usbvision: fix NULL-deref at probe

commit eacb975b48272f54532b62f515a3cf7eefa35123 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory beyond the endpoint array should a
malicious device lack the expected endpoints.

Fixes: 2a9f8b5d25be ("V4L/DVB (5206): Usbvision: set alternate interface
modification")

Cc: Thierry MERLE <thierry.merle@free.fr>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2017-03-13 09:53:55 -03:00 committed by Greg Kroah-Hartman
parent a3adb4721a
commit 736f41a474

View File

@ -1506,7 +1506,14 @@ static int usbvision_probe(struct usb_interface *intf,
}
for (i = 0; i < usbvision->num_alt; i++) {
u16 tmp = le16_to_cpu(uif->altsetting[i].endpoint[1].desc.
u16 tmp;
if (uif->altsetting[i].desc.bNumEndpoints < 2) {
ret = -ENODEV;
goto err_pkt;
}
tmp = le16_to_cpu(uif->altsetting[i].endpoint[1].desc.
wMaxPacketSize);
usbvision->alt_max_pkt_size[i] =
(tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);