| Message ID | 20210723095323.205593-1-mdevaev@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: gadget: f_hid: fixed NULL pointer dereference | expand |
On Fri, Jul 23, 2021 at 12:53:23PM +0300, Maxim Devaev wrote: > Disconnecting and reconnecting the USB cable can lead to crashes > and a variety of kernel log spam. > > The problem was found and reproduced on the Raspberry Pi. The patch > was created in Raspberry's own fork [1]. Since I was one of those > who discovered and diagnosed the problem [2], I propose this patch > for adoption to the kernel upstream with the consent of the author. > It has been tested since January 2021 and is guaranteed to fix > the described problem without breaking anything. > > Signed-off-by: Maxim Devaev <mdevaev@gmail.com> > Signed-off-by: Phil Elwell <phil@raspberrypi.com> > Link: https://github.com/raspberrypi/linux/commit/a6e47d5f4efbd2ea6a0b6565cd2f9b7bb217ded5 [1] > Link: https://github.com/raspberrypi/linux/issues/3870 [2] Who is the original author here? Please put their name as the "From:" line in the changelog so we can give proper credit if it was not you. > --- > drivers/usb/gadget/function/f_hid.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c > index 02683ac07..4975bbf02 100644 > --- a/drivers/usb/gadget/function/f_hid.c > +++ b/drivers/usb/gadget/function/f_hid.c > @@ -338,6 +338,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, > > spin_lock_irqsave(&hidg->write_spinlock, flags); > > + if (!hidg->req) { > + spin_unlock_irqrestore(&hidg->write_spinlock, flags); > + return -ESHUTDOWN; > + } > + > #define WRITE_COND (!hidg->write_pending) > try_again: > /* write queue */ > @@ -358,7 +363,13 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, > count = min_t(unsigned, count, hidg->report_length); > > spin_unlock_irqrestore(&hidg->write_spinlock, flags); > - status = copy_from_user(req->buf, buffer, count); > + if (req) { Test for !req and then abort, and then continue on. No need for moving the copy_from_user line in, right? Should make the change smaller overall. > + status = copy_from_user(req->buf, buffer, count); > + } else { > + ERROR(hidg->func.config->cdev, "hidg->req is NULL\n"); > + status = -ESHUTDOWN; > + goto release_write_pending; > + } > > if (status != 0) { > ERROR(hidg->func.config->cdev, > @@ -387,10 +398,13 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, > > spin_unlock_irqrestore(&hidg->write_spinlock, flags); > > + if (!hidg->in_ep->enabled) { > + ERROR(hidg->func.config->cdev, "in_ep is disabled\n"); > + status = -ESHUTDOWN; > + goto release_write_pending; > + } Blank line after this please. > status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC); > if (status < 0) { > - ERROR(hidg->func.config->cdev, > - "usb_ep_queue error on int endpoint %zd\n", status); > goto release_write_pending; Are the braces still needed here? thanks, greg k-h
> Greg KH <gregkh@linuxfoundation.org> writes: > Who is the original author here? Please put their name as the "From:" > line in the changelog so we can give proper credit if it was not you. Phil Elwell. Fixed. > Test for !req and then abort, and then continue on. No need for moving > the copy_from_user line in, right? Should make the change smaller > overall. Fixed. > Blank line after this please. Added. > Are the braces still needed here? No, you're right. Thanks for the review! Here the new version of the patch: From 72a504af8e3df3d7a44e9954b8cf03268795c07f Mon Sep 17 00:00:00 2001 From: Phil Elwell <phil@raspberrypi.com> Date: Fri, 23 Jul 2021 11:59:49 +0300 Subject: [PATCH] usb: gadget: f_hid: fixed NULL pointer dereference Disconnecting and reconnecting the USB cable can lead to crashes and a variety of kernel log spam. The problem was found and reproduced on the Raspberry Pi [1] and the original fix was created in Raspberry's own fork [2]. Signed-off-by: Maxim Devaev <mdevaev@gmail.com> Signed-off-by: Phil Elwell <phil@raspberrypi.com> Link: https://github.com/raspberrypi/linux/issues/3870 [1] Link: https://github.com/raspberrypi/linux/commit/a6e47d5f4efbd2ea6a0b6565cd2f9b7bb217ded5 [2] --- drivers/usb/gadget/function/f_hid.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index 02683ac07..08e73e812 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -338,6 +338,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, spin_lock_irqsave(&hidg->write_spinlock, flags); + if (!hidg->req) { + spin_unlock_irqrestore(&hidg->write_spinlock, flags); + return -ESHUTDOWN; + } + #define WRITE_COND (!hidg->write_pending) try_again: /* write queue */ @@ -358,8 +363,14 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, count = min_t(unsigned, count, hidg->report_length); spin_unlock_irqrestore(&hidg->write_spinlock, flags); - status = copy_from_user(req->buf, buffer, count); + if (!req) { + ERROR(hidg->func.config->cdev, "hidg->req is NULL\n"); + status = -ESHUTDOWN; + goto release_write_pending; + } + + status = copy_from_user(req->buf, buffer, count); if (status != 0) { ERROR(hidg->func.config->cdev, "copy_from_user error\n"); @@ -387,14 +398,17 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, spin_unlock_irqrestore(&hidg->write_spinlock, flags); + if (!hidg->in_ep->enabled) { + ERROR(hidg->func.config->cdev, "in_ep is disabled\n"); + status = -ESHUTDOWN; + goto release_write_pending; + } + status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC); - if (status < 0) { - ERROR(hidg->func.config->cdev, - "usb_ep_queue error on int endpoint %zd\n", status); + if (status < 0) goto release_write_pending; - } else { + else status = count; - } return status; release_write_pending:
On Fri, Jul 23, 2021 at 06:22:03PM +0300, Maxim Devaev wrote: > > Greg KH <gregkh@linuxfoundation.org> writes: > > Who is the original author here? Please put their name as the "From:" > > line in the changelog so we can give proper credit if it was not you. > > Phil Elwell. Fixed. > > > Test for !req and then abort, and then continue on. No need for moving > > the copy_from_user line in, right? Should make the change smaller > > overall. > > Fixed. > > > Blank line after this please. > > Added. > > > Are the braces still needed here? > > No, you're right. > > Thanks for the review! Here the new version of the patch: > > From 72a504af8e3df3d7a44e9954b8cf03268795c07f Mon Sep 17 00:00:00 2001 > From: Phil Elwell <phil@raspberrypi.com> > Date: Fri, 23 Jul 2021 11:59:49 +0300 > Subject: [PATCH] usb: gadget: f_hid: fixed NULL pointer dereference <snip> Please resend as a v2 in a format that I can apply it in (as a new email.) thanks, greg k-h
> Greg KH <gregkh@linuxfoundation.org> writes: s a v2 in a format that I can apply it in (as a new > email.) Sent as ("[PATCH v2] usb: gadget: f_hid: fixed NULL pointer dereference")
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index 02683ac07..4975bbf02 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -338,6 +338,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, spin_lock_irqsave(&hidg->write_spinlock, flags); + if (!hidg->req) { + spin_unlock_irqrestore(&hidg->write_spinlock, flags); + return -ESHUTDOWN; + } + #define WRITE_COND (!hidg->write_pending) try_again: /* write queue */ @@ -358,7 +363,13 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, count = min_t(unsigned, count, hidg->report_length); spin_unlock_irqrestore(&hidg->write_spinlock, flags); - status = copy_from_user(req->buf, buffer, count); + if (req) { + status = copy_from_user(req->buf, buffer, count); + } else { + ERROR(hidg->func.config->cdev, "hidg->req is NULL\n"); + status = -ESHUTDOWN; + goto release_write_pending; + } if (status != 0) { ERROR(hidg->func.config->cdev, @@ -387,10 +398,13 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer, spin_unlock_irqrestore(&hidg->write_spinlock, flags); + if (!hidg->in_ep->enabled) { + ERROR(hidg->func.config->cdev, "in_ep is disabled\n"); + status = -ESHUTDOWN; + goto release_write_pending; + } status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC); if (status < 0) { - ERROR(hidg->func.config->cdev, - "usb_ep_queue error on int endpoint %zd\n", status); goto release_write_pending; } else { status = count;