1 files changed, 13 insertions, 5 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index bf705ba97231..3a95fcb17a9e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1276,22 +1276,30 @@ SCTP_STATIC int sctp_setsockopt_connectx(struct sock* sk,
 }
 
 /*
- * New (hopefully final) interface for the API.  The option buffer is used
- * both for the returned association id and the addresses.
+ * New (hopefully final) interface for the API.
+ * We use the sctp_getaddrs_old structure so that use-space library
+ * can avoid any unnecessary allocations.   The only defferent part
+ * is that we store the actual length of the address buffer into the
+ * addrs_num structure member.  That way we can re-use the existing
+ * code.
  */
 SCTP_STATIC int sctp_getsockopt_connectx3(struct sock* sk, int len,
                                         char __user *optval,
                                         int __user *optlen)
 {
+        struct sctp_getaddrs_old param;
         sctp_assoc_t assoc_id = 0;
         int err = 0;
 
-        if (len < sizeof(assoc_id))
+        if (len < sizeof(param))
                 return -EINVAL;
 
+        if (copy_from_user(&param, optval, sizeof(param)))
+                return -EFAULT;
+
         err = __sctp_setsockopt_connectx(sk,
-                        (struct sockaddr __user *)(optval + sizeof(assoc_id)),
-                        len - sizeof(assoc_id), &assoc_id);
+                        (struct sockaddr __user *)param.addrs,
+                        param.addr_num, &assoc_id);
 
         if (err == 0 || err == -EINPROGRESS) {
                 if (copy_to_user(optval, &assoc_id, sizeof(assoc_id)))