[DLM] Telnet to port 21064 can stop all lockspaces

This patch fixes Red Hat bz#245892

Opening a tcp connection from a cluster member to another cluster member
targeting the dlm port it is enough to stop every dlm operation in the cluster.
This means that GFS and rgmanager will hang.

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index fc0bff7..73d44f5 100644 (file)
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -720,11 +720,17 @@ static int tcp_accept_from_sock(struct connection *con)
                        INIT_WORK(&othercon->rwork, process_recv_sockets);
                        set_bit(CF_IS_OTHERCON, &othercon->flags);
                        newcon->othercon = othercon;
+                       othercon->sock = newsock;
+                       newsock->sk->sk_user_data = othercon;
+                       add_sock(newsock, othercon);
+                       addcon = othercon;
+               }
+               else {
+                       printk("Extra connection from node %d attempted\n", nodeid);
+                       result = -EAGAIN;
+                       up_write(&newcon->sock_sem);
+                       goto accept_err;
                }
-               othercon->sock = newsock;
-               newsock->sk->sk_user_data = othercon;
-               add_sock(newsock, othercon);
-               addcon = othercon;
        }
        else {
                newsock->sk->sk_user_data = newcon;