In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: fix OOB read in rtw_restruct_wmm_ie()
rtw_restruct_wmm_ie() scans in_ie for a WMM IE with:
while (i < in_len) {
…
if (i + 5 < in_len && in_ie[i] == 0xDD && …) {
…
break;
}
i += (in_ie[i + 1] + 2); /* to the next IE element */
}
When the "i + 5 < in_len" match check fails simply because i is
within 5 bytes of the end of the buffer (i.e. no WMM IE was found
near the tail of in_ie), execution falls through to
"i += (in_ie[i + 1] + 2)", which reads in_ie[i + 1]. If i == in_len
– 1 at that point, this is a 1-byte out-of-bounds read of an
attacker-influenced IE buffer built from association/scan data.
Commit a75281626fc8f ("staging: rtl8723bs: fix potential
out-of-bounds read in rtw_restruct_wmm_ie") added the "i + 5 <
in_len" guard to the match condition itself, but did not add an
equivalent guard before the fallthrough advance, so the same class
of OOB read remained reachable through the non-matching path.
Add an explicit bounds check before advancing to the next IE.
