In the Linux kernel, the following vulnerability has been resolved: btrfs: fix transaction use-after-free in raid stripe insertion If allocation of a RAID stripe extent fails, btrfs_insert_one_raid_extent() aborts and ends the transact…

Overview

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix transaction use-after-free in raid stripe insertion

If allocation of a RAID stripe extent fails, btrfs_insert_one_raid_extent() aborts and ends the transaction before returning -ENOMEM.

btrfs_finish_one_ordered(), the production caller through btrfs_insert_raid_extent(), still owns the transaction handle. It handles the error by aborting the transaction and then reaches the common exit path, which ends the transaction again.

The premature end can free the handle and drop its transaction reference. Transaction cleanup can then free the transaction before the caller's second abort accesses the handle and transaction, resulting in use-after-free.

Keep the abort at the failure site, but let the caller's common exit path end the transaction once, after it has finished using both objects.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.