tipc: fix memory leak of group member when peer node is lost

When a group member receives a member WITHDRAW event, this might have
two reasons: either the peer member is leaving the group, or the link
to the member's node has been lost.

In the latter case we need to issue a DOWN event to the user right away,
and let function tipc_group_filter_msg() perform delete of the member
item. However, in this case we miss to change the state of the member
item to MBR_LEAVING, so the member item is not deleted, and we have a
memory leak.

We now separate better between the four sub-cases of a WITHRAW event
and make sure that each case is handled correctly.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 9 deletions

diff --git a/net/tipc/group.c b/net/tipc/group.c
index e5b03f08f076..8e12ab55346b 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -850,17 +850,26 @@ void tipc_group_member_evt(struct tipc_group *grp,
                 *usr_wakeup = true;
                 m->usr_pending = false;
                 node_up = tipc_node_is_up(net, node);
-
-                /* Hold back event if more messages might be expected */
-                if (m->state != MBR_LEAVING && node_up) {
-                        m->event_msg = skb;
-                        tipc_group_decr_active(grp, m);
-                        m->state = MBR_LEAVING;
-                } else {
-                        if (node_up)
+                m->event_msg = NULL;
+
+                if (node_up) {
+                        /* Hold back event if a LEAVE msg should be expected */
+                        if (m->state != MBR_LEAVING) {
+                                m->event_msg = skb;
+                                tipc_group_decr_active(grp, m);
+                                m->state = MBR_LEAVING;
+                        } else {
                                 msg_set_grp_bc_seqno(hdr, m->bc_syncpt);
-                        else
+                                __skb_queue_tail(inputq, skb);
+                        }
+                } else {
+                        if (m->state != MBR_LEAVING) {
+                                tipc_group_decr_active(grp, m);
+                                m->state = MBR_LEAVING;
                                 msg_set_grp_bc_seqno(hdr, m->bc_rcv_nxt);
+                        } else {
+                                msg_set_grp_bc_seqno(hdr, m->bc_syncpt);
+                        }
                         __skb_queue_tail(inputq, skb);
                 }
                 list_del_init(&m->list);