5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas commit b54e03d9b3697d25f4a0063cf717d459c5e3ad94 upstream. A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain. Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected. Link: https://lore.kernel.org/20260629-b4-disp-94fb6521-v1-2-6953bcc0421f@proton.me Fixes: 6714d8e86bf4 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem") Signed-off-by: Bryam Vargas Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/dlm/dlmrecovery.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/fs/ocfs2/dlm/dlmrecovery.c +++ b/fs/ocfs2/dlm/dlmrecovery.c @@ -1368,6 +1368,15 @@ int dlm_mig_lockres_handler(struct o2net if (!dlm_grab(dlm)) return -EINVAL; + if (mres->lockname_len > DLM_LOCKID_NAME_MAX || + mres->num_locks > DLM_MAX_MIGRATABLE_LOCKS || + be16_to_cpu(msg->data_len) < struct_size(mres, ml, mres->num_locks)) { + mlog(ML_ERROR, "%s: invalid lockres migration message from %u\n", + dlm->name, mres->master); + dlm_put(dlm); + return -EINVAL; + } + if (!dlm_joined(dlm)) { mlog(ML_ERROR, "Domain %s not joined! " "lockres %.*s, master %u\n",