NFSv4.x: Fix wraparound issues when validing the callback sequence id
We need to make sure that we don't allow args->csa_sequenceid == 0.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 345df63..79c93b3 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -354,23 +354,15 @@
* a single outstanding callback request at a time.
*/
static __be32
-validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
+validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
+ const struct cb_sequenceargs * args)
{
- struct nfs4_slot *slot;
-
- dprintk("%s enter. slotid %u seqid %u\n",
- __func__, args->csa_slotid, args->csa_sequenceid);
+ dprintk("%s enter. slotid %u seqid %u, slot table seqid: %u\n",
+ __func__, args->csa_slotid, args->csa_sequenceid, slot->seq_nr);
if (args->csa_slotid > tbl->server_highest_slotid)
return htonl(NFS4ERR_BADSLOT);
- slot = tbl->slots + args->csa_slotid;
- dprintk("%s slot table seqid: %u\n", __func__, slot->seq_nr);
-
- /* Normal */
- if (likely(args->csa_sequenceid == slot->seq_nr + 1))
- goto out_ok;
-
/* Replay */
if (args->csa_sequenceid == slot->seq_nr) {
dprintk("%s seqid %u is a replay\n",
@@ -386,16 +378,14 @@
}
/* Wraparound */
- if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
- slot->seq_nr = 1;
- goto out_ok;
- }
+ if (unlikely(slot->seq_nr == 0xFFFFFFFFU)) {
+ if (args->csa_sequenceid == 1)
+ return htonl(NFS4_OK);
+ } else if (likely(args->csa_sequenceid == slot->seq_nr + 1))
+ return htonl(NFS4_OK);
/* Misordered request */
return htonl(NFS4ERR_SEQ_MISORDERED);
-out_ok:
- tbl->highest_used_slotid = args->csa_slotid;
- return htonl(NFS4_OK);
}
/*
@@ -486,6 +476,13 @@
goto out_unlock;
}
+ status = validate_seqid(tbl, slot, args);
+ if (status)
+ goto out_unlock;
+
+ cps->slotid = args->csa_slotid;
+ tbl->highest_used_slotid = args->csa_slotid;
+
memcpy(&res->csr_sessionid, &args->csa_sessionid,
sizeof(res->csr_sessionid));
res->csr_sequenceid = args->csa_sequenceid;
@@ -493,12 +490,6 @@
res->csr_highestslotid = tbl->server_highest_slotid;
res->csr_target_highestslotid = tbl->target_highest_slotid;
- status = validate_seqid(tbl, args);
- if (status)
- goto out_unlock;
-
- cps->slotid = args->csa_slotid;
-
/* The ca_maxresponsesize_cached is 0 with no DRC */
if (args->csa_cachethis != 0)
return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
@@ -518,7 +509,7 @@
* If CB_SEQUENCE returns an error, then the state of the slot
* (sequence ID, cached reply) MUST NOT change.
*/
- slot->seq_nr++;
+ slot->seq_nr = args->csa_sequenceid;
out_unlock:
spin_unlock(&tbl->slot_tbl_lock);
