Red Hat: CVE-2021-47461: kernel: userfaultfd: fix a race between writeprotect and exit_mmap() (Multiple Advisories)

Red Hat: CVE-2021-47461: kernel: userfaultfd: fix a race between writeprotect and exit_mmap() (Multiple Advisories)

Severity

6

CVSS

(AV:L/AC:H/Au:S/C:C/I:C/A:C)

Published

05/22/2024

Created

08/13/2024

Added

08/12/2024

Modified

02/10/2025

Description

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a race between writeprotect and exit_mmap() A race is possible when a process exits, its VMAs are removed by exit_mmap() and at the same time userfaultfd_writeprotect() is called. The race was detected by KASAN on a development kernel, but it appears to be possible on vanilla kernels as well. Use mmget_not_zero() to prevent the race as done in other userfaultfd operations.

Solution(s)

• redhat-upgrade-kernel
• redhat-upgrade-kernel-rt

References

• CVE-2021-47461
• RHSA-2024:10262
• RHSA-2024:5101
• RHSA-2024:5102