CVE-2022-49479

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

mt76: fix tx status related use-after-free race on station removal

There is a small race window where ongoing tx activity can lead to a skb getting added to the status tracking idr after that idr has already been cleaned up, which will keep the wcid linked in the status poll list. Fix this by only adding status skbs if the wcid pointer is still assigned in dev->wcid, which gets cleared early by mt76_sta_pre_rcu_remove

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/ddd426d72aca4054045a9bd3b80a4ce1d398f11f
• https://git.kernel.org/stable/c/ef7f9f894cfd0b2e471206409a529af4a26ddd55
• https://git.kernel.org/stable/c/fcfe1b5e162bf473c1d47760962cec8523c00466