tcp: fix possible sk_priority leak in tcp_v4_send_reset()

When tcp_v4_send_reset() is called with @sk == NULL,
we do not change ctl_sk->sk_priority, which could have been
set from a prior invocation.

Change tcp_v4_send_reset() to set sk_priority and sk_mark
fields before calling ip_send_unicast_reply().

This means tcp_v4_send_reset() and tcp_v4_send_ack()
no longer have to clear ctl_sk->sk_mark after
their call to ip_send_unicast_reply().

Fixes: f6c0f5d209fa ("tcp: honor SO_PRIORITY in TIME_WAIT state")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Antoine Tenart <atenart@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 39bda2b..06d2573 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -829,6 +829,9 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
                                   inet_twsk(sk)->tw_priority : sk->sk_priority;
                transmit_time = tcp_transmit_time(sk);
                xfrm_sk_clone_policy(ctl_sk, sk);
+       } else {
+               ctl_sk->sk_mark = 0;
+               ctl_sk->sk_priority = 0;
        }
        ip_send_unicast_reply(ctl_sk,
                              skb, &TCP_SKB_CB(skb)->header.h4.opt,
@@ -836,7 +839,6 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
                              &arg, arg.iov[0].iov_len,
                              transmit_time);
 
-       ctl_sk->sk_mark = 0;
        xfrm_sk_free_policy(ctl_sk);
        sock_net_set(ctl_sk, &init_net);
        __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
@@ -935,7 +937,6 @@ static void tcp_v4_send_ack(const struct sock *sk,
                              &arg, arg.iov[0].iov_len,
                              transmit_time);
 
-       ctl_sk->sk_mark = 0;
        sock_net_set(ctl_sk, &init_net);
        __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
        local_bh_enable();