clear message structure before filling it in

This change clears the message structure before filling it in. This prevents uninitialized stack data from vfs to leak to the other endpoint.

minix/servers/vfs/request.c

@@ -187,6 +187,7 @@ int req_create(
 	panic("req_create: cpf_grant_direct failed");
 
   /* Fill in request message */
+  memset(&m, 0, sizeof(m));
   m.m_type = REQ_CREATE;
   m.m_vfs_fs_create.inode = inode_nr;
   m.m_vfs_fs_create.mode = omode;