From de058420767df21e2b6b0f3bb36d1616fb962032 Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Wed, 15 Apr 2020 16:40:28 +0800 Subject: [PATCH] tipc: Fix potential tipc_node refcnt leak in tipc_rcv tipc_rcv() invokes tipc_node_find() twice, which returns a reference of the specified tipc_node object to "n" with increased refcnt. When tipc_rcv() returns or a new object is assigned to "n", the original local reference of "n" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in some paths of tipc_rcv(), which forget to decrease the refcnt increased by tipc_node_find() and will cause a refcnt leak. Fix this issue by calling tipc_node_put() before the original object pointed by "n" becomes invalid. Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: David S. Miller --- net/tipc/node.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/tipc/node.c b/net/tipc/node.c index 10292c942384..803a3a6d0f50 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -2038,6 +2038,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b) n = tipc_node_find_by_id(net, ehdr->id); } tipc_crypto_rcv(net, (n) ? n->crypto_rx : NULL, &skb, b); + tipc_node_put(n); if (!skb) return; @@ -2090,7 +2091,7 @@ rcv: /* Check/update node state before receiving */ if (unlikely(skb)) { if (unlikely(skb_linearize(skb))) - goto discard; + goto out_node_put; tipc_node_write_lock(n); if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) { if (le->link) { @@ -2119,6 +2120,7 @@ rcv: if (!skb_queue_empty(&xmitq)) tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr, n); +out_node_put: tipc_node_put(n); discard: kfree_skb(skb);