From ba9e04a7ddf4f22a10e05bf9403db6b97743c7bf Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Tue, 8 Sep 2020 14:09:34 -0700 Subject: ip: fix tos reflection in ack and reset packets Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we echo the TOS value of the received packets in the response. However, we do not want to echo the lower 2 ECN bits in accordance with RFC 3168 6.1.5 robustness principles. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/ip_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/ipv4/ip_output.c') diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 61f802d5350c..e6f2ada9e7d5 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -74,6 +74,7 @@ #include #include #include +#include #include #include #include @@ -1703,7 +1704,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, if (IS_ERR(rt)) return; - inet_sk(sk)->tos = arg->tos; + inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK; sk->sk_protocol = ip_hdr(skb)->protocol; sk->sk_bound_dev_if = arg->bound_dev_if; -- cgit v1.2.3-58-ga151