsigned long)compat_ptr(tmp),
> >> +				     &kp->m.userptr))
> >> +				return -EFAULT;
> >> +			break;
> >> +		}
> >> +		case V4L2_MEMORY_OVERLAY:
> >> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
> >> +				return -EFAULT;
> > 
> > Is there a reason to split this off from MMAP handling? The code is the
> > same.
> 
> Huh, I missed this as well. I merged MMAP and OVERLAY elsewhere.
> 
> > 
> >>  			break;
> >>  		case V4L2_MEMORY_DMABUF:
> >> -			if (get_user(kp->m.fd, &up->m.fd))
> >> +			if (convert_in_user(&kp->m.fd, &up->m.fd))
> >>  				return -EFAULT;
> >>  			break;
> >>  		}
> >> @@ -465,8 +571,12 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
> >> +static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
> >> +			     struct v4l2_buffer32 __user *up)
> >>  {
> >> +	u32 type;
> >> +	u32 length;
> >> +	enum v4l2_memory memory;
> >>  	struct v4l2_plane32 __user *uplane32;
> >>  	struct v4l2_plane __user *uplane;
> >>  	compat_caddr_t p;
> >> @@ -474,53 +584,60 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
> >>  	int ret;
> >>  
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(kp->index, &up->index) ||
> >> -	    put_user(kp->type, &up->type) ||
> >> -	    put_user(kp->flags, &up->flags) ||
> >> -	    put_user(kp->memory, &up->memory))
> >> +	    convert_in_user(&up->index, &kp->index) ||
> >> +	    get_user(type, &kp->type) ||
> >> +	    put_user(type, &up->type) ||
> >> +	    convert_in_user(&up->flags, &kp->flags) ||
> >> +	    get_user(memory, &kp->memory) ||
> >> +	    put_user(memory, &up->memory))
> >>  		return -EFAULT;
> >>  
> >> -	if (put_user(kp->bytesused, &up->bytesused) ||
> >> -	    put_user(kp->field, &up->field) ||
> >> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> >> -	    put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
> >> -	    copy_to_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
> >> -	    put_user(kp->sequence, &up->sequence) ||
> >> -	    put_user(kp->reserved2, &up->reserved2) ||
> >> -	    put_user(kp->reserved, &up->reserved) ||
> >> -	    put_user(kp->length, &up->length))
> >> +	if (convert_in_user(&up->bytesused, &kp->bytesused) ||
> >> +	    convert_in_user(&up->field, &kp->field) ||
> >> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
> >> +	    convert_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
> >> +	    copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
> >> +	    convert_in_user(&up->sequence, &kp->sequence) ||
> >> +	    convert_in_user(&up->reserved2, &kp->reserved2) ||
> >> +	    convert_in_user(&up->reserved, &kp->reserved) ||
> >> +	    get_user(length, &kp->length) ||
> >> +	    put_user(length, &up->length))
> >>  		return -EFAULT;
> >>  
> >> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
> >> -		num_planes = kp->length;
> >> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
> >> +		num_planes = length;
> >>  		if (num_planes == 0)
> >>  			return 0;
> >>  
> >> -		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
> >> +		if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
> >> +			return -EFAULT;
> >>  		if (get_user(p, &up->m.planes))
> >>  			return -EFAULT;
> >>  		uplane32 = compat_ptr(p);
> >>  
> >>  		while (--num_planes >= 0) {
> > 
> > 
> > while (num_planes--) {
> > 
> > Or rather: s/num_planes/length/
> > 
> > Then you can remove num_planes.
> 
> I will probably keep num_planes. It's more descriptive than 'length'.

You have two u32 local variables for the same purpose. I'd suggest to leave
either.

> 
> > 
> >> -			ret = put_v4l2_plane32(uplane, uplane32, kp->memory);
> >> +			ret = put_v4l2_plane32(uplane, uplane32, memory);
> >>  			if (ret)
> >>  				return ret;
> >>  			++uplane;
> >>  			++uplane32;
> >>  		}
> >>  	} else {
> >> -		switch (kp->memory) {
> >> +		switch (memory) {
> >>  		case V4L2_MEMORY_MMAP:
> >> -		case V4L2_MEMORY_OVERLAY:
> >> -			if (put_user(kp->m.offset, &up->m.offset))
> >> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
> >>  				return -EFAULT;
> >>  			break;
> >>  		case V4L2_MEMORY_USERPTR:
> >> -			if (put_user(kp->m.userptr, &up->m.userptr))
> >> +			if (convert_in_user(&up->m.userptr, &kp->m.userptr))
> >> +				return -EFAULT;
> >> +			break;
> >> +		case V4L2_MEMORY_OVERLAY:
> >> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
> > 
> > Combine with MMAP case?
> 
> Hmm. I did combine this, but I probably lost that change after some later
> patch modifications. Thanks for noticing.
> 
> > 
> >>  				return -EFAULT;
> >>  			break;
> >>  		case V4L2_MEMORY_DMABUF:
> >> -			if (put_user(kp->m.fd, &up->m.fd))
> >> +			if (convert_in_user(&up->m.fd, &kp->m.fd))
> >>  				return -EFAULT;
> >>  			break;
> >>  		}
> >> @@ -545,29 +662,32 @@ struct v4l2_framebuffer32 {
> >>  	} fmt;
> >>  };
> >>  
> >> -static int get_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
> >> +static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> >> +				  struct v4l2_framebuffer32 __user *up)
> >>  {
> >> -	u32 tmp;
> >> +	compat_caddr_t tmp;
> >>  
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >>  	    get_user(tmp, &up->base) ||
> >> -	    get_user(kp->capability, &up->capability) ||
> >> -	    get_user(kp->flags, &up->flags) ||
> >> -	    copy_from_user(&kp->fmt, &up->fmt, sizeof(up->fmt)))
> >> +	    put_user((__force void *)compat_ptr(tmp), &kp->base) ||
> >> +	    convert_in_user(&kp->capability, &up->capability) ||
> >> +	    convert_in_user(&kp->flags, &up->flags) ||
> >> +	    copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
> >>  		return -EFAULT;
> >> -	kp->base = (__force void *)compat_ptr(tmp);
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
> >> +static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> >> +				  struct v4l2_framebuffer32 __user *up)
> >>  {
> >> -	u32 tmp = (u32)((unsigned long)kp->base);
> >> +	void *base;
> >>  
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(tmp, &up->base) ||
> >> -	    put_user(kp->capability, &up->capability) ||
> >> -	    put_user(kp->flags, &up->flags) ||
> >> -	    copy_to_user(&up->fmt, &kp->fmt, sizeof(up->fmt)))
> >> +	    get_user(base, &kp->base) ||
> >> +	    put_user(ptr_to_compat(base), &up->base) ||
> >> +	    convert_in_user(&up->capability, &kp->capability) ||
> >> +	    convert_in_user(&up->flags, &kp->flags) ||
> >> +	    copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >> @@ -586,16 +706,18 @@ struct v4l2_input32 {
> >>  
> >>  /* The 64-bit v4l2_input struct has extra padding at the end of the struct.
> >>     Otherwise it is identical to the 32-bit version. */
> >> -static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
> >> +static inline int get_v4l2_input32(struct v4l2_input __user *kp,
> >> +				   struct v4l2_input32 __user *up)
> >>  {
> >> -	if (copy_from_user(kp, up, sizeof(*up)))
> >> +	if (copy_in_user(kp, up, sizeof(*up)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >>  
> >> -static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
> >> +static inline int put_v4l2_input32(struct v4l2_input __user *kp,
> >> +				   struct v4l2_input32 __user *up)
> >>  {
> >> -	if (copy_to_user(up, kp, sizeof(*up)))
> >> +	if (copy_in_user(up, kp, sizeof(*up)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >> @@ -648,39 +770,58 @@ static inline bool ctrl_is_pointer(struct file *file, u32 id)
> >>  	return !ret && (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
> >>  }
> >>  
> >> +static int bufsize_v4l2_ext_controls32(struct v4l2_ext_controls32 __user *up)
> >> +{
> >> +	u32 count;
> >> +
> >> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> +	    get_user(count, &up->count))
> >> +		return -EFAULT;
> >> +	if (count > V4L2_CID_MAX_CTRLS)
> >> +		return -EINVAL;
> >> +	return count * sizeof(struct v4l2_ext_control);
> >> +}
> >> +
> >>  static int get_v4l2_ext_controls32(struct file *file,
> >> -				   struct v4l2_ext_controls *kp,
> >> -				   struct v4l2_ext_controls32 __user *up)
> >> +				   struct v4l2_ext_controls __user *kp,
> >> +				   struct v4l2_ext_controls32 __user *up,
> >> +				   void __user *aux_buf, int aux_space)
> >>  {
> >>  	struct v4l2_ext_control32 __user *ucontrols;
> >>  	struct v4l2_ext_control __user *kcontrols;
> >> +	u32 count;
> >>  	unsigned int n;
> > 
> > u32 n
> > 
> >>  	compat_caddr_t p;
> >>  
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    get_user(kp->which, &up->which) ||
> >> -	    get_user(kp->count, &up->count) ||
> >> -	    get_user(kp->error_idx, &up->error_idx) ||
> >> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> >> +	    convert_in_user(&kp->which, &up->which) ||
> >> +	    get_user(count, &up->count) ||
> >> +	    put_user(count, &kp->count) ||
> >> +	    convert_in_user(&kp->error_idx, &up->error_idx) ||
> >> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> >>  		return -EFAULT;
> >> -	if (kp->count == 0) {
> >> -		kp->controls = NULL;
> >> -		return 0;
> >> -	} else if (kp->count > V4L2_CID_MAX_CTRLS) {
> >> +	if (count == 0)
> >> +		return put_user(NULL, &kp->controls);
> >> +	else if (kp->count > V4L2_CID_MAX_CTRLS)
> > 
> > count

    ^

Could you comment on this one...

> > 
> >>  		return -EINVAL;
> >> -	}
> >>  	if (get_user(p, &up->controls))
> >>  		return -EFAULT;
> >>  	ucontrols = compat_ptr(p);
> >> -	if (!access_ok(VERIFY_READ, ucontrols, kp->count * sizeof(*ucontrols)))
> >> +	if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))

						^

...for, as far as I see, this may overflow?

> >> +		return -EFAULT;
> >> +	if (aux_space < count * sizeof(*kcontrols))
> >>  		return -EFAULT;
> >> -	kcontrols = compat_alloc_user_space(kp->count * sizeof(*kcontrols));
> >> -	kp->controls = (__force struct v4l2_ext_control *)kcontrols;
> >> -	for (n = 0; n < kp->count; n++) {
> >> +	kcontrols = aux_buf;
> >> +	if (put_user((__force struct v4l2_ext_control *)kcontrols,
> >> +		     &kp->controls))
> >> +		return -EFAULT;
> >> +
> >> +	for (n = 0; n < count; n++) {
> >>  		u32 id;
> >>  
> >>  		if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
> >>  			return -EFAULT;
> >> +
> >>  		if (get_user(id, &kcontrols->id))
> >>  			return -EFAULT;
> > 
> > Newline here, too? Not really a problem with this patch though.
> > 
> >>  		if (ctrl_is_pointer(file, id)) {
> >> @@ -699,36 +840,47 @@ static int get_v4l2_ext_controls32(struct file *file,
> >>  }
> >>  
> >>  static int put_v4l2_ext_controls32(struct file *file,
> >> -				   struct v4l2_ext_controls *kp,
> >> +				   struct v4l2_ext_controls __user *kp,
> >>  				   struct v4l2_ext_controls32 __user *up)
> >>  {
> >>  	struct v4l2_ext_control32 __user *ucontrols;
> >> -	struct v4l2_ext_control __user *kcontrols =
> >> -		(__force struct v4l2_ext_control __user *)kp->controls;
> >> -	int n = kp->count;
> >> +	struct v4l2_ext_control __user *kcontrols;
> >> +	u32 count;
> >> +	unsigned int n;
> > 
> > u32 n
> > 
> >>  	compat_caddr_t p;
> >>  
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(kp->which, &up->which) ||
> >> -	    put_user(kp->count, &up->count) ||
> >> -	    put_user(kp->error_idx, &up->error_idx) ||
> >> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >> +	    get_user(kcontrols, &kp->controls) ||
> > 
> > How about doing this as last? "controls" is the last member of the struct.
> > 
> >> +	    convert_in_user(&up->which, &kp->which) ||
> >> +	    get_user(count, &kp->count) ||
> >> +	    put_user(count, &up->count) ||
> >> +	    convert_in_user(&up->error_idx, &kp->error_idx) ||
> >> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >>  		return -EFAULT;
> >> -	if (!kp->count)
> >> +	if (!count)
> >>  		return 0;
> >>  
> >>  	if (get_user(p, &up->controls))
> >>  		return -EFAULT;
> >>  	ucontrols = compat_ptr(p);
> >> -	if (!access_ok(VERIFY_WRITE, ucontrols, n * sizeof(*ucontrols)))
> >> +	if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
> >>  		return -EFAULT;
> >>  
> >> -	while (--n >= 0) {
> >> -		unsigned size = sizeof(*ucontrols);
> >> +	for (n = 0; n < count; n++) {
> >> +		unsigned int size = sizeof(*ucontrols);
> >>  		u32 id;
> >>  
> >> +		if (copy_in_user(&ucontrols->id, &kcontrols->id,
> >> +				 sizeof(ucontrols->id)) ||
> > 
> > get_user(id, &kcontrols->id) ||
> > put_user(id, &ucontrols->id) ||
> > 
> >> +		    copy_in_user(&ucontrols->size, &kcontrols->size,
> >> +				 sizeof(ucontrols->size)) ||
> > 
> > convert_in_user() ?
> > 
> >> +		    copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
> >> +				 sizeof(ucontrols->reserved2)))
> >> +			return -EFAULT;
> >> +
> >>  		if (get_user(id, &kcontrols->id))
> >>  			return -EFAULT;
> > 
> > ...and the above if () can be removed.
> > 
> >> +
> >>  		/* Do not modify the pointer when copying a pointer control.
> >>  		   The contents of the pointer was changed, not the pointer
> >>  		   itself. */
> >> @@ -736,6 +888,7 @@ static int put_v4l2_ext_controls32(struct file *file,
> >>  			size -= sizeof(ucontrols->value64);
> > 
> > This chunk is yearning for newlines. Not a fault of this patch though.
> > 
> >>  		if (copy_in_user(ucontrols, kcontrols, size))
> >>  			return -EFAULT;
> >> +
> >>  		ucontrols++;
> >>  		kcontrols++;
> >>  	}
> >> @@ -755,17 +908,18 @@ struct v4l2_event32 {
> >>  	__u32				reserved[8];
> >>  };
> >>  
> >> -static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *up)
> >> +static int put_v4l2_event32(struct v4l2_event __user *kp,
> >> +			    struct v4l2_event32 __user *up)
> >>  {
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(kp->type, &up->type) ||
> >> -	    copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
> >> -	    put_user(kp->pending, &up->pending) ||
> >> -	    put_user(kp->sequence, &up->sequence) ||
> >> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
> >> -	    put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
> >> -	    put_user(kp->id, &up->id) ||
> >> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
> >> +	    convert_in_user(&up->type, &kp->type) ||
> >> +	    copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
> >> +	    convert_in_user(&up->pending, &kp->pending) ||
> >> +	    convert_in_user(&up->sequence, &kp->sequence) ||
> >> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
> >> +	    convert_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
> >> +	    convert_in_user(&up->id, &kp->id) ||
> >> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >> @@ -778,31 +932,34 @@ struct v4l2_edid32 {
> >>  	compat_caddr_t edid;
> >>  };
> >>  
> >> -static int get_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
> >> +static int get_v4l2_edid32(struct v4l2_edid __user *kp,
> >> +			   struct v4l2_edid32 __user *up)
> >>  {
> >> -	u32 tmp;
> >> +	compat_uptr_t tmp;
> >>  
> >>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >> -	    get_user(kp->pad, &up->pad) ||
> >> -	    get_user(kp->start_block, &up->start_block) ||
> >> -	    get_user(kp->blocks, &up->blocks) ||
> >> +	    convert_in_user(&kp->pad, &up->pad) ||
> >> +	    convert_in_user(&kp->start_block, &up->start_block) ||
> >> +	    convert_in_user(&kp->blocks, &up->blocks) ||
> >>  	    get_user(tmp, &up->edid) ||
> >> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> >> +	    put_user(compat_ptr(tmp), &kp->edid) ||
> >> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> >>  		return -EFAULT;
> >> -	kp->edid = (__force u8 *)compat_ptr(tmp);
> >>  	return 0;
> >>  }
> >>  
> >> -static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
> >> +static int put_v4l2_edid32(struct v4l2_edid __user *kp,
> >> +			   struct v4l2_edid32 __user *up)
> >>  {
> >> -	u32 tmp = (u32)((unsigned long)kp->edid);
> >> +	void *edid;
> >>  
> >>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >> -	    put_user(kp->pad, &up->pad) ||
> >> -	    put_user(kp->start_block, &up->start_block) ||
> >> -	    put_user(kp->blocks, &up->blocks) ||
> >> -	    put_user(tmp, &up->edid) ||
> >> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >> +	    convert_in_user(&up->pad, &kp->pad) ||
> >> +	    convert_in_user(&up->start_block, &kp->start_block) ||
> >> +	    convert_in_user(&up->blocks, &kp->blocks) ||
> >> +	    get_user(edid, &kp->edid) ||
> >> +	    put_user(ptr_to_compat(edid), &up->edid) ||
> >> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >>  		return -EFAULT;
> >>  	return 0;
> >>  }
> >> @@ -835,22 +992,30 @@ static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
> >>  #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
> >>  #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
> >>  
> >> +static void __user *alloc_userspace(unsigned int size, int aux_space, long *err)
> > 
> > This one is weird. Rather than following the pattern and returning an error
> > and assigning the result to a pointer passed to it, it does exactly the
> > opposite. I'd change that. I guess this is a matter of opinion to some
> > degree at least, though.
> 
> I agree, I'll change that.
> 
> > 
> >> +{
> >> +	void __user *up_native;
> >> +
> >> +	if (aux_space < 0) {
> >> +		*err = aux_space;
> >> +		return NULL;
> >> +	}
> >> +	up_native = compat_alloc_user_space(size + aux_space);
> >> +	if (!up_native)
> >> +		*err = -ENOMEM;
> >> +	else if (clear_user(up_native, size))
> >> +		*err = -EFAULT;
> >> +	else
> >> +		return up_native;
> >> +	return NULL;
> >> +}
> >> +
> >>  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> >>  {
> >> -	union {
> >> -		struct v4l2_format v2f;
> >> -		struct v4l2_buffer v2b;
> >> -		struct v4l2_framebuffer v2fb;
> >> -		struct v4l2_input v2i;
> >> -		struct v4l2_standard v2s;
> >> -		struct v4l2_ext_controls v2ecs;
> >> -		struct v4l2_event v2ev;
> >> -		struct v4l2_create_buffers v2crt;
> >> -		struct v4l2_edid v2edid;
> >> -		unsigned long vx;
> >> -		int vi;
> >> -	} karg;
> >>  	void __user *up = compat_ptr(arg);
> >> +	void __user *up_native = NULL;
> >> +	void __user *aux_buf;
> >> +	int aux_space;
> > 
> > size_t?
> > 
> >>  	int compatible_arg = 1;
> >>  	long err = 0;
> >>  
> >> @@ -889,30 +1054,47 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >>  	case VIDIOC_STREAMOFF:
> >>  	case VIDIOC_S_INPUT:
> >>  	case VIDIOC_S_OUTPUT:
> >> -		err = get_user(karg.vi, (s32 __user *)up);
> >> +		up_native = alloc_userspace(sizeof(unsigned int __user),
> >> +					    0, &err);
> >> +		if (!err && convert_in_user((unsigned int __user *)up_native,
> >> +					    (compat_uint_t __user *)up))
> >> +			return -EFAULT;
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_G_INPUT:
> >>  	case VIDIOC_G_OUTPUT:
> >> +		up_native = alloc_userspace(sizeof(unsigned int __user),
> >> +					    0, &err);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_G_EDID:
> >>  	case VIDIOC_S_EDID:
> >> -		err = get_v4l2_edid32(&karg.v2edid, up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_edid), 0, &err);
> >> +		err = err ? : get_v4l2_edid32(up_native, up);
> > 
> > I'd write this as:
> > 
> > 		if (!err)
> > 			err = get_v4l2_edid32(native_up, up);
> > 
> > Same below.
> > 
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_G_FMT:
> >>  	case VIDIOC_S_FMT:
> >>  	case VIDIOC_TRY_FMT:
> >> -		err = get_v4l2_format32(&karg.v2f, up);
> >> +		aux_space = bufsize_v4l2_format32(up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_format),
> >> +					    aux_space, &err);
> >> +		aux_buf = up_native + sizeof(struct v4l2_format);
> >> +		err = err ? : get_v4l2_format32(up_native, up,
> >> +						aux_buf, aux_space);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_CREATE_BUFS:
> >> -		err = get_v4l2_create32(&karg.v2crt, up);
> >> +		aux_space = bufsize_v4l2_create32(up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_create_buffers),
> >> +					    aux_space, &err);
> >> +		aux_buf = up_native + sizeof(struct v4l2_create_buffers);
> >> +		err = err ? : get_v4l2_create32(up_native, up,
> >> +						aux_buf, aux_space);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >> @@ -920,36 +1102,54 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >>  	case VIDIOC_QUERYBUF:
> >>  	case VIDIOC_QBUF:
> >>  	case VIDIOC_DQBUF:
> >> -		err = get_v4l2_buffer32(&karg.v2b, up);
> >> +		aux_space = bufsize_v4l2_buffer32(up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_buffer),
> >> +					    aux_space, &err);
> >> +		aux_buf = up_native + sizeof(struct v4l2_buffer);
> >> +		err = err ? : get_v4l2_buffer32(up_native, up,
> >> +						aux_buf, aux_space);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_S_FBUF:
> >> -		err = get_v4l2_framebuffer32(&karg.v2fb, up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
> >> +					    0, &err);
> >> +		err = err ? : get_v4l2_framebuffer32(up_native, up);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_G_FBUF:
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
> >> +					    0, &err);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_ENUMSTD:
> >> -		err = get_v4l2_standard32(&karg.v2s, up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_standard),
> >> +					    0, &err);
> >> +		err = err ? : get_v4l2_standard32(up_native, up);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_ENUMINPUT:
> >> -		err = get_v4l2_input32(&karg.v2i, up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_input), 0, &err);
> >> +		err = err ? : get_v4l2_input32(up_native, up);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  
> >>  	case VIDIOC_G_EXT_CTRLS:
> >>  	case VIDIOC_S_EXT_CTRLS:
> >>  	case VIDIOC_TRY_EXT_CTRLS:
> >> -		err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
> >> +		aux_space = bufsize_v4l2_ext_controls32(up);
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_ext_controls),
> >> +					    aux_space, &err);
> >> +		aux_buf = up_native + sizeof(struct v4l2_ext_controls);
> >> +		err = err ? : get_v4l2_ext_controls32(file, up_native, up,
> >> +						      aux_buf, aux_space);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  	case VIDIOC_DQEVENT:
> >> +		up_native = alloc_userspace(sizeof(struct v4l2_event), 0, &err);
> >>  		compatible_arg = 0;
> >>  		break;
> >>  	}
> >> @@ -958,13 +1158,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >>  
> >>  	if (compatible_arg)
> >>  		err = native_ioctl(file, cmd, (unsigned long)up);
> >> -	else {
> >> -		mm_segment_t old_fs = get_fs();
> >> -
> >> -		set_fs(KERNEL_DS);
> >> -		err = native_ioctl(file, cmd, (unsigned long)&karg);
> >> -		set_fs(old_fs);
> >> -	}
> >> +	else
> >> +		err = native_ioctl(file, cmd, (unsigned long)up_native);
> >>  
> >>  	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
> >>  		return err;
> >> @@ -976,11 +1171,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >>  	case VIDIOC_G_EXT_CTRLS:
> >>  	case VIDIOC_S_EXT_CTRLS:
> >>  	case VIDIOC_TRY_EXT_CTRLS:
> >> -		if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
> >> +		if (put_v4l2_ext_controls32(file, up_native, up))
> >>  			err = -EFAULT;
> >>  		break;
> >>  	case VIDIOC_S_EDID:
> >> -		if (put_v4l2_edid32(&karg.v2edid, up))
> >> +		if (put_v4l2_edid32(up_native, up))
> >>  			err = -EFAULT;
> >>  		break;
> >>  	}
> >> @@ -992,44 +1187,45 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >>  	case VIDIOC_S_OUTPUT:
> >>  	case VIDIOC_G_INPUT:
> >>  	case VIDIOC_G_OUTPUT:
> >> -		err = put_user(((s32)karg.vi), (s32 __user *)up);
> >> +		err = convert_in_user((compat_uint_t __user *)up,
> >> +				      ((unsigned int __user *)up_native));
> > 
> > Do note that convert_in_user() returns Boolean. This will effectively yield
> > 1 in case of an error here. How about changing convert_in_user() to return
> > whatever get_user / put_user do, to avoid errors in the future?
> 
> That's better indeed. Good catch.
> 
> > 
> >>  		break;
> >>  
> >>  	case VIDIOC_G_FBUF:
> >> -		err = put_v4l2_framebuffer32(&karg.v2fb, up);
> >> +		err = put_v4l2_framebuffer32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_DQEVENT:
> >> -		err = put_v4l2_event32(&karg.v2ev, up);
> >> +		err = put_v4l2_event32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_G_EDID:
> >> -		err = put_v4l2_edid32(&karg.v2edid, up);
> >> +		err = put_v4l2_edid32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_G_FMT:
> >>  	case VIDIOC_S_FMT:
> >>  	case VIDIOC_TRY_FMT:
> >> -		err = put_v4l2_format32(&karg.v2f, up);
> >> +		err = put_v4l2_format32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_CREATE_BUFS:
> >> -		err = put_v4l2_create32(&karg.v2crt, up);
> >> +		err = put_v4l2_create32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_PREPARE_BUF:
> >>  	case VIDIOC_QUERYBUF:
> >>  	case VIDIOC_QBUF:
> >>  	case VIDIOC_DQBUF:
> >> -		err = put_v4l2_buffer32(&karg.v2b, up);
> >> +		err = put_v4l2_buffer32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_ENUMSTD:
> >> -		err = put_v4l2_standard32(&karg.v2s, up);
> >> +		err = put_v4l2_standard32(up_native, up);
> >>  		break;
> >>  
> >>  	case VIDIOC_ENUMINPUT:
> >> -		err = put_v4l2_input32(&karg.v2i, up);
> >> +		err = put_v4l2_input32(up_native, up);
> >>  		break;
> >>  	}
> >>  	return err;
> > 
> 
> Thanks for the thorough review! Much appreciated.

You're welcome. And thanks for working on this!

Hans Verkuil Jan. 30, 2018, 9:37 a.m. UTC | #4

Hi Sakari,

On 01/29/2018 06:06 PM, Sakari Ailus wrote:
> Hi Hans,
> 
> Thanks for your efforts on this patch and the patchset. Please see my comments below.
> 
> On Fri, Jan 26, 2018 at 01:43:27PM +0100, Hans Verkuil wrote:
>> From: Daniel Mentz <[e-mail]>
>>
>> The 32-bit compat v4l2 ioctl is implemented based on its 64-bit
> 
> s/v4l2 ioctl/V4L2 IOCTL handling/
> 
> ?
> 
>> equivalent. It converts 32-bit data structures into its 64-bit
>> equivalents and needs to provide the data to the 64-bit ioctl in user
>> space memory which is commonly allocated using
>> compat_alloc_user_space(). However, due to how that function is
>> implemented, it can only be called a single time for every syscall
>> invocation.  Supposedly to avoid this limitation, the existing code uses
>> a mix of memory from the kernel stack and memory allocated through
>> compat_alloc_user_space(). Under normal circumstances, this would not
>> work, because the 64-bit ioctl expects all pointers to point to user
>> space memory. As a workaround, set_fs(KERNEL_DS) is called to
>> temporarily disable this extra safety check and allow kernel pointers.
>> However, this might introduce a security vulnerability: The
>> result of the 32-bit to 64-bit conversion is writeable by user space
>> because the output buffer has been allocated via
>> compat_alloc_user_space(). A malicious user space process could then
>> manipulate pointers inside this output buffer, and due to the previous
>> set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer
>> prevent kernel memory access.
>>
>> The new approach is to pre-calculate the total amount of user space
>> memory that is needed, allocate it using compat_alloc_user_space() and
>> then divide up the allocated memory to accommodate all data structures
>> that need to be converted.
>>
>> An alternative approach would have been to retain the union type karg
>> that they allocated on the kernel stack in do_video_ioctl(), copy all
>> data from user space into karg and then back to user space. However,
>> we decided against this approach because it does not align with other
>> compat syscall implementations. Instead, we tried to replicate the
>> get_user/put_user pairs as found in other places in the kernel:
>>
>> if (get_user(clipcount, &up->clipcount) ||
>>     put_user(clipcount, &kp->clipcount)) return -EFAULT;
>>
>> Notes from [e-mail]:
>>
>> This patch was taken from
>> https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7
>>
>> Clearly nobody could be bothered to upstream this patch or at minimum
>> tell us :-( We only heard about this a week ago.
> 
> This is very sad indeed. I would really hope that we'll never run into
> something this again!
> 
>>
>> This patch was rebased and cleaned up. Compared to the original I
>> also swapped the order of the convert_in_user arguments so that they
>> matched copy_in_user. It was hard to review otherwise. I also replaced
>> the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.
> 
> The result looks more complicated than it should be.
> 
> I wonder if the result could be made cleaner by separating the argument
> checking and copying from / to user space in video_usercopy. That
> separation almost completely exists already. Rather than mangling the
> compat argument struct to look like a user-provided 64-bit argument struct,
> copying the arguments from and to the user space would be separately done
> to 32-bit compat IOCTL arguments.
> 
> I suppose that wouldn't be a trivial change either, so for now I'd maintain
> the approach and later consider how to make this more maintainable in the
> future. Still, that approach is quite different and it'd be easier to
> switch from status quo rather than this last patch, suggesting to start
> with a revert, should we embark into this direction.
> 
> What do you think?
> 
>>
>> Signed-off-by: Daniel Mentz <[e-mail]>
>> Signed-off-by: Hans Verkuil <[e-mail]>
>> ---
>>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 700 ++++++++++++++++----------
>>  1 file changed, 448 insertions(+), 252 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> index 2aa9b43daf60..27a5a0961cbd 100644
>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> @@ -22,6 +22,14 @@
>>  #include <media/v4l2-ctrls.h>
>>  #include <media/v4l2-ioctl.h>
>>  
>> +/* Use the same argument order as copy_in_user */
>> +#define convert_in_user(to, from)			\
> 
> This doesn't really convert anything. How about calling it assign_in_user,
> for example?

Done.

> 
>> +({							\
>> +	typeof(*from) val;				\
> 
> "val" is very short, easily leading to hard-to-find namespace collisions.
> At least the versions of GCC I've used happily get this wrong without a
> warning.
> 
> How about __convert_in_user_tmp instead?

I stuck to __assign_tmp, I think __convert_in_user_tmp is overly paranoid :-)

> 
>> +							\
>> +	get_user(val, from) || put_user(val, to);	\

I'm keeping this. I thought about changing || to '? :' but I chickened out making
that change. I'll fix the G/S_INPUT/OUTPUT handling instead.

>> +})
>> +
>>  static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>  {
>>  	long ret = -ENOIOCTLCMD;
>> @@ -48,37 +56,41 @@ struct v4l2_window32 {
>>  	__u8                    global_alpha;
>>  };
>>  
>> -static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
>> +static int get_v4l2_window32(struct v4l2_window __user *kp,
>> +			     struct v4l2_window32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>>  	struct v4l2_clip32 __user *uclips;
>>  	struct v4l2_clip __user *kclips;
>>  	compat_caddr_t p;
>> -	u32 n;
>> +	u32 clipcount;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
>> -	    get_user(kp->field, &up->field) ||
>> -	    get_user(kp->chromakey, &up->chromakey) ||
>> -	    get_user(kp->clipcount, &up->clipcount) ||
>> -	    get_user(kp->global_alpha, &up->global_alpha))
>> +	    copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
>> +	    convert_in_user(&kp->field, &up->field) ||
>> +	    convert_in_user(&kp->chromakey, &up->chromakey) ||
>> +	    convert_in_user(&kp->global_alpha, &up->global_alpha) ||
>> +	    get_user(clipcount, &up->clipcount) ||
>> +	    put_user(clipcount, &kp->clipcount))
>>  		return -EFAULT;
>> -	if (kp->clipcount > 2048)
>> +	if (clipcount > 2048)
>>  		return -EINVAL;
>> -	if (!kp->clipcount) {
>> -		kp->clips = NULL;
>> -		return 0;
>> -	}
>> +	if (!clipcount)
>> +		return put_user(NULL, &kp->clips) ? -EFAULT : 0;
> 
> Isn't this what put_user would return anyway?

Changed.

> 
>>  
>> -	n = kp->clipcount;
>>  	if (get_user(p, &up->clips))
>>  		return -EFAULT;
>>  	uclips = compat_ptr(p);
>> -	kclips = compat_alloc_user_space(n * sizeof(*kclips));
>> -	kp->clips = kclips;
>> -	while (n--) {
>> +	if (aux_space < clipcount * sizeof(*kclips))
>> +		return -EFAULT;
>> +	kclips = aux_buf;
>> +	if (put_user(kclips, &kp->clips))
>> +		return -EFAULT;
>> +
>> +	while (clipcount--) {
>>  		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
>>  			return -EFAULT;
>> -		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
>> +		if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
>>  			return -EFAULT;
>>  		uclips++;
>>  		kclips++;
>> @@ -86,26 +98,28 @@ static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
>> +static int put_v4l2_window32(struct v4l2_window __user *kp,
>> +			     struct v4l2_window32 __user *up)
>>  {
>>  	struct v4l2_clip __user *kclips = kp->clips;
>>  	struct v4l2_clip32 __user *uclips;
>> -	int n = kp->clipcount;
>>  	compat_caddr_t p;
>> -
>> -	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
>> -	    put_user(kp->field, &up->field) ||
>> -	    put_user(kp->chromakey, &up->chromakey) ||
>> -	    put_user(kp->clipcount, &up->clipcount) ||
>> -	    put_user(kp->global_alpha, &up->global_alpha))
>> +	u32 clipcount;
>> +
>> +	if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
>> +	    convert_in_user(&up->field, &kp->field) ||
>> +	    convert_in_user(&up->chromakey, &kp->chromakey) ||
>> +	    convert_in_user(&up->global_alpha, &kp->global_alpha) ||
>> +	    get_user(clipcount, &kp->clipcount) ||
>> +	    put_user(clipcount, &up->clipcount))
>>  		return -EFAULT;
>> -	if (!kp->clipcount)
>> +	if (!clipcount)
>>  		return 0;
>>  
>>  	if (get_user(p, &up->clips))
>>  		return -EFAULT;
>>  	uclips = compat_ptr(p);
>> -	while (n--) {
>> +	while (clipcount--) {
>>  		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
>>  			return -EFAULT;
>>  		uclips++;
>> @@ -145,107 +159,161 @@ struct v4l2_create_buffers32 {
>>  	__u32			reserved[8];
>>  };
>>  
>> -static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int __bufsize_v4l2_format32(struct v4l2_format32 __user *up)
> 
> This is effectively returning the size of the non-compat struct, or just
> the part of which is variable. How about calling it __bufsize_v4l2_format
> instead? The same for other such functions.

Done.

> 
> I'd also separate the size calculated by the function and the return value.

Done. Much nicer indeed.

> 
>>  {
>> -	if (get_user(kp->type, &up->type))
>> +	u32 type;
>> +
>> +	if (get_user(type, &up->type))
>>  		return -EFAULT;
>>  
>> -	switch (kp->type) {
>> +	switch (type) {
>> +	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
>> +		u32 clipcount;
>> +
>> +		if (get_user(clipcount, &up->fmt.win.clipcount))
>> +			return -EFAULT;
>> +		if (clipcount > 2048)
>> +			return -EINVAL;
>> +		return clipcount * sizeof(struct v4l2_clip);
>> +	}
>> +	default:
>> +		return 0;
>> +	}
>> +}
>> +
>> +static int bufsize_v4l2_format32(struct v4l2_format32 __user *up)
>> +{
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>> +		return -EFAULT;
> 
> Newline?

Didn't do this. I didn't think it improved the code.

> 
>> +	return __bufsize_v4l2_format32(up);
>> +}
>> +
>> +static int __get_v4l2_format32(struct v4l2_format __user *kp,
>> +			       struct v4l2_format32 __user *up,
>> +			       void __user *aux_buf, int aux_space)
>> +{
>> +	u32 type;
>> +
>> +	if (get_user(type, &up->type) || put_user(type, &kp->type))
>> +		return -EFAULT;
>> +
>> +	switch (type) {
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>> -		return copy_from_user(&kp->fmt.pix, &up->fmt.pix,
>> -				      sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
>> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
>> -		return copy_from_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
>> -				      sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
>> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
>> -		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win);
>> +		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
>> +					 aux_buf, aux_space);
>>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
>> -		return copy_from_user(&kp->fmt.vbi, &up->fmt.vbi,
>> -				      sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
>> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
>> -		return copy_from_user(&kp->fmt.sliced, &up->fmt.sliced,
>> -				      sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
>> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
>> -		return copy_from_user(&kp->fmt.sdr, &up->fmt.sdr,
>> -				      sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
>> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_META_CAPTURE:
>> -		return copy_from_user(&kp->fmt.meta, &up->fmt.meta,
>> -				      sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>> +		return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
>> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>>  }
>>  
>> -static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int get_v4l2_format32(struct v4l2_format __user *kp,
>> +			     struct v4l2_format32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>> +{
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>> +		return -EFAULT;
>> +	return __get_v4l2_format32(kp, up, aux_buf, aux_space);
>> +}
>> +
>> +static int bufsize_v4l2_create32(struct v4l2_create_buffers32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
>>  		return -EFAULT;
>> -	return __get_v4l2_format32(kp, up);
>> +	return __bufsize_v4l2_format32(&up->format);
>>  }
>>  
>> -static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
>> +static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
>> +			     struct v4l2_create_buffers32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
>> +	    copy_in_user(kp, up,
>> +			 offsetof(struct v4l2_create_buffers32, format)))
>>  		return -EFAULT;
>> -	return __get_v4l2_format32(&kp->format, &up->format);
>> +	return __get_v4l2_format32(&kp->format, &up->format,
>> +				   aux_buf, aux_space);
>>  }
>>  
>> -static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int __put_v4l2_format32(struct v4l2_format __user *kp,
>> +			       struct v4l2_format32 __user *up)
>>  {
>> -	if (put_user(kp->type, &up->type))
>> +	u32 type;
>> +
>> +	if (get_user(type, &kp->type))
>>  		return -EFAULT;
>>  
>> -	switch (kp->type) {
>> +	switch (type) {
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>> -		return copy_to_user(&up->fmt.pix, &kp->fmt.pix,
>> -				    sizeof(kp->fmt.pix)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
>> +				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
>> -		return copy_to_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
>> -				    sizeof(kp->fmt.pix_mp)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
>> +				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
>>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
>>  		return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
>>  	case V4L2_BUF_TYPE_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_VBI_OUTPUT:
>> -		return copy_to_user(&up->fmt.vbi, &kp->fmt.vbi,
>> -				    sizeof(kp->fmt.vbi)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
>> +				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
>>  	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
>> -		return copy_to_user(&up->fmt.sliced, &kp->fmt.sliced,
>> -				    sizeof(kp->fmt.sliced)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
>> +				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_SDR_CAPTURE:
>>  	case V4L2_BUF_TYPE_SDR_OUTPUT:
>> -		return copy_to_user(&up->fmt.sdr, &kp->fmt.sdr,
>> -				    sizeof(kp->fmt.sdr)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
>> +				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
>>  	case V4L2_BUF_TYPE_META_CAPTURE:
>> -		return copy_to_user(&up->fmt.meta, &kp->fmt.meta,
>> -				    sizeof(kp->fmt.meta)) ?  -EFAULT : 0;
>> +		return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
>> +				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>>  }
>>  
>> -static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
>> +static int put_v4l2_format32(struct v4l2_format __user *kp,
>> +			     struct v4l2_format32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))
> 
> For some pointers we do perform such checks, for others we don't. While
> this patch doesn't change this, it'd be good to align this by either
> introducing it everywhere or removing it everywhere.
> 
> I guess that can be done separately.

Didn't touch this. It wouldn't hurt to review the code. I'll see if I can do
that later this week.

> 
>>  		return -EFAULT;
>>  	return __put_v4l2_format32(kp, up);
>>  }
>>  
>> -static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
>> +static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
>> +			     struct v4l2_create_buffers32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format)) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    copy_in_user(up, kp,
>> +			 offsetof(struct v4l2_create_buffers32, format)) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>>  	return __put_v4l2_format32(&kp->format, &up->format);
>>  }
>> @@ -259,25 +327,27 @@ struct v4l2_standard32 {
>>  	__u32		     reserved[4];
>>  };
>>  
>> -static int get_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
>> +static int get_v4l2_standard32(struct v4l2_standard __user *kp,
>> +			       struct v4l2_standard32 __user *up)
>>  {
>>  	/* other fields are not set by the user, nor used by the driver */
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->index, &up->index))
>> +	    convert_in_user(&kp->index, &up->index))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
>> +static int put_v4l2_standard32(struct v4l2_standard __user *kp,
>> +			       struct v4l2_standard32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->index, &up->index) ||
>> -	    put_user(kp->id, &up->id) ||
>> -	    copy_to_user(up->name, kp->name, 24) ||
>> -	    copy_to_user(&up->frameperiod, &kp->frameperiod,
>> -			 sizeof(kp->frameperiod)) ||
>> -	    put_user(kp->framelines, &up->framelines) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&up->index, &kp->index) ||
>> +	    copy_in_user(&up->id, &kp->id, sizeof(up->id)) ||
> 
> Why not convert_in_user()?

Changed.

> 
>> +	    copy_in_user(up->name, kp->name, 24) ||
>> +	    copy_in_user(&up->frameperiod, &kp->frameperiod,
>> +			 sizeof(up->frameperiod)) ||
>> +	    convert_in_user(&up->framelines, &kp->framelines) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -317,10 +387,10 @@ struct v4l2_buffer32 {
>>  	__u32			reserved;
>>  };
>>  
>> -static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
>> +static int get_v4l2_plane32(struct v4l2_plane __user *up,
>> +			    struct v4l2_plane32 __user *up32,
>>  			    enum v4l2_memory memory)
>>  {
>> -	void __user *up_pln;
>>  	compat_long_t p;
> 
> Shouldn't this be compat_ulong_t?

Changed.

> 
>>  
>>  	if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
>> @@ -336,10 +406,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_USERPTR:
>> -		if (get_user(p, &up32->m.userptr))
>> -			return -EFAULT;
>> -		up_pln = compat_ptr(p);
>> -		if (put_user((unsigned long)up_pln, &up->m.userptr))
>> +		if (get_user(p, &up32->m.userptr) ||
>> +		    put_user((unsigned long)compat_ptr(p), &up->m.userptr))
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_DMABUF:
>> @@ -351,7 +419,8 @@ static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
>> +static int put_v4l2_plane32(struct v4l2_plane __user *up,
>> +			    struct v4l2_plane32 __user *up32,
>>  			    enum v4l2_memory memory)
>>  {
>>  	unsigned long p;
>> @@ -375,8 +444,7 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  			return -EFAULT;
>>  		break;
>>  	case V4L2_MEMORY_DMABUF:
>> -		if (copy_in_user(&up32->m.fd, &up->m.fd,
>> -				 sizeof(up->m.fd)))
>> +		if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
>>  			return -EFAULT;
>>  		break;
>>  	}
>> @@ -384,37 +452,68 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
>>  	return 0;
>>  }
>>  
>> -static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
>> +static int bufsize_v4l2_buffer32(struct v4l2_buffer32 __user *up)
>> +{
>> +	u32 type;
>> +	u32 length;
>> +
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> +	    get_user(type, &up->type) ||
>> +	    get_user(length, &up->length))
>> +		return -EFAULT;
>> +
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		if (length > VIDEO_MAX_PLANES)
>> +			return -EINVAL;
>> +
>> +		/* We don't really care if userspace decides to kill itself
> 
> /*
>  * ...

Changed here and elsewhere.

> 
>> +		 * by passing a very big length value
>> +		 */
>> +		return length * sizeof(struct v4l2_plane);
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
>> +			     struct v4l2_buffer32 __user *up,
>> +			     void __user *aux_buf, int aux_space)
>>  {
>> +	u32 type;
>> +	u32 length;
>> +	enum v4l2_memory memory;
>>  	struct v4l2_plane32 __user *uplane32;
>>  	struct v4l2_plane __user *uplane;
>>  	compat_caddr_t p;
>> +	int num_planes;
> 
> u32?

Changed.

> 
>>  	int ret;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->index, &up->index) ||
>> -	    get_user(kp->type, &up->type) ||
>> -	    get_user(kp->flags, &up->flags) ||
>> -	    get_user(kp->memory, &up->memory) ||
>> -	    get_user(kp->length, &up->length))
>> +	    convert_in_user(&kp->index, &up->index) ||
>> +	    get_user(type, &up->type) ||
>> +	    put_user(type, &kp->type) ||
>> +	    convert_in_user(&kp->flags, &up->flags) ||
>> +	    get_user(memory, &up->memory) ||
>> +	    put_user(memory, &kp->memory) ||
>> +	    get_user(length, &up->length) ||
>> +	    put_user(length, &kp->length))
>>  		return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_OUTPUT(kp->type))
>> -		if (get_user(kp->bytesused, &up->bytesused) ||
>> -		    get_user(kp->field, &up->field) ||
>> -		    get_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -		    get_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec))
>> +	if (V4L2_TYPE_IS_OUTPUT(type))
>> +		if (convert_in_user(&kp->bytesused, &up->bytesused) ||
>> +		    convert_in_user(&kp->field, &up->field) ||
>> +		    convert_in_user(&kp->timestamp.tv_sec,
>> +				    &up->timestamp.tv_sec) ||
>> +		    convert_in_user(&kp->timestamp.tv_usec,
>> +				    &up->timestamp.tv_usec))
>>  			return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>> -		unsigned int num_planes;
>> -
>> -		if (kp->length == 0) {
>> -			kp->m.planes = NULL;
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		num_planes = length;
> 
> Do you need a local variable for just that?

I moved the u32 num_planes declaration above to here. I still kept it
though since I think it helps understand what 'length' stands for.

> 
>> +		if (num_planes == 0) {
>>  			/* num_planes == 0 is legal, e.g. when userspace doesn't
>>  			 * need planes array on DQBUF*/
>> -			return 0;
>> -		} else if (kp->length > VIDEO_MAX_PLANES) {
>> +			return put_user(NULL, &kp->m.planes);
>> +		} else if (num_planes > VIDEO_MAX_PLANES) {
>>  			return -EINVAL;
>>  		}
>>  
>> @@ -423,40 +522,47 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  
>>  		uplane32 = compat_ptr(p);
>>  		if (!access_ok(VERIFY_READ, uplane32,
>> -			       kp->length * sizeof(*uplane32)))
>> +				num_planes * sizeof(*uplane32)))
> 
> Alignment.

Changed.

> 
>>  			return -EFAULT;
>>  
>>  		/* We don't really care if userspace decides to kill itself
>>  		 * by passing a very big num_planes value */
>> -		uplane = compat_alloc_user_space(kp->length * sizeof(*uplane));
>> -		kp->m.planes = (__force struct v4l2_plane *)uplane;
>> +		if (aux_space < num_planes * sizeof(*uplane))
>> +			return -EFAULT;
>> +
>> +		uplane = aux_buf;
>> +		if (put_user((__force struct v4l2_plane *)uplane,
>> +					&kp->m.planes))
>> +			return -EFAULT;
>>  
>> -		for (num_planes = 0; num_planes < kp->length; num_planes++) {
>> -			ret = get_v4l2_plane32(uplane, uplane32, kp->memory);
>> +		while (--num_planes >= 0) {
> 
> while (num_planes--) {
> 
> ?

Changed.

> 
>> +			ret = get_v4l2_plane32(uplane, uplane32, memory);
>>  			if (ret)
>>  				return ret;
>> -			++uplane;
>> -			++uplane32;
>> +			uplane++;
>> +			uplane32++;
>>  		}
>>  	} else {
>> -		switch (kp->memory) {
>> +		switch (memory) {
>>  		case V4L2_MEMORY_MMAP:
>> -		case V4L2_MEMORY_OVERLAY:
>> -			if (get_user(kp->m.offset, &up->m.offset))
>> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
>>  				return -EFAULT;
>>  			break;
>> -		case V4L2_MEMORY_USERPTR:
>> -			{
>> -				compat_long_t tmp;
>> -
>> -				if (get_user(tmp, &up->m.userptr))
>> -					return -EFAULT;
>> +		case V4L2_MEMORY_USERPTR: {
>> +			compat_long_t tmp;
> 
> compat_ulong_t, I'd call it "userptr". The latter is entirely up to you.

Changed.

> 
>>  
>> -				kp->m.userptr = (unsigned long)compat_ptr(tmp);
>> -			}
>> +			if (get_user(tmp, &up->m.userptr) ||
>> +			    put_user((unsigned long)compat_ptr(tmp),
>> +				     &kp->m.userptr))
>> +				return -EFAULT;
>> +			break;
>> +		}
>> +		case V4L2_MEMORY_OVERLAY:
>> +			if (convert_in_user(&kp->m.offset, &up->m.offset))
>> +				return -EFAULT;
> 
> Is there a reason to split this off from MMAP handling? The code is the
> same.

Changed.

> 
>>  			break;
>>  		case V4L2_MEMORY_DMABUF:
>> -			if (get_user(kp->m.fd, &up->m.fd))
>> +			if (convert_in_user(&kp->m.fd, &up->m.fd))
>>  				return -EFAULT;
>>  			break;
>>  		}
>> @@ -465,8 +571,12 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
>> +static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
>> +			     struct v4l2_buffer32 __user *up)
>>  {
>> +	u32 type;
>> +	u32 length;
>> +	enum v4l2_memory memory;
>>  	struct v4l2_plane32 __user *uplane32;
>>  	struct v4l2_plane __user *uplane;
>>  	compat_caddr_t p;
>> @@ -474,53 +584,60 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>>  	int ret;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->index, &up->index) ||
>> -	    put_user(kp->type, &up->type) ||
>> -	    put_user(kp->flags, &up->flags) ||
>> -	    put_user(kp->memory, &up->memory))
>> +	    convert_in_user(&up->index, &kp->index) ||
>> +	    get_user(type, &kp->type) ||
>> +	    put_user(type, &up->type) ||
>> +	    convert_in_user(&up->flags, &kp->flags) ||
>> +	    get_user(memory, &kp->memory) ||
>> +	    put_user(memory, &up->memory))
>>  		return -EFAULT;
>>  
>> -	if (put_user(kp->bytesused, &up->bytesused) ||
>> -	    put_user(kp->field, &up->field) ||
>> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -	    put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
>> -	    copy_to_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
>> -	    put_user(kp->sequence, &up->sequence) ||
>> -	    put_user(kp->reserved2, &up->reserved2) ||
>> -	    put_user(kp->reserved, &up->reserved) ||
>> -	    put_user(kp->length, &up->length))
>> +	if (convert_in_user(&up->bytesused, &kp->bytesused) ||
>> +	    convert_in_user(&up->field, &kp->field) ||
>> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
>> +	    convert_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
>> +	    copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
>> +	    convert_in_user(&up->sequence, &kp->sequence) ||
>> +	    convert_in_user(&up->reserved2, &kp->reserved2) ||
>> +	    convert_in_user(&up->reserved, &kp->reserved) ||
>> +	    get_user(length, &kp->length) ||
>> +	    put_user(length, &up->length))
>>  		return -EFAULT;
>>  
>> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>> -		num_planes = kp->length;
>> +	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
>> +		num_planes = length;
>>  		if (num_planes == 0)
>>  			return 0;
>>  
>> -		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
>> +		if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
>> +			return -EFAULT;
>>  		if (get_user(p, &up->m.planes))
>>  			return -EFAULT;
>>  		uplane32 = compat_ptr(p);
>>  
>>  		while (--num_planes >= 0) {
> 
> 
> while (num_planes--) {

Changed.

> 
> Or rather: s/num_planes/length/
> 
> Then you can remove num_planes.

But kept num_planes.

> 
>> -			ret = put_v4l2_plane32(uplane, uplane32, kp->memory);
>> +			ret = put_v4l2_plane32(uplane, uplane32, memory);
>>  			if (ret)
>>  				return ret;
>>  			++uplane;
>>  			++uplane32;
>>  		}
>>  	} else {
>> -		switch (kp->memory) {
>> +		switch (memory) {
>>  		case V4L2_MEMORY_MMAP:
>> -		case V4L2_MEMORY_OVERLAY:
>> -			if (put_user(kp->m.offset, &up->m.offset))
>> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
>>  				return -EFAULT;
>>  			break;
>>  		case V4L2_MEMORY_USERPTR:
>> -			if (put_user(kp->m.userptr, &up->m.userptr))
>> +			if (convert_in_user(&up->m.userptr, &kp->m.userptr))
>> +				return -EFAULT;
>> +			break;
>> +		case V4L2_MEMORY_OVERLAY:
>> +			if (convert_in_user(&up->m.offset, &kp->m.offset))
> 
> Combine with MMAP case?

Changed.

> 
>>  				return -EFAULT;
>>  			break;
>>  		case V4L2_MEMORY_DMABUF:
>> -			if (put_user(kp->m.fd, &up->m.fd))
>> +			if (convert_in_user(&up->m.fd, &kp->m.fd))
>>  				return -EFAULT;
>>  			break;
>>  		}
>> @@ -545,29 +662,32 @@ struct v4l2_framebuffer32 {
>>  	} fmt;
>>  };
>>  
>> -static int get_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
>> +static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
>> +				  struct v4l2_framebuffer32 __user *up)
>>  {
>> -	u32 tmp;
>> +	compat_caddr_t tmp;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>>  	    get_user(tmp, &up->base) ||
>> -	    get_user(kp->capability, &up->capability) ||
>> -	    get_user(kp->flags, &up->flags) ||
>> -	    copy_from_user(&kp->fmt, &up->fmt, sizeof(up->fmt)))
>> +	    put_user((__force void *)compat_ptr(tmp), &kp->base) ||
>> +	    convert_in_user(&kp->capability, &up->capability) ||
>> +	    convert_in_user(&kp->flags, &up->flags) ||
>> +	    copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
>>  		return -EFAULT;
>> -	kp->base = (__force void *)compat_ptr(tmp);
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
>> +static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
>> +				  struct v4l2_framebuffer32 __user *up)
>>  {
>> -	u32 tmp = (u32)((unsigned long)kp->base);
>> +	void *base;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(tmp, &up->base) ||
>> -	    put_user(kp->capability, &up->capability) ||
>> -	    put_user(kp->flags, &up->flags) ||
>> -	    copy_to_user(&up->fmt, &kp->fmt, sizeof(up->fmt)))
>> +	    get_user(base, &kp->base) ||
>> +	    put_user(ptr_to_compat(base), &up->base) ||
>> +	    convert_in_user(&up->capability, &kp->capability) ||
>> +	    convert_in_user(&up->flags, &kp->flags) ||
>> +	    copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -586,16 +706,18 @@ struct v4l2_input32 {
>>  
>>  /* The 64-bit v4l2_input struct has extra padding at the end of the struct.
>>     Otherwise it is identical to the 32-bit version. */
>> -static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
>> +static inline int get_v4l2_input32(struct v4l2_input __user *kp,
>> +				   struct v4l2_input32 __user *up)
>>  {
>> -	if (copy_from_user(kp, up, sizeof(*up)))
>> +	if (copy_in_user(kp, up, sizeof(*up)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>>  
>> -static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
>> +static inline int put_v4l2_input32(struct v4l2_input __user *kp,
>> +				   struct v4l2_input32 __user *up)
>>  {
>> -	if (copy_to_user(up, kp, sizeof(*up)))
>> +	if (copy_in_user(up, kp, sizeof(*up)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -648,39 +770,58 @@ static inline bool ctrl_is_pointer(struct file *file, u32 id)
>>  	return !ret && (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
>>  }
>>  
>> +static int bufsize_v4l2_ext_controls32(struct v4l2_ext_controls32 __user *up)
>> +{
>> +	u32 count;
>> +
>> +	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> +	    get_user(count, &up->count))
>> +		return -EFAULT;
>> +	if (count > V4L2_CID_MAX_CTRLS)
>> +		return -EINVAL;
>> +	return count * sizeof(struct v4l2_ext_control);
>> +}
>> +
>>  static int get_v4l2_ext_controls32(struct file *file,
>> -				   struct v4l2_ext_controls *kp,
>> -				   struct v4l2_ext_controls32 __user *up)
>> +				   struct v4l2_ext_controls __user *kp,
>> +				   struct v4l2_ext_controls32 __user *up,
>> +				   void __user *aux_buf, int aux_space)
>>  {
>>  	struct v4l2_ext_control32 __user *ucontrols;
>>  	struct v4l2_ext_control __user *kcontrols;
>> +	u32 count;
>>  	unsigned int n;
> 
> u32 n

Changed.

> 
>>  	compat_caddr_t p;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->which, &up->which) ||
>> -	    get_user(kp->count, &up->count) ||
>> -	    get_user(kp->error_idx, &up->error_idx) ||
>> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&kp->which, &up->which) ||
>> +	    get_user(count, &up->count) ||
>> +	    put_user(count, &kp->count) ||
>> +	    convert_in_user(&kp->error_idx, &up->error_idx) ||
>> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>> -	if (kp->count == 0) {
>> -		kp->controls = NULL;
>> -		return 0;
>> -	} else if (kp->count > V4L2_CID_MAX_CTRLS) {
>> +	if (count == 0)
>> +		return put_user(NULL, &kp->controls);
>> +	else if (kp->count > V4L2_CID_MAX_CTRLS)
> 
> count

Changed.

> 
>>  		return -EINVAL;
>> -	}
>>  	if (get_user(p, &up->controls))
>>  		return -EFAULT;
>>  	ucontrols = compat_ptr(p);
>> -	if (!access_ok(VERIFY_READ, ucontrols, kp->count * sizeof(*ucontrols)))
>> +	if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))
>> +		return -EFAULT;
>> +	if (aux_space < count * sizeof(*kcontrols))
>>  		return -EFAULT;
>> -	kcontrols = compat_alloc_user_space(kp->count * sizeof(*kcontrols));
>> -	kp->controls = (__force struct v4l2_ext_control *)kcontrols;
>> -	for (n = 0; n < kp->count; n++) {
>> +	kcontrols = aux_buf;
>> +	if (put_user((__force struct v4l2_ext_control *)kcontrols,
>> +		     &kp->controls))
>> +		return -EFAULT;
>> +
>> +	for (n = 0; n < count; n++) {
>>  		u32 id;
>>  
>>  		if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
>>  			return -EFAULT;
>> +
>>  		if (get_user(id, &kcontrols->id))
>>  			return -EFAULT;
> 
> Newline here, too? Not really a problem with this patch though.

Changed.

> 
>>  		if (ctrl_is_pointer(file, id)) {
>> @@ -699,36 +840,47 @@ static int get_v4l2_ext_controls32(struct file *file,
>>  }
>>  
>>  static int put_v4l2_ext_controls32(struct file *file,
>> -				   struct v4l2_ext_controls *kp,
>> +				   struct v4l2_ext_controls __user *kp,
>>  				   struct v4l2_ext_controls32 __user *up)
>>  {
>>  	struct v4l2_ext_control32 __user *ucontrols;
>> -	struct v4l2_ext_control __user *kcontrols =
>> -		(__force struct v4l2_ext_control __user *)kp->controls;
>> -	int n = kp->count;
>> +	struct v4l2_ext_control __user *kcontrols;
>> +	u32 count;
>> +	unsigned int n;
> 
> u32 n

Changed.

> 
>>  	compat_caddr_t p;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->which, &up->which) ||
>> -	    put_user(kp->count, &up->count) ||
>> -	    put_user(kp->error_idx, &up->error_idx) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>> +	    get_user(kcontrols, &kp->controls) ||
> 
> How about doing this as last? "controls" is the last member of the struct.

Changed.

> 
>> +	    convert_in_user(&up->which, &kp->which) ||
>> +	    get_user(count, &kp->count) ||
>> +	    put_user(count, &up->count) ||
>> +	    convert_in_user(&up->error_idx, &kp->error_idx) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>> -	if (!kp->count)
>> +	if (!count)
>>  		return 0;
>>  
>>  	if (get_user(p, &up->controls))
>>  		return -EFAULT;
>>  	ucontrols = compat_ptr(p);
>> -	if (!access_ok(VERIFY_WRITE, ucontrols, n * sizeof(*ucontrols)))
>> +	if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
>>  		return -EFAULT;
>>  
>> -	while (--n >= 0) {
>> -		unsigned size = sizeof(*ucontrols);
>> +	for (n = 0; n < count; n++) {
>> +		unsigned int size = sizeof(*ucontrols);
>>  		u32 id;
>>  
>> +		if (copy_in_user(&ucontrols->id, &kcontrols->id,
>> +				 sizeof(ucontrols->id)) ||
> 
> get_user(id, &kcontrols->id) ||
> put_user(id, &ucontrols->id) ||

Changed.

> 
>> +		    copy_in_user(&ucontrols->size, &kcontrols->size,
>> +				 sizeof(ucontrols->size)) ||
> 
> convert_in_user() ?

Changed.

> 
>> +		    copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
>> +				 sizeof(ucontrols->reserved2)))
>> +			return -EFAULT;
>> +
>>  		if (get_user(id, &kcontrols->id))
>>  			return -EFAULT;
> 
> ...and the above if () can be removed.

Done.

> 
>> +
>>  		/* Do not modify the pointer when copying a pointer control.
>>  		   The contents of the pointer was changed, not the pointer
>>  		   itself. */
>> @@ -736,6 +888,7 @@ static int put_v4l2_ext_controls32(struct file *file,
>>  			size -= sizeof(ucontrols->value64);
> 
> This chunk is yearning for newlines. Not a fault of this patch though.
> 
>>  		if (copy_in_user(ucontrols, kcontrols, size))
>>  			return -EFAULT;
>> +
>>  		ucontrols++;
>>  		kcontrols++;
>>  	}
>> @@ -755,17 +908,18 @@ struct v4l2_event32 {
>>  	__u32				reserved[8];
>>  };
>>  
>> -static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *up)
>> +static int put_v4l2_event32(struct v4l2_event __user *kp,
>> +			    struct v4l2_event32 __user *up)
>>  {
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->type, &up->type) ||
>> -	    copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
>> -	    put_user(kp->pending, &up->pending) ||
>> -	    put_user(kp->sequence, &up->sequence) ||
>> -	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
>> -	    put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
>> -	    put_user(kp->id, &up->id) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
>> +	    convert_in_user(&up->type, &kp->type) ||
>> +	    copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
>> +	    convert_in_user(&up->pending, &kp->pending) ||
>> +	    convert_in_user(&up->sequence, &kp->sequence) ||
>> +	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
>> +	    convert_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
>> +	    convert_in_user(&up->id, &kp->id) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -778,31 +932,34 @@ struct v4l2_edid32 {
>>  	compat_caddr_t edid;
>>  };
>>  
>> -static int get_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>> +static int get_v4l2_edid32(struct v4l2_edid __user *kp,
>> +			   struct v4l2_edid32 __user *up)
>>  {
>> -	u32 tmp;
>> +	compat_uptr_t tmp;
>>  
>>  	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
>> -	    get_user(kp->pad, &up->pad) ||
>> -	    get_user(kp->start_block, &up->start_block) ||
>> -	    get_user(kp->blocks, &up->blocks) ||
>> +	    convert_in_user(&kp->pad, &up->pad) ||
>> +	    convert_in_user(&kp->start_block, &up->start_block) ||
>> +	    convert_in_user(&kp->blocks, &up->blocks) ||
>>  	    get_user(tmp, &up->edid) ||
>> -	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>> +	    put_user(compat_ptr(tmp), &kp->edid) ||
>> +	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
>>  		return -EFAULT;
>> -	kp->edid = (__force u8 *)compat_ptr(tmp);
>>  	return 0;
>>  }
>>  
>> -static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>> +static int put_v4l2_edid32(struct v4l2_edid __user *kp,
>> +			   struct v4l2_edid32 __user *up)
>>  {
>> -	u32 tmp = (u32)((unsigned long)kp->edid);
>> +	void *edid;
>>  
>>  	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
>> -	    put_user(kp->pad, &up->pad) ||
>> -	    put_user(kp->start_block, &up->start_block) ||
>> -	    put_user(kp->blocks, &up->blocks) ||
>> -	    put_user(tmp, &up->edid) ||
>> -	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>> +	    convert_in_user(&up->pad, &kp->pad) ||
>> +	    convert_in_user(&up->start_block, &kp->start_block) ||
>> +	    convert_in_user(&up->blocks, &kp->blocks) ||
>> +	    get_user(edid, &kp->edid) ||
>> +	    put_user(ptr_to_compat(edid), &up->edid) ||
>> +	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
>>  		return -EFAULT;
>>  	return 0;
>>  }
>> @@ -835,22 +992,30 @@ static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
>>  #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
>>  #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
>>  
>> +static void __user *alloc_userspace(unsigned int size, int aux_space, long *err)
> 
> This one is weird. Rather than following the pattern and returning an error
> and assigning the result to a pointer passed to it, it does exactly the
> opposite. I'd change that. I guess this is a matter of opinion to some
> degree at least, though.

Changed. It much nicer now.

> 
>> +{
>> +	void __user *up_native;
>> +
>> +	if (aux_space < 0) {
>> +		*err = aux_space;
>> +		return NULL;
>> +	}
>> +	up_native = compat_alloc_user_space(size + aux_space);
>> +	if (!up_native)
>> +		*err = -ENOMEM;
>> +	else if (clear_user(up_native, size))
>> +		*err = -EFAULT;
>> +	else
>> +		return up_native;
>> +	return NULL;
>> +}
>> +
>>  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>  {
>> -	union {
>> -		struct v4l2_format v2f;
>> -		struct v4l2_buffer v2b;
>> -		struct v4l2_framebuffer v2fb;
>> -		struct v4l2_input v2i;
>> -		struct v4l2_standard v2s;
>> -		struct v4l2_ext_controls v2ecs;
>> -		struct v4l2_event v2ev;
>> -		struct v4l2_create_buffers v2crt;
>> -		struct v4l2_edid v2edid;
>> -		unsigned long vx;
>> -		int vi;
>> -	} karg;
>>  	void __user *up = compat_ptr(arg);
>> +	void __user *up_native = NULL;
>> +	void __user *aux_buf;
>> +	int aux_space;
> 
> size_t?

I went with u32 :-)

> 
>>  	int compatible_arg = 1;
>>  	long err = 0;
>>  
>> @@ -889,30 +1054,47 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_STREAMOFF:
>>  	case VIDIOC_S_INPUT:
>>  	case VIDIOC_S_OUTPUT:
>> -		err = get_user(karg.vi, (s32 __user *)up);
>> +		up_native = alloc_userspace(sizeof(unsigned int __user),
>> +					    0, &err);
>> +		if (!err && convert_in_user((unsigned int __user *)up_native,
>> +					    (compat_uint_t __user *)up))
>> +			return -EFAULT;
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_INPUT:
>>  	case VIDIOC_G_OUTPUT:
>> +		up_native = alloc_userspace(sizeof(unsigned int __user),
>> +					    0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_EDID:
>>  	case VIDIOC_S_EDID:
>> -		err = get_v4l2_edid32(&karg.v2edid, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_edid), 0, &err);
>> +		err = err ? : get_v4l2_edid32(up_native, up);
> 
> I'd write this as:
> 
> 		if (!err)
> 			err = get_v4l2_edid32(native_up, up);
> 
> Same below.

Done.

> 
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_FMT:
>>  	case VIDIOC_S_FMT:
>>  	case VIDIOC_TRY_FMT:
>> -		err = get_v4l2_format32(&karg.v2f, up);
>> +		aux_space = bufsize_v4l2_format32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_format),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_format);
>> +		err = err ? : get_v4l2_format32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_CREATE_BUFS:
>> -		err = get_v4l2_create32(&karg.v2crt, up);
>> +		aux_space = bufsize_v4l2_create32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_create_buffers),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_create_buffers);
>> +		err = err ? : get_v4l2_create32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>> @@ -920,36 +1102,54 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_QUERYBUF:
>>  	case VIDIOC_QBUF:
>>  	case VIDIOC_DQBUF:
>> -		err = get_v4l2_buffer32(&karg.v2b, up);
>> +		aux_space = bufsize_v4l2_buffer32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_buffer),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_buffer);
>> +		err = err ? : get_v4l2_buffer32(up_native, up,
>> +						aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_S_FBUF:
>> -		err = get_v4l2_framebuffer32(&karg.v2fb, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
>> +					    0, &err);
>> +		err = err ? : get_v4l2_framebuffer32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_FBUF:
>> +		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
>> +					    0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_ENUMSTD:
>> -		err = get_v4l2_standard32(&karg.v2s, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_standard),
>> +					    0, &err);
>> +		err = err ? : get_v4l2_standard32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_ENUMINPUT:
>> -		err = get_v4l2_input32(&karg.v2i, up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_input), 0, &err);
>> +		err = err ? : get_v4l2_input32(up_native, up);
>>  		compatible_arg = 0;
>>  		break;
>>  
>>  	case VIDIOC_G_EXT_CTRLS:
>>  	case VIDIOC_S_EXT_CTRLS:
>>  	case VIDIOC_TRY_EXT_CTRLS:
>> -		err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
>> +		aux_space = bufsize_v4l2_ext_controls32(up);
>> +		up_native = alloc_userspace(sizeof(struct v4l2_ext_controls),
>> +					    aux_space, &err);
>> +		aux_buf = up_native + sizeof(struct v4l2_ext_controls);
>> +		err = err ? : get_v4l2_ext_controls32(file, up_native, up,
>> +						      aux_buf, aux_space);
>>  		compatible_arg = 0;
>>  		break;
>>  	case VIDIOC_DQEVENT:
>> +		up_native = alloc_userspace(sizeof(struct v4l2_event), 0, &err);
>>  		compatible_arg = 0;
>>  		break;
>>  	}
>> @@ -958,13 +1158,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  
>>  	if (compatible_arg)
>>  		err = native_ioctl(file, cmd, (unsigned long)up);
>> -	else {
>> -		mm_segment_t old_fs = get_fs();
>> -
>> -		set_fs(KERNEL_DS);
>> -		err = native_ioctl(file, cmd, (unsigned long)&karg);
>> -		set_fs(old_fs);
>> -	}
>> +	else
>> +		err = native_ioctl(file, cmd, (unsigned long)up_native);
>>  
>>  	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
>>  		return err;
>> @@ -976,11 +1171,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_G_EXT_CTRLS:
>>  	case VIDIOC_S_EXT_CTRLS:
>>  	case VIDIOC_TRY_EXT_CTRLS:
>> -		if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
>> +		if (put_v4l2_ext_controls32(file, up_native, up))
>>  			err = -EFAULT;
>>  		break;
>>  	case VIDIOC_S_EDID:
>> -		if (put_v4l2_edid32(&karg.v2edid, up))
>> +		if (put_v4l2_edid32(up_native, up))
>>  			err = -EFAULT;
>>  		break;
>>  	}
>> @@ -992,44 +1187,45 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>>  	case VIDIOC_S_OUTPUT:
>>  	case VIDIOC_G_INPUT:
>>  	case VIDIOC_G_OUTPUT:
>> -		err = put_user(((s32)karg.vi), (s32 __user *)up);
>> +		err = convert_in_user((compat_uint_t __user *)up,
>> +				      ((unsigned int __user *)up_native));
> 
> Do note that convert_in_user() returns Boolean. This will effectively yield
> 1 in case of an error here. How about changing convert_in_user() to return
> whatever get_user / put_user do, to avoid errors in the future?

As mentioned at the top I decided not to change convert_in_user (now assign_in_user)
and modified this code here instead.

> 
>>  		break;
>>  
>>  	case VIDIOC_G_FBUF:
>> -		err = put_v4l2_framebuffer32(&karg.v2fb, up);
>> +		err = put_v4l2_framebuffer32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_DQEVENT:
>> -		err = put_v4l2_event32(&karg.v2ev, up);
>> +		err = put_v4l2_event32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_G_EDID:
>> -		err = put_v4l2_edid32(&karg.v2edid, up);
>> +		err = put_v4l2_edid32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_G_FMT:
>>  	case VIDIOC_S_FMT:
>>  	case VIDIOC_TRY_FMT:
>> -		err = put_v4l2_format32(&karg.v2f, up);
>> +		err = put_v4l2_format32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_CREATE_BUFS:
>> -		err = put_v4l2_create32(&karg.v2crt, up);
>> +		err = put_v4l2_create32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_PREPARE_BUF:
>>  	case VIDIOC_QUERYBUF:
>>  	case VIDIOC_QBUF:
>>  	case VIDIOC_DQBUF:
>> -		err = put_v4l2_buffer32(&karg.v2b, up);
>> +		err = put_v4l2_buffer32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_ENUMSTD:
>> -		err = put_v4l2_standard32(&karg.v2s, up);
>> +		err = put_v4l2_standard32(up_native, up);
>>  		break;
>>  
>>  	case VIDIOC_ENUMINPUT:
>> -		err = put_v4l2_input32(&karg.v2i, up);
>> +		err = put_v4l2_input32(up_native, up);
>>  		break;
>>  	}
>>  	return err;
> 

Regards,

	Hans

Patch

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 2aa9b43daf60..27a5a0961cbd 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -22,6 +22,14 @@ 
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-ioctl.h>
 
+/* Use the same argument order as copy_in_user */
+#define convert_in_user(to, from)			\
+({							\
+	typeof(*from) val;				\
+							\
+	get_user(val, from) || put_user(val, to);	\
+})
+
 static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	long ret = -ENOIOCTLCMD;
@@ -48,37 +56,41 @@  struct v4l2_window32 {
 	__u8                    global_alpha;
 };
 
-static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
+static int get_v4l2_window32(struct v4l2_window __user *kp,
+			     struct v4l2_window32 __user *up,
+			     void __user *aux_buf, int aux_space)
 {
 	struct v4l2_clip32 __user *uclips;
 	struct v4l2_clip __user *kclips;
 	compat_caddr_t p;
-	u32 n;
+	u32 clipcount;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
-	    get_user(kp->field, &up->field) ||
-	    get_user(kp->chromakey, &up->chromakey) ||
-	    get_user(kp->clipcount, &up->clipcount) ||
-	    get_user(kp->global_alpha, &up->global_alpha))
+	    copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
+	    convert_in_user(&kp->field, &up->field) ||
+	    convert_in_user(&kp->chromakey, &up->chromakey) ||
+	    convert_in_user(&kp->global_alpha, &up->global_alpha) ||
+	    get_user(clipcount, &up->clipcount) ||
+	    put_user(clipcount, &kp->clipcount))
 		return -EFAULT;
-	if (kp->clipcount > 2048)
+	if (clipcount > 2048)
 		return -EINVAL;
-	if (!kp->clipcount) {
-		kp->clips = NULL;
-		return 0;
-	}
+	if (!clipcount)
+		return put_user(NULL, &kp->clips) ? -EFAULT : 0;
 
-	n = kp->clipcount;
 	if (get_user(p, &up->clips))
 		return -EFAULT;
 	uclips = compat_ptr(p);
-	kclips = compat_alloc_user_space(n * sizeof(*kclips));
-	kp->clips = kclips;
-	while (n--) {
+	if (aux_space < clipcount * sizeof(*kclips))
+		return -EFAULT;
+	kclips = aux_buf;
+	if (put_user(kclips, &kp->clips))
+		return -EFAULT;
+
+	while (clipcount--) {
 		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
 			return -EFAULT;
-		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
+		if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
 			return -EFAULT;
 		uclips++;
 		kclips++;
@@ -86,26 +98,28 @@  static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
 	return 0;
 }
 
-static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
+static int put_v4l2_window32(struct v4l2_window __user *kp,
+			     struct v4l2_window32 __user *up)
 {
 	struct v4l2_clip __user *kclips = kp->clips;
 	struct v4l2_clip32 __user *uclips;
-	int n = kp->clipcount;
 	compat_caddr_t p;
-
-	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
-	    put_user(kp->field, &up->field) ||
-	    put_user(kp->chromakey, &up->chromakey) ||
-	    put_user(kp->clipcount, &up->clipcount) ||
-	    put_user(kp->global_alpha, &up->global_alpha))
+	u32 clipcount;
+
+	if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
+	    convert_in_user(&up->field, &kp->field) ||
+	    convert_in_user(&up->chromakey, &kp->chromakey) ||
+	    convert_in_user(&up->global_alpha, &kp->global_alpha) ||
+	    get_user(clipcount, &kp->clipcount) ||
+	    put_user(clipcount, &up->clipcount))
 		return -EFAULT;
-	if (!kp->clipcount)
+	if (!clipcount)
 		return 0;
 
 	if (get_user(p, &up->clips))
 		return -EFAULT;
 	uclips = compat_ptr(p);
-	while (n--) {
+	while (clipcount--) {
 		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
 			return -EFAULT;
 		uclips++;
@@ -145,107 +159,161 @@  struct v4l2_create_buffers32 {
 	__u32			reserved[8];
 };
 
-static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+static int __bufsize_v4l2_format32(struct v4l2_format32 __user *up)
 {
-	if (get_user(kp->type, &up->type))
+	u32 type;
+
+	if (get_user(type, &up->type))
 		return -EFAULT;
 
-	switch (kp->type) {
+	switch (type) {
+	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
+		u32 clipcount;
+
+		if (get_user(clipcount, &up->fmt.win.clipcount))
+			return -EFAULT;
+		if (clipcount > 2048)
+			return -EINVAL;
+		return clipcount * sizeof(struct v4l2_clip);
+	}
+	default:
+		return 0;
+	}
+}
+
+static int bufsize_v4l2_format32(struct v4l2_format32 __user *up)
+{
+	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
+		return -EFAULT;
+	return __bufsize_v4l2_format32(up);
+}
+
+static int __get_v4l2_format32(struct v4l2_format __user *kp,
+			       struct v4l2_format32 __user *up,
+			       void __user *aux_buf, int aux_space)
+{
+	u32 type;
+
+	if (get_user(type, &up->type) || put_user(type, &kp->type))
+		return -EFAULT;
+
+	switch (type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
-		return copy_from_user(&kp->fmt.pix, &up->fmt.pix,
-				      sizeof(kp->fmt.pix)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
+				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
-		return copy_from_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
-				      sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
+				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
-		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win);
+		return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
+					 aux_buf, aux_space);
 	case V4L2_BUF_TYPE_VBI_CAPTURE:
 	case V4L2_BUF_TYPE_VBI_OUTPUT:
-		return copy_from_user(&kp->fmt.vbi, &up->fmt.vbi,
-				      sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
+				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
 	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
-		return copy_from_user(&kp->fmt.sliced, &up->fmt.sliced,
-				      sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
+				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_SDR_CAPTURE:
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
-		return copy_from_user(&kp->fmt.sdr, &up->fmt.sdr,
-				      sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
+				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_META_CAPTURE:
-		return copy_from_user(&kp->fmt.meta, &up->fmt.meta,
-				      sizeof(kp->fmt.meta)) ? -EFAULT : 0;
+		return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
+				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
 	default:
 		return -EINVAL;
 	}
 }
 
-static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+static int get_v4l2_format32(struct v4l2_format __user *kp,
+			     struct v4l2_format32 __user *up,
+			     void __user *aux_buf, int aux_space)
+{
+	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
+		return -EFAULT;
+	return __get_v4l2_format32(kp, up, aux_buf, aux_space);
+}
+
+static int bufsize_v4l2_create32(struct v4l2_create_buffers32 __user *up)
 {
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)))
 		return -EFAULT;
-	return __get_v4l2_format32(kp, up);
+	return __bufsize_v4l2_format32(&up->format);
 }
 
-static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
+static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
+			     struct v4l2_create_buffers32 __user *up,
+			     void __user *aux_buf, int aux_space)
 {
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
+	    copy_in_user(kp, up,
+			 offsetof(struct v4l2_create_buffers32, format)))
 		return -EFAULT;
-	return __get_v4l2_format32(&kp->format, &up->format);
+	return __get_v4l2_format32(&kp->format, &up->format,
+				   aux_buf, aux_space);
 }
 
-static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+static int __put_v4l2_format32(struct v4l2_format __user *kp,
+			       struct v4l2_format32 __user *up)
 {
-	if (put_user(kp->type, &up->type))
+	u32 type;
+
+	if (get_user(type, &kp->type))
 		return -EFAULT;
 
-	switch (kp->type) {
+	switch (type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
-		return copy_to_user(&up->fmt.pix, &kp->fmt.pix,
-				    sizeof(kp->fmt.pix)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
+				    sizeof(kp->fmt.pix)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
-		return copy_to_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
-				    sizeof(kp->fmt.pix_mp)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
+				    sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_VIDEO_OVERLAY:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
 		return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
 	case V4L2_BUF_TYPE_VBI_CAPTURE:
 	case V4L2_BUF_TYPE_VBI_OUTPUT:
-		return copy_to_user(&up->fmt.vbi, &kp->fmt.vbi,
-				    sizeof(kp->fmt.vbi)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
+				    sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
 	case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
-		return copy_to_user(&up->fmt.sliced, &kp->fmt.sliced,
-				    sizeof(kp->fmt.sliced)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
+				    sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_SDR_CAPTURE:
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
-		return copy_to_user(&up->fmt.sdr, &kp->fmt.sdr,
-				    sizeof(kp->fmt.sdr)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
+				    sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
 	case V4L2_BUF_TYPE_META_CAPTURE:
-		return copy_to_user(&up->fmt.meta, &kp->fmt.meta,
-				    sizeof(kp->fmt.meta)) ?  -EFAULT : 0;
+		return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
+				    sizeof(kp->fmt.meta)) ? -EFAULT : 0;
 	default:
 		return -EINVAL;
 	}
 }
 
-static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+static int put_v4l2_format32(struct v4l2_format __user *kp,
+			     struct v4l2_format32 __user *up)
 {
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))
 		return -EFAULT;
 	return __put_v4l2_format32(kp, up);
 }
 
-static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
+static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
+			     struct v4l2_create_buffers32 __user *up)
 {
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format)) ||
-	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
+	    copy_in_user(up, kp,
+			 offsetof(struct v4l2_create_buffers32, format)) ||
+	    copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
 		return -EFAULT;
 	return __put_v4l2_format32(&kp->format, &up->format);
 }
@@ -259,25 +327,27 @@  struct v4l2_standard32 {
 	__u32		     reserved[4];
 };
 
-static int get_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
+static int get_v4l2_standard32(struct v4l2_standard __user *kp,
+			       struct v4l2_standard32 __user *up)
 {
 	/* other fields are not set by the user, nor used by the driver */
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    get_user(kp->index, &up->index))
+	    convert_in_user(&kp->index, &up->index))
 		return -EFAULT;
 	return 0;
 }
 
-static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32 __user *up)
+static int put_v4l2_standard32(struct v4l2_standard __user *kp,
+			       struct v4l2_standard32 __user *up)
 {
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(kp->index, &up->index) ||
-	    put_user(kp->id, &up->id) ||
-	    copy_to_user(up->name, kp->name, 24) ||
-	    copy_to_user(&up->frameperiod, &kp->frameperiod,
-			 sizeof(kp->frameperiod)) ||
-	    put_user(kp->framelines, &up->framelines) ||
-	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
+	    convert_in_user(&up->index, &kp->index) ||
+	    copy_in_user(&up->id, &kp->id, sizeof(up->id)) ||
+	    copy_in_user(up->name, kp->name, 24) ||
+	    copy_in_user(&up->frameperiod, &kp->frameperiod,
+			 sizeof(up->frameperiod)) ||
+	    convert_in_user(&up->framelines, &kp->framelines) ||
+	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
 		return -EFAULT;
 	return 0;
 }
@@ -317,10 +387,10 @@  struct v4l2_buffer32 {
 	__u32			reserved;
 };
 
-static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
+static int get_v4l2_plane32(struct v4l2_plane __user *up,
+			    struct v4l2_plane32 __user *up32,
 			    enum v4l2_memory memory)
 {
-	void __user *up_pln;
 	compat_long_t p;
 
 	if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
@@ -336,10 +406,8 @@  static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
 			return -EFAULT;
 		break;
 	case V4L2_MEMORY_USERPTR:
-		if (get_user(p, &up32->m.userptr))
-			return -EFAULT;
-		up_pln = compat_ptr(p);
-		if (put_user((unsigned long)up_pln, &up->m.userptr))
+		if (get_user(p, &up32->m.userptr) ||
+		    put_user((unsigned long)compat_ptr(p), &up->m.userptr))
 			return -EFAULT;
 		break;
 	case V4L2_MEMORY_DMABUF:
@@ -351,7 +419,8 @@  static int get_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
 	return 0;
 }
 
-static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __user *up32,
+static int put_v4l2_plane32(struct v4l2_plane __user *up,
+			    struct v4l2_plane32 __user *up32,
 			    enum v4l2_memory memory)
 {
 	unsigned long p;
@@ -375,8 +444,7 @@  static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
 			return -EFAULT;
 		break;
 	case V4L2_MEMORY_DMABUF:
-		if (copy_in_user(&up32->m.fd, &up->m.fd,
-				 sizeof(up->m.fd)))
+		if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
 			return -EFAULT;
 		break;
 	}
@@ -384,37 +452,68 @@  static int put_v4l2_plane32(struct v4l2_plane __user *up, struct v4l2_plane32 __
 	return 0;
 }
 
-static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
+static int bufsize_v4l2_buffer32(struct v4l2_buffer32 __user *up)
+{
+	u32 type;
+	u32 length;
+
+	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
+	    get_user(type, &up->type) ||
+	    get_user(length, &up->length))
+		return -EFAULT;
+
+	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
+		if (length > VIDEO_MAX_PLANES)
+			return -EINVAL;
+
+		/* We don't really care if userspace decides to kill itself
+		 * by passing a very big length value
+		 */
+		return length * sizeof(struct v4l2_plane);
+	}
+	return 0;
+}
+
+static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
+			     struct v4l2_buffer32 __user *up,
+			     void __user *aux_buf, int aux_space)
 {
+	u32 type;
+	u32 length;
+	enum v4l2_memory memory;
 	struct v4l2_plane32 __user *uplane32;
 	struct v4l2_plane __user *uplane;
 	compat_caddr_t p;
+	int num_planes;
 	int ret;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    get_user(kp->index, &up->index) ||
-	    get_user(kp->type, &up->type) ||
-	    get_user(kp->flags, &up->flags) ||
-	    get_user(kp->memory, &up->memory) ||
-	    get_user(kp->length, &up->length))
+	    convert_in_user(&kp->index, &up->index) ||
+	    get_user(type, &up->type) ||
+	    put_user(type, &kp->type) ||
+	    convert_in_user(&kp->flags, &up->flags) ||
+	    get_user(memory, &up->memory) ||
+	    put_user(memory, &kp->memory) ||
+	    get_user(length, &up->length) ||
+	    put_user(length, &kp->length))
 		return -EFAULT;
 
-	if (V4L2_TYPE_IS_OUTPUT(kp->type))
-		if (get_user(kp->bytesused, &up->bytesused) ||
-		    get_user(kp->field, &up->field) ||
-		    get_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
-		    get_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec))
+	if (V4L2_TYPE_IS_OUTPUT(type))
+		if (convert_in_user(&kp->bytesused, &up->bytesused) ||
+		    convert_in_user(&kp->field, &up->field) ||
+		    convert_in_user(&kp->timestamp.tv_sec,
+				    &up->timestamp.tv_sec) ||
+		    convert_in_user(&kp->timestamp.tv_usec,
+				    &up->timestamp.tv_usec))
 			return -EFAULT;
 
-	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
-		unsigned int num_planes;
-
-		if (kp->length == 0) {
-			kp->m.planes = NULL;
+	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
+		num_planes = length;
+		if (num_planes == 0) {
 			/* num_planes == 0 is legal, e.g. when userspace doesn't
 			 * need planes array on DQBUF*/
-			return 0;
-		} else if (kp->length > VIDEO_MAX_PLANES) {
+			return put_user(NULL, &kp->m.planes);
+		} else if (num_planes > VIDEO_MAX_PLANES) {
 			return -EINVAL;
 		}
 
@@ -423,40 +522,47 @@  static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 
 		uplane32 = compat_ptr(p);
 		if (!access_ok(VERIFY_READ, uplane32,
-			       kp->length * sizeof(*uplane32)))
+				num_planes * sizeof(*uplane32)))
 			return -EFAULT;
 
 		/* We don't really care if userspace decides to kill itself
 		 * by passing a very big num_planes value */
-		uplane = compat_alloc_user_space(kp->length * sizeof(*uplane));
-		kp->m.planes = (__force struct v4l2_plane *)uplane;
+		if (aux_space < num_planes * sizeof(*uplane))
+			return -EFAULT;
+
+		uplane = aux_buf;
+		if (put_user((__force struct v4l2_plane *)uplane,
+					&kp->m.planes))
+			return -EFAULT;
 
-		for (num_planes = 0; num_planes < kp->length; num_planes++) {
-			ret = get_v4l2_plane32(uplane, uplane32, kp->memory);
+		while (--num_planes >= 0) {
+			ret = get_v4l2_plane32(uplane, uplane32, memory);
 			if (ret)
 				return ret;
-			++uplane;
-			++uplane32;
+			uplane++;
+			uplane32++;
 		}
 	} else {
-		switch (kp->memory) {
+		switch (memory) {
 		case V4L2_MEMORY_MMAP:
-		case V4L2_MEMORY_OVERLAY:
-			if (get_user(kp->m.offset, &up->m.offset))
+			if (convert_in_user(&kp->m.offset, &up->m.offset))
 				return -EFAULT;
 			break;
-		case V4L2_MEMORY_USERPTR:
-			{
-				compat_long_t tmp;
-
-				if (get_user(tmp, &up->m.userptr))
-					return -EFAULT;
+		case V4L2_MEMORY_USERPTR: {
+			compat_long_t tmp;
 
-				kp->m.userptr = (unsigned long)compat_ptr(tmp);
-			}
+			if (get_user(tmp, &up->m.userptr) ||
+			    put_user((unsigned long)compat_ptr(tmp),
+				     &kp->m.userptr))
+				return -EFAULT;
+			break;
+		}
+		case V4L2_MEMORY_OVERLAY:
+			if (convert_in_user(&kp->m.offset, &up->m.offset))
+				return -EFAULT;
 			break;
 		case V4L2_MEMORY_DMABUF:
-			if (get_user(kp->m.fd, &up->m.fd))
+			if (convert_in_user(&kp->m.fd, &up->m.fd))
 				return -EFAULT;
 			break;
 		}
@@ -465,8 +571,12 @@  static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 	return 0;
 }
 
-static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user *up)
+static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
+			     struct v4l2_buffer32 __user *up)
 {
+	u32 type;
+	u32 length;
+	enum v4l2_memory memory;
 	struct v4l2_plane32 __user *uplane32;
 	struct v4l2_plane __user *uplane;
 	compat_caddr_t p;
@@ -474,53 +584,60 @@  static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 	int ret;
 
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(kp->index, &up->index) ||
-	    put_user(kp->type, &up->type) ||
-	    put_user(kp->flags, &up->flags) ||
-	    put_user(kp->memory, &up->memory))
+	    convert_in_user(&up->index, &kp->index) ||
+	    get_user(type, &kp->type) ||
+	    put_user(type, &up->type) ||
+	    convert_in_user(&up->flags, &kp->flags) ||
+	    get_user(memory, &kp->memory) ||
+	    put_user(memory, &up->memory))
 		return -EFAULT;
 
-	if (put_user(kp->bytesused, &up->bytesused) ||
-	    put_user(kp->field, &up->field) ||
-	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
-	    put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
-	    copy_to_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
-	    put_user(kp->sequence, &up->sequence) ||
-	    put_user(kp->reserved2, &up->reserved2) ||
-	    put_user(kp->reserved, &up->reserved) ||
-	    put_user(kp->length, &up->length))
+	if (convert_in_user(&up->bytesused, &kp->bytesused) ||
+	    convert_in_user(&up->field, &kp->field) ||
+	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
+	    convert_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
+	    copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
+	    convert_in_user(&up->sequence, &kp->sequence) ||
+	    convert_in_user(&up->reserved2, &kp->reserved2) ||
+	    convert_in_user(&up->reserved, &kp->reserved) ||
+	    get_user(length, &kp->length) ||
+	    put_user(length, &up->length))
 		return -EFAULT;
 
-	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
-		num_planes = kp->length;
+	if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
+		num_planes = length;
 		if (num_planes == 0)
 			return 0;
 
-		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
+		if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
+			return -EFAULT;
 		if (get_user(p, &up->m.planes))
 			return -EFAULT;
 		uplane32 = compat_ptr(p);
 
 		while (--num_planes >= 0) {
-			ret = put_v4l2_plane32(uplane, uplane32, kp->memory);
+			ret = put_v4l2_plane32(uplane, uplane32, memory);
 			if (ret)
 				return ret;
 			++uplane;
 			++uplane32;
 		}
 	} else {
-		switch (kp->memory) {
+		switch (memory) {
 		case V4L2_MEMORY_MMAP:
-		case V4L2_MEMORY_OVERLAY:
-			if (put_user(kp->m.offset, &up->m.offset))
+			if (convert_in_user(&up->m.offset, &kp->m.offset))
 				return -EFAULT;
 			break;
 		case V4L2_MEMORY_USERPTR:
-			if (put_user(kp->m.userptr, &up->m.userptr))
+			if (convert_in_user(&up->m.userptr, &kp->m.userptr))
+				return -EFAULT;
+			break;
+		case V4L2_MEMORY_OVERLAY:
+			if (convert_in_user(&up->m.offset, &kp->m.offset))
 				return -EFAULT;
 			break;
 		case V4L2_MEMORY_DMABUF:
-			if (put_user(kp->m.fd, &up->m.fd))
+			if (convert_in_user(&up->m.fd, &kp->m.fd))
 				return -EFAULT;
 			break;
 		}
@@ -545,29 +662,32 @@  struct v4l2_framebuffer32 {
 	} fmt;
 };
 
-static int get_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
+static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
+				  struct v4l2_framebuffer32 __user *up)
 {
-	u32 tmp;
+	compat_caddr_t tmp;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
 	    get_user(tmp, &up->base) ||
-	    get_user(kp->capability, &up->capability) ||
-	    get_user(kp->flags, &up->flags) ||
-	    copy_from_user(&kp->fmt, &up->fmt, sizeof(up->fmt)))
+	    put_user((__force void *)compat_ptr(tmp), &kp->base) ||
+	    convert_in_user(&kp->capability, &up->capability) ||
+	    convert_in_user(&kp->flags, &up->flags) ||
+	    copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
 		return -EFAULT;
-	kp->base = (__force void *)compat_ptr(tmp);
 	return 0;
 }
 
-static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_framebuffer32 __user *up)
+static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
+				  struct v4l2_framebuffer32 __user *up)
 {
-	u32 tmp = (u32)((unsigned long)kp->base);
+	void *base;
 
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(tmp, &up->base) ||
-	    put_user(kp->capability, &up->capability) ||
-	    put_user(kp->flags, &up->flags) ||
-	    copy_to_user(&up->fmt, &kp->fmt, sizeof(up->fmt)))
+	    get_user(base, &kp->base) ||
+	    put_user(ptr_to_compat(base), &up->base) ||
+	    convert_in_user(&up->capability, &kp->capability) ||
+	    convert_in_user(&up->flags, &kp->flags) ||
+	    copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
 		return -EFAULT;
 	return 0;
 }
@@ -586,16 +706,18 @@  struct v4l2_input32 {
 
 /* The 64-bit v4l2_input struct has extra padding at the end of the struct.
    Otherwise it is identical to the 32-bit version. */
-static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
+static inline int get_v4l2_input32(struct v4l2_input __user *kp,
+				   struct v4l2_input32 __user *up)
 {
-	if (copy_from_user(kp, up, sizeof(*up)))
+	if (copy_in_user(kp, up, sizeof(*up)))
 		return -EFAULT;
 	return 0;
 }
 
-static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __user *up)
+static inline int put_v4l2_input32(struct v4l2_input __user *kp,
+				   struct v4l2_input32 __user *up)
 {
-	if (copy_to_user(up, kp, sizeof(*up)))
+	if (copy_in_user(up, kp, sizeof(*up)))
 		return -EFAULT;
 	return 0;
 }
@@ -648,39 +770,58 @@  static inline bool ctrl_is_pointer(struct file *file, u32 id)
 	return !ret && (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
 }
 
+static int bufsize_v4l2_ext_controls32(struct v4l2_ext_controls32 __user *up)
+{
+	u32 count;
+
+	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
+	    get_user(count, &up->count))
+		return -EFAULT;
+	if (count > V4L2_CID_MAX_CTRLS)
+		return -EINVAL;
+	return count * sizeof(struct v4l2_ext_control);
+}
+
 static int get_v4l2_ext_controls32(struct file *file,
-				   struct v4l2_ext_controls *kp,
-				   struct v4l2_ext_controls32 __user *up)
+				   struct v4l2_ext_controls __user *kp,
+				   struct v4l2_ext_controls32 __user *up,
+				   void __user *aux_buf, int aux_space)
 {
 	struct v4l2_ext_control32 __user *ucontrols;
 	struct v4l2_ext_control __user *kcontrols;
+	u32 count;
 	unsigned int n;
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    get_user(kp->which, &up->which) ||
-	    get_user(kp->count, &up->count) ||
-	    get_user(kp->error_idx, &up->error_idx) ||
-	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
+	    convert_in_user(&kp->which, &up->which) ||
+	    get_user(count, &up->count) ||
+	    put_user(count, &kp->count) ||
+	    convert_in_user(&kp->error_idx, &up->error_idx) ||
+	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
 		return -EFAULT;
-	if (kp->count == 0) {
-		kp->controls = NULL;
-		return 0;
-	} else if (kp->count > V4L2_CID_MAX_CTRLS) {
+	if (count == 0)
+		return put_user(NULL, &kp->controls);
+	else if (kp->count > V4L2_CID_MAX_CTRLS)
 		return -EINVAL;
-	}
 	if (get_user(p, &up->controls))
 		return -EFAULT;
 	ucontrols = compat_ptr(p);
-	if (!access_ok(VERIFY_READ, ucontrols, kp->count * sizeof(*ucontrols)))
+	if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))
+		return -EFAULT;
+	if (aux_space < count * sizeof(*kcontrols))
 		return -EFAULT;
-	kcontrols = compat_alloc_user_space(kp->count * sizeof(*kcontrols));
-	kp->controls = (__force struct v4l2_ext_control *)kcontrols;
-	for (n = 0; n < kp->count; n++) {
+	kcontrols = aux_buf;
+	if (put_user((__force struct v4l2_ext_control *)kcontrols,
+		     &kp->controls))
+		return -EFAULT;
+
+	for (n = 0; n < count; n++) {
 		u32 id;
 
 		if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
 			return -EFAULT;
+
 		if (get_user(id, &kcontrols->id))
 			return -EFAULT;
 		if (ctrl_is_pointer(file, id)) {
@@ -699,36 +840,47 @@  static int get_v4l2_ext_controls32(struct file *file,
 }
 
 static int put_v4l2_ext_controls32(struct file *file,
-				   struct v4l2_ext_controls *kp,
+				   struct v4l2_ext_controls __user *kp,
 				   struct v4l2_ext_controls32 __user *up)
 {
 	struct v4l2_ext_control32 __user *ucontrols;
-	struct v4l2_ext_control __user *kcontrols =
-		(__force struct v4l2_ext_control __user *)kp->controls;
-	int n = kp->count;
+	struct v4l2_ext_control __user *kcontrols;
+	u32 count;
+	unsigned int n;
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(kp->which, &up->which) ||
-	    put_user(kp->count, &up->count) ||
-	    put_user(kp->error_idx, &up->error_idx) ||
-	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
+	    get_user(kcontrols, &kp->controls) ||
+	    convert_in_user(&up->which, &kp->which) ||
+	    get_user(count, &kp->count) ||
+	    put_user(count, &up->count) ||
+	    convert_in_user(&up->error_idx, &kp->error_idx) ||
+	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
 		return -EFAULT;
-	if (!kp->count)
+	if (!count)
 		return 0;
 
 	if (get_user(p, &up->controls))
 		return -EFAULT;
 	ucontrols = compat_ptr(p);
-	if (!access_ok(VERIFY_WRITE, ucontrols, n * sizeof(*ucontrols)))
+	if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
 		return -EFAULT;
 
-	while (--n >= 0) {
-		unsigned size = sizeof(*ucontrols);
+	for (n = 0; n < count; n++) {
+		unsigned int size = sizeof(*ucontrols);
 		u32 id;
 
+		if (copy_in_user(&ucontrols->id, &kcontrols->id,
+				 sizeof(ucontrols->id)) ||
+		    copy_in_user(&ucontrols->size, &kcontrols->size,
+				 sizeof(ucontrols->size)) ||
+		    copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
+				 sizeof(ucontrols->reserved2)))
+			return -EFAULT;
+
 		if (get_user(id, &kcontrols->id))
 			return -EFAULT;
+
 		/* Do not modify the pointer when copying a pointer control.
 		   The contents of the pointer was changed, not the pointer
 		   itself. */
@@ -736,6 +888,7 @@  static int put_v4l2_ext_controls32(struct file *file,
 			size -= sizeof(ucontrols->value64);
 		if (copy_in_user(ucontrols, kcontrols, size))
 			return -EFAULT;
+
 		ucontrols++;
 		kcontrols++;
 	}
@@ -755,17 +908,18 @@  struct v4l2_event32 {
 	__u32				reserved[8];
 };
 
-static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *up)
+static int put_v4l2_event32(struct v4l2_event __user *kp,
+			    struct v4l2_event32 __user *up)
 {
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(kp->type, &up->type) ||
-	    copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
-	    put_user(kp->pending, &up->pending) ||
-	    put_user(kp->sequence, &up->sequence) ||
-	    put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
-	    put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
-	    put_user(kp->id, &up->id) ||
-	    copy_to_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
+	    convert_in_user(&up->type, &kp->type) ||
+	    copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
+	    convert_in_user(&up->pending, &kp->pending) ||
+	    convert_in_user(&up->sequence, &kp->sequence) ||
+	    convert_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
+	    convert_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
+	    convert_in_user(&up->id, &kp->id) ||
+	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
 		return -EFAULT;
 	return 0;
 }
@@ -778,31 +932,34 @@  struct v4l2_edid32 {
 	compat_caddr_t edid;
 };
 
-static int get_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
+static int get_v4l2_edid32(struct v4l2_edid __user *kp,
+			   struct v4l2_edid32 __user *up)
 {
-	u32 tmp;
+	compat_uptr_t tmp;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    get_user(kp->pad, &up->pad) ||
-	    get_user(kp->start_block, &up->start_block) ||
-	    get_user(kp->blocks, &up->blocks) ||
+	    convert_in_user(&kp->pad, &up->pad) ||
+	    convert_in_user(&kp->start_block, &up->start_block) ||
+	    convert_in_user(&kp->blocks, &up->blocks) ||
 	    get_user(tmp, &up->edid) ||
-	    copy_from_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
+	    put_user(compat_ptr(tmp), &kp->edid) ||
+	    copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
 		return -EFAULT;
-	kp->edid = (__force u8 *)compat_ptr(tmp);
 	return 0;
 }
 
-static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
+static int put_v4l2_edid32(struct v4l2_edid __user *kp,
+			   struct v4l2_edid32 __user *up)
 {
-	u32 tmp = (u32)((unsigned long)kp->edid);
+	void *edid;
 
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    put_user(kp->pad, &up->pad) ||
-	    put_user(kp->start_block, &up->start_block) ||
-	    put_user(kp->blocks, &up->blocks) ||
-	    put_user(tmp, &up->edid) ||
-	    copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
+	    convert_in_user(&up->pad, &kp->pad) ||
+	    convert_in_user(&up->start_block, &kp->start_block) ||
+	    convert_in_user(&up->blocks, &kp->blocks) ||
+	    get_user(edid, &kp->edid) ||
+	    put_user(ptr_to_compat(edid), &up->edid) ||
+	    copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
 		return -EFAULT;
 	return 0;
 }
@@ -835,22 +992,30 @@  static int put_v4l2_edid32(struct v4l2_edid *kp, struct v4l2_edid32 __user *up)
 #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
 #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
 
+static void __user *alloc_userspace(unsigned int size, int aux_space, long *err)
+{
+	void __user *up_native;
+
+	if (aux_space < 0) {
+		*err = aux_space;
+		return NULL;
+	}
+	up_native = compat_alloc_user_space(size + aux_space);
+	if (!up_native)
+		*err = -ENOMEM;
+	else if (clear_user(up_native, size))
+		*err = -EFAULT;
+	else
+		return up_native;
+	return NULL;
+}
+
 static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	union {
-		struct v4l2_format v2f;
-		struct v4l2_buffer v2b;
-		struct v4l2_framebuffer v2fb;
-		struct v4l2_input v2i;
-		struct v4l2_standard v2s;
-		struct v4l2_ext_controls v2ecs;
-		struct v4l2_event v2ev;
-		struct v4l2_create_buffers v2crt;
-		struct v4l2_edid v2edid;
-		unsigned long vx;
-		int vi;
-	} karg;
 	void __user *up = compat_ptr(arg);
+	void __user *up_native = NULL;
+	void __user *aux_buf;
+	int aux_space;
 	int compatible_arg = 1;
 	long err = 0;
 
@@ -889,30 +1054,47 @@  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_STREAMOFF:
 	case VIDIOC_S_INPUT:
 	case VIDIOC_S_OUTPUT:
-		err = get_user(karg.vi, (s32 __user *)up);
+		up_native = alloc_userspace(sizeof(unsigned int __user),
+					    0, &err);
+		if (!err && convert_in_user((unsigned int __user *)up_native,
+					    (compat_uint_t __user *)up))
+			return -EFAULT;
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_G_INPUT:
 	case VIDIOC_G_OUTPUT:
+		up_native = alloc_userspace(sizeof(unsigned int __user),
+					    0, &err);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_G_EDID:
 	case VIDIOC_S_EDID:
-		err = get_v4l2_edid32(&karg.v2edid, up);
+		up_native = alloc_userspace(sizeof(struct v4l2_edid), 0, &err);
+		err = err ? : get_v4l2_edid32(up_native, up);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_G_FMT:
 	case VIDIOC_S_FMT:
 	case VIDIOC_TRY_FMT:
-		err = get_v4l2_format32(&karg.v2f, up);
+		aux_space = bufsize_v4l2_format32(up);
+		up_native = alloc_userspace(sizeof(struct v4l2_format),
+					    aux_space, &err);
+		aux_buf = up_native + sizeof(struct v4l2_format);
+		err = err ? : get_v4l2_format32(up_native, up,
+						aux_buf, aux_space);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_CREATE_BUFS:
-		err = get_v4l2_create32(&karg.v2crt, up);
+		aux_space = bufsize_v4l2_create32(up);
+		up_native = alloc_userspace(sizeof(struct v4l2_create_buffers),
+					    aux_space, &err);
+		aux_buf = up_native + sizeof(struct v4l2_create_buffers);
+		err = err ? : get_v4l2_create32(up_native, up,
+						aux_buf, aux_space);
 		compatible_arg = 0;
 		break;
 
@@ -920,36 +1102,54 @@  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_QUERYBUF:
 	case VIDIOC_QBUF:
 	case VIDIOC_DQBUF:
-		err = get_v4l2_buffer32(&karg.v2b, up);
+		aux_space = bufsize_v4l2_buffer32(up);
+		up_native = alloc_userspace(sizeof(struct v4l2_buffer),
+					    aux_space, &err);
+		aux_buf = up_native + sizeof(struct v4l2_buffer);
+		err = err ? : get_v4l2_buffer32(up_native, up,
+						aux_buf, aux_space);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_S_FBUF:
-		err = get_v4l2_framebuffer32(&karg.v2fb, up);
+		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
+					    0, &err);
+		err = err ? : get_v4l2_framebuffer32(up_native, up);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_G_FBUF:
+		up_native = alloc_userspace(sizeof(struct v4l2_framebuffer),
+					    0, &err);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_ENUMSTD:
-		err = get_v4l2_standard32(&karg.v2s, up);
+		up_native = alloc_userspace(sizeof(struct v4l2_standard),
+					    0, &err);
+		err = err ? : get_v4l2_standard32(up_native, up);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_ENUMINPUT:
-		err = get_v4l2_input32(&karg.v2i, up);
+		up_native = alloc_userspace(sizeof(struct v4l2_input), 0, &err);
+		err = err ? : get_v4l2_input32(up_native, up);
 		compatible_arg = 0;
 		break;
 
 	case VIDIOC_G_EXT_CTRLS:
 	case VIDIOC_S_EXT_CTRLS:
 	case VIDIOC_TRY_EXT_CTRLS:
-		err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
+		aux_space = bufsize_v4l2_ext_controls32(up);
+		up_native = alloc_userspace(sizeof(struct v4l2_ext_controls),
+					    aux_space, &err);
+		aux_buf = up_native + sizeof(struct v4l2_ext_controls);
+		err = err ? : get_v4l2_ext_controls32(file, up_native, up,
+						      aux_buf, aux_space);
 		compatible_arg = 0;
 		break;
 	case VIDIOC_DQEVENT:
+		up_native = alloc_userspace(sizeof(struct v4l2_event), 0, &err);
 		compatible_arg = 0;
 		break;
 	}
@@ -958,13 +1158,8 @@  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 
 	if (compatible_arg)
 		err = native_ioctl(file, cmd, (unsigned long)up);
-	else {
-		mm_segment_t old_fs = get_fs();
-
-		set_fs(KERNEL_DS);
-		err = native_ioctl(file, cmd, (unsigned long)&karg);
-		set_fs(old_fs);
-	}
+	else
+		err = native_ioctl(file, cmd, (unsigned long)up_native);
 
 	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
 		return err;
@@ -976,11 +1171,11 @@  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_G_EXT_CTRLS:
 	case VIDIOC_S_EXT_CTRLS:
 	case VIDIOC_TRY_EXT_CTRLS:
-		if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
+		if (put_v4l2_ext_controls32(file, up_native, up))
 			err = -EFAULT;
 		break;
 	case VIDIOC_S_EDID:
-		if (put_v4l2_edid32(&karg.v2edid, up))
+		if (put_v4l2_edid32(up_native, up))
 			err = -EFAULT;
 		break;
 	}
@@ -992,44 +1187,45 @@  static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_S_OUTPUT:
 	case VIDIOC_G_INPUT:
 	case VIDIOC_G_OUTPUT:
-		err = put_user(((s32)karg.vi), (s32 __user *)up);
+		err = convert_in_user((compat_uint_t __user *)up,
+				      ((unsigned int __user *)up_native));
 		break;
 
 	case VIDIOC_G_FBUF:
-		err = put_v4l2_framebuffer32(&karg.v2fb, up);
+		err = put_v4l2_framebuffer32(up_native, up);
 		break;
 
 	case VIDIOC_DQEVENT:
-		err = put_v4l2_event32(&karg.v2ev, up);
+		err = put_v4l2_event32(up_native, up);
 		break;
 
 	case VIDIOC_G_EDID:
-		err = put_v4l2_edid32(&karg.v2edid, up);
+		err = put_v4l2_edid32(up_native, up);
 		break;
 
 	case VIDIOC_G_FMT:
 	case VIDIOC_S_FMT:
 	case VIDIOC_TRY_FMT:
-		err = put_v4l2_format32(&karg.v2f, up);
+		err = put_v4l2_format32(up_native, up);
 		break;
 
 	case VIDIOC_CREATE_BUFS:
-		err = put_v4l2_create32(&karg.v2crt, up);
+		err = put_v4l2_create32(up_native, up);
 		break;
 
 	case VIDIOC_PREPARE_BUF:
 	case VIDIOC_QUERYBUF:
 	case VIDIOC_QBUF:
 	case VIDIOC_DQBUF:
-		err = put_v4l2_buffer32(&karg.v2b, up);
+		err = put_v4l2_buffer32(up_native, up);
 		break;
 
 	case VIDIOC_ENUMSTD:
-		err = put_v4l2_standard32(&karg.v2s, up);
+		err = put_v4l2_standard32(up_native, up);
 		break;
 
 	case VIDIOC_ENUMINPUT:
-		err = put_v4l2_input32(&karg.v2i, up);
+		err = put_v4l2_input32(up_native, up);
 		break;
 	}
 	return err;