Thread (194 messages) 194 messages, 10 authors, 2012-06-27

[ 167/175] net: fix a potential rcu_read_lock() imbalance in rt6_fill_node()

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2012-03-30 21:36:12
Also in: lkml

3.3-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Eric Dumazet <redacted>

[ Upstream commit 94f826b8076e2cb92242061e92f21b5baa3eccc2 ]

Commit f2c31e32b378 (net: fix NULL dereferences in check_peer_redir() )
added a regression in rt6_fill_node(), leading to rcu_read_lock()
imbalance.

Thats because NLA_PUT() can make a jump to nla_put_failure label.

Fix this by using nla_put()

Many thanks to Ben Greear for his help

Reported-by: Ben Greear <redacted>
Reported-by: Dave Jones <redacted>
Signed-off-by: Eric Dumazet <redacted>
Tested-by: Ben Greear <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/route.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2461,8 +2461,12 @@ static int rt6_fill_node(struct net *net
 
 	rcu_read_lock();
 	n = dst_get_neighbour_noref(&rt->dst);
-	if (n)
-		NLA_PUT(skb, RTA_GATEWAY, 16, &n->primary_key);
+	if (n) {
+		if (nla_put(skb, RTA_GATEWAY, 16, &n->primary_key) < 0) {
+			rcu_read_unlock();
+			goto nla_put_failure;
+		}
+	}
 	rcu_read_unlock();
 
 	if (rt->dst.dev)

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