sctp: hold endpoint before calling cb in sctp_transport_lookup_process

The same fix in commit 5ec7d18d1813 ("sctp: use call_rcu to free endpoint")
is also needed for dumping one asoc and sock after the lookup.

Fixes: 86fdb3448cc1 ("sctp: ensure ep is not destroyed before doing the dump")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 7 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index ad5028a07b18..da08671a3f80 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5317,23 +5317,31 @@ int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *),
 }
 EXPORT_SYMBOL_GPL(sctp_for_each_endpoint);
 
-int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
-				  struct net *net,
+int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net,
 				  const union sctp_addr *laddr,
 				  const union sctp_addr *paddr, void *p)
 {
 	struct sctp_transport *transport;
-	int err;
+	struct sctp_endpoint *ep;
+	int err = -ENOENT;
 
 	rcu_read_lock();
 	transport = sctp_addrs_lookup_transport(net, laddr, paddr);
+	if (!transport) {
+		rcu_read_unlock();
+		return err;
+	}
+	ep = transport->asoc->ep;
+	if (!sctp_endpoint_hold(ep)) { /* asoc can be peeled off */
+		sctp_transport_put(transport);
+		rcu_read_unlock();
+		return err;
+	}
 	rcu_read_unlock();
-	if (!transport)
-		return -ENOENT;
 
-	err = cb(transport, p);
+	err = cb(ep, transport, p);
+	sctp_endpoint_put(ep);
 	sctp_transport_put(transport);
-
 	return err;
 }
 EXPORT_SYMBOL_GPL(sctp_transport_lookup_process);