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>

1 files changed, 9 insertions, 4 deletions

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;
 	}