From 8aa637bf6d70d2fb2ad4d708d8b9dd02b1c095df Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 26 Oct 2021 11:55:11 +0200 Subject: media: uvcvideo: fix division by zero at stream start 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 Reviewed-by: Kieran Bingham Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/uvc/uvc_video.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/media') diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 9f37eaf28ce7..1b4cc934109e 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -1963,6 +1963,10 @@ 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); } -- cgit v1.2.3