CVE-2023-53618

A file-system validation flaw was found in the Linux kernel B-tree File System (Btrfs) in the way relocation tree keys are accepted. Crafted on-disk data could present a relocation tree for a non-subvolume tree, leading to internal assertions and a crash during tree merging.

A local user mounting or accessing a crafted image could use this flaw to crash the system, resulting in a denial of service.

Relocation trees are only valid for subvolume trees. The code did not reject invalid relocation keys that referenced non-subvolume trees (for example, the quota tree), allowing inconsistent metadata to reach code paths that assume proper back-references. The fix teaches the tree checker to reject such keys and exits gracefully when encountered.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent module btrfs from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.