1 | /* Make sure longjmp fortification catches bad signal stacks. |
2 | Copyright (C) 2013-2024 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 | #include <setjmp.h> |
20 | #include <signal.h> |
21 | #include <string.h> |
22 | |
23 | static char buf[SIGSTKSZ * 4]; |
24 | static jmp_buf jb; |
25 | |
26 | static void |
27 | handler (int sig) |
28 | { |
29 | if (sig == SIGUSR1) |
30 | { |
31 | if (setjmp (jb) != 0) |
32 | { |
33 | puts ("setjmp should not have been called" ); |
34 | kill (pid: getpid (), SIGTERM); |
35 | } |
36 | } |
37 | else if (sig == SIGABRT) |
38 | { |
39 | /* Yeah it worked. */ |
40 | _exit (0); |
41 | } |
42 | } |
43 | |
44 | static int |
45 | do_test (void) |
46 | { |
47 | stack_t ss; |
48 | |
49 | set_fortify_handler (handler); |
50 | |
51 | /* Create a valid signal stack and enable it. */ |
52 | ss.ss_sp = buf; |
53 | ss.ss_size = sizeof (buf); |
54 | ss.ss_flags = 0; |
55 | if (sigaltstack (ss: &ss, NULL) < 0) |
56 | { |
57 | printf ("first sigaltstack failed: %m\n" ); |
58 | return 1; |
59 | } |
60 | |
61 | /* Trigger the signal handler which will create a jmpbuf that points to the |
62 | end of the signal stack. */ |
63 | signal (SIGUSR1, handler: handler); |
64 | kill (pid: getpid (), SIGUSR1); |
65 | |
66 | /* Shrink the signal stack so the jmpbuf is now invalid. |
67 | We adjust the start & end to handle stacks that grow up & down. */ |
68 | ss.ss_sp = buf + sizeof (buf) / 2; |
69 | ss.ss_size = sizeof (buf) / 4; |
70 | if (sigaltstack (ss: &ss, NULL) < 0) |
71 | { |
72 | printf ("second sigaltstack failed: %m\n" ); |
73 | return 1; |
74 | } |
75 | |
76 | /* This should fail. */ |
77 | longjmp (jb, 1); |
78 | |
79 | puts ("longjmp returned and shouldn't" ); |
80 | return 1; |
81 | } |
82 | |
83 | #include <support/test-driver.c> |
84 | |