l2tp: fix oops in L2TP IP sockets for connect() AF_UNSPEC case

[ Upstream commit c51ce49735 ]

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 <levinsasha928@gmail.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Chapman 2012-05-29 23:13:23 +00:00 committed by Greg Kroah-Hartman
parent be078c8003
commit ea1ae37f4a

View file

@ -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))
@ -284,6 +291,8 @@ 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);
@ -304,13 +313,14 @@ static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len
__be32 saddr;
int oif, rc;
rc = -EINVAL;
if (addr_len < sizeof(*lsa))
goto out;
if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
return -EINVAL;
if (addr_len < sizeof(*lsa))
return -EINVAL;
rc = -EAFNOSUPPORT;
if (lsa->l2tp_family != AF_INET)
goto out;
return -EAFNOSUPPORT;
lock_sock(sk);
@ -364,6 +374,14 @@ 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)
{
@ -599,7 +617,7 @@ 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,