1 files changed, 43 insertions, 10 deletions

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 51a641002e10..8364223422d0 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -382,6 +382,8 @@ struct cma_hdr {
 #define CMA_VERSION 0x00
 
 struct cma_req_info {
+	struct sockaddr_storage listen_addr_storage;
+	struct sockaddr_storage src_addr_storage;
 	struct ib_device *device;
 	int port;
 	union ib_gid local_gid;
@@ -1340,11 +1342,11 @@ static bool validate_net_dev(struct net_device *net_dev,
 }
 
 static struct net_device *cma_get_net_dev(struct ib_cm_event *ib_event,
-					  const struct cma_req_info *req)
+					  struct cma_req_info *req)
 {
-	struct sockaddr_storage listen_addr_storage, src_addr_storage;
-	struct sockaddr *listen_addr = (struct sockaddr *)&listen_addr_storage,
-			*src_addr = (struct sockaddr *)&src_addr_storage;
+	struct sockaddr *listen_addr =
+			(struct sockaddr *)&req->listen_addr_storage;
+	struct sockaddr *src_addr = (struct sockaddr *)&req->src_addr_storage;
 	struct net_device *net_dev;
 	const union ib_gid *gid = req->has_gid ? &req->local_gid : NULL;
 	int err;
@@ -1359,11 +1361,6 @@ static struct net_device *cma_get_net_dev(struct ib_cm_event *ib_event,
 	if (!net_dev)
 		return ERR_PTR(-ENODEV);
 
-	if (!validate_net_dev(net_dev, listen_addr, src_addr)) {
-		dev_put(net_dev);
-		return ERR_PTR(-EHOSTUNREACH);
-	}
-
 	return net_dev;
 }
 
@@ -1490,15 +1487,51 @@ static struct rdma_id_private *cma_id_from_event(struct ib_cm_id *cm_id,
 		}
 	}
 
+	/*
+	 * Net namespace might be getting deleted while route lookup,
+	 * cm_id lookup is in progress. Therefore, perform netdevice
+	 * validation, cm_id lookup under rcu lock.
+	 * RCU lock along with netdevice state check, synchronizes with
+	 * netdevice migrating to different net namespace and also avoids
+	 * case where net namespace doesn't get deleted while lookup is in
+	 * progress.
+	 * If the device state is not IFF_UP, its properties such as ifindex
+	 * and nd_net cannot be trusted to remain valid without rcu lock.
+	 * net/core/dev.c change_net_namespace() ensures to synchronize with
+	 * ongoing operations on net device after device is closed using
+	 * synchronize_net().
+	 */
+	rcu_read_lock();
+	if (*net_dev) {
+		/*
+		 * If netdevice is down, it is likely that it is administratively
+		 * down or it might be migrating to different namespace.
+		 * In that case avoid further processing, as the net namespace
+		 * or ifindex may change.
+		 */
+		if (((*net_dev)->flags & IFF_UP) == 0) {
+			id_priv = ERR_PTR(-EHOSTUNREACH);
+			goto err;
+		}
+
+		if (!validate_net_dev(*net_dev,
+				 (struct sockaddr *)&req.listen_addr_storage,
+				 (struct sockaddr *)&req.src_addr_storage)) {
+			id_priv = ERR_PTR(-EHOSTUNREACH);
+			goto err;
+		}
+	}
+
 	bind_list = cma_ps_find(*net_dev ? dev_net(*net_dev) : &init_net,
 				rdma_ps_from_service_id(req.service_id),
 				cma_port_from_service_id(req.service_id));
 	id_priv = cma_find_listener(bind_list, cm_id, ib_event, &req, *net_dev);
+err:
+	rcu_read_unlock();
 	if (IS_ERR(id_priv) && *net_dev) {
 		dev_put(*net_dev);
 		*net_dev = NULL;
 	}
-
 	return id_priv;
 }