| Message ID | 20171211080546.89418-1-cpaasch@apple.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] tcp md5sig: Use skb's saddr when replying to an incoming segment | expand |
On Mon, 2017-12-11 at 00:05 -0800, Christoph Paasch wrote: > 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> > --- > net/ipv4/tcp_ipv4.c | 2 +- > net/ipv6/tcp_ipv6.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) Reviewed-by: Eric Dumazet <edumazet@google.com> Thanks !
From: Christoph Paasch <cpaasch@apple.com> Date: Mon, 11 Dec 2017 00:05:46 -0800 > 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> Applied and queued up for -stable, thanks.
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 77ea45da0fe9..94e28350f420 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -848,7 +848,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 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); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 1f04ec0e4a7a..7178476b3d2f 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -994,7 +994,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 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); }
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> --- net/ipv4/tcp_ipv4.c | 2 +- net/ipv6/tcp_ipv6.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)