4.14-stable review patch. If anyone has any objections, please let me know.
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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 @@ -844,7 +844,7 @@ static void tcp_v4_reqsk_send_ack(const tcp_time_stamp_raw() + tcp_rsk(req)->ts_off, 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 @@ -988,7 +988,7 @@ static void tcp_v6_reqsk_send_ack(const req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, tcp_time_stamp_raw() + tcp_rsk(req)->ts_off, 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); }