Description

In the Linux kernel, the following vulnerability has been resolved:

tmpfs: fix race on handling dquot rbtree

A syzkaller reproducer found a race while attempting to remove dquot
information from the rb tree.

Fetching the rb_tree root node must also be protected by the
dqopt->dqio_sem, otherwise, giving the right timing, shmem_release_dquot()
will trigger a warning because it couldn't find a node in the tree, when
the real reason was the root node changing before the search starts:

Thread 1 Thread 2
- shmem_release_dquot() - shmem_{acquire,release}_dquot()

- fetch ROOT - Fetch ROOT

- acquire dqio_sem
- wait dqio_sem

- do something, triger a tree rebalance
- release dqio_sem

- acquire dqio_sem
- start searching for the node, but
from the wrong location, missing
the node, and triggering a warning.

Classification

CVE ID: CVE-2024-27058

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 17.81% (scored less or equal to compared to others)

EPSS Date: 2025-02-03 (when was this score calculated)

References

https://git.kernel.org/stable/c/c7077f43f30d817d10a9f8245e51576ac114b2f0
https://git.kernel.org/stable/c/617d55b90e73c7b4aa2733ca6cc3f9b72d1124bb
https://git.kernel.org/stable/c/f82f184874d2761ebaa60dccf577921a0dbb3810
https://git.kernel.org/stable/c/0a69b6b3a026543bc215ccc866d0aea5579e6ce2

Timeline