[SCTP]: Allow unspecified port in sctp_bindx()

Allow sctp_bindx() to accept multiple address with
unspecified port.  In this case, all addresses inherit
the first bound port.  We still catch full mis-matches.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index d370c945a75..a5b6e559451 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -333,12 +333,19 @@ SCTP_STATIC int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
         if (!sp->pf->bind_verify(sp, addr))
                 return -EADDRNOTAVAIL;
 
-        /* We must either be unbound, or bind to the same port.  */
-        if (bp->port && (snum != bp->port)) {
-                SCTP_DEBUG_PRINTK("sctp_do_bind:"
+        /* We must either be unbound, or bind to the same port.
+         * It's OK to allow 0 ports if we are already bound.
+         * We'll just inhert an already bound port in this case
+         */
+        if (bp->port) {
+                if (!snum)
+                        snum = bp->port;
+                else if (snum != bp->port) {
+                        SCTP_DEBUG_PRINTK("sctp_do_bind:"
                                   " New port %d does not match existing port "
                                   "%d.\n", snum, bp->port);
-                return -EINVAL;
+                        return -EINVAL;
+                }
         }
 
         if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE))