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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>
This commit is contained in:
Trond Myklebust 2016-01-23 16:57:58 -05:00
parent 80f9642724
commit 5f83d86cf5
1 changed files with 17 additions and 26 deletions
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43
fs/nfs/callback_proc.c
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@ -354,23 +354,15 @@ out:
* 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 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
}
/* 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 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
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 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
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 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
* 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);