Commit 5a542133 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller

tcp: Fix data-races around sysctl_tcp_fastopen.

While reading sysctl_tcp_fastopen, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 2100c8d2 ("net-tcp: Fast Open base")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 79539f34
......@@ -217,7 +217,7 @@ int inet_listen(struct socket *sock, int backlog)
* because the socket was in TCP_LISTEN state previously but
* was shutdown() rather than close().
*/
tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
tcp_fastopen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen);
if ((tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) &&
(tcp_fastopen & TFO_SERVER_ENABLE) &&
!inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
......
......@@ -1150,7 +1150,8 @@ static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
struct sockaddr *uaddr = msg->msg_name;
int err, flags;
if (!(sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) ||
if (!(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) &
TFO_CLIENT_ENABLE) ||
(uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
uaddr->sa_family == AF_UNSPEC))
return -EOPNOTSUPP;
......@@ -3617,7 +3618,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
case TCP_FASTOPEN_CONNECT:
if (val > 1 || val < 0) {
err = -EINVAL;
} else if (net->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) {
} else if (READ_ONCE(net->ipv4.sysctl_tcp_fastopen) &
TFO_CLIENT_ENABLE) {
if (sk->sk_state == TCP_CLOSE)
tp->fastopen_connect = val;
else
......
......@@ -332,7 +332,7 @@ static bool tcp_fastopen_no_cookie(const struct sock *sk,
const struct dst_entry *dst,
int flag)
{
return (sock_net(sk)->ipv4.sysctl_tcp_fastopen & flag) ||
return (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) & flag) ||
tcp_sk(sk)->fastopen_no_cookie ||
(dst && dst_metric(dst, RTAX_FASTOPEN_NO_COOKIE));
}
......@@ -347,7 +347,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
const struct dst_entry *dst)
{
bool syn_data = TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1;
int tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
int tcp_fastopen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen);
struct tcp_fastopen_cookie valid_foc = { .len = -1 };
struct sock *child;
int ret = 0;
......
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