net: core: Support UID-based routing.

This contains the following commits:

1. cc2f522 net: core: Add a UID range to fib rules.
2. d7ed2bd net: core: Use the socket UID in routing lookups.
3. 2f9306a net: core: Add a RTA_UID attribute to routes.
    This is so that userspace can do per-UID route lookups.
4. 8e46efb net: ipv6: Use the UID in IPv6 PMTUD
    IPv4 PMTUD already does this because ipv4_sk_update_pmtu
    uses __build_flow_key, which includes the UID.

Bug: 15413527
Change-Id: I81bd31dae655de9cce7d7a1f9a905dc1c2feba7c
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>

13 files changed, 23 insertions, 6 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index f0081f9cc84..ae17f62189a 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -695,6 +695,7 @@ 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 = sock_i_uid(sk);
 		security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
 		final_p = fl6_update_dst(&fl6, np->opt, &final);
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index bb02e176cb7..b903e19463c 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -630,7 +630,7 @@ static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (type == NDISC_REDIRECT)
 		ip6_redirect(skb, net, 0, 0);
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, INVALID_UID);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 4b56cbbc789..00b4a5f6eea 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 = sock_i_uid(sk);
 
 	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 40ffd72243a..fdc81cb29e8 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -449,7 +449,7 @@ static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (type == NDISC_REDIRECT)
 		ip6_redirect(skb, net, 0, 0);
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, INVALID_UID);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 28da4003e84..12b1a942dc9 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -90,7 +90,7 @@ 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, INVALID_UID);
 	else if (type == NDISC_REDIRECT)
 		ip6_redirect(skb, net, 0, 0);
 
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index f1493138d21..65a46058c85 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -84,6 +84,7 @@ 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 = sock_i_uid(sk);
 	security_req_classify_flow(req, flowi6_to_flowi(fl6));
 
 	dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
@@ -211,6 +212,7 @@ 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 = sock_i_uid(sk);
 	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 
 	final_p = fl6_update_dst(fl6, np->opt, &final);
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 7af5aee75d9..a1beb59a841 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -78,7 +78,7 @@ static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (type == NDISC_REDIRECT)
 		ip6_redirect(skb, net, 0, 0);
 	else
-		ip6_update_pmtu(skb, net, info, 0, 0);
+		ip6_update_pmtu(skb, net, info, 0, 0, INVALID_UID);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index 8d1c2064056..5f0d294b36c 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -159,6 +159,7 @@ int ping_v6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 	fl6.saddr = np->saddr;
 	fl6.daddr = *daddr;
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sock_i_uid(sk);
 	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 eedff8ccded..dfef31581f8 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -761,6 +761,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	memset(&fl6, 0, sizeof(fl6));
 
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sock_i_uid(sk);
 
 	if (sin6) {
 		if (addr_len < SIN6_LEN_RFC2133)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 8ecf44af7c2..bad36468dcd 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1099,7 +1099,7 @@ 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;
@@ -1112,6 +1112,7 @@ 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)
@@ -1123,7 +1124,7 @@ 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, sock_i_uid(sk));
 }
 EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);
 
@@ -2199,6 +2200,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
 	[RTA_PRIORITY]          = { .type = NLA_U32 },
 	[RTA_METRICS]           = { .type = NLA_NESTED },
 	[RTA_MULTIPATH]		= { .len = sizeof(struct rtnexthop) },
+	[RTA_UID]		= { .type = NLA_U32 },
 };
 
 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -2585,6 +2587,12 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh)
 	if (tb[RTA_OIF])
 		oif = nla_get_u32(tb[RTA_OIF]);
 
+	if (tb[RTA_UID])
+		fl6.flowi6_uid = make_kuid(current_user_ns(),
+					   nla_get_u32(tb[RTA_UID]));
+	else
+		fl6.flowi6_uid = iif ? INVALID_UID : current_uid();
+
 	if (iif) {
 		struct net_device *dev;
 		int flags = 0;
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 1efbc6f44a6..ba8622daffd 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 = sock_i_uid(sk);
 		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 6e882dadb4f..a4fc647deb0 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -252,6 +252,7 @@ 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 = sock_i_uid(sk);
 
 	final_p = fl6_update_dst(&fl6, np->opt, &final);
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 42923b14dfa..e6dd85da906 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1147,6 +1147,7 @@ do_udp_sendmsg:
 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
 
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sock_i_uid(sk);
 
 	if (msg->msg_controllen) {
 		opt = &opt_space;