CVE-2021-47388 Information

Description

In the Linux kernel the following vulnerability has been resolved:

mac80211: fix use-after-free in CCMP/GCMP RX

When PN checking is done in mac80211 for fragmentation we need to copy the PN to the RX struct so we can later use it to do a comparison since commit bf30ca922a0c (\mac80211: check defrag PN against current frame).

Unfortunately in that commit I used the ‘hdr’ variable without it being necessarily valid so use-after-free could occur if it was necessary to reallocate (parts of) the frame.

Fix this by reloading the variable after the code that results in the reallocations if any.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=214401.

Reference

https://git.kernel.org/stable/c/447d001b875d0e7f211c4ba004916028da994258 https://git.kernel.org/stable/c/31de381aef0ab1b342f62485118dc8a19363dc78 https://git.kernel.org/stable/c/f556e1d6fb9f2923a9a36f3df638c7d79ba09dbb https://git.kernel.org/stable/c/3d5d629c99c468458022e9b381789de3595bf4dd https://git.kernel.org/stable/c/50149e0866a82cef33e680ee68dc380a5bc75d32 https://git.kernel.org/stable/c/57de2dcb18742dc2860861c9f496da7d42b67da0 https://git.kernel.org/stable/c/27d3eb5616ee2c0a3b30c3fa34813368ed1f3dc9 https://git.kernel.org/stable/c/94513069eb549737bcfc3d988d6ed4da948a2de8