CVE-2024-35793

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

debugfs: fix wait/cancellation handling during remove

Ben Greear further reports deadlocks during concurrent debugfs remove while files are being accessed, even though the code in question now uses debugfs cancellations. Turns out that despite all the review on the locking, we missed completely that the logic is wrong: if the refcount hits zero we can finish (and need not wait for the completion), but if it doesnt we have to trigger all the cancellations. As written, we can never get into the loop triggering the cancellations. Fix this, and explain it better while at it.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/3d08cca5fd0aabb62b7015067ab40913b33da906
• https://git.kernel.org/stable/c/952c3fce297f12c7ff59380adb66b564e2bc9b64
• https://git.kernel.org/stable/c/e88b5ae01901c4a655a53158397746334778a57b
• https://git.kernel.org/stable/c/3d08cca5fd0aabb62b7015067ab40913b33da906
• https://git.kernel.org/stable/c/952c3fce297f12c7ff59380adb66b564e2bc9b64
• https://git.kernel.org/stable/c/e88b5ae01901c4a655a53158397746334778a57b