CVE-2023-52569: btrfs: remove BUG() after failure to insert delayed dir index item

Vulnerability summary

CVE-2023-52569 is a medium (CVSS 5.5) Reachable Assertion vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15.2% of scored vulnerabilities.

Timeline

1. 02-03-2024
   PublishedVulnerability first disclosed.
2. 23-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: remove BUG() after failure to insert delayed dir index item Instead of calling BUG() when we fail to insert a delayed dir index item into the delayed node's tree, we can just release all the resources we have allocated/acquired before and return the error to the caller. This is fine because all existing call chains undo anything they have done before calling btrfs_insert_delayed_dir_index() or BUG_ON (when creating pending snapshots in the transaction commit path). So remove the BUG() call and do proper error handling. This relates to a syzbot report linked below, but does not fix it because it only prevents hitting a BUG(), it does not fix the issue where somehow we attempt to use twice the same index number for different index items.

• CWE-617Reachable AssertionThe product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.