xfs: fix cursor and pointer handling when recovering iunlink buckets

Summary

In the Linux kernel, the following vulnerability has been resolved: xfs: fix cursor and pointer handling when recovering iunlink buckets LOLLM pointed out a bug in xlog_recover_iunlink_bucket: 1. We don't null out prev_ip after releasing it, which can lead to UAF problems if the inodegc flush call in the loop fails. at which point I noticed even more bugs: 2. If the inodegc flush inside the loop fails, we also leak @ip. 3. We set prev_agino to agino having already advanced agino, which results in inodes with i_prev_unlinked set to itself. 4. If we exit the bottom of the loop with prev_ip set, then prev_ip aliases ip and we also set its i_prev_unlinked to itself. Bugs 3 and 4 introduce loops into the unlinked list, though these loops don't surface because we immediately flush each unlinked inode after loading it. Fix all of these issues.

Timeline

1. Oct 18, 2026, 3:14 PM UTCCVE published
2. Oct 24, 2026, 2:08 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 04755d2e5821b3afbaadd09fe5df58d04de36484 · fixed in 47a948ba653a463d429e02fda2f06a3d6b78666d; From 04755d2e5821b3afbaadd09fe5df58d04de36484 · fixed in 8c9d5b8a96d6b93eb24e07b4163c89341ba29bd1; From 04755d2e5821b3afbaadd09fe5df58d04de36484 · fixed in 66a2179d02668f8df44b1a249899006f3ba38ea0; From 04755d2e5821b3afbaadd09fe5df58d04de36484 · fixed in 961c717e6bf0e53c2c2b1fe4aef1add9390fedab; From 04755d2e5821b3afbaadd09fe5df58d04de36484 · fixed in 65f39d09d73718611cee40399179323b5d4ead00

• Linux Linux

  6.0

• KernelLinux

  From 6.0.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.113; From 6.13.0 · fixed in 6.18.55; From 6.19.0 · fixed in 7.2.9

References 5