From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam01on0135.outbound.protection.outlook.com ([104.47.34.135]:24293 "EHLO NAM01-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1031992AbeCAP1O (ORCPT ); Thu, 1 Mar 2018 10:27:14 -0500 From: Sasha Levin To: "stable@vger.kernel.org" , "stable-commits@vger.kernel.org" CC: Christoph Paasch , "David S . Miller" , Sasha Levin Subject: [added to the 4.1 stable tree] tcp md5sig: Use skb's saddr when replying to an incoming segment Date: Thu, 1 Mar 2018 15:23:23 +0000 Message-ID: <20180301152116.1486-89-alexander.levin@microsoft.com> References: <20180301152116.1486-1-alexander.levin@microsoft.com> In-Reply-To: <20180301152116.1486-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Christoph Paasch This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ 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 t= cp_v{4,6}_do_calc_md5_hash().") Signed-off-by: Christoph Paasch Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_ipv4.c | 2 +- net/ipv6/tcp_ipv6.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 2923f7f7932a..38e9dc5b735d 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -814,7 +814,7 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, stru= ct sk_buff *skb, 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); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2f0f1b415fbe..9f274781ba57 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -940,7 +940,7 @@ static void tcp_v6_reqsk_send_ack(struct sock *sk, stru= ct sk_buff *skb, tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, tcp_rsk(req)->rcv_nxt, req->rcv_wnd, 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); } =20 --=20 2.14.1