sctp: add dif and sdif check in asoc and ep lookup

This patch at first adds a pernet global l3mdev_accept to decide if it
accepts the packets from a l3mdev when a SCTP socket doesn't bind to
any interface. It's set to 1 to avoid any possible incompatible issue,
and in next patch, a sysctl will be introduced to allow to change it.

Then similar to inet/udp_sk_bound_dev_eq(), sctp_sk_bound_dev_eq() is
added to check either dif or sdif is equal to sk_bound_dev_if, and to
check sid is 0 or l3mdev_accept is 1 if sk_bound_dev_if is not set.
This function is used to match a association or a endpoint, namely
called by sctp_addrs_lookup_transport() and sctp_endpoint_is_match().
All functions that needs updating are:

sctp_rcv():
  asoc:
  __sctp_rcv_lookup()
    __sctp_lookup_association() -> sctp_addrs_lookup_transport()
    __sctp_rcv_lookup_harder()
      __sctp_rcv_init_lookup()
         __sctp_lookup_association() -> sctp_addrs_lookup_transport()
      __sctp_rcv_walk_lookup()
         __sctp_rcv_asconf_lookup()
           __sctp_lookup_association() -> sctp_addrs_lookup_transport()

  ep:
  __sctp_rcv_lookup_endpoint() -> sctp_endpoint_is_match()

sctp_connect():
  sctp_endpoint_is_peeled_off()
    __sctp_lookup_association()
      sctp_has_association()
        sctp_lookup_association()
          __sctp_lookup_association() -> sctp_addrs_lookup_transport()

sctp_diag_dump_one():
  sctp_transport_lookup_process() -> sctp_addrs_lookup_transport()

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 76 insertions, 56 deletions

diff --git a/net/sctp/diag.c b/net/sctp/diag.c
index d9c6d8f30f09..a557009e9832 100644
--- a/net/sctp/diag.c
+++ b/net/sctp/diag.c
@@ -426,6 +426,7 @@ static int sctp_diag_dump_one(struct netlink_callback *cb,
 	struct net *net = sock_net(skb->sk);
 	const struct nlmsghdr *nlh = cb->nlh;
 	union sctp_addr laddr, paddr;
+	int dif = req->id.idiag_if;
 	struct sctp_comm_param commp = {
 		.skb = skb,
 		.r = req,
@@ -454,7 +455,7 @@ static int sctp_diag_dump_one(struct netlink_callback *cb,
 	}
 
 	return sctp_transport_lookup_process(sctp_sock_dump_one,
-					     net, &laddr, &paddr, &commp);
+					     net, &laddr, &paddr, &commp, dif);
 }
 
 static void sctp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index efffde7f2328..7e77b450697c 100644
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -246,12 +246,15 @@ void sctp_endpoint_put(struct sctp_endpoint *ep)
 /* Is this the endpoint we are looking for?  */
 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 					       struct net *net,
-					       const union sctp_addr *laddr)
+					       const union sctp_addr *laddr,
+					       int dif, int sdif)
 {
+	int bound_dev_if = READ_ONCE(ep->base.sk->sk_bound_dev_if);
 	struct sctp_endpoint *retval = NULL;
 
-	if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
-	    net_eq(ep->base.net, net)) {
+	if (net_eq(ep->base.net, net) &&
+	    sctp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif) &&
+	    (htons(ep->base.bind_addr.port) == laddr->v4.sin_port)) {
 		if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 					 sctp_sk(ep->base.sk)))
 			retval = ep;
@@ -298,6 +301,7 @@ out:
 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 				 const union sctp_addr *paddr)
 {
+	int bound_dev_if = READ_ONCE(ep->base.sk->sk_bound_dev_if);
 	struct sctp_sockaddr_entry *addr;
 	struct net *net = ep->base.net;
 	struct sctp_bind_addr *bp;
@@ -307,7 +311,8 @@ bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 	 * so the address_list can not change.
 	 */
 	list_for_each_entry(addr, &bp->address_list, list) {
-		if (sctp_has_association(net, &addr->a, paddr))
+		if (sctp_has_association(net, &addr->a, paddr,
+					 bound_dev_if, bound_dev_if))
 			return true;
 	}
 
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 4f43afa8678f..bf70371301ff 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -50,16 +50,19 @@ static struct sctp_association *__sctp_rcv_lookup(struct net *net,
 				      struct sk_buff *skb,
 				      const union sctp_addr *paddr,
 				      const union sctp_addr *laddr,
-				      struct sctp_transport **transportp);
+				      struct sctp_transport **transportp,
+				      int dif, int sdif);
 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
 					struct net *net, struct sk_buff *skb,
 					const union sctp_addr *laddr,
-					const union sctp_addr *daddr);
+					const union sctp_addr *daddr,
+					int dif, int sdif);
 static struct sctp_association *__sctp_lookup_association(
 					struct net *net,
 					const union sctp_addr *local,
 					const union sctp_addr *peer,
-					struct sctp_transport **pt);
+					struct sctp_transport **pt,
+					int dif, int sdif);
 
 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
 
@@ -92,11 +95,11 @@ int sctp_rcv(struct sk_buff *skb)
 	struct sctp_chunk *chunk;
 	union sctp_addr src;
 	union sctp_addr dest;
-	int bound_dev_if;
 	int family;
 	struct sctp_af *af;
 	struct net *net = dev_net(skb->dev);
 	bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb);
+	int dif, sdif;
 
 	if (skb->pkt_type != PACKET_HOST)
 		goto discard_it;
@@ -141,6 +144,8 @@ int sctp_rcv(struct sk_buff *skb)
 	/* Initialize local addresses for lookups. */
 	af->from_skb(&src, skb, 1);
 	af->from_skb(&dest, skb, 0);
+	dif = af->skb_iif(skb);
+	sdif = af->skb_sdif(skb);
 
 	/* If the packet is to or from a non-unicast address,
 	 * silently discard the packet.
@@ -157,36 +162,16 @@ int sctp_rcv(struct sk_buff *skb)
 	    !af->addr_valid(&dest, NULL, skb))
 		goto discard_it;
 
-	asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
+	asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport, dif, sdif);
 
 	if (!asoc)
-		ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src);
+		ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src, dif, sdif);
 
 	/* Retrieve the common input handling substructure. */
 	rcvr = asoc ? &asoc->base : &ep->base;
 	sk = rcvr->sk;
 
 	/*
-	 * If a frame arrives on an interface and the receiving socket is
-	 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
-	 */
-	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
-	if (bound_dev_if && (bound_dev_if != af->skb_iif(skb))) {
-		if (transport) {
-			sctp_transport_put(transport);
-			asoc = NULL;
-			transport = NULL;
-		} else {
-			sctp_endpoint_put(ep);
-			ep = NULL;
-		}
-		sk = net->sctp.ctl_sock;
-		ep = sctp_sk(sk)->ep;
-		sctp_endpoint_hold(ep);
-		rcvr = &ep->base;
-	}
-
-	/*
 	 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
 	 * An SCTP packet is called an "out of the blue" (OOTB)
 	 * packet if it is correctly formed, i.e., passed the
@@ -485,6 +470,8 @@ struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
 	struct sctp_association *asoc;
 	struct sctp_transport *transport = NULL;
 	__u32 vtag = ntohl(sctphdr->vtag);
+	int sdif = inet_sdif(skb);
+	int dif = inet_iif(skb);
 
 	*app = NULL; *tpp = NULL;
 
@@ -500,7 +487,7 @@ struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
 	/* Look for an association that matches the incoming ICMP error
 	 * packet.
 	 */
-	asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
+	asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport, dif, sdif);
 	if (!asoc)
 		return NULL;
 
@@ -850,7 +837,8 @@ static inline __u32 sctp_hashfn(const struct net *net, __be16 lport,
 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
 					struct net *net, struct sk_buff *skb,
 					const union sctp_addr *laddr,
-					const union sctp_addr *paddr)
+					const union sctp_addr *paddr,
+					int dif, int sdif)
 {
 	struct sctp_hashbucket *head;
 	struct sctp_endpoint *ep;
@@ -863,7 +851,7 @@ static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
 	head = &sctp_ep_hashtable[hash];
 	read_lock(&head->lock);
 	sctp_for_each_hentry(ep, &head->chain) {
-		if (sctp_endpoint_is_match(ep, net, laddr))
+		if (sctp_endpoint_is_match(ep, net, laddr, dif, sdif))
 			goto hit;
 	}
 
@@ -990,14 +978,26 @@ void sctp_unhash_transport(struct sctp_transport *t)
 			sctp_hash_params);
 }
 
+bool sctp_sk_bound_dev_eq(struct net *net, int bound_dev_if, int dif, int sdif)
+{
+	bool l3mdev_accept = true;
+
+#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
+	l3mdev_accept = !!READ_ONCE(net->sctp.l3mdev_accept);
+#endif
+	return inet_bound_dev_eq(l3mdev_accept, bound_dev_if, dif, sdif);
+}
+
 /* return a transport with holding it */
 struct sctp_transport *sctp_addrs_lookup_transport(
 				struct net *net,
 				const union sctp_addr *laddr,
-				const union sctp_addr *paddr)
+				const union sctp_addr *paddr,
+				int dif, int sdif)
 {
 	struct rhlist_head *tmp, *list;
 	struct sctp_transport *t;
+	int bound_dev_if;
 	struct sctp_hash_cmp_arg arg = {
 		.paddr = paddr,
 		.net   = net,
@@ -1011,7 +1011,9 @@ struct sctp_transport *sctp_addrs_lookup_transport(
 		if (!sctp_transport_hold(t))
 			continue;
 
-		if (sctp_bind_addr_match(&t->asoc->base.bind_addr,
+		bound_dev_if = READ_ONCE(t->asoc->base.sk->sk_bound_dev_if);
+		if (sctp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif) &&
+		    sctp_bind_addr_match(&t->asoc->base.bind_addr,
 					 laddr, sctp_sk(t->asoc->base.sk)))
 			return t;
 		sctp_transport_put(t);
@@ -1048,12 +1050,13 @@ static struct sctp_association *__sctp_lookup_association(
 					struct net *net,
 					const union sctp_addr *local,
 					const union sctp_addr *peer,
-					struct sctp_transport **pt)
+					struct sctp_transport **pt,
+					int dif, int sdif)
 {
 	struct sctp_transport *t;
 	struct sctp_association *asoc = NULL;
 
-	t = sctp_addrs_lookup_transport(net, local, peer);
+	t = sctp_addrs_lookup_transport(net, local, peer, dif, sdif);
 	if (!t)
 		goto out;
 
@@ -1069,12 +1072,13 @@ static
 struct sctp_association *sctp_lookup_association(struct net *net,
 						 const union sctp_addr *laddr,
 						 const union sctp_addr *paddr,
-						 struct sctp_transport **transportp)
+						 struct sctp_transport **transportp,
+						 int dif, int sdif)
 {
 	struct sctp_association *asoc;
 
 	rcu_read_lock();
-	asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
+	asoc = __sctp_lookup_association(net, laddr, paddr, transportp, dif, sdif);
 	rcu_read_unlock();
 
 	return asoc;
@@ -1083,11 +1087,12 @@ struct sctp_association *sctp_lookup_association(struct net *net,
 /* Is there an association matching the given local and peer addresses? */
 bool sctp_has_association(struct net *net,
 			  const union sctp_addr *laddr,
-			  const union sctp_addr *paddr)
+			  const union sctp_addr *paddr,
+			  int dif, int sdif)
 {
 	struct sctp_transport *transport;
 
-	if (sctp_lookup_association(net, laddr, paddr, &transport)) {
+	if (sctp_lookup_association(net, laddr, paddr, &transport, dif, sdif)) {
 		sctp_transport_put(transport);
 		return true;
 	}
@@ -1115,7 +1120,8 @@ bool sctp_has_association(struct net *net,
  */
 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
 	struct sk_buff *skb,
-	const union sctp_addr *laddr, struct sctp_transport **transportp)
+	const union sctp_addr *laddr, struct sctp_transport **transportp,
+	int dif, int sdif)
 {
 	struct sctp_association *asoc;
 	union sctp_addr addr;
@@ -1154,7 +1160,7 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
 		if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
 			continue;
 
-		asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
+		asoc = __sctp_lookup_association(net, laddr, paddr, transportp, dif, sdif);
 		if (asoc)
 			return asoc;
 	}
@@ -1181,7 +1187,8 @@ static struct sctp_association *__sctp_rcv_asconf_lookup(
 					struct sctp_chunkhdr *ch,
 					const union sctp_addr *laddr,
 					__be16 peer_port,
-					struct sctp_transport **transportp)
+					struct sctp_transport **transportp,
+					int dif, int sdif)
 {
 	struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch;
 	struct sctp_af *af;
@@ -1201,7 +1208,7 @@ static struct sctp_association *__sctp_rcv_asconf_lookup(
 	if (!af->from_addr_param(&paddr, param, peer_port, 0))
 		return NULL;
 
-	return __sctp_lookup_association(net, laddr, &paddr, transportp);
+	return __sctp_lookup_association(net, laddr, &paddr, transportp, dif, sdif);
 }
 
 
@@ -1217,7 +1224,8 @@ static struct sctp_association *__sctp_rcv_asconf_lookup(
 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
 				      struct sk_buff *skb,
 				      const union sctp_addr *laddr,
-				      struct sctp_transport **transportp)
+				      struct sctp_transport **transportp,
+				      int dif, int sdif)
 {
 	struct sctp_association *asoc = NULL;
 	struct sctp_chunkhdr *ch;
@@ -1260,7 +1268,7 @@ static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
 				asoc = __sctp_rcv_asconf_lookup(
 						net, ch, laddr,
 						sctp_hdr(skb)->source,
-						transportp);
+						transportp, dif, sdif);
 			break;
 		default:
 			break;
@@ -1285,7 +1293,8 @@ static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
 				      struct sk_buff *skb,
 				      const union sctp_addr *laddr,
-				      struct sctp_transport **transportp)
+				      struct sctp_transport **transportp,
+				      int dif, int sdif)
 {
 	struct sctp_chunkhdr *ch;
 
@@ -1309,9 +1318,9 @@ static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
 
 	/* If this is INIT/INIT-ACK look inside the chunk too. */
 	if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
-		return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
+		return __sctp_rcv_init_lookup(net, skb, laddr, transportp, dif, sdif);
 
-	return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
+	return __sctp_rcv_walk_lookup(net, skb, laddr, transportp, dif, sdif);
 }
 
 /* Lookup an association for an inbound skb. */
@@ -1319,11 +1328,12 @@ static struct sctp_association *__sctp_rcv_lookup(struct net *net,
 				      struct sk_buff *skb,
 				      const union sctp_addr *paddr,
 				      const union sctp_addr *laddr,
-				      struct sctp_transport **transportp)
+				      struct sctp_transport **transportp,
+				      int dif, int sdif)
 {
 	struct sctp_association *asoc;
 
-	asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
+	asoc = __sctp_lookup_association(net, laddr, paddr, transportp, dif, sdif);
 	if (asoc)
 		goto out;
 
@@ -1331,7 +1341,7 @@ static struct sctp_association *__sctp_rcv_lookup(struct net *net,
 	 * SCTP Implementors Guide, 2.18 Handling of address
 	 * parameters within the INIT or INIT-ACK.
 	 */
-	asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
+	asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp, dif, sdif);
 	if (asoc)
 		goto out;
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index a18cf0471a8d..909a89a1cff4 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1394,6 +1394,10 @@ static int __net_init sctp_defaults_init(struct net *net)
 	/* Initialize maximum autoclose timeout. */
 	net->sctp.max_autoclose		= INT_MAX / HZ;
 
+#ifdef CONFIG_NET_L3_MASTER_DEV
+	net->sctp.l3mdev_accept = 1;
+#endif
+
 	status = sctp_sysctl_net_register(net);
 	if (status)
 		goto err_sysctl_register;
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 4306164238ef..5acbdf0d38f3 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5315,14 +5315,14 @@ EXPORT_SYMBOL_GPL(sctp_for_each_endpoint);
 
 int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net,
 				  const union sctp_addr *laddr,
-				  const union sctp_addr *paddr, void *p)
+				  const union sctp_addr *paddr, void *p, int dif)
 {
 	struct sctp_transport *transport;
 	struct sctp_endpoint *ep;
 	int err = -ENOENT;
 
 	rcu_read_lock();
-	transport = sctp_addrs_lookup_transport(net, laddr, paddr);
+	transport = sctp_addrs_lookup_transport(net, laddr, paddr, dif, dif);
 	if (!transport) {
 		rcu_read_unlock();
 		return err;