1  /* Copyright (C) 1993-2023 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 Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the 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     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include <sys/types.h>
      20  #include <unistd.h>
      21  #include <hurd.h>
      22  #include <hurd/id.h>
      23  #include <string.h>
      24  
      25  int
      26  __setreuid (uid_t ruid, uid_t euid)
      27  {
      28    auth_t newauth;
      29    error_t err;
      30  
      31  retry:
      32    HURD_CRITICAL_BEGIN;
      33    __mutex_lock (&_hurd_id.lock);
      34    err = _hurd_check_ids ();
      35  
      36    if (!err)
      37      {
      38        /* Make a new auth handle which has RUID as the real uid,
      39  	 and EUID as the first element in the list of effective uids.  */
      40  
      41        uid_t *newgen, *newaux;
      42        size_t ngen, naux;
      43  
      44        newgen = _hurd_id.gen.uids;
      45        ngen = _hurd_id.gen.nuids;
      46        if (euid != -1)
      47  	{
      48  	  if (_hurd_id.gen.nuids == 0)
      49  	    {
      50  	      /* No effective uids now.  The new set will be just UID.  */
      51  	      newgen = &euid;
      52  	      ngen = 1;
      53  	    }
      54  	  else
      55  	    {
      56  	      _hurd_id.gen.uids[0] = euid;
      57  	      _hurd_id.valid = 0;
      58  	    }
      59  	}
      60  
      61        newaux = _hurd_id.aux.uids;
      62        naux = _hurd_id.aux.nuids;
      63        if (ruid != -1)
      64  	{
      65  	  if (_hurd_id.aux.nuids == 0)
      66  	    {
      67  	      newaux = &ruid;
      68  	      naux = 1;
      69  	    }
      70  	  else
      71  	    {
      72  	      _hurd_id.aux.uids[0] = ruid;
      73  	      _hurd_id.valid = 0;
      74  	    }
      75  	}
      76  
      77        err = __USEPORT (AUTH, __auth_makeauth
      78  		       (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
      79  			newgen, ngen, newaux, naux,
      80  			_hurd_id.gen.gids, _hurd_id.gen.ngids,
      81  			_hurd_id.aux.gids, _hurd_id.aux.ngids,
      82  			&newauth));
      83      }
      84    __mutex_unlock (&_hurd_id.lock);
      85    HURD_CRITICAL_END;
      86    if (err == EINTR)
      87      /* Got a signal while inside an RPC of the critical section, retry again */
      88      goto retry;
      89  
      90    if (err)
      91      return __hurd_fail (err);
      92  
      93    /* Install the new handle and reauthenticate everything.  */
      94    err = __setauth (newauth);
      95    __mach_port_deallocate (__mach_task_self (), newauth);
      96    return err;
      97  }
      98  
      99  weak_alias (__setreuid, setreuid)