| From foo@baz Sun Dec 31 11:13:15 CET 2017 |
| From: Christoph Paasch <cpaasch@apple.com> |
| Date: Mon, 11 Dec 2017 00:05:46 -0800 |
| Subject: tcp md5sig: Use skb's saddr when replying to an incoming segment |
| |
| From: Christoph Paasch <cpaasch@apple.com> |
| |
| |
| [ Upstream commit 30791ac41927ebd3e75486f9504b6d2280463bf0 ] |
| |
| The MD5-key that belongs to a connection is identified by the peer's |
| IP-address. When we are in tcp_v4(6)_reqsk_send_ack(), we are replying |
| to an incoming segment from tcp_check_req() that failed the seq-number |
| checks. |
| |
| Thus, to find the correct key, we need to use the skb's saddr and not |
| the daddr. |
| |
| This bug seems to have been there since quite a while, but probably got |
| unnoticed because the consequences are not catastrophic. We will call |
| tcp_v4_reqsk_send_ack only to send a challenge-ACK back to the peer, |
| thus the connection doesn't really fail. |
| |
| Fixes: 9501f9722922 ("tcp md5sig: Let the caller pass appropriate key for tcp_v{4,6}_do_calc_md5_hash().") |
| Signed-off-by: Christoph Paasch <cpaasch@apple.com> |
| Reviewed-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/ipv4/tcp_ipv4.c | 2 +- |
| net/ipv6/tcp_ipv6.c | 2 +- |
| 2 files changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/net/ipv4/tcp_ipv4.c |
| +++ b/net/ipv4/tcp_ipv4.c |
| @@ -828,7 +828,7 @@ static void tcp_v4_reqsk_send_ack(const |
| tcp_time_stamp, |
| req->ts_recent, |
| 0, |
| - tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr, |
| + tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr, |
| AF_INET), |
| inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, |
| ip_hdr(skb)->tos); |
| --- a/net/ipv6/tcp_ipv6.c |
| +++ b/net/ipv6/tcp_ipv6.c |
| @@ -962,7 +962,7 @@ static void tcp_v6_reqsk_send_ack(const |
| tcp_rsk(req)->rcv_nxt, |
| req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, |
| tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, |
| - tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), |
| + tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr), |
| 0, 0); |
| } |
| |
