CVE-2024-27058 Information

May 04, 2024 cve

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_acquirerelease_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.

Reference

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

Share on: