From c3c359817d6e99f8d02a718787109779bbd92b02 Mon Sep 17 00:00:00 2001
From: Sabrina Dubroca <sd@queasysnail.net>
Date: Wed, 4 Dec 2019 15:35:52 +0100
Subject: [PATCH 2/3] net: ipv6: add net argument to ip6_dst_lookup_flow

[ Upstream commit c4e85f73afb6384123e5ef1bba3315b2e3ad031e ]

Fixes CVE-2020-1749
Backported from v5.5-rc1
Patch 2/3

This will be used in the conversion of ipv6_stub to ip6_dst_lookup_flow,
as some modules currently pass a net argument without a socket to
ip6_dst_lookup. This is equivalent to commit 343d60aada5a ("ipv6: change
ipv6_stub_impl.ipv6_dst_lookup to take net argument").

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Carsten Schmid <carsten_schmid@mentor.com>
---
 include/net/ipv6.h               | 2 +-
 net/dccp/ipv6.c                  | 6 +++---
 net/ipv6/af_inet6.c              | 2 +-
 net/ipv6/datagram.c              | 2 +-
 net/ipv6/inet6_connection_sock.c | 4 ++--
 net/ipv6/ip6_output.c            | 8 ++++----
 net/ipv6/raw.c                   | 2 +-
 net/ipv6/syncookies.c            | 2 +-
 net/ipv6/tcp_ipv6.c              | 4 ++--
 net/l2tp/l2tp_ip6.c              | 2 +-
 net/sctp/ipv6.c                  | 4 ++--
 11 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 6294d20a5f0e..cc57e136228b 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -862,7 +862,7 @@ static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
 
 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
 		   struct flowi6 *fl6);
-struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
+struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
 				      const struct in6_addr *final_dst);
 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 					 const struct in6_addr *final_dst);
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 58a401e9cf09..b438bed6749d 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -211,7 +211,7 @@ static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req
 	final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
 	rcu_read_unlock();
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		dst = NULL;
@@ -282,7 +282,7 @@ static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
 	security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
 
 	/* sk = NULL, but it is safe for now. RST socket required. */
-	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
+	dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL);
 	if (!IS_ERR(dst)) {
 		skb_dst_set(skb, dst);
 		ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0);
@@ -912,7 +912,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 	final_p = fl6_update_dst(&fl6, opt, &final);
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto failure;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 73c5275a6a85..12aa241ad533 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -717,7 +717,7 @@ int inet6_sk_rebuild_header(struct sock *sk)
 					 &final);
 		rcu_read_unlock();
 
-		dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+		dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 		if (IS_ERR(dst)) {
 			sk->sk_route_caps = 0;
 			sk->sk_err_soft = -PTR_ERR(dst);
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 1ee3e0d2b587..16a28f4307fb 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -88,7 +88,7 @@ int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr)
 	final_p = fl6_update_dst(&fl6, opt, &final);
 	rcu_read_unlock();
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto out;
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 890adadcda16..92fe9e565da0 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -52,7 +52,7 @@ struct dst_entry *inet6_csk_route_req(const struct sock *sk,
 	fl6->flowi6_uid = sk->sk_uid;
 	security_req_classify_flow(req, flowi6_to_flowi(fl6));
 
-	dst = ip6_dst_lookup_flow(sk, fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
 	if (IS_ERR(dst))
 		return NULL;
 
@@ -107,7 +107,7 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 
 	dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 	if (!dst) {
-		dst = ip6_dst_lookup_flow(sk, fl6, final_p);
+		dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
 
 		if (!IS_ERR(dst))
 			ip6_dst_store(sk, dst, NULL, NULL);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 2af849ba33c9..5198bc123204 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1089,19 +1089,19 @@ EXPORT_SYMBOL_GPL(ip6_dst_lookup);
  *	It returns a valid dst pointer on success, or a pointer encoded
  *	error code.
  */
-struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
+struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
 				      const struct in6_addr *final_dst)
 {
 	struct dst_entry *dst = NULL;
 	int err;
 
-	err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
+	err = ip6_dst_lookup_tail(net, sk, &dst, fl6);
 	if (err)
 		return ERR_PTR(err);
 	if (final_dst)
 		fl6->daddr = *final_dst;
 
-	return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
+	return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0);
 }
 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 
@@ -1126,7 +1126,7 @@ struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 
 	dst = ip6_sk_dst_check(sk, dst, fl6);
 	if (!dst)
-		dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
+		dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst);
 
 	return dst;
 }
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index ac428311965f..3d9d20074203 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -929,7 +929,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto out;
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 4e7817abc0b9..0fe8ffcda1d7 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -238,7 +238,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 		fl6.flowi6_uid = sk->sk_uid;
 		security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 
-		dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+		dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 		if (IS_ERR(dst))
 			goto out_free;
 	}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7b4ce3f9e2f4..a516490de3db 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -252,7 +252,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto failure;
@@ -865,7 +865,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
 	 * Underlying function will use this to retrieve the network
 	 * namespace
 	 */
-	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
+	dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL);
 	if (!IS_ERR(dst)) {
 		skb_dst_set(buff, dst);
 		ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, tclass);
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index bec13226ce4f..6efdfc9b5c43 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -629,7 +629,7 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 	if (IS_ERR(dst)) {
 		err = PTR_ERR(dst);
 		goto out;
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 53a66ee1331f..2320077ad5f4 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -270,7 +270,7 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
 	final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 	rcu_read_unlock();
 
-	dst = ip6_dst_lookup_flow(sk, fl6, final_p);
+	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
 	if (!asoc || saddr)
 		goto out;
 
@@ -323,7 +323,7 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
 		fl6->saddr = laddr->a.v6.sin6_addr;
 		fl6->fl6_sport = laddr->a.v6.sin6_port;
 		final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
-		bdst = ip6_dst_lookup_flow(sk, fl6, final_p);
+		bdst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
 
 		if (IS_ERR(bdst))
 			continue;
-- 
2.17.1

