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tcp: Fix data-races around sysctl_tcp_fastopen.

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[ Upstream commit 5a54213318c43f4009ae158347aa6016e3b9b55a ]

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

Fixes: 2100c8d2d9 ("net-tcp: Fast Open base")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:54 -07:00 committed by Greg Kroah-Hartman
parent 78420d8e46
commit 25d53d858a
3 changed files with 7 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/ipv4/af_inet.c
View File

@ -219,7 +219,7 @@ 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) {

6
net/ipv4/tcp.c
View File

@ -1148,7 +1148,8 @@ 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;
@ -3127,7 +3128,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
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

4
net/ipv4/tcp_fastopen.c
View File

@ -349,7 +349,7 @@ 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));
}
@ -364,7 +364,7 @@ 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;