CVE-2021-47602

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

mac80211: track only QoS data frames for admission control

For admission control, obviously all of that only works for QoS data frames, otherwise we cannot even access the QoS field in the header.

Syzbot reported (see below) an uninitialized value here due to a status of a non-QoS nullfunc packet, which isnt even long enough to contain the QoS header.

Fix this to only do anything for QoS data packets.

Weakness

The product accesses or uses a pointer that has not been initialized.

Affected Software

Extended Description

If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the product to read from or write to unexpected memory locations, leading to a denial of service. If the uninitialized pointer is used as a function call, then arbitrary functions could be invoked. If an attacker can influence the portion of uninitialized memory that is contained in the pointer, this weakness could be leveraged to execute code or perform other attacks. Depending on memory layout, associated memory management behaviors, and product operation, the attacker might be able to influence the contents of the uninitialized pointer, thus gaining more fine-grained control of the memory location to be accessed.

References

• https://git.kernel.org/stable/c/42d08e97b196479f593499e887a9ab81446a34b9
• https://git.kernel.org/stable/c/46b9e29db2012a4d2a40a26101862e002ccf387b
• https://git.kernel.org/stable/c/69f054d6642c8f6173724ce17e7ee3ff66b8f682
• https://git.kernel.org/stable/c/d5e568c3a4ec2ddd23e7dc5ad5b0c64e4f22981a
• https://git.kernel.org/stable/c/eed897a22230e3231a740eddd7d6d95ba476625f