--- a/sysdeps/mach/hurd/sendmsg.c
+++ b/sysdeps/mach/hurd/sendmsg.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001,2002,2004,2010 Free Software Foundation, Inc.
+/* Copyright (C) 2001,2002,2004,2010,2013 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -17,6 +17,7 @@
 
 #include <errno.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ -38,6 +39,9 @@
   int *fds, nfds;
   struct sockaddr_un *addr = message->msg_name;
   socklen_t addr_len = message->msg_namelen;
+  struct cmsgcred *ucredp = NULL;
+  void *control = message->msg_control;
+  socklen_t controllen = message->msg_controllen;
   addr_port_t aport = MACH_PORT_NULL;
   union
   {
@@ -106,6 +110,33 @@
 	}
     }
 
+  /* SCM_CREDS support: Create and send the ancillary data  */
+  cmsg = CMSG_FIRSTHDR (message);
+  if (cmsg != NULL && cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS)
+    {
+      for (; cmsg; cmsg = CMSG_NXTHDR (message, cmsg))
+	{
+	  ucredp = (struct cmsgcred *) CMSG_DATA(cmsg);
+	  process_t proc = getproc ();
+	  auth_t auth = getauth ();
+	  nports = 2;
+	  ports = __alloca (nports * sizeof (mach_port_t));
+	  ports[0] = proc;
+	  ports[1] = auth;
+
+	  /* Fill in credentials data */
+	  ucredp->cmcred_pid = __getpid();
+	  ucredp->cmcred_uid = __getuid();
+	  ucredp->cmcred_euid = __geteuid();
+	  ucredp->cmcred_gid = __getgid();
+	  /* egid not in struct csmgcred */
+	  ucredp->cmcred_ngroups =
+	    __getgroups (sizeof (ucredp->cmcred_groups) / sizeof (gid_t),
+			 ucredp->cmcred_groups);
+	}
+      goto label;
+    }
+
   /* SCM_RIGHTS support: get the number of fds to send.  */
   cmsg = CMSG_FIRSTHDR (message);
   for (; cmsg; cmsg = CMSG_NXTHDR (message, cmsg))
@@ -147,6 +178,7 @@
 	}
     }
 
+ label:
   if (addr)
     {
       if (addr->sun_family == AF_LOCAL)
@@ -188,8 +220,8 @@
 						   ports,
 						   MACH_MSG_TYPE_COPY_SEND,
 						   nports,
-						   message->msg_control,
-						   message->msg_controllen,
+						   control,
+						   controllen,
 						   &amount);
 			      __mach_port_deallocate (__mach_task_self (),
 						      aport);