ocfs2: validate orphan slot during inode read

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.