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
do_test_1(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
do_test(void)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>
89