From: Wei Wang weiwan@google.com
stable inclusion from linux-4.19.148 commit 2fc322bf67594e240eb23b4e0c6c8a09c69f9918
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[ Upstream commit ba9e04a7ddf4f22a10e05bf9403db6b97743c7bf ]
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 weiwan@google.com Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com
Signed-off-by: Aichun Li liaichun@huawei.com Reviewed-by: wangxiaopeng wangxiaopeng7@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/ipv4/ip_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index fbf30122e8bf..f0faf1193dd8 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -73,6 +73,7 @@ #include <net/icmp.h> #include <net/checksum.h> #include <net/inetpeer.h> +#include <net/inet_ecn.h> #include <net/lwtunnel.h> #include <linux/bpf-cgroup.h> #include <linux/igmp.h> @@ -1582,7 +1583,7 @@ 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_priority = skb->priority; sk->sk_protocol = ip_hdr(skb)->protocol;