Messages in this thread Patch in this message | | | Date | Sat, 20 Sep 2008 20:12:58 +1200 | From | Ralph Loader <> | Subject | Buffer overflow in uvc-video. |
| |
Hi,
There appears to be a buffer overflow in drivers/media/video/uvc/uvc_ctrl.c:
Sep 20 17:53:12 i kernel: BUG kmalloc-8 (Not tainted): Redzone overwritten Sep 20 17:53:12 i kernel: -------------------------------------------------------------------- --------- Sep 20 17:53:12 i kernel: Sep 20 17:53:12 i kernel: INFO: 0xf2c5ce08-0xf2c5ce0b. First byte 0xa1 instead of 0xcc Sep 20 17:53:12 i kernel: INFO: Allocated in uvc_query_v4l2_ctrl+0x3c/0x239 [uvcvideo] age=13 cpu=1 pid=4975 ...
A fixed size 8-byte buffer is allocated, and a variable size field is read into it; there is no particular bound on the size of the field (it is dependent on hardware and configuration) and it can overflow [also verified by inserting printk's.]
The patch below attempts to size the buffer to the correctly; I do not know if sufficient validation of that size is carried out.
Cheers, Ralph Loader.
diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ct rl.c index 6ef3e52..feab12a 100644 --- a/drivers/media/video/uvc/uvc_ctrl.c +++ b/drivers/media/video/uvc/uvc_ctrl.c @@ -592,7 +592,7 @@ int uvc_query_v4l2_ctrl(struct uvc_video_device *video, if (ctrl == NULL) return -EINVAL; - data = kmalloc(8, GFP_KERNEL); + data = kmalloc(ctrl->info->size, GFP_KERNEL); if (data == NULL) return -ENOMEM;
| |