sysdeps/unix/sysv/linux/x86_64/tst-cet-vfork-1.c

   1 /* Verify that child of the vfork-calling function can't return when
   2    shadow stack is in use.
   3    Copyright (C) 2020-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <stdio.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <sys/types.h>
  24 #include <sys/wait.h>
  25 #include <x86intrin.h>
  26 #include <support/test-driver.h>
  27
  28 __attribute__ ((noclone, noinline))
  29 static void
  30 do_test_1 (void)
  31 {
  32   pid_t p1;
  33
  34   /* NB: Since child return pops shadow stack which is shared with
  35      parent, child must not return after vfork.  */
  36
  37   if ((p1 = vfork ()) == 0)
  38     {
  39       /* Child return should trigger SIGSEGV due to shadow stack
  40          mismatch.  */
  41       return;
  42     }
  43   else if (p1 == -1)
  44     {
  45       puts ("vfork failed");
  46       _exit (EXIT_FAILURE);
  47     }
  48
  49   int r;
  50   if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
  51     {
  52       puts ("waitpid failed");
  53       _exit (EXIT_FAILURE);
  54     }
  55
  56    if (!WIFSIGNALED (r) || WTERMSIG (r) != SIGSEGV)
  57     {
  58       puts ("Child not terminated with SIGSEGV");
  59       _exit (EXIT_FAILURE);
  60     }
  61
  62   /* Parent exits immediately so that parent returns without triggering
  63      SIGSEGV when shadow stack is in use.  */
  64   _exit (EXIT_SUCCESS);
  65 }
  66
  67 static int
  68 do_test (void)
  69 {
  70   /* NB: This test should trigger SIGSEGV with shadow stack enabled.  */
  71   if (_get_ssp () == 0)
  72     return EXIT_UNSUPPORTED;
  73   do_test_1 ();
  74   /* Child exits immediately so that child returns without triggering
  75      SIGSEGV when shadow stack is in use.  */
  76   _exit (EXIT_FAILURE);
  77 }
  78
  79 #include <support/test-driver.c>