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581c785b | 1 | /* Copyright (C) 2005-2022 Free Software Foundation, Inc. |
35f1e827 | 2 | This file is part of the GNU C Library. |
35f1e827 UD |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
35f1e827 UD |
17 | |
18 | #include <errno.h> | |
36fe25fd | 19 | #include <getopt.h> |
35f1e827 UD |
20 | #include <stdbool.h> |
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
24 | #include <sys/wait.h> | |
25 | #include <stackguard-macros.h> | |
903ae060 | 26 | #include <tls.h> |
35f1e827 UD |
27 | #include <unistd.h> |
28 | ||
29 | static const char *command; | |
30 | static bool child; | |
31 | static uintptr_t stack_chk_guard_copy; | |
32 | static bool stack_chk_guard_copy_set; | |
33 | static int fds[2]; | |
34 | ||
35 | static void __attribute__ ((constructor)) | |
36 | con (void) | |
37 | { | |
38 | stack_chk_guard_copy = STACK_CHK_GUARD; | |
39 | stack_chk_guard_copy_set = true; | |
40 | } | |
41 | ||
42 | static int | |
43 | uintptr_t_cmp (const void *a, const void *b) | |
44 | { | |
45 | if (*(uintptr_t *) a < *(uintptr_t *) b) | |
46 | return 1; | |
47 | if (*(uintptr_t *) a > *(uintptr_t *) b) | |
48 | return -1; | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int | |
53 | do_test (void) | |
54 | { | |
55 | if (!stack_chk_guard_copy_set) | |
56 | { | |
57 | puts ("constructor has not been run"); | |
58 | return 1; | |
59 | } | |
60 | ||
61 | if (stack_chk_guard_copy != STACK_CHK_GUARD) | |
62 | { | |
63 | puts ("STACK_CHK_GUARD changed between constructor and do_test"); | |
64 | return 1; | |
65 | } | |
66 | ||
67 | if (child) | |
68 | { | |
69 | write (2, &stack_chk_guard_copy, sizeof (stack_chk_guard_copy)); | |
70 | return 0; | |
71 | } | |
72 | ||
73 | if (command == NULL) | |
74 | { | |
75 | puts ("missing --command or --child argument"); | |
76 | return 1; | |
77 | } | |
78 | ||
79 | #define N 16 | |
80 | uintptr_t child_stack_chk_guards[N + 1]; | |
81 | child_stack_chk_guards[N] = stack_chk_guard_copy; | |
82 | int i; | |
83 | for (i = 0; i < N; ++i) | |
84 | { | |
85 | if (pipe (fds) < 0) | |
86 | { | |
87 | printf ("couldn't create pipe: %m\n"); | |
88 | return 1; | |
89 | } | |
90 | ||
91 | pid_t pid = fork (); | |
92 | if (pid < 0) | |
93 | { | |
94 | printf ("fork failed: %m\n"); | |
95 | return 1; | |
96 | } | |
97 | ||
98 | if (!pid) | |
99 | { | |
100 | if (stack_chk_guard_copy != STACK_CHK_GUARD) | |
101 | { | |
102 | puts ("STACK_CHK_GUARD changed after fork"); | |
103 | exit (1); | |
104 | } | |
105 | ||
106 | close (fds[0]); | |
107 | close (2); | |
108 | dup2 (fds[1], 2); | |
109 | close (fds[1]); | |
110 | ||
111 | system (command); | |
112 | exit (0); | |
113 | } | |
114 | ||
115 | close (fds[1]); | |
116 | ||
117 | if (TEMP_FAILURE_RETRY (read (fds[0], &child_stack_chk_guards[i], | |
118 | sizeof (uintptr_t))) != sizeof (uintptr_t)) | |
119 | { | |
120 | puts ("could not read stack_chk_guard value from child"); | |
121 | return 1; | |
122 | } | |
123 | ||
124 | close (fds[0]); | |
125 | ||
126 | pid_t termpid; | |
127 | int status; | |
128 | termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)); | |
129 | if (termpid == -1) | |
130 | { | |
131 | printf ("waitpid failed: %m\n"); | |
132 | return 1; | |
133 | } | |
134 | else if (termpid != pid) | |
135 | { | |
136 | printf ("waitpid returned %ld != %ld\n", | |
137 | (long int) termpid, (long int) pid); | |
138 | return 1; | |
139 | } | |
140 | else if (!WIFEXITED (status) || WEXITSTATUS (status)) | |
141 | { | |
142 | puts ("child hasn't exited with exit status 0"); | |
143 | return 1; | |
144 | } | |
145 | } | |
146 | ||
147 | qsort (child_stack_chk_guards, N + 1, sizeof (uintptr_t), uintptr_t_cmp); | |
148 | ||
149 | uintptr_t default_guard = 0; | |
150 | unsigned char *p = (unsigned char *) &default_guard; | |
151 | p[sizeof (uintptr_t) - 1] = 255; | |
152 | p[sizeof (uintptr_t) - 2] = '\n'; | |
153 | p[0] = 0; | |
154 | ||
155 | /* Test if the stack guard canaries are either randomized, | |
156 | or equal to the default stack guard canary value. | |
157 | Even with randomized stack guards it might happen | |
158 | that the random number generator generates the same | |
159 | values, but if that happens in more than half from | |
160 | the 16 runs, something is very wrong. */ | |
161 | int ndifferences = 0; | |
162 | int ndefaults = 0; | |
9c84384c | 163 | for (i = 0; i < N; ++i) |
35f1e827 UD |
164 | { |
165 | if (child_stack_chk_guards[i] != child_stack_chk_guards[i+1]) | |
166 | ndifferences++; | |
167 | else if (child_stack_chk_guards[i] == default_guard) | |
168 | ndefaults++; | |
169 | } | |
170 | ||
171 | printf ("differences %d defaults %d\n", ndifferences, ndefaults); | |
172 | ||
173 | if (ndifferences < N / 2 && ndefaults < N / 2) | |
174 | { | |
175 | puts ("stack guard canaries are not randomized enough"); | |
176 | puts ("nor equal to the default canary value"); | |
177 | return 1; | |
178 | } | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | #define OPT_COMMAND 10000 | |
184 | #define OPT_CHILD 10001 | |
185 | #define CMDLINE_OPTIONS \ | |
186 | { "command", required_argument, NULL, OPT_COMMAND }, \ | |
187 | { "child", no_argument, NULL, OPT_CHILD }, | |
36fe25fd WSM |
188 | |
189 | static void __attribute__((used)) | |
190 | cmdline_process_function (int c) | |
191 | { | |
192 | switch (c) | |
193 | { | |
194 | case OPT_COMMAND: | |
195 | command = optarg; | |
196 | break; | |
197 | case OPT_CHILD: | |
198 | child = true; | |
199 | break; | |
200 | } | |
201 | } | |
202 | #define CMDLINE_PROCESS cmdline_process_function | |
203 | ||
204 | #include <support/test-driver.c> |