Description: [hurd] recvmsg: don't try to resolve invalid address
 Hurd's PF_LOCAL implementation doesn't return an address when calling
 __recv. recvmsg wasn't catching that and tried to call
 __socket_whatis_address on MACH_PORT_NULL, causing Hurd to send
 SIGLOST to the process. Properly handle this, analogously to how
 recvfrom does it.
Author: Christian Seiler <christian@iwakd.de>
Bug: https://lists.gnu.org/archive/html/bug-hurd/2016-08/msg00000.html
Last-Update: 2016-08-05
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
--- a/sysdeps/mach/hurd/recvmsg.c
+++ b/sysdeps/mach/hurd/recvmsg.c
@@ -202,7 +202,7 @@ __libc_recvmsg (int fd, struct msghdr *m
 					       &message->msg_flags, amount)))
     return __hurd_sockfail (fd, flags, err);
 
-  if (message->msg_name != NULL)
+  if (message->msg_name != NULL && aport != MACH_PORT_NULL)
     {
       char *buf = message->msg_name;
       mach_msg_type_number_t buflen = message->msg_namelen;
@@ -236,6 +236,8 @@ __libc_recvmsg (int fd, struct msghdr *m
       if (buflen > 0)
 	((struct sockaddr *) message->msg_name)->sa_family = type;
     }
+  else if (message->msg_name != NULL)
+    message->msg_namelen = 0;
 
   __mach_port_deallocate (__mach_task_self (), aport);