CVE-2024-35797

Source
https://nvd.nist.gov/vuln/detail/CVE-2024-35797
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-35797.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2024-35797
Downstream
Related
Published
2024-05-17T14:15:11Z
Modified
2024-11-21T09:20:55Z
Summary
[none]
Details

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 getshadowfromswapcache() on it will result in an out-of-bounds access to swapper_spaces[].

Validate the entry with nonswapentry() 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 _removemapping; swapin, invalidation, or swapoff have removed the shadow from swapcache after we saw the shmem swap entry.

This will send a NULL to workingsettestrecent(). 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 getshadowfromswapcache() returning NULL.

References

Affected packages

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.7.12-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}