From: Stephen Hemminger <shemminger@osdl.org>
To: Henner Eisen <eis@baty.hanse.de>, "David S. Miller" <davem@redhat.com>
Cc: linux-x25@vger.kernel.org, netdev@oss.sgi.com
Subject: [PATCH] Fix X.25 use after free.
Date: Tue, 5 Aug 2003 15:01:10 -0700 [thread overview]
Message-ID: <20030805150110.0e2753ab.shemminger@osdl.org> (raw)
The conversion from cli/sti to locking in X.25 must not have been tested
on a real SMP with memory debugging enabled. It OOPS right away if
I do:
modprobe x25; ifconfig -a
The problem is that it dereferences the socket after it has already been
freed. The fix for this is to make the call to sock_put, later in
x25_destroy_socket do the free. Also, need a go to avoid references
in x25_release.
This patch is against 2.6.0-test2.
diff -urNp -X dontdiff net-2.5/net/x25/af_x25.c linux-2.5-net/net/x25/af_x25.c
--- net-2.5/net/x25/af_x25.c 2003-08-01 11:12:02.000000000 -0700
+++ linux-2.5-net/net/x25/af_x25.c 2003-08-05 12:14:42.000000000 -0700
@@ -350,8 +350,11 @@ void x25_destroy_socket(struct sock *sk)
sk->sk_timer.function = x25_destroy_timer;
sk->sk_timer.data = (unsigned long)sk;
add_timer(&sk->sk_timer);
- } else
- sk_free(sk);
+ } else {
+ /* drop last reference so sock_put will free */
+ __sock_put(sk);
+ }
+
release_sock(sk);
sock_put(sk);
}
@@ -553,7 +556,7 @@ static int x25_release(struct socket *so
case X25_STATE_2:
x25_disconnect(sk, 0, 0, 0);
x25_destroy_socket(sk);
- break;
+ goto out;
case X25_STATE_1:
case X25_STATE_3:
next reply other threads:[~2003-08-05 22:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-05 22:01 Stephen Hemminger [this message]
2003-08-06 0:34 ` [PATCH] Fix X.25 use after free James Morris
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