CVE-2024-57942: netfs: Fix ceph copy to cache on write-begin

Vulnerability summary

CVE-2024-57942 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.4% of scored vulnerabilities.

Timeline

1. 21-01-2025
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix ceph copy to cache on write-begin At the end of netfs_unlock_read_folio() in which folios are marked appropriately for copying to the cache (either with by being marked dirty and having their private data set or by having PG_private_2 set) and then unlocked, the folio_queue struct has the entry pointing to the folio cleared. This presents a problem for netfs_pgpriv2_write_to_the_cache(), which is used to write folios marked with PG_private_2 to the cache as it expects to be able to trawl the folio_queue list thereafter to find the relevant folios, leading to a hang. Fix this by not clearing the folio_queue entry if we're going to do the deprecated copy-to-cache. The clearance will be done instead as the folios are written to the cache. This can be reproduced by starting cachefiles, mounting a ceph filesystem with "-o fsc" and writing to it.

No weakness data has been published for this record.