From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2024-27058: tmpfs: fix race on handling dquot rbtree 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. The Linux kernel CVE team has assigned CVE-2024-27058 to this issue. Affected and fixed versions =========================== Issue introduced in 6.6 with commit eafc474e2029 and fixed in 6.6.24 with commit c7077f43f30d Issue introduced in 6.6 with commit eafc474e2029 and fixed in 6.7.12 with commit 617d55b90e73 Issue introduced in 6.6 with commit eafc474e2029 and fixed in 6.8.3 with commit f82f184874d2 Issue introduced in 6.6 with commit eafc474e2029 and fixed in 6.9 with commit 0a69b6b3a026 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-27058 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: mm/shmem_quota.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: 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