elf/enbl-secure.c

   1 /* Define and initialize the `__libc_enable_secure' flag.  Generic version.
   2    Copyright (C) 1996-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This file is used in the static libc.  For the shared library,
  20    dl-sysdep.c defines and initializes __libc_enable_secure.  */
  21
  22 /* Mark symbols hidden in static PIE for early self relocation to work.  */
  23 #if BUILD_PIE_DEFAULT
  24 # pragma GCC visibility push(hidden)
  25 #endif
  26 #include <startup.h>
  27 #include <libc-internal.h>
  28
  29 /* If nonzero __libc_enable_secure is already set.  */
  30 int __libc_enable_secure_decided;
  31 /* Safest assumption, if somehow the initializer isn't run.  */
  32 int __libc_enable_secure = 1;
  33
  34 void
  35 __libc_init_secure (void)
  36 {
  37   if (__libc_enable_secure_decided == 0)
  38     __libc_enable_secure = (startup_geteuid () != startup_getuid ()
  39                             || startup_getegid () != startup_getgid ());
  40 }