1 | /* Copyright (C) 2005-2024 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
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 |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <errno.h> |
19 | #include <pthread.h> |
20 | #include <stdbool.h> |
21 | #include <stddef.h> |
22 | #include <stdio.h> |
23 | #include <stdlib.h> |
24 | #include <string.h> |
25 | #include <sys/wait.h> |
26 | #include <stackguard-macros.h> |
27 | #include <tls.h> |
28 | #include <unistd.h> |
29 | |
30 | #include <support/xunistd.h> |
31 | #include <support/xstdlib.h> |
32 | |
33 | static const char *command; |
34 | static bool child; |
35 | static uintptr_t stack_chk_guard_copy; |
36 | static bool stack_chk_guard_copy_set; |
37 | static int fds[2]; |
38 | |
39 | static void __attribute__ ((constructor)) |
40 | con (void) |
41 | { |
42 | stack_chk_guard_copy = STACK_CHK_GUARD; |
43 | stack_chk_guard_copy_set = true; |
44 | } |
45 | |
46 | static int |
47 | uintptr_t_cmp (const void *a, const void *b) |
48 | { |
49 | if (*(uintptr_t *) a < *(uintptr_t *) b) |
50 | return 1; |
51 | if (*(uintptr_t *) a > *(uintptr_t *) b) |
52 | return -1; |
53 | return 0; |
54 | } |
55 | |
56 | static void * |
57 | tf (void *arg) |
58 | { |
59 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
60 | { |
61 | puts (s: "STACK_CHK_GUARD changed in thread" ); |
62 | return (void *) 1L; |
63 | } |
64 | return NULL; |
65 | } |
66 | |
67 | static int |
68 | do_test (void) |
69 | { |
70 | if (!stack_chk_guard_copy_set) |
71 | { |
72 | puts (s: "constructor has not been run" ); |
73 | return 1; |
74 | } |
75 | |
76 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
77 | { |
78 | puts (s: "STACK_CHK_GUARD changed between constructor and do_test" ); |
79 | return 1; |
80 | } |
81 | |
82 | if (child) |
83 | { |
84 | int i; |
85 | pthread_t th[4]; |
86 | void *ret; |
87 | for (i = 0; i < 4; ++i) |
88 | if (pthread_create (newthread: &th[i], NULL, start_routine: tf, NULL)) |
89 | { |
90 | puts (s: "thread creation failed" ); |
91 | return 1; |
92 | } |
93 | for (i = 0; i < 4; ++i) |
94 | if (pthread_join (th: th[i], thread_return: &ret)) |
95 | { |
96 | puts (s: "thread join failed" ); |
97 | return 1; |
98 | } |
99 | else if (ret != NULL) |
100 | return 1; |
101 | |
102 | xwrite (2, &stack_chk_guard_copy, sizeof (stack_chk_guard_copy)); |
103 | return 0; |
104 | } |
105 | |
106 | if (command == NULL) |
107 | { |
108 | puts (s: "missing --command or --child argument" ); |
109 | return 1; |
110 | } |
111 | |
112 | #define N 16 |
113 | uintptr_t child_stack_chk_guards[N + 1]; |
114 | child_stack_chk_guards[N] = stack_chk_guard_copy; |
115 | int i; |
116 | for (i = 0; i < N; ++i) |
117 | { |
118 | if (pipe (pipedes: fds) < 0) |
119 | { |
120 | printf (format: "couldn't create pipe: %m\n" ); |
121 | return 1; |
122 | } |
123 | |
124 | pid_t pid = fork (); |
125 | if (pid < 0) |
126 | { |
127 | printf (format: "fork failed: %m\n" ); |
128 | return 1; |
129 | } |
130 | |
131 | if (!pid) |
132 | { |
133 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
134 | { |
135 | puts (s: "STACK_CHK_GUARD changed after fork" ); |
136 | exit (1); |
137 | } |
138 | |
139 | close (fd: fds[0]); |
140 | close (fd: 2); |
141 | dup2 (fd: fds[1], fd2: 2); |
142 | close (fd: fds[1]); |
143 | |
144 | xsystem (cmd: command); |
145 | |
146 | exit (0); |
147 | } |
148 | |
149 | close (fd: fds[1]); |
150 | |
151 | if (TEMP_FAILURE_RETRY (read (fds[0], &child_stack_chk_guards[i], |
152 | sizeof (uintptr_t))) != sizeof (uintptr_t)) |
153 | { |
154 | puts (s: "could not read stack_chk_guard value from child" ); |
155 | return 1; |
156 | } |
157 | |
158 | close (fd: fds[0]); |
159 | |
160 | pid_t termpid; |
161 | int status; |
162 | termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)); |
163 | if (termpid == -1) |
164 | { |
165 | printf (format: "waitpid failed: %m\n" ); |
166 | return 1; |
167 | } |
168 | else if (termpid != pid) |
169 | { |
170 | printf (format: "waitpid returned %ld != %ld\n" , |
171 | (long int) termpid, (long int) pid); |
172 | return 1; |
173 | } |
174 | else if (!WIFEXITED (status) || WEXITSTATUS (status)) |
175 | { |
176 | puts (s: "child hasn't exited with exit status 0" ); |
177 | return 1; |
178 | } |
179 | } |
180 | |
181 | qsort (child_stack_chk_guards, N + 1, sizeof (uintptr_t), uintptr_t_cmp); |
182 | |
183 | uintptr_t default_guard = 0; |
184 | unsigned char *p = (unsigned char *) &default_guard; |
185 | p[sizeof (uintptr_t) - 1] = 255; |
186 | p[sizeof (uintptr_t) - 2] = '\n'; |
187 | p[0] = 0; |
188 | |
189 | /* Test if the stack guard canaries are either randomized, |
190 | or equal to the default stack guard canary value. |
191 | Even with randomized stack guards it might happen |
192 | that the random number generator generates the same |
193 | values, but if that happens in more than half from |
194 | the 16 runs, something is very wrong. */ |
195 | int ndifferences = 0; |
196 | int ndefaults = 0; |
197 | for (i = 0; i < N; ++i) |
198 | { |
199 | if (child_stack_chk_guards[i] != child_stack_chk_guards[i+1]) |
200 | ndifferences++; |
201 | else if (child_stack_chk_guards[i] == default_guard) |
202 | ndefaults++; |
203 | } |
204 | |
205 | printf (format: "differences %d defaults %d\n" , ndifferences, ndefaults); |
206 | |
207 | if (ndifferences < N / 2 && ndefaults < N / 2) |
208 | { |
209 | puts (s: "stack guard canaries are not randomized enough" ); |
210 | puts (s: "nor equal to the default canary value" ); |
211 | return 1; |
212 | } |
213 | |
214 | return 0; |
215 | } |
216 | |
217 | #define OPT_COMMAND 10000 |
218 | #define OPT_CHILD 10001 |
219 | #define CMDLINE_OPTIONS \ |
220 | { "command", required_argument, NULL, OPT_COMMAND }, \ |
221 | { "child", no_argument, NULL, OPT_CHILD }, |
222 | #define CMDLINE_PROCESS \ |
223 | case OPT_COMMAND: \ |
224 | command = optarg; \ |
225 | break; \ |
226 | case OPT_CHILD: \ |
227 | child = true; \ |
228 | break; |
229 | #define TEST_FUNCTION do_test () |
230 | #include "../test-skeleton.c" |
231 | |