Subject: [PATCH] tcp: Fix MD5 signature checking on IPv4 mapped sockets

From: John Dykstra <[email-masked]>
Date: Thu, 16 Jul 2009 02:13:21 +0000

Fix MD5 signature checking so that an IPv4 active open
to an IPv6 socket can succeed.  In particular, use the
correct address family's signature generation function
for the SYN/ACK.

Reported-by:   Stephen Hemminger <[email-masked]>
Signed-off-by: John Dykstra <[email-masked]>
---
 include/net/tcp.h     |    5 +++++
 net/ipv4/tcp_ipv4.c   |    1 +
 net/ipv4/tcp_output.c |    3 ++-
 net/ipv6/tcp_ipv6.c   |    1 +
 4 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 19f4150..88af843 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1425,6 +1425,11 @@ struct tcp_request_sock_ops {
 #ifdef CONFIG_TCP_MD5SIG
 	struct tcp_md5sig_key	*(*md5_lookup) (struct sock *sk,
 						struct request_sock *req);
+	int			(*calc_md5_hash) (char *location,
+						  struct tcp_md5sig_key *md5,
+						  struct sock *sk,
+						  struct request_sock *req,
+						  struct sk_buff *skb);
 #endif
 };
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5a1ca26..7c107eb 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1160,6 +1160,7 @@ struct request_sock_ops tcp_request_sock_ops __read_mostly = {
 #ifdef CONFIG_TCP_MD5SIG
 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
 	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
+	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
 };
 #endif
 
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 5bdf08d..17b049f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2261,7 +2261,8 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 #ifdef CONFIG_TCP_MD5SIG
 	/* Okay, we have all we need - do the md5 hash if needed */
 	if (md5) {
-		tp->af_specific->calc_md5_hash(md5_hash_location,
+		tcp_rsk(req)->af_specific->calc_md5_hash(md5_hash_location,
+
 					       md5, NULL, req, skb);
 	}
 #endif
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 58810c6..ae3d657 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -896,6 +896,7 @@ struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 #ifdef CONFIG_TCP_MD5SIG
 static struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 	.md5_lookup	=	tcp_v6_reqsk_md5_lookup,
+	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
 };
 #endif
 
-- 
1.5.4.3