CVE-2024-35797

medium

Published 2024-09-11 · Modified 2024-11-03

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CVSS v3

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CVSS v4 NEW

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not yet in upstream

VIR risk

5.5

Description

In the Linux kernel, the following vulnerability has been resolved: mm: cachestat: fix two shmem bugs When cachestat on shmem races with swapping and invalidation, there are two possible bugs: 1) A swapin error can have resulted in a poisoned swap entry in the shmem inode's xarray. Calling get_shadow_from_swap_cache() on it will result in an out-of-bounds access to swapper_spaces[]. Validate the entry with non_swap_entry() before going further. 2) When we find a valid swap entry in the shmem's inode, the shadow entry in the swapcache might not exist yet: swap IO is still in progress and we're before __remove_mapping; swapin, invalidation, or swapoff have removed the shadow from swapcache after we saw the shmem swap entry. This will send a NULL to workingset_test_recent(). The latter purely operates on pointer bits, so it won't crash - node 0, memcg ID 0, eviction timestamp 0, etc. are all valid inputs - but it's a bogus test. In theory that could result in a false "recently evicted" count. Such a false positive wouldn't be the end of the world. But for code clarity and (future) robustness, be explicit about this case. Bail on get_shadow_from_swap_cache() returning NULL.

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

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OS impact

OS	Version	Status	Fixed in
rhel	9	fixed
sles		affected
rocky	9	fixed
debian	bookworm	fixed	`0`
debian	bullseye	fixed	`0`
debian	forky	fixed	`6.7.12-1`
debian	sid	fixed	`6.7.12-1`
debian	trixie	fixed	`6.7.12-1`
almalinux	9	fixed	`kernel-headers-5.14.0-427.35.1.el9_4.aarch64.rpm`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.