Commit 692925fe authored by Jon Paul Maloy's avatar Jon Paul Maloy Committed by Greg Kroah-Hartman

tipc: fix premature addition of node to lookup table

[ Upstream commit d5c91fb7 ]

In commit 52666986 ("tipc: let broadcast packet reception
use new link receive function") we introduced a new per-node
broadcast reception link instance. This link is created at the
moment the node itself is created. Unfortunately, the allocation
is done after the node instance has already been added to the node
lookup hash table. This creates a potential race condition, where
arriving broadcast packets are able to find and access the node
before it has been fully initialized, and before the above mentioned
link has been created. The result is occasional crashes in the function
tipc_bcast_rcv(), which is trying to access the not-yet existing link.

We fix this by deferring the addition of the node instance until after
it has been fully initialized in the function tipc_node_create().
Acked-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1bd36785
......@@ -168,12 +168,6 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
skb_queue_head_init(&n_ptr->bc_entry.inputq1);
__skb_queue_head_init(&n_ptr->bc_entry.arrvq);
skb_queue_head_init(&n_ptr->bc_entry.inputq2);
hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
if (n_ptr->addr < temp_node->addr)
break;
}
list_add_tail_rcu(&n_ptr->list, &temp_node->list);
n_ptr->state = SELF_DOWN_PEER_LEAVING;
n_ptr->signature = INVALID_NODE_SIG;
n_ptr->active_links[0] = INVALID_BEARER_ID;
......@@ -193,6 +187,12 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
tipc_node_get(n_ptr);
setup_timer(&n_ptr->timer, tipc_node_timeout, (unsigned long)n_ptr);
n_ptr->keepalive_intv = U32_MAX;
hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
if (n_ptr->addr < temp_node->addr)
break;
}
list_add_tail_rcu(&n_ptr->list, &temp_node->list);
exit:
spin_unlock_bh(&tn->node_list_lock);
return n_ptr;
......
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