1 | /* Make sure longjmp fortification catches bad signal stacks. |
2 | Copyright (C) 2013-2022 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 int do_test (void); |
24 | #define TEST_FUNCTION do_test () |
25 | #include "../test-skeleton.c" |
26 | |
27 | static char buf[SIGSTKSZ * 4]; |
28 | static jmp_buf jb; |
29 | |
30 | static void |
31 | handler (int sig) |
32 | { |
33 | if (sig == SIGUSR1) |
34 | { |
35 | if (setjmp (jb) != 0) |
36 | { |
37 | puts (s: "setjmp should not have been called" ); |
38 | kill (pid: getpid (), SIGTERM); |
39 | } |
40 | } |
41 | else if (sig == SIGABRT) |
42 | { |
43 | /* Yeah it worked. */ |
44 | _exit (0); |
45 | } |
46 | } |
47 | |
48 | static int |
49 | do_test (void) |
50 | { |
51 | stack_t ss; |
52 | |
53 | set_fortify_handler (handler); |
54 | |
55 | /* Create a valid signal stack and enable it. */ |
56 | ss.ss_sp = buf; |
57 | ss.ss_size = sizeof (buf); |
58 | ss.ss_flags = 0; |
59 | if (sigaltstack (ss: &ss, NULL) < 0) |
60 | { |
61 | printf (format: "first sigaltstack failed: %m\n" ); |
62 | return 1; |
63 | } |
64 | |
65 | /* Trigger the signal handler which will create a jmpbuf that points to the |
66 | end of the signal stack. */ |
67 | signal (SIGUSR1, handler: handler); |
68 | kill (pid: getpid (), SIGUSR1); |
69 | |
70 | /* Shrink the signal stack so the jmpbuf is now invalid. |
71 | We adjust the start & end to handle stacks that grow up & down. */ |
72 | ss.ss_sp = buf + sizeof (buf) / 2; |
73 | ss.ss_size = sizeof (buf) / 4; |
74 | if (sigaltstack (ss: &ss, NULL) < 0) |
75 | { |
76 | printf (format: "second sigaltstack failed: %m\n" ); |
77 | return 1; |
78 | } |
79 | |
80 | /* This should fail. */ |
81 | longjmp (env: jb, val: 1); |
82 | |
83 | puts (s: "longjmp returned and shouldn't" ); |
84 | return 1; |
85 | } |
86 | |