In the implementation of the futex (fast userspace mutex) system call, the use of stack memory after release was discovered and eliminated. This, in turn, allowed an attacker to execute their code in the kernel context, with all the resulting security implications. The vulnerability was located in the error handling code.
Oplossing This vulnerability appeared in the Linux mainline on January 28 and was included in the kernels 5.10.12, 5.4.94, 4.19.172, 4.14.218 two days ago.
During the discussion of this fix, it was suggested that this vulnerability exists in all kernels starting from 2008:
https://www.openwall.com/lists/oss-security/2021/01/29/3
FWIW, this commit has:
Fixes: 1b7558e457ed ("futexes: fix fault handling in futex_lock_pi")
and that other commit is from 2008. So probably all currently
maintained Linux distros and deployments are affected, unless something
else mitigated the issue in some kernel versions.
Bron: linux.org.ru
