In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: bound element ID read when checking non-inheritance
cfg80211_is_element_inherited() reads the first data octet of the candidate element (id = elem->data[0]) to look it up in an extension non-inheritance list. It does so after testing elem->id, but without verifying that the element actually has a data octet. A zero-length extension element (WLAN_EID_EXTENSION with length 0) therefore makes it read one octet past the end of the element.
_ieee802_11_parse_elems_full() runs this check for every element of a frame once a non-inheritance context exists – e.g. while parsing a per-STA profile of a Multi-Link element in a (re)association response, or a non-transmitted BSS profile – so a crafted frame from an AP can trigger a one-octet slab-out-of-bounds read during element parsing:
BUG: KASAN: slab-out-of-bounds in cfg80211_is_element_inherited Read of size 1 … in net/wireless/scan.c
Return early (treat the element as inherited) when an extension element carries no data, mirroring the existing handling of empty ID lists.
The bug was found by fuzzing ieee802_11_parse_elems_full() under KASAN.
References
- https://git.kernel.org/stable/c/11ac7a5e75f5132f1778e0c60981d30dc29fb869
- https://git.kernel.org/stable/c/20c308d9a57722801961f816395bf825f7bde6bc
- https://git.kernel.org/stable/c/84bd907361c56fbd5523eceb2682cb39da059bd5
- https://git.kernel.org/stable/c/cb8afea4655ff004fa7feee825d5c79783525383
- https://git.kernel.org/stable/c/ddf2773bcc8e49a43c561f22ec1e7924215d7947