CVE-2021-43057

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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://bugs.chromium.org/p/project-zero/issues/detail?id=2229
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.8
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a3727a8bac0a9e77c70820655fd8715523ba3db7
• https://security.netapp.com/advisory/ntap-20211125-0001/
• https://bugs.chromium.org/p/project-zero/issues/detail?id=2229
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.8
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a3727a8bac0a9e77c70820655fd8715523ba3db7
• https://security.netapp.com/advisory/ntap-20211125-0001/