Merge tag 'v6.18-rc3-smb-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Improve check for malformed payload

 - Fix free transport smbdirect potential race

 - Fix potential race in credit allocation during smbdirect negotiation

* tag 'v6.18-rc3-smb-server-fixes' of git://git.samba.org/ksmbd:
  smb: server: let smb_direct_cm_handler() call ib_drain_qp() after smb_direct_disconnect_rdma_work()
  smb: server: call smb_direct_post_recv_credits() when the negotiation is done
  ksmbd: transport_ipc: validate payload size before reading handle

Author: torvalds

fs/smb/server/transport_ipc.c

@@ -263,10 +263,16 @@ static void ipc_msg_handle_free(int handle)
 
 static int handle_response(int type, void *payload, size_t sz)
 {
-	unsigned int handle = *(unsigned int *)payload;
+	unsigned int handle;
 	struct ipc_msg_table_entry *entry;
 	int ret = 0;
 
+	/* Prevent 4-byte read beyond declared payload size */
+	if (sz < sizeof(unsigned int))
+		return -EINVAL;
+
+	handle = *(unsigned int *)payload;
+
 	ipc_update_last_active();
 	down_read(&ipc_msg_table_lock);
 	hash_for_each_possible(ipc_msg_table, entry, ipc_table_hlist, handle) {

fs/smb/server/transport_rdma.c

@@ -418,9 +418,6 @@ static struct smb_direct_transport *alloc_transport(struct rdma_cm_id *cm_id)
 
 	sc->ib.dev = sc->rdma.cm_id->device;
 
-	INIT_WORK(&sc->recv_io.posted.refill_work,
-		  smb_direct_post_recv_credits);
-	INIT_WORK(&sc->idle.immediate_work, smb_direct_send_immediate_work);
 	INIT_DELAYED_WORK(&sc->idle.timer_work, smb_direct_idle_connection_timer);
 
 	conn = ksmbd_conn_alloc();
@@ -469,6 +466,9 @@ static void free_transport(struct smb_direct_transport *t)
 	disable_delayed_work_sync(&sc->idle.timer_work);
 	disable_work_sync(&sc->idle.immediate_work);
 
+	if (sc->rdma.cm_id)
+		rdma_lock_handler(sc->rdma.cm_id);
+
 	if (sc->ib.qp) {
 		ib_drain_qp(sc->ib.qp);
 		sc->ib.qp = NULL;
@@ -497,8 +497,10 @@ static void free_transport(struct smb_direct_transport *t)
 		ib_free_cq(sc->ib.recv_cq);
 	if (sc->ib.pd)
 		ib_dealloc_pd(sc->ib.pd);
-	if (sc->rdma.cm_id)
+	if (sc->rdma.cm_id) {
+		rdma_unlock_handler(sc->rdma.cm_id);
 		rdma_destroy_id(sc->rdma.cm_id);
+	}
 
 	smb_direct_destroy_pools(sc);
 	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
@@ -1727,10 +1729,10 @@ static int smb_direct_cm_handler(struct rdma_cm_id *cm_id,
 	}
 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
 	case RDMA_CM_EVENT_DISCONNECTED: {
-		ib_drain_qp(sc->ib.qp);
-
 		sc->status = SMBDIRECT_SOCKET_DISCONNECTED;
 		smb_direct_disconnect_rdma_work(&sc->disconnect_work);
+		if (sc->ib.qp)
+			ib_drain_qp(sc->ib.qp);
 		break;
 	}
 	case RDMA_CM_EVENT_CONNECT_ERROR: {
@@ -1904,7 +1906,6 @@ static int smb_direct_prepare_negotiation(struct smbdirect_socket *sc)
 		goto out_err;
 	}
 
-	smb_direct_post_recv_credits(&sc->recv_io.posted.refill_work);
 	return 0;
 out_err:
 	put_recvmsg(sc, recvmsg);
@@ -2249,8 +2250,8 @@ static int smb_direct_prepare(struct ksmbd_transport *t)
 		return -ECONNABORTED;
 
 	ret = smb_direct_check_recvmsg(recvmsg);
-	if (ret == -ECONNABORTED)
-		goto out;
+	if (ret)
+		goto put;
 
 	req = (struct smbdirect_negotiate_req *)recvmsg->packet;
 	sp->max_recv_size = min_t(int, sp->max_recv_size,
@@ -2265,14 +2266,38 @@ static int smb_direct_prepare(struct ksmbd_transport *t)
 	sc->recv_io.credits.target = min_t(u16, sc->recv_io.credits.target, sp->recv_credit_max);
 	sc->recv_io.credits.target = max_t(u16, sc->recv_io.credits.target, 1);
 
-	ret = smb_direct_send_negotiate_response(sc, ret);
-out:
+put:
 	spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);
 	sc->recv_io.reassembly.queue_length--;
 	list_del(&recvmsg->list);
 	spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);
 	put_recvmsg(sc, recvmsg);
 
+	if (ret == -ECONNABORTED)
+		return ret;
+
+	if (ret)
+		goto respond;
+
+	/*
+	 * We negotiated with success, so we need to refill the recv queue.
+	 * We do that with sc->idle.immediate_work still being disabled
+	 * via smbdirect_socket_init(), so that queue_work(sc->workqueue,
+	 * &sc->idle.immediate_work) in smb_direct_post_recv_credits()
+	 * is a no-op.
+	 *
+	 * The message that grants the credits to the client is
+	 * the negotiate response.
+	 */
+	INIT_WORK(&sc->recv_io.posted.refill_work, smb_direct_post_recv_credits);
+	smb_direct_post_recv_credits(&sc->recv_io.posted.refill_work);
+	if (unlikely(sc->first_error))
+		return sc->first_error;
+	INIT_WORK(&sc->idle.immediate_work, smb_direct_send_immediate_work);
+
+respond:
+	ret = smb_direct_send_negotiate_response(sc, ret);
+
 	return ret;
 }