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* [PATCH net] ping: implement proper locking
@ 2017-03-24 23:29 Eric Dumazet
  2017-03-25  0:30 ` Solar Designer
  2017-03-25  2:10 ` David Miller
  0 siblings, 2 replies; 6+ messages in thread
From: Eric Dumazet @ 2017-03-24 23:29 UTC (permalink / raw)
  To: David Miller; +Cc: netdev, Solar Designer, Andrey Konovalov, Eric Dumazet

From: Eric Dumazet <edumazet@google.com>

We got a report of yet another bug in ping

http://www.openwall.com/lists/oss-security/2017/03/24/6

->disconnect() is not called with socket lock held.

Fix this by acquiring ping rwlock earlier.

Thanks to Alexander and Andrey for letting us know of this problem.

Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind")
Reported-by: Solar Designer <solar@openwall.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
---
 net/ipv4/ping.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 2af6244b83e27ae384e96cf071c10c5a89674804..ccfbce13a6333a65dab64e4847dd510dfafb1b43 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -156,17 +156,18 @@ int ping_hash(struct sock *sk)
 void ping_unhash(struct sock *sk)
 {
 	struct inet_sock *isk = inet_sk(sk);
+
 	pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
+	write_lock_bh(&ping_table.lock);
 	if (sk_hashed(sk)) {
-		write_lock_bh(&ping_table.lock);
 		hlist_nulls_del(&sk->sk_nulls_node);
 		sk_nulls_node_init(&sk->sk_nulls_node);
 		sock_put(sk);
 		isk->inet_num = 0;
 		isk->inet_sport = 0;
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-		write_unlock_bh(&ping_table.lock);
 	}
+	write_unlock_bh(&ping_table.lock);
 }
 EXPORT_SYMBOL_GPL(ping_unhash);
 

^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2017-03-25  3:51 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-03-24 23:29 [PATCH net] ping: implement proper locking Eric Dumazet
2017-03-25  0:30 ` Solar Designer
2017-03-25  2:10 ` David Miller
2017-03-25  2:33   ` Eric Dumazet
2017-03-25  2:36   ` [PATCH v2 " Eric Dumazet
2017-03-25  3:51     ` David Miller

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