ipc: fix file descriptor leakage with unhandled messages

The sendmsg()/recvmsg() API is used to establish communication between
the DPDK processes. The API supposes inter-process file descriptors
sending and conversion, the recipient sees the resulting descriptors
in the received message - the operating systems creates ones in the
right context.

The message receiving is performed by EAL in the dedicated thread
and it might happen the message is received by EAL and not handled
by addressed PMD or application due to some reasons (timeouts, race
condition, etc). EAL just dropped unhandled messages causing the
file descriptor leakage if these ones were presented in the message.

The patch closes the descriptors (if any) in unhandled messages.

Fixes: 783b6e5 ("eal: add synchronous multi-process communication")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

lib/eal/common/eal_common_proc.c

@@ -321,6 +321,15 @@ read_msg(int fd, struct mp_msg_internal *m, struct sockaddr_un *s)
 	return msglen;
 }
 
+static void
+cleanup_msg_fds(const struct rte_mp_msg *msg)
+{
+	int i;
+
+	for (i = 0; i < msg->num_fds; i++)
+		close(msg->fds[i]);
+}
+
 static void
 process_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
 {
@@ -349,8 +358,10 @@ process_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
 			else if (pending_req->type == REQUEST_TYPE_ASYNC)
 				req = async_reply_handle_thread_unsafe(
 						pending_req);
-		} else
+		} else {
 			RTE_LOG(ERR, EAL, "Drop mp reply: %s\n", msg->name);
+			cleanup_msg_fds(msg);
+		}
 		pthread_mutex_unlock(&pending_requests.lock);
 
 		if (req != NULL)
@@ -380,6 +391,7 @@ process_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
 			RTE_LOG(ERR, EAL, "Cannot find action: %s\n",
 				msg->name);
 		}
+		cleanup_msg_fds(msg);
 	} else if (action(msg, s->sun_path) < 0) {
 		RTE_LOG(ERR, EAL, "Fail to handle message: %s\n", msg->name);
 	}