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media: uvcvideo: fix division by zero at stream start

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commit 8aa637bf6d70d2fb2ad4d708d8b9dd02b1c095df upstream.

Add the missing bulk-endpoint max-packet sanity check to
uvc_video_start_transfer() to avoid division by zero in
uvc_alloc_urb_buffers() in case a malicious device has broken
descriptors (or when doing descriptor fuzz testing).

Note that USB core will reject URBs submitted for endpoints with zero
wMaxPacketSize but that drivers doing packet-size calculations still
need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
endpoint descriptors with maxpacket=0")).

Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
Cc: stable@vger.kernel.org      # 2.6.26
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2021-10-26 11:55:11 +02:00 committed by Greg Kroah-Hartman
parent 4c3f70be6f
commit 93c4506f9f
1 changed files with 4 additions and 0 deletions
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4
drivers/media/usb/uvc/uvc_video.c
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@ -1915,6 +1915,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
if (ep == NULL)
return -EIO;
/* Reject broken descriptors. */
if (usb_endpoint_maxp(&ep->desc) == 0)
return -EIO;
ret = uvc_init_video_bulk(stream, ep, gfp_flags);
}