In the Linux kernel, the following vulnerability has been resolved:
media: s2255: bound JPEG frame size before copying into the buffer
s2255_fillbuff() memcpy()s vc->jpg_size bytes of a captured JPEG/MJPEG
frame into the vb2 plane. vc->jpg_size is taken verbatim from the
S2255_MARKER_FRAME header the device sends (pdword[4] in save_frame())
and, unlike the frame payload length just above it, is never bounded:
payload = le32_to_cpu(pdword[3]);
if (payload > vc->req_image_size) /* payload is checked … */
return -EINVAL;
vc->pkt_size = payload;
vc->jpg_size = le32_to_cpu(pdword[4]); /* … jpg_size is not */
A malicious or malfunctioning device can therefore report a jpg_size
larger than the destination vb2 plane, and the memcpy() writes past it.
jpg_size is a signed int, so a value with the top bit set also turns
into a huge length.
Reject a frame whose jpg_size is negative or exceeds the plane size
before copying it.
