wifi: mac80211: keep fallback association elements alive

Overview

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: keep fallback association elements alive

Associating to a non-transmitted MBSSID profile reads freed memory while determining the operating channel and applying HT capabilities.

When an association response omits WMM, HT, or VHT information, ieee80211_assoc_config_link() parses the cached BSS IEs and copies the missing element pointers out of that fallback parse. For a non-transmitted MBSSID profile those pointers refer to merged-profile storage owned by the parse object, and the fallback block frees that object at its end. The copied pointers are used afterwards to determine the operating channel, configure bandwidth, and apply HT capabilities.

Keep the fallback parse result alive until association setup finishes.

[reorder variable declaration]

Affected

• Linux >= 5023b14cf4df4d22e1a80738167f3438c9e62e5f < 1d9644753d46c86b4e5c05bd6d9d35339ea27331
• Linux >= 5023b14cf4df4d22e1a80738167f3438c9e62e5f < d0183cd1f6a2dba9e63be20af2f65093c9c8d121
• Linux >= 5023b14cf4df4d22e1a80738167f3438c9e62e5f < 0878594c5806dd29fa5e16cc026ce19158afdad2
• Linux >= 5023b14cf4df4d22e1a80738167f3438c9e62e5f < a10a2f80476d166fd81c361ec0319493671b694e
• Linux 5.2

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.