sysdeps/unix/sysv/linux/x86/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) 2020-2021 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 <stdlib.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26 #include <x86intrin.h>
  27 #include <support/test-driver.h>
  28 #include <support/xsignal.h>
  29 #include <support/xunistd.h>
  30
  31 __attribute__ ((noclone, noinline))
  32 static void
  33 do_test_1 (void)
  34 {
  35   pid_t p1;
  36   int fd[2];
  37
  38   if (pipe (fd) == -1)
  39     {
  40       puts ("pipe failed");
  41       _exit (EXIT_FAILURE);
  42     }
  43
  44   if ((p1 = vfork ()) == 0)
  45     {
  46       pid_t p = getpid ();
  47       TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p)));
  48       /* Child return should trigger SIGSEGV.  */
  49       return;
  50     }
  51   else if (p1 == -1)
  52     {
  53       puts ("vfork failed");
  54       _exit (EXIT_FAILURE);
  55     }
  56
  57   pid_t p2 = 0;
  58   if (TEMP_FAILURE_RETRY (read (fd[0], &p2, sizeof (pid_t)))
  59       != sizeof (pid_t))
  60     puts ("pipd read failed");
  61   else
  62     {
  63       int r;
  64       if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
  65         puts ("waitpid failed");
  66       else if (r != 0)
  67         puts ("pip write in child failed");
  68     }
  69
  70   /* Parent exits immediately so that parent returns without triggering
  71      SIGSEGV when shadow stack isn't in use.  */
  72   _exit (EXIT_FAILURE);
  73 }
  74
  75 static int
  76 do_test (void)
  77 {
  78   /* NB: This test should trigger SIGSEGV with shadow stack enabled.  */
  79   if (_get_ssp () == 0)
  80     return EXIT_UNSUPPORTED;
  81   do_test_1 ();
  82   /* Child exits immediately so that child returns without triggering
  83      SIGSEGV when shadow stack isn't in use.  */
  84   _exit (EXIT_FAILURE);
  85 }
  86
  87 #define EXPECTED_SIGNAL (_get_ssp () == 0 ? 0 : SIGSEGV)
  88 #include <support/test-driver.c>