On Wed, Nov 16, 2016 at 8:30 AM, Guillaume Nault <g.na...@alphalink.fr> wrote: > diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c > index fce25af..982f6c4 100644 > --- a/net/l2tp/l2tp_ip.c > +++ b/net/l2tp/l2tp_ip.c > @@ -251,8 +251,6 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr > *uaddr, int addr_len) > 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) > @@ -267,6 +265,9 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr > *uaddr, int addr_len) > read_unlock_bh(&l2tp_ip_lock); > > lock_sock(sk); > + if (!sock_flag(sk, SOCK_ZAPPED)) > + goto out; > + > if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct > sockaddr_l2tpip)) > goto out; > > diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c > index ad3468c..9978d01 100644 > --- a/net/l2tp/l2tp_ip6.c > +++ b/net/l2tp/l2tp_ip6.c > @@ -269,8 +269,6 @@ static int l2tp_ip6_bind(struct sock *sk, struct sockaddr > *uaddr, int addr_len) > int addr_type; > int err; > > - if (!sock_flag(sk, SOCK_ZAPPED)) > - return -EINVAL; > if (addr->l2tp_family != AF_INET6) > return -EINVAL; > if (addr_len < sizeof(*addr)) > @@ -296,6 +294,9 @@ static int l2tp_ip6_bind(struct sock *sk, struct sockaddr > *uaddr, int addr_len) > lock_sock(sk); > > err = -EINVAL; > + if (!sock_flag(sk, SOCK_ZAPPED)) > + goto out_unlock; > + > if (sk->sk_state != TCP_CLOSE) > goto out_unlock;
Makes sense, it should prevent a concurrent caller adding the socket into bind table twice after passing __l2tp_ip_bind_lookup() check.
