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.

Classification

CVE ID: CVE-2024-57942

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 11.7% (scored less or equal to compared to others)

EPSS Date: 2025-02-19 (when was this score calculated)

References

https://git.kernel.org/stable/c/43b8d3249b0b71bad239d42dbe08ce6c938ba000
https://git.kernel.org/stable/c/38cf8e945721ffe708fa675507465da7f4f2a9f7

Timeline