CVE-2022-49539

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

rtw89: ser: fix CAM leaks occurring in L2 reset

The CAM, meaning address CAM and bssid CAM here, will get leaks during SER (system error recover) L2 reset process and ieee80211_restart_hw() which is called by L2 reset process eventually.

The normal flow would be like -> add interface (acquire 1) -> enter ips (release 1) -> leave ips (acquire 1) -> connection (occupy 1) <(A) 1 leak after L2 reset if non-sec connection>

The ieee80211_restart_hw() flow (under connection) -> ieee80211 reconfig -> add interface (acquire 1) -> leave ips (acquire 1) -> connection (occupy (A) + 2) <(B) 1 more leak>

Originally, CAM is released before HW restart only if connection is under security. Now, release CAM whatever connection it is to fix leak in (A). OTOH, check if CAM is already valid to avoid acquiring multiple times to fix (B).

Besides, if AP mode, release address CAM of all stations before HW restart.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/b169f877f001a474fb89939842c390518160bcc5
• https://git.kernel.org/stable/c/f6aff772c9978844529618d86aafb53e5d3ae161