From: Dan Carpenter Date: Thu, 5 Jan 2012 05:27:57 +0000 (-0300) Subject: [media] V4L/DVB: v4l2-ioctl: integer overflow in video_usercopy() X-Git-Tag: v3.3-rc1~48^2~53 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6c06108be53ca5e94d8b0e93883d534dd9079646;p=platform%2Fkernel%2Flinux-3.10.git [media] V4L/DVB: v4l2-ioctl: integer overflow in video_usercopy() If ctrls->count is too high the multiplication could overflow and array_size would be lower than expected. Mauro and Hans Verkuil suggested that we cap it at 1024. That comes from the maximum number of controls with lots of room for expantion. $ grep V4L2_CID include/linux/videodev2.h | wc -l 211 Cc: stable Signed-off-by: Dan Carpenter Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index e1da8fc..639abee 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -2226,6 +2226,10 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size, struct v4l2_ext_controls *ctrls = parg; if (ctrls->count != 0) { + if (ctrls->count > V4L2_CID_MAX_CTRLS) { + ret = -EINVAL; + break; + } *user_ptr = (void __user *)ctrls->controls; *kernel_ptr = (void *)&ctrls->controls; *array_size = sizeof(struct v4l2_ext_control) diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 6bfaa76..b2e1331 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -1132,6 +1132,7 @@ struct v4l2_querymenu { #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000 /* User-class control IDs defined by V4L2 */ +#define V4L2_CID_MAX_CTRLS 1024 #define V4L2_CID_BASE (V4L2_CTRL_CLASS_USER | 0x900) #define V4L2_CID_USER_BASE V4L2_CID_BASE /* IDs reserved for driver specific controls */