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.
History

Wed, 11 Sep 2024 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2024-05-17T13:23:08.204Z

Updated: 2024-08-02T03:21:47.505Z

Reserved: 2024-05-17T12:19:12.340Z

Link: CVE-2024-35797

cve-icon Vulnrichment

Updated: 2024-08-02T03:21:47.505Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2024-05-17T14:15:11.937

Modified: 2024-05-17T18:35:35.070

Link: CVE-2024-35797

cve-icon Redhat

Severity : Moderate

Publid Date: 2024-05-17T00:00:00Z

Links: CVE-2024-35797 - Bugzilla