CVE-2023-53636

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

clk: microchip: fix potential UAF in auxdev release callback

Similar to commit 1c11289b34ab (peci: cpu: Fix use-after-free in adev_release()), the auxiliary device is not torn down in the correct order. If auxiliary_device_add() fails, the release callback will be called twice, resulting in a UAF. Due to timing, the auxdev code in this driver took inspiration from the aforementioned commit, and thus its bugs too!

Moving auxiliary_device_uninit() to the unregister callback instead avoids the issue.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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/5b4052aa956e11bcd19e50ca559eb38dcb46201b
• https://git.kernel.org/stable/c/7455b7007b9e93bcc2bc9c1c6c73a228e3152069
• https://git.kernel.org/stable/c/934406b2d42eaf3fc57f5546cc68ff7ab9680bb3
• https://git.kernel.org/stable/c/d7d6dacf39ed102d7667721ca1700022c9c8b11a