CVE-2024-35797
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…
Does this matter?
Lower severity and a low EPSS score (0.67%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.67% probability · 50th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/24a0e73d544439bb9329fbbafac44299e548a677Patch
- https://git.kernel.org/stable/c/b79f9e1ff27c994a4c452235ba09e672ec698e23Patch
- https://git.kernel.org/stable/c/d5d39c707a4cf0bcc84680178677b97aa2cb2627Patch
- https://git.kernel.org/stable/c/d962f6c583458037dc7e529659b2b02b9dd3d94bPatch
- https://git.kernel.org/stable/c/24a0e73d544439bb9329fbbafac44299e548a677Patch
- https://git.kernel.org/stable/c/b79f9e1ff27c994a4c452235ba09e672ec698e23Patch
- https://git.kernel.org/stable/c/d5d39c707a4cf0bcc84680178677b97aa2cb2627Patch
- https://git.kernel.org/stable/c/d962f6c583458037dc7e529659b2b02b9dd3d94bPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.