nfs41: Backchannel: CB_SEQUENCE validation (68f3f901) · Commits · 戴 / test

fs/nfs/callback_proc.c

+67 −4

Original line number	Diff line number	Diff line
		@@ -104,6 +104,57 @@ out:

		#if defined(CONFIG_NFS_V4_1)

		/*
		* Validate the sequenceID sent by the server.
		* Return success if the sequenceID is one more than what we last saw on
		* this slot, accounting for wraparound. Increments the slot's sequence.
		*
		* We don't yet implement a duplicate request cache, so at this time
		* we will log replays, and process them as if we had not seen them before,
		* but we don't bump the sequence in the slot. Not too worried about it,
		* since we only currently implement idempotent callbacks anyway.
		*
		* We have a single slot backchannel at this time, so we don't bother
		* checking the used_slots bit array on the table. The lower layer guarantees
		* a single outstanding callback request at a time.
		*/
		static int
		validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
		{
		struct nfs4_slot *slot;

		dprintk("%s enter. slotid %d seqid %d\n",
		__func__, slotid, seqid);

		if (slotid > NFS41_BC_MAX_CALLBACKS)
		return htonl(NFS4ERR_BADSLOT);

		slot = tbl->slots + slotid;
		dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);

		/* Normal */
		if (likely(seqid == slot->seq_nr + 1)) {
		slot->seq_nr++;
		return htonl(NFS4_OK);
		}

		/* Replay */
		if (seqid == slot->seq_nr) {
		dprintk("%s seqid %d is a replay - no DRC available\n",
		__func__, seqid);
		return htonl(NFS4_OK);
		}

		/* Wraparound */
		if (seqid == 1 && (slot->seq_nr + 1) == 0) {
		slot->seq_nr = 1;
		return htonl(NFS4_OK);
		}

		/* Misordered request */
		return htonl(NFS4ERR_SEQ_MISORDERED);
		}

		/*
		* Returns a pointer to a held 'struct nfs_client' that matches the server's
		* address, major version number, and session ID. It is the caller's
		@@ -140,18 +191,27 @@ out:
		return NULL;
		}

		/* FIXME: validate args->cbs_{sequence,slot}id */
		/* FIXME: referring calls should be processed */
		unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
		struct cb_sequenceres *res)
		{
		int i;
		unsigned status = 0;
		struct nfs_client *clp;
		int i, status;

		for (i = 0; i < args->csa_nrclists; i++)
		kfree(args->csa_rclists[i].rcl_refcalls);
		kfree(args->csa_rclists);

		status = htonl(NFS4ERR_BADSESSION);
		clp = find_client_with_session(args->csa_addr, 4, &args->csa_sessionid);
		if (clp == NULL)
		goto out;

		status = validate_seqid(&clp->cl_session->bc_slot_table,
		args->csa_slotid, args->csa_sequenceid);
		if (status)
		goto out_putclient;

		memcpy(&res->csr_sessionid, &args->csa_sessionid,
		sizeof(res->csr_sessionid));
		res->csr_sequenceid = args->csa_sequenceid;
		@@ -159,9 +219,12 @@ unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
		res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
		res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;

		out_putclient:
		nfs_put_client(clp);
		out:
		dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
		res->csr_status = status;
		return status;
		return res->csr_status;
		}

		#endif /* CONFIG_NFS_V4_1 */

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