net: inet: Support UID-based routing in IP protocols.

- Use the UID in routing lookups made by protocol connect() and
  sendmsg() functions.
- Make sure that routing lookups triggered by incoming packets
  (e.g., Path MTU discovery) take the UID of the socket into
  account.
- For packets not associated with a userspace socket, (e.g., ping
  replies) use UID 0 inside the user namespace corresponding to
  the network namespace the socket belongs to. This allows
  all namespaces to apply routing and iptables rules to
  kernel-originated traffic in that namespaces by matching UID 0.
  This is better than using the UID of the kernel socket that is
  sending the traffic, because the UID of kernel sockets created
  at namespace creation time (e.g., the per-processor ICMP and
  TCP sockets) is the UID of the user that created the socket,
  which might not be mapped in the namespace.

[Backport of net-next e2d118a1cb5e60d077131a09db1d81b90a5295fe]

Bug: 16355602
Change-Id: I126f8359887b5b5bbac68daf0ded89e899cb7cb0
Tested: compiles allnoconfig, allyesconfig, allmodconfig
Tested: https://android-review.googlesource.com/253302
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>

16 files changed, 36 insertions, 12 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 112e14fa8..db3b20e10 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -702,6 +702,7 @@ int inet6_sk_rebuild_header(struct sock *sk)
 		fl6.flowi6_mark = sk->sk_mark;
 		fl6.fl6_dport = inet->inet_dport;
 		fl6.fl6_sport = inet->inet_sport;
+		fl6.flowi6_uid = sk->sk_uid;
 		security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
 		rcu_read_lock();
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index bb02e176c..15e41c5be 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -628,9 +628,9 @@ static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		return;
 
 	if (type == NDISC_REDIRECT)
-		ip6_redirect(skb, net, 0, 0);
+		ip6_redirect(skb, net, 0, 0, sock_net_uid(net, NULL));
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 6d7763950..0a3605e29 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -162,6 +162,7 @@ ipv4_connected:
 	fl6.flowi6_mark = sk->sk_mark;
 	fl6.fl6_dport = inet->inet_dport;
 	fl6.fl6_sport = inet->inet_sport;
+	fl6.flowi6_uid = sk->sk_uid;
 
 	if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 		fl6.flowi6_oif = np->mcast_oif;
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 40ffd7224..4ad65258f 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -447,9 +447,9 @@ static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		return;
 
 	if (type == NDISC_REDIRECT)
-		ip6_redirect(skb, net, 0, 0);
+		ip6_redirect(skb, net, 0, 0, sock_net_uid(net, NULL));
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 33101f4e3..b0220040e 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -90,9 +90,9 @@ static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	struct net *net = dev_net(skb->dev);
 
 	if (type == ICMPV6_PKT_TOOBIG)
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
 	else if (type == NDISC_REDIRECT)
-		ip6_redirect(skb, net, 0, 0);
+		ip6_redirect(skb, net, 0, 0, sock_net_uid(net, NULL));
 
 	if (!(type & ICMPV6_INFOMSG_MASK))
 		if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
@@ -467,6 +467,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 	fl6.flowi6_oif = iif;
 	fl6.fl6_icmp_type = type;
 	fl6.fl6_icmp_code = code;
+	fl6.flowi6_uid = sock_net_uid(net, NULL);
 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 
 	sk = icmpv6_xmit_lock(net);
@@ -572,6 +573,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 	fl6.flowi6_oif = skb->dev->ifindex;
 	fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
 	fl6.flowi6_mark = mark;
+	fl6.flowi6_uid = sock_net_uid(net, NULL);
 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 
 	sk = icmpv6_xmit_lock(net);
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 0f13c1572..71d60021d 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -86,6 +86,7 @@ struct dst_entry *inet6_csk_route_req(struct sock *sk,
 	fl6->flowi6_mark = inet_rsk(req)->ir_mark;
 	fl6->fl6_dport = inet_rsk(req)->rmt_port;
 	fl6->fl6_sport = inet_rsk(req)->loc_port;
+	fl6->flowi6_uid = sk->sk_uid;
 	security_req_classify_flow(req, flowi6_to_flowi(fl6));
 
 	dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
@@ -213,6 +214,7 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 	fl6->flowi6_mark = sk->sk_mark;
 	fl6->fl6_sport = inet->inet_sport;
 	fl6->fl6_dport = inet->inet_dport;
+	fl6->flowi6_uid = sk->sk_uid;
 	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 
 	rcu_read_lock();
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 11fb37c19..577f01139 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -800,6 +800,8 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
+	fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
+
 	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
 	if (err != 0) {
 		/* XXX: send ICMP error even if DF is not set. */
@@ -850,6 +852,8 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
 		fl6.flowi6_mark = skb->mark;
 
+	fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
+
 	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
 	if (err != 0) {
 		if (err == -EMSGSIZE)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 12984e679..39078665f 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1075,6 +1075,8 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6));
 	fl6.flowi6_proto = IPPROTO_IPIP;
 
+	fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
+
 	dsfield = ipv4_get_dsfield(iph);
 
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
@@ -1126,6 +1128,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6));
 	fl6.flowi6_proto = IPPROTO_IPV6;
+	fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
 
 	dsfield = ipv6_get_dsfield(ipv6h);
 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 7af5aee75..a4a4e1c2c 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -76,9 +76,9 @@ static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		return;
 
 	if (type == NDISC_REDIRECT)
-		ip6_redirect(skb, net, 0, 0);
+		ip6_redirect(skb, net, 0, 0, sock_net_uid(net, NULL));
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
index d38e6a8d8..e48d26bed 100644
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -27,6 +27,7 @@ int ip6_route_me_harder(struct sk_buff *skb)
 	struct flowi6 fl6 = {
 		.flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
 		.flowi6_mark = skb->mark,
+		.flowi6_uid = sock_net_uid(net, skb->sk),
 		.daddr = iph->daddr,
 		.saddr = iph->saddr,
 	};
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index 004dcde01..52d0adde7 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -143,6 +143,7 @@ int ping_v6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 	fl6.daddr = *daddr;
 	fl6.flowi6_oif = oif;
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sk->sk_uid;
 	fl6.fl6_icmp_type = user_icmph.icmp6_type;
 	fl6.fl6_icmp_code = user_icmph.icmp6_code;
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index b3be89b7b..5dc153c9b 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -760,6 +760,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	memset(&fl6, 0, sizeof(fl6));
 
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sk->sk_uid;
 
 	if (sin6) {
 		if (addr_len < SIN6_LEN_RFC2133)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 23d56bdc5..886c7f453 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1145,7 +1145,7 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 }
 
 void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
-		     int oif, u32 mark)
+		     int oif, u32 mark, kuid_t uid)
 {
 	const struct ipv6hdr *iph = (struct ipv6hdr *) skb->data;
 	struct dst_entry *dst;
@@ -1158,6 +1158,7 @@ void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
 	fl6.daddr = iph->daddr;
 	fl6.saddr = iph->saddr;
 	fl6.flowlabel = ip6_flowinfo(iph);
+	fl6.flowi6_uid = uid;
 
 	dst = ip6_route_output(net, NULL, &fl6);
 	if (!dst->error)
@@ -1169,11 +1170,12 @@ EXPORT_SYMBOL_GPL(ip6_update_pmtu);
 void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu)
 {
 	ip6_update_pmtu(skb, sock_net(sk), mtu,
-			sk->sk_bound_dev_if, sk->sk_mark);
+			sk->sk_bound_dev_if, sk->sk_mark, sk->sk_uid);
 }
 EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);
 
-void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark)
+void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
+		  kuid_t uid)
 {
 	const struct ipv6hdr *iph = (struct ipv6hdr *) skb->data;
 	struct dst_entry *dst;
@@ -1186,6 +1188,7 @@ void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark)
 	fl6.daddr = iph->daddr;
 	fl6.saddr = iph->saddr;
 	fl6.flowlabel = ip6_flowinfo(iph);
+	fl6.flowi6_uid = uid;
 
 	dst = ip6_route_output(net, NULL, &fl6);
 	if (!dst->error)
@@ -1196,7 +1199,8 @@ EXPORT_SYMBOL_GPL(ip6_redirect);
 
 void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk)
 {
-	ip6_redirect(skb, sock_net(sk), sk->sk_bound_dev_if, sk->sk_mark);
+	ip6_redirect(skb, sock_net(sk), sk->sk_bound_dev_if, sk->sk_mark,
+		     sk->sk_uid);
 }
 EXPORT_SYMBOL_GPL(ip6_sk_redirect);
 
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index a596f3883..0428544a2 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -243,6 +243,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 		fl6.flowi6_mark = ireq->ir_mark;
 		fl6.fl6_dport = inet_rsk(req)->rmt_port;
 		fl6.fl6_sport = inet_sk(sk)->inet_sport;
+		fl6.flowi6_uid = sk->sk_uid;
 		security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 
 		dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index cd7a73dcc..86557bcf5 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -253,6 +253,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	fl6.flowi6_mark = sk->sk_mark;
 	fl6.fl6_dport = usin->sin6_port;
 	fl6.fl6_sport = inet->inet_sport;
+	fl6.flowi6_uid = sk->sk_uid;
 
 	opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 	final_p = fl6_update_dst(&fl6, opt, &final);
@@ -798,6 +799,7 @@ static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq,
 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 	fl6.fl6_dport = t1->dest;
 	fl6.fl6_sport = t1->source;
+	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 
 	/* Pass a socket to ip6_dst_lookup either it is for RST
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1e822757c..e4d286dae 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1149,6 +1149,7 @@ do_udp_sendmsg:
 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
 
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sk->sk_uid;
 
 	if (msg->msg_controllen) {
 		opt = &opt_space;