l2tp: Fix locking in l2tp_ip.c
Both l2tp_ip_connect() and l2tp_ip_sendmsg() must take the socket
lock. They both modify socket state non-atomically, and in particular
l2tp_ip_sendmsg() increments socket private counters without using
atomic operations.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 8189960..bd0cc0b 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -311,6 +311,8 @@
if (lsa->l2tp_family != AF_INET)
goto out;
+ lock_sock(sk);
+
sk_dst_reset(sk);
oif = sk->sk_bound_dev_if;
@@ -356,6 +358,7 @@
rc = 0;
out:
+ release_sock(sk);
return rc;
}
@@ -420,18 +423,23 @@
int connected = 0;
__be32 daddr;
+ lock_sock(sk);
+
+ rc = -ENOTCONN;
if (sock_flag(sk, SOCK_DEAD))
- return -ENOTCONN;
+ goto out;
/* Get and verify the address. */
if (msg->msg_name) {
struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
+ rc = -EINVAL;
if (msg->msg_namelen < sizeof(*lip))
- return -EINVAL;
+ goto out;
if (lip->l2tp_family != AF_INET) {
+ rc = -EAFNOSUPPORT;
if (lip->l2tp_family != AF_UNSPEC)
- return -EAFNOSUPPORT;
+ goto out;
}
daddr = lip->l2tp_addr.s_addr;
@@ -510,12 +518,15 @@
lsa->tx_errors++;
}
+out:
+ release_sock(sk);
return rc;
no_route:
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
- return -EHOSTUNREACH;
+ rc = -EHOSTUNREACH;
+ goto out;
}
static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,