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[v2] Input: MT - limit max slots

Message ID da964ce1-3e4b-40d0-bc31-81de01f99715@I-love.SAKURA.ne.jp (mailing list archive)
State New
Headers show
Series [v2] Input: MT - limit max slots | expand

Commit Message

Tetsuo Handa April 27, 2024, 11:15 a.m. UTC
syzbot is reporting too large allocation at input_mt_init_slots(), for
num_slots is supplied from userspace using ioctl(UI_DEV_CREATE).

Since nobody knows possible max slots, this patch chose 1024.

Reported-by: syzbot <syzbot+0122fa359a69694395d5@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
Changes in v2:
  Limit max slots instead of using __GFP_NOWARN.

 drivers/input/input-mt.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Tetsuo Handa May 27, 2024, 10:35 a.m. UTC | #1
Who can take this patch?

On 2024/04/27 20:15, Tetsuo Handa wrote:
> syzbot is reporting too large allocation at input_mt_init_slots(), for
> num_slots is supplied from userspace using ioctl(UI_DEV_CREATE).
> 
> Since nobody knows possible max slots, this patch chose 1024.
> 
> Reported-by: syzbot <syzbot+0122fa359a69694395d5@syzkaller.appspotmail.com>
> Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5
> Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
> Changes in v2:
>   Limit max slots instead of using __GFP_NOWARN.
> 
>  drivers/input/input-mt.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
> index 14b53dac1253..6b04a674f832 100644
> --- a/drivers/input/input-mt.c
> +++ b/drivers/input/input-mt.c
> @@ -46,6 +46,9 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
>  		return 0;
>  	if (mt)
>  		return mt->num_slots != num_slots ? -EINVAL : 0;
> +	/* Arbitrary limit for avoiding too large memory allocation. */
> +	if (num_slots > 1024)
> +		return -EINVAL;
>  
>  	mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
>  	if (!mt)
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Patch

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index 14b53dac1253..6b04a674f832 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -46,6 +46,9 @@  int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
 		return 0;
 	if (mt)
 		return mt->num_slots != num_slots ? -EINVAL : 0;
+	/* Arbitrary limit for avoiding too large memory allocation. */
+	if (num_slots > 1024)
+		return -EINVAL;
 
 	mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
 	if (!mt)