[PATCH 4.19 12/61] tipc: purge deferredq list for each grp member in tipc_group_delete

[Greg Kroah-Hartman]

From: Xin Long <lucien.xin@xxxxxxxxx>

[ Upstream commit 5cf02612b33f104fe1015b2dfaf1758ad3675588 ]

Syzbot reported a memleak caused by grp members' deferredq list not
purged when the grp is be deleted.

The issue occurs when more(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt) in
tipc_group_filter_msg() and the skb will stay in deferredq.

So fix it by calling __skb_queue_purge for each member's deferredq
in tipc_group_delete() when a tipc sk leaves the grp.

Fixes: b87a5ea31c93 ("tipc: guarantee group unicast doesn't bypass group broadcast")
Reported-by: syzbot+78fbe679c8ca8d264a8d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Ying Xue <ying.xue@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tipc/group.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -218,6 +218,7 @@ void tipc_group_delete(struct net *net,
 
 	rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
 		tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
+		__skb_queue_purge(&m->deferredq);
 		list_del(&m->list);
 		kfree(m);
 	}