Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761466Ab2FHFQv (ORCPT ); Fri, 8 Jun 2012 01:16:51 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43308 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761384Ab2FHFH0 (ORCPT ); Fri, 8 Jun 2012 01:07:26 -0400 Message-Id: <20120608041849.860434443@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 08 Jun 2012 05:19:47 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, James Chapman , Sasha Levin Subject: [ 67/82] l2tp: fix oops in L2TP IP sockets for connect() AF_UNSPEC case In-Reply-To: <20120608041840.861504477@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3738 Lines: 117 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Chapman [ Upstream commit c51ce49735c183ef2592db70f918ee698716276b ] An application may call connect() to disconnect a socket using an address with family AF_UNSPEC. The L2TP IP sockets were not handling this case when the socket is not bound and an attempt to connect() using AF_UNSPEC in such cases would result in an oops. This patch addresses the problem by protecting the sk_prot->disconnect() call against trying to unhash the socket before it is bound. The patch also adds more checks that the sockaddr supplied to bind() and connect() calls is valid. RIP: 0010:[] [] inet_unhash+0x50/0xd0 RSP: 0018:ffff88001989be28 EFLAGS: 00010293 Stack: ffff8800407a8000 0000000000000000 ffff88001989be78 ffffffff82e3a249 ffffffff82e3a050 ffff88001989bec8 ffff88001989be88 ffff8800407a8000 0000000000000010 ffff88001989bec8 ffff88001989bea8 ffffffff82e42639 Call Trace: [] udp_disconnect+0x1f9/0x290 [] inet_dgram_connect+0x29/0x80 [] sys_connect+0x9c/0x100 Reported-by: Sasha Levin Signed-off-by: James Chapman Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_ip.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 2a2a3e7..2fbbe1f 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -251,9 +251,16 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) { struct inet_sock *inet = inet_sk(sk); struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr; - int ret = -EINVAL; + int ret; int chk_addr_ret; + if (!sock_flag(sk, SOCK_ZAPPED)) + return -EINVAL; + if (addr_len < sizeof(struct sockaddr_l2tpip)) + return -EINVAL; + if (addr->l2tp_family != AF_INET) + return -EINVAL; + ret = -EADDRINUSE; read_lock_bh(&l2tp_ip_lock); if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id)) @@ -283,6 +290,8 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) sk_del_node_init(sk); write_unlock_bh(&l2tp_ip_lock); ret = 0; + sock_reset_flag(sk, SOCK_ZAPPED); + out: release_sock(sk); @@ -303,13 +312,14 @@ static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len __be32 saddr; int oif, rc; - rc = -EINVAL; + if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */ + return -EINVAL; + if (addr_len < sizeof(*lsa)) - goto out; + return -EINVAL; - rc = -EAFNOSUPPORT; if (lsa->l2tp_family != AF_INET) - goto out; + return -EAFNOSUPPORT; lock_sock(sk); @@ -363,6 +373,14 @@ out: return rc; } +static int l2tp_ip_disconnect(struct sock *sk, int flags) +{ + if (sock_flag(sk, SOCK_ZAPPED)) + return 0; + + return udp_disconnect(sk, flags); +} + static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) { @@ -598,7 +616,7 @@ static struct proto l2tp_ip_prot = { .close = l2tp_ip_close, .bind = l2tp_ip_bind, .connect = l2tp_ip_connect, - .disconnect = udp_disconnect, + .disconnect = l2tp_ip_disconnect, .ioctl = udp_ioctl, .destroy = l2tp_ip_destroy_sock, .setsockopt = ip_setsockopt, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/