media: uvcvideo: Fix 1-byte out-of-bounds read in uvc_parse_format()

The buffer length check before calling uvc_parse_format() only ensured
that the buffer has at least 3 bytes (buflen > 2), buf the function
accesses buffer[3], requiring at least 4 bytes.

This can lead to an out-of-bounds read if the buffer has exactly 3 bytes.

Fix it by checking that the buffer has at least 4 bytes in
uvc_parse_format().

Signed-off-by: Youngjun Lee <yjjuny.lee@samsung.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
Cc: stable@vger.kernel.org
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20250610124107.37360-1-yjjuny.lee@samsung.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 916c2d13e26898722447e4df1bd2cb8e9fddb94a..62eb45435d8bec5c955720ecb46fb8936871e6cc 100644 (file)
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -344,6 +344,9 @@ static int uvc_parse_format(struct uvc_device *dev,
        u8 ftype;
        int ret;
 
+       if (buflen < 4)
+               return -EINVAL;
+
        format->type = buffer[2];
        format->index = buffer[3];
        format->frames = frames;