sysdeps/mach/hurd/setuid.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 97 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <sys/types.h>
  22 #include <hurd.h>
  23 #include <hurd/id.h>
  24 #include <string.h>
  25
  26 /* Set the user ID of the calling process to UID.
  27    If the calling process is the super-user, the real
  28    and effective user IDs, and the saved set-user-ID to UID;
  29    if not, the effective user ID is set to UID.  */
  30 int
  31 __setuid (uid)
  32      uid_t uid;
  33 {
  34   auth_t newauth;
  35   error_t err;
  36
  37   HURD_CRITICAL_BEGIN;
  38   __mutex_lock (&_hurd_id.lock);
  39   err = _hurd_check_ids ();
  40
  41   if (!err)
  42     {
  43       /* Make a new auth handle which has UID as the real uid,
  44          and as the first element in the list of effective uids.  */
  45
  46       uid_t *newgen, *newaux, auxbuf[2];
  47       size_t ngen, naux;
  48
  49       newaux = _hurd_id.aux.uids;
  50       naux = _hurd_id.aux.nuids;
  51       if (_hurd_id.gen.nuids == 0)
  52         {
  53           /* No effective uids now.  The new set will be just UID.  */
  54           newgen = &uid;
  55           ngen = 1;
  56         }
  57       else if (_hurd_id.gen.uids[0] == 0)
  58         {
  59           /* We are root; set the effective, real, and saved to UID.  */
  60           _hurd_id.gen.uids[0] = uid;
  61           _hurd_id.valid = 0;
  62           newgen = _hurd_id.gen.uids;
  63           ngen = _hurd_id.gen.nuids;
  64           if (_hurd_id.aux.nuids < 2)
  65             {
  66               newaux = auxbuf;
  67               naux = 2;
  68             }
  69           newaux[0] = newaux[1] = uid;
  70         }
  71       else
  72         {
  73           /* We are not root; just change the effective UID.  */
  74           /* XXX that implies an unprivileged setuid(0) will give
  75              the caller root, no questions asked! */
  76           _hurd_id.gen.uids[0] = uid;
  77           _hurd_id.valid = 0;
  78           newgen = _hurd_id.gen.uids;
  79           ngen = _hurd_id.gen.nuids;
  80         }
  81
  82       err = __USEPORT (AUTH, __auth_makeauth
  83                        (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
  84                         newgen, ngen, newaux, naux,
  85                         _hurd_id.gen.gids, _hurd_id.gen.ngids,
  86                         _hurd_id.aux.gids, _hurd_id.aux.ngids,
  87                         &newauth));
  88     }
  89   __mutex_unlock (&_hurd_id.lock);
  90   HURD_CRITICAL_END;
  91
  92   if (err)
  93     return __hurd_fail (err);
  94
  95   /* Install the new handle and reauthenticate everything.  */
  96   err = __setauth (newauth);
  97   __mach_port_deallocate (__mach_task_self (), newauth);
  98   return err;
  99 }
 100
 101 weak_alias (__setuid, setuid)