In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate orphan slot during inode read Patch series "ocfs2: validate active orphan slots during inode read". OCFS2 trusts active ordinary and append-DIO orphan…

Overview

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

ocfs2: validate orphan slot during inode read

Patch series "ocfs2: validate active orphan slots during inode read".

OCFS2 trusts active ordinary and append-DIO orphan slots read from dinodes. A corrupted slot can therefore index osb_orphan_wipes or the slot-local system-inode cache outside their allocations before the corruption is reported.

Patch 1 validates the ordinary orphan slot used by inode wipe processing. Patch 2 validates the append-DIO orphan slot used by DIO completion and orphan recovery. Both checks reject corrupt metadata at the existing inode validation boundary.

This patch (of 2):

[BUG] A corrupted dinode with OCFS2_ORPHANED_FL can carry an i_orphaned_slot outside the mounted filesystem slot range. ocfs2_wipe_inode() uses it to index osb_orphan_wipes before looking up the orphan directory, causing an out-of-bounds memory access.

BUG: KASAN: slab-use-after-free in ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 Read of size 8 at addr ffff88800b767c00 by task kworker/u8:3/85 Call Trace: ... ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 ocfs2_wipe_inode+0x292/0xf70 fs/ocfs2/inode.c:840 ocfs2_delete_inode fs/ocfs2/inode.c:1155 [inline] ocfs2_evict_inode+0x6c9/0x1170 fs/ocfs2/inode.c:1295 evict+0x38e/0x8f0 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput fs/inode.c:1966 [inline] iput+0x55b/0x8b0 fs/inode.c:1926 ocfs2_recover_orphans+0x610/0xe40 fs/ocfs2/journal.c:2374 ocfs2_complete_recovery+0x5af/0xd00 fs/ocfs2/journal.c:1373 ...

[CAUSE] ocfs2_validate_inode_block() validates i_suballoc_slot but leaves the active ordinary orphan slot unchecked. Downstream consumers assume that the value is smaller than osb->max_slots.

[FIX] Reject an active i_orphaned_slot outside the slot range during dinode validation, before the inode reaches orphan wipe processing.

Remediation

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