O2net: Disallow o2net accept connection request from itself.

Currently, o2net_accept_one() is allowed to accept a connection from listening node itself, such a fake connection will not be successfully established due to no handshake detected afterwards, and later end up with triggering connecting worker in a loop.

We're going to fix this by treating such connection request as 'invalid', since we've got no chance of requesting connection from a node to itself in a OCFS2 cluster.

The fix doesn't hurt user's scan for o2net-listener, it always gets a successful connection from userpace.

Signed-off-by Tristan Ye <[email protected]>

Acked-by Sunil Mushran <[email protected]>

---
fs/ocfs2/cluster/tcp.c | 17 ++++++++++++-----

1 files changed, 12 insertions(+), 5 deletions(-)

fs/ocfs2/cluster/tcp.c +12 -5

index aa75ca3..1361997 100644
@@ -1759,6 +1759,7 @@ static int o2net_accept_one(struct socket *sock)
   struct sockaddr_in sin;
   struct socket *new_sock = NULL;
   struct o2nm_node *node = NULL;
+    struct o2nm_node *local_node = NULL;
   struct o2net_sock_container *sc = NULL;
   struct o2net_node *nn;
 

@@ -1796,11 +1797,15 @@ static int o2net_accept_one(struct socket *sock)
       goto out;
   }
 
-    if (o2nm_this_node() > node->nd_num) {
-        mlog(ML_NOTICE, "unexpected connect attempted from a lower "
-             "numbered node '%s' at " "%pI4:%d with num %u\n",
-             node->nd_name, &sin.sin_addr.s_addr,
-             ntohs(sin.sin_port), node->nd_num);
+    if (o2nm_this_node() >= node->nd_num) {
+        local_node = o2nm_get_node_by_num(o2nm_this_node());
+        mlog(ML_NOTICE, "unexpected connect attempt seen at node '%s' ("
+             "%u, %pI4:%d) from node '%s' (%u, %pI4:%d)\n",
+             local_node->nd_name, local_node->nd_num,
+             &(local_node->nd_ipv4_address),
+             ntohs(local_node->nd_ipv4_port),
+             node->nd_name, node->nd_num, &sin.sin_addr.s_addr,
+             ntohs(sin.sin_port));
       ret = -EINVAL;
       goto out;
   }

@@ -1857,6 +1862,8 @@ out:
       sock_release(new_sock);
   if (node)
       o2nm_node_put(node);
+    if (local_node)
+        o2nm_node_put(local_node);
   if (sc)
       sc_put(sc);
   return ret;

Signature · 7 lines

1.5.5


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Currently, o2net_accept_one() is allowed to accept a connection from listening node itself, such a fake connection will not be successfully established due to no handshake detected afterwards, and later end up with triggering connecting worker in a loop.

We're going to fix this by treating such connection request as 'invalid', since we've got no chance of requesting connection from a node to itself in a OCFS2 cluster.

The fix doesn't hurt user's scan for o2net-listener, it always gets a successful connection from userpace.

Signed-off-by Tristan Ye <[email protected]>

Acked-by Sunil Mushran <[email protected]>