tipc: correct initial value for group congestion flag

In commit 60c25306 ("tipc: fix race between poll() and
setsockopt()") we introduced a pointer from struct tipc_group to the
'group_is_connected' flag in struct tipc_sock, so that this field can
be checked without dereferencing the group pointer of the latter struct.

The initial value for this flag is correctly set to 'false' when a
group is created, but we miss the case when no group is created at
all, in which case the initial value should be 'true'. This has the
effect that SOCK_RDM/DGRAM sockets sending datagrams never receive
POLLOUT if they request so.

This commit corrects this bug.

Fixes: 60c25306 ("tipc: fix race between poll() and setsockopt()")
Reported-by: Hoang Le <hoang.h.le@dektek.com.au>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/group.c

@@ -189,6 +189,7 @@ struct tipc_group *tipc_group_create(struct net *net, u32 portid,
 	grp->loopback = mreq->flags & TIPC_GROUP_LOOPBACK;
 	grp->events = mreq->flags & TIPC_GROUP_MEMBER_EVTS;
 	grp->open = group_is_open;
+	*grp->open = false;
 	filter |= global ? TIPC_SUB_CLUSTER_SCOPE : TIPC_SUB_NODE_SCOPE;
 	if (tipc_topsrv_kern_subscr(net, portid, type, 0, ~0,
 				    filter, &grp->subid))

net/tipc/socket.c

@@ -473,6 +473,7 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
 	sk->sk_write_space = tipc_write_space;
 	sk->sk_destruct = tipc_sock_destruct;
 	tsk->conn_timeout = CONN_TIMEOUT_DEFAULT;
+	tsk->group_is_open = true;
 	atomic_set(&tsk->dupl_rcvcnt, 0);
 
 	/* Start out with safe limits until we receive an advertised window */