[merged mm-nonmm-stable] ocfs2-bound-namelen-in-dlm_migrate_request_handler.patch removed from -mm tree

The quilt patch titled
     Subject: ocfs2: bound namelen in dlm_migrate_request_handler
has been removed from the -mm tree.  Its filename was
     ocfs2-bound-namelen-in-dlm_migrate_request_handler.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Bryam Vargas <[email protected]>
Subject: ocfs2: bound namelen in dlm_migrate_request_handler
Date: Mon, 29 Jun 2026 00:01:43 -0500

Patch series "ocfs2/dlm: bound peer-controlled lengths in the o2dlm".

The o2dlm receive handlers trust u8 length and count fields from the wire
without bounding them, so a node in a DLM domain can corrupt or panic any
other node with a malformed message.  Three defects:

  - dlm_migrate_request_handler() passes migrate->namelen unchecked to
    dlm_init_mle(), which memcpy()s it into the 32-byte mname[] of an
    o2dlm_mle slab object: a heap out-of-bounds write of up to ~215
    attacker-controlled bytes.

  - dlm_mig_lockres_handler() passes mres->lockname_len unchecked to
    dlm_init_lockres(), which memcpy()s it into the 32-byte o2dlm_lockname
    slab object: a heap out-of-bounds write of up to ~223 bytes.

  - the same handler trusts mres->num_locks without checking that the
    message is large enough to hold that many entries, so
    dlm_process_recovery_data() walks mres->ml[] past the kmalloc(data_len)
    copy and trips a BUG_ON (an out-of-bounds read ending in a panic).

The other o2dlm receive handlers already reject an oversized name; the
migration and recovery handlers have omitted it since the DLM was added
(see the Fixes tags).  Patch 1 bounds namelen; patch 2 validates
lockname_len, num_locks, and the payload size.  Conforming recovery and
migration traffic is unaffected.

o2net authenticates peers only by the DLM domain key, so any node that has
joined the domain -- including a compromised or malicious member -- can
send these messages.  There is no local trigger; the attacker must already
be a member of the cluster.

Each sink was confirmed under KASAN with an out-of-tree module mirroring
it exactly -- a kmem_cache/kmalloc of the real destination size, then the
same unclamped memcpy/loop: slab-out-of-bounds Write for the two writes,
Read for the recovery walk, and a panic.  A userspace AddressSanitizer
build faults identically under -m32 and -m64.  Scrubbed logs are available
on request.

I reported this privately to [email protected] and the ocfs2 maintainers
on 2026-06-20; with no response after the standard embargo period I am
posting the fix publicly.  I have no embargo requirement.


This patch (of 2):

A node receiving a DLM_MIGRATE_REQUEST message trusts the peer-supplied
name length (migrate->namelen) without bounding it.  dlm_init_mle() then
copies that many bytes into the fixed DLM_LOCKID_NAME_MAX-byte mname[]
array of an o2dlm_mle slab object, so a malformed message from a cluster
peer overflows the slab object by up to ~215 bytes: a heap out-of-bounds
write of attacker-controlled data, reachable by any node in the domain.

Reject an oversized name, the way dlm_master_request_handler() and the
other o2dlm receive handlers already do; the migration handler omits the
check entirely.  Conforming messages are unaffected.

Link: https://lore.kernel.org/[email protected]
Link: https://lore.kernel.org/[email protected]
Fixes: 6714d8e86bf4 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem")
Signed-off-by: Bryam Vargas <[email protected]>
Reviewed-by: Joseph Qi <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Heming Zhao <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Jun Piao <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 fs/ocfs2/dlm/dlmmaster.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-bound-namelen-in-dlm_migrate_request_handler
+++ a/fs/ocfs2/dlm/dlmmaster.c
@@ -3099,6 +3099,12 @@ int dlm_migrate_request_handler(struct o
 
 	name = migrate->name;
 	namelen = migrate->namelen;
+	if (namelen > DLM_LOCKID_NAME_MAX) {
+		mlog(ML_ERROR, "%s: invalid name length %u in migrate request\n",
+		     dlm->name, namelen);
+		ret = -EINVAL;
+		goto leave;
+	}
 	hash = dlm_lockid_hash(name, namelen);
 
 	/* preallocate.. if this fails, abort */
_

Patches currently in -mm which might be from [email protected] are