Red Hat: CVE-2021-47491: kernel: mm: khugepaged: skip huge page collapse for special files (Multiple Advisories)

Red Hat: CVE-2021-47491: kernel: mm: khugepaged: skip huge page collapse for special files (Multiple Advisories)

Severity

5

CVSS

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

Published

05/22/2024

Created

08/13/2024

Added

08/12/2024

Modified

08/12/2024

Description

In the Linux kernel, the following vulnerability has been resolved: mm: khugepaged: skip huge page collapse for special files The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC.The intended usecase is to avoid TLB misses for large text segments.But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission.This may cause bugs, like [1] and [2]. This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface. [[email protected]: fix vm_file check [3]]

Solution(s)

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

References

• CVE-2021-47491
• RHSA-2024:5101
• RHSA-2024:5102