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tcp md5sig: Use skb's saddr when replying to an incoming segment

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[ Upstream commit 30791ac419 ]

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: 9501f97229 ("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>
This commit is contained in:
Christoph Paasch
2017-12-11 00:05:46 -08:00
committed by Greg Kroah-Hartman
parent a4bf8efd2b
commit 7887a700ce
2 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
net/ipv4/tcp_ipv4.c
View File

@ -828,7 +828,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
tcp_time_stamp, tcp_time_stamp,
req->ts_recent, req->ts_recent,
0, 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), AF_INET),
inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
ip_hdr(skb)->tos); ip_hdr(skb)->tos);

2
net/ipv6/tcp_ipv6.c
View File

@ -962,7 +962,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
tcp_rsk(req)->rcv_nxt, tcp_rsk(req)->rcv_nxt,
req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, 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); 0, 0);
} }