diff mbox series

[5.6,063/167] tipc: Fix potential tipc_node refcnt leak in tipc_rcv

Message ID 20200428182232.923942002@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH April 28, 2020, 6:23 p.m. UTC 
From: Xiyu Yang <xiyuyang19@fudan.edu.cn>

[ Upstream commit de058420767df21e2b6b0f3bb36d1616fb962032 ]

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 <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/tipc/node.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -2037,6 +2037,7 @@  void tipc_rcv(struct net *net, struct sk
 		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;
 
@@ -2089,7 +2090,7 @@  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) {
@@ -2118,6 +2119,7 @@  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);