lkml.org 
[lkml]   [2022]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 23/62] tcp: Fix data-races around sysctl_tcp_fastopen.
    Date
    From: Kuniyuki Iwashima <kuniyu@amazon.com>

    [ Upstream commit 5a54213318c43f4009ae158347aa6016e3b9b55a ]

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

    Fixes: 2100c8d2d9db ("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>
    ---
    net/ipv4/af_inet.c | 2 +-
    net/ipv4/tcp.c | 6 ++++--
    net/ipv4/tcp_fastopen.c | 4 ++--
    3 files changed, 7 insertions(+), 5 deletions(-)

    diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
    index dadd42a07c07..229519001cc3 100644
    --- a/net/ipv4/af_inet.c
    +++ b/net/ipv4/af_inet.c
    @@ -218,7 +218,7 @@ 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) {
    diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
    index 0f89d0f2c21f..7acc0d07f148 100644
    --- a/net/ipv4/tcp.c
    +++ b/net/ipv4/tcp.c
    @@ -1160,7 +1160,8 @@ 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;
    @@ -3056,7 +3057,8 @@ 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
    diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
    index 119d2c2f3b04..f726591de7c7 100644
    --- a/net/ipv4/tcp_fastopen.c
    +++ b/net/ipv4/tcp_fastopen.c
    @@ -313,7 +313,7 @@ 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));
    }
    @@ -328,7 +328,7 @@ 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;

    --
    2.35.1


    \
     
     \ /
      Last update: 2022-07-27 18:37    [W:4.020 / U:0.044 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site