[PATCH v2] [media] uvcvideo: Prevent heap overflow in uvc driver

[PATCH v2] [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

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.

Originally-from: Richard Simmons <rssimmo@amazon.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Fixes CVE-2017-0627.

v2: Combination of v1 with the fix suggested by Richard Simmons
    Perform validation after uvc_ctrl_fill_xu_info()
    Take into account that ctrl->info.size is in bytes
    Also validate mapping->size

 drivers/media/usb/uvc/uvc_ctrl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index c2ee6e39fd0c..d3e3164f43fd 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2002,6 +2002,13 @@ 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', "
-- 
2.7.4

Re: [PATCH v2] [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

On Fri, Jun 30, 2017 at 09:21:56AM -0700, Guenter Roeck wrote:
> 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.
> 
> Originally-from: Richard Simmons <rssimmo@amazon.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Any comments ?

Thanks,
Guenter

> ---
> Fixes CVE-2017-0627.
> 
> v2: Combination of v1 with the fix suggested by Richard Simmons
>     Perform validation after uvc_ctrl_fill_xu_info()
>     Take into account that ctrl->info.size is in bytes
>     Also validate mapping->size
> 
>  drivers/media/usb/uvc/uvc_ctrl.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index c2ee6e39fd0c..d3e3164f43fd 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -2002,6 +2002,13 @@ 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', "
> -- 
> 2.7.4
> 

Re: [PATCH v2] [media] uvcvideo: Prevent heap overflow in uvc driver

[Guenter Roeck]

Any comments / feedback ?

Thanks,
Guenter

On Fri, Jun 30, 2017 at 09:21:56AM -0700, Guenter Roeck wrote:
> 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.
> 
> Originally-from: Richard Simmons <rssimmo@amazon.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Fixes CVE-2017-0627.
> 
> v2: Combination of v1 with the fix suggested by Richard Simmons
>     Perform validation after uvc_ctrl_fill_xu_info()
>     Take into account that ctrl->info.size is in bytes
>     Also validate mapping->size
> 
>  drivers/media/usb/uvc/uvc_ctrl.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index c2ee6e39fd0c..d3e3164f43fd 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -2002,6 +2002,13 @@ 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', "
> -- 
> 2.7.4
> 

Re: [PATCH v2] [media] uvcvideo: Prevent heap overflow in uvc driver

[Laurent Pinchart]

Hi Guenter,

Thank you for the patch and sorry for the late reply.

On Friday 30 Jun 2017 09:21:56 Guenter Roeck wrote:
> 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.
> 
> Originally-from: Richard Simmons <rssimmo@amazon.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

This looks good to me.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

and taken in my tree for v4.14 with a Cc: stable@vger.kernel.org tag to get it 
backported to stable kernels.

> ---
> Fixes CVE-2017-0627.
> 
> v2: Combination of v1 with the fix suggested by Richard Simmons
>     Perform validation after uvc_ctrl_fill_xu_info()
>     Take into account that ctrl->info.size is in bytes
>     Also validate mapping->size
> 
>  drivers/media/usb/uvc/uvc_ctrl.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..d3e3164f43fd 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -2002,6 +2002,13 @@ 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', 
"

-- 
Regards,

Laurent Pinchart