3.2-stable review patch. If anyone has any objections, please let me know.
------------------ From: James Chapman <[email protected]> [ 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:[<ffffffff82e133b0>] [<ffffffff82e133b0>] inet_unhash+0x50/0xd0 RSP: 0018:ffff88001989be28 EFLAGS: 00010293 Stack: ffff8800407a8000 0000000000000000 ffff88001989be78 ffffffff82e3a249 ffffffff82e3a050 ffff88001989bec8 ffff88001989be88 ffff8800407a8000 0000000000000010 ffff88001989bec8 ffff88001989bea8 ffffffff82e42639 Call Trace: [<ffffffff82e3a249>] udp_disconnect+0x1f9/0x290 [<ffffffff82e42639>] inet_dgram_connect+0x29/0x80 [<ffffffff82d012fc>] sys_connect+0x9c/0x100 Reported-by: Sasha Levin <[email protected]> Signed-off-by: James Chapman <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- 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 stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
