7.8
CWE
416
Advisory Published
Updated

CVE-2022-48991: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths

First published: Mon Oct 21 2024(Updated: )

In the Linux kernel, the following vulnerability has been resolved: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of the security impact of this only came in commit 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Linux kernel>=4.8<4.9.337
Linux Linux kernel>=4.10<4.14.303
Linux Linux kernel>=4.15<4.19.270
Linux Linux kernel>=4.20<5.4.227
Linux Linux kernel>=5.5<5.10.159
Linux Linux kernel>=5.11<5.15.83
Linux Linux kernel>=5.16<6.0.13
Linux Linux kernel=6.1-rc1
Linux Linux kernel=6.1-rc2
Linux Linux kernel=6.1-rc3
Linux Linux kernel=6.1-rc4
Linux Linux kernel=6.1-rc5
Linux Linux kernel=6.1-rc6
Linux Linux kernel=6.1-rc7

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