[PATCH] [media] uvcvideo: Prevent heap overflow in uvc driver

[PATCH] [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

From: Robb Glasser <rglasser@google.com>

The size of uvc_control_mapping is user controlled leading to a
potential heap overflow in the uvc driver. This adds a check to verify
the user provided size fits within the bounds of the defined buffer
size.

Signed-off-by: Robb Glasser <rglasser@google.com>
[groeck: cherry picked from
 https://source.codeaurora.org/quic/la/kernel/msm-3.10
 commit b7b99e55bc7770187913ed092990852ea52d7892;
 updated subject]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Fixes CVE-2017-0627.

 drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index c2ee6e39fd0c..252ab991396f 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 	if (!found)
 		return -ENOENT;
 
+	if (ctrl->info.size < mapping->size)
+		return -EINVAL;
+
 	if (mutex_lock_interruptible(&chain->ctrl_mutex))
 		return -ERESTARTSYS;
 
-- 
2.7.4

Re: [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

On Mon, May 22, 2017 at 12:48:04PM -0700, Guenter Roeck wrote:
> From: Robb Glasser <rglasser@google.com>
> 
> The size of uvc_control_mapping is user controlled leading to a
> potential heap overflow in the uvc driver. This adds a check to verify
> the user provided size fits within the bounds of the defined buffer
> size.
> 
> Signed-off-by: Robb Glasser <rglasser@google.com>
> [groeck: cherry picked from
>  https://source.codeaurora.org/quic/la/kernel/msm-3.10
>  commit b7b99e55bc7770187913ed092990852ea52d7892;
>  updated subject]
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Fixes CVE-2017-0627.
> 
Please do not apply this patch. It is buggy.

Guenter

>  drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index c2ee6e39fd0c..252ab991396f 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>  	if (!found)
>  		return -ENOENT;
>  
> +	if (ctrl->info.size < mapping->size)
> +		return -EINVAL;
> +
>  	if (mutex_lock_interruptible(&chain->ctrl_mutex))
>  		return -ERESTARTSYS;
>  

Re: [media] uvcvideo: Prevent heap overflow in uvc driver

[Laurent Pinchart]

Hi Guenter,

On Wednesday 28 Jun 2017 07:36:43 Guenter Roeck wrote:
> On Mon, May 22, 2017 at 12:48:04PM -0700, Guenter Roeck wrote:
> > From: Robb Glasser <rglasser@google.com>
> > 
> > The size of uvc_control_mapping is user controlled leading to a
> > potential heap overflow in the uvc driver. This adds a check to verify
> > the user provided size fits within the bounds of the defined buffer
> > size.
> > 
> > Signed-off-by: Robb Glasser <rglasser@google.com>
> > [groeck: cherry picked from
> > 
> >  https://source.codeaurora.org/quic/la/kernel/msm-3.10
> >  commit b7b99e55bc7770187913ed092990852ea52d7892;
> >  updated subject]
> > 
> > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > ---
> > Fixes CVE-2017-0627.
> 
> Please do not apply this patch. It is buggy.

I apologize for not noticing the initial patch, even if it looks like it was 
all for the best. Will you send a new version ?

> >  drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> > b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..252ab991396f
> > 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain
> > *chain,
> >  	if (!found)
> >  		return -ENOENT;
> > 
> > +	if (ctrl->info.size < mapping->size)
> > +		return -EINVAL;
> > +
> > 
> >  	if (mutex_lock_interruptible(&chain->ctrl_mutex))
> >  		return -ERESTARTSYS;

-- 
Regards,

Laurent Pinchart

Re: [media] uvcvideo: Prevent heap overflow in uvc driver

[Laurent Pinchart]

Hi Guenter,

On Wednesday 28 Jun 2017 20:59:17 Laurent Pinchart wrote:
> On Wednesday 28 Jun 2017 07:36:43 Guenter Roeck wrote:
> > On Mon, May 22, 2017 at 12:48:04PM -0700, Guenter Roeck wrote:
> >> From: Robb Glasser <rglasser@google.com>
> >> 
> >> The size of uvc_control_mapping is user controlled leading to a
> >> potential heap overflow in the uvc driver. This adds a check to verify
> >> the user provided size fits within the bounds of the defined buffer
> >> size.
> >> 
> >> Signed-off-by: Robb Glasser <rglasser@google.com>
> >> [groeck: cherry picked from
> >> 
> >>  https://source.codeaurora.org/quic/la/kernel/msm-3.10
> >>  commit b7b99e55bc7770187913ed092990852ea52d7892;
> >>  updated subject]
> >> 
> >> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> >> ---
> >> Fixes CVE-2017-0627.
> > 
> > Please do not apply this patch. It is buggy.
> 
> I apologize for not noticing the initial patch, even if it looks like it was
> all for the best. Will you send a new version ?
> 
> >>  drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
> >>  1 file changed, 3 insertions(+)
> >> 
> >> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> >> b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..252ab991396f
> >> 100644
> >> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> >> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> >> @@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain
> >> *chain,
> >>  	if (!found)
> >>  		return -ENOENT;
> >> 
> >> +	if (ctrl->info.size < mapping->size)
> >> +		return -EINVAL;
> >> +

By the way, I believe the right fix should be

	if (mapping->offset + mapping->size > ctrl->info.size * 8)
		return -EINVAL;

Both mapping->offset and mapping->size are 8-bit integers, so there's no risk 
of overflow in the addition. If we want to safeguard against a possible future 
bug if the type of the fields change, we could add

	if (mapping->offset + mapping->size < mapping->offset)
		return -EINVAL;

> >>  	if (mutex_lock_interruptible(&chain->ctrl_mutex))
> >>  		return -ERESTARTSYS;

-- 
Regards,

Laurent Pinchart

Re: [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

On Wed, Jun 28, 2017 at 09:18:37PM +0300, Laurent Pinchart wrote:
> Hi Guenter,
> 
> On Wednesday 28 Jun 2017 20:59:17 Laurent Pinchart wrote:
> > On Wednesday 28 Jun 2017 07:36:43 Guenter Roeck wrote:
> > > On Mon, May 22, 2017 at 12:48:04PM -0700, Guenter Roeck wrote:
> > >> From: Robb Glasser <rglasser@google.com>
> > >> 
> > >> The size of uvc_control_mapping is user controlled leading to a
> > >> potential heap overflow in the uvc driver. This adds a check to verify
> > >> the user provided size fits within the bounds of the defined buffer
> > >> size.
> > >> 
> > >> Signed-off-by: Robb Glasser <rglasser@google.com>
> > >> [groeck: cherry picked from
> > >> 
> > >>  https://source.codeaurora.org/quic/la/kernel/msm-3.10
> > >>  commit b7b99e55bc7770187913ed092990852ea52d7892;
> > >>  updated subject]
> > >> 
> > >> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > >> ---
> > >> Fixes CVE-2017-0627.
> > > 
> > > Please do not apply this patch. It is buggy.
> > 
> > I apologize for not noticing the initial patch, even if it looks like it was
> > all for the best. Will you send a new version ?
> > 
> > >>  drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
> > >>  1 file changed, 3 insertions(+)
> > >> 
> > >> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> > >> b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..252ab991396f
> > >> 100644
> > >> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > >> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > >> @@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain
> > >> *chain,
> > >>  	if (!found)
> > >>  		return -ENOENT;
> > >> 
> > >> +	if (ctrl->info.size < mapping->size)
> > >> +		return -EINVAL;
> > >> +
> 
> By the way, I believe the right fix should be
> 
> 	if (mapping->offset + mapping->size > ctrl->info.size * 8)
> 		return -EINVAL;
> 
> Both mapping->offset and mapping->size are 8-bit integers, so there's no risk 
> of overflow in the addition. If we want to safeguard against a possible future 
> bug if the type of the fields change, we could add
> 
> 	if (mapping->offset + mapping->size < mapping->offset)
> 		return -EINVAL;
> 

I currently have this:

@@ -2004,6 +2004,13 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 		goto done;
 	}
 
+	/* validate that the user provided bit-size and offset is valid */
+	if ((mapping->size > 32) ||
+	    ((mapping->offset + mapping->size) > (ctrl->info.size * 8))) {
+		ret = -EINVAL;
+		goto done;
+	}
+
 	list_for_each_entry(map, &ctrl->info.mappings, list) {
 		if (mapping->id == map->id) {
 			uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', "

This version originates from Richard Simmons. Copying him to see if he wants
to submit it himself.

Guenter