1  /* Copyright (C) 2017-2023 Free Software Foundation, Inc.
       2  
       3  This file is part of GCC.
       4  
       5  GCC is free software; you can redistribute it and/or modify
       6  it under the terms of the GNU General Public License as published by
       7  the Free Software Foundation; either version 3, or (at your option)
       8  any later version.
       9  
      10  GCC is distributed in the hope that it will be useful,
      11  but WITHOUT ANY WARRANTY; without even the implied warranty of
      12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13  GNU General Public License for more details.
      14  
      15  Under Section 7 of GPL version 3, you are granted additional
      16  permissions described in the GCC Runtime Library Exception, version
      17  3.1, as published by the Free Software Foundation.
      18  
      19  You should have received a copy of the GNU General Public License and
      20  a copy of the GCC Runtime Library Exception along with this program;
      21  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      22  <http://www.gnu.org/licenses/>.  */
      23  
      24  #ifndef _SECURE_GETENV_H
      25  #define _SECURE_GETENV_H 1
      26  
      27  /* Secure getenv() which returns NULL if running as SUID/SGID.  */
      28  #ifndef HAVE_SECURE_GETENV
      29  #if defined (HAVE_UNISTD_H) && defined (HAVE_GETUID) \
      30    && defined (HAVE_GETEUID) && defined (HAVE_GETGID) \
      31    && defined (HAVE_GETEGID)
      32  
      33  #include <unistd.h>
      34  
      35  #if SUPPORTS_WEAKREF && defined (HAVE___SECURE_GETENV)
      36  static char* weak_secure_getenv (const char*)
      37    __attribute__((__weakref__("__secure_getenv")));
      38  #endif
      39  
      40  /* Implementation of secure_getenv() for targets where it is not provided but
      41     we have at least means to test real and effective IDs.  */
      42  
      43  static inline char *
      44  secure_getenv (const char *name)
      45  {
      46  #if SUPPORTS_WEAKREF && defined (HAVE___SECURE_GETENV)
      47    if (weak_secure_getenv)
      48      return weak_secure_getenv (name);
      49  #endif
      50  
      51    if ((getuid () == geteuid ()) && (getgid () == getegid ()))
      52      return getenv (name);
      53    else
      54      return NULL;
      55  }
      56  #else
      57  #define secure_getenv getenv
      58  #endif
      59  #endif
      60  
      61  #endif /* _SECURE_GETENV_H.  */