kdbus: add name registry implementation

Hi Daniel,

The patch 29dc02b6af35: "kdbus: add name registry implementation" from Sep 11, 2014, has a potential issue:

ipc/kdbus/names.c
697 /**

   698   * kdbus_cmd_list() - handle KDBUS_CMD_LIST
   699   * @conn:               connection to operate on
   700   * @argp:               command payload
   701   *
   702   * Return: 0 on success, negative error code on failure.
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

We're supposed to return negative on failure.

   703   */
   704  int kdbus_cmd_list(struct kdbus_conn *conn, void __user *argp)
   705  {
   706          struct kdbus_name_registry *reg = conn->ep->bus->name_registry;
   707          struct kdbus_pool_slice *slice = NULL;
   708          struct kdbus_cmd_list *cmd;
   709          size_t pos, size;
   710          int ret;
   711  
   712          struct kdbus_arg argv[] = {
   713                  { .type = KDBUS_ITEM_NEGOTIATE },
   714          };
   715          struct kdbus_args args = {
   716                  .allowed_flags = KDBUS_FLAG_NEGOTIATE |

We allow KDBUS_FLAG_NEGOTIATE.

   717                                   KDBUS_LIST_UNIQUE |
   718                                   KDBUS_LIST_NAMES |
   719                                   KDBUS_LIST_ACTIVATORS |
   720                                   KDBUS_LIST_QUEUED,
   721                  .argv = argv,
   722                  .argc = ARRAY_SIZE(argv),
   723          };
   724  
   725          ret = kdbus_args_parse(&args, argp, &cmd);
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

We means this can return 1, I think. I picked this call at random but it seems like some of other the places which call kdbus_args_parse() might have an issue here as well. This might be obvious to someone more familiar with kdbus code.

726 if (ret != 0)
727 return ret;
728

regards,
dan carpenter