1 | /* Copyright (C) 2005-2022 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 | static const char *command; |
31 | static bool child; |
32 | static uintptr_t stack_chk_guard_copy; |
33 | static bool stack_chk_guard_copy_set; |
34 | static int fds[2]; |
35 | |
36 | static void __attribute__ ((constructor)) |
37 | con (void) |
38 | { |
39 | stack_chk_guard_copy = STACK_CHK_GUARD; |
40 | stack_chk_guard_copy_set = true; |
41 | } |
42 | |
43 | static int |
44 | uintptr_t_cmp (const void *a, const void *b) |
45 | { |
46 | if (*(uintptr_t *) a < *(uintptr_t *) b) |
47 | return 1; |
48 | if (*(uintptr_t *) a > *(uintptr_t *) b) |
49 | return -1; |
50 | return 0; |
51 | } |
52 | |
53 | static void * |
54 | tf (void *arg) |
55 | { |
56 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
57 | { |
58 | puts (s: "STACK_CHK_GUARD changed in thread" ); |
59 | return (void *) 1L; |
60 | } |
61 | return NULL; |
62 | } |
63 | |
64 | static int |
65 | do_test (void) |
66 | { |
67 | if (!stack_chk_guard_copy_set) |
68 | { |
69 | puts (s: "constructor has not been run" ); |
70 | return 1; |
71 | } |
72 | |
73 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
74 | { |
75 | puts (s: "STACK_CHK_GUARD changed between constructor and do_test" ); |
76 | return 1; |
77 | } |
78 | |
79 | if (child) |
80 | { |
81 | int i; |
82 | pthread_t th[4]; |
83 | void *ret; |
84 | for (i = 0; i < 4; ++i) |
85 | if (pthread_create (newthread: &th[i], NULL, start_routine: tf, NULL)) |
86 | { |
87 | puts (s: "thread creation failed" ); |
88 | return 1; |
89 | } |
90 | for (i = 0; i < 4; ++i) |
91 | if (pthread_join (th: th[i], thread_return: &ret)) |
92 | { |
93 | puts (s: "thread join failed" ); |
94 | return 1; |
95 | } |
96 | else if (ret != NULL) |
97 | return 1; |
98 | |
99 | write (2, &stack_chk_guard_copy, sizeof (stack_chk_guard_copy)); |
100 | return 0; |
101 | } |
102 | |
103 | if (command == NULL) |
104 | { |
105 | puts (s: "missing --command or --child argument" ); |
106 | return 1; |
107 | } |
108 | |
109 | #define N 16 |
110 | uintptr_t child_stack_chk_guards[N + 1]; |
111 | child_stack_chk_guards[N] = stack_chk_guard_copy; |
112 | int i; |
113 | for (i = 0; i < N; ++i) |
114 | { |
115 | if (pipe (pipedes: fds) < 0) |
116 | { |
117 | printf (format: "couldn't create pipe: %m\n" ); |
118 | return 1; |
119 | } |
120 | |
121 | pid_t pid = fork (); |
122 | if (pid < 0) |
123 | { |
124 | printf (format: "fork failed: %m\n" ); |
125 | return 1; |
126 | } |
127 | |
128 | if (!pid) |
129 | { |
130 | if (stack_chk_guard_copy != STACK_CHK_GUARD) |
131 | { |
132 | puts (s: "STACK_CHK_GUARD changed after fork" ); |
133 | exit (1); |
134 | } |
135 | |
136 | close (fd: fds[0]); |
137 | close (fd: 2); |
138 | dup2 (fd: fds[1], fd2: 2); |
139 | close (fd: fds[1]); |
140 | |
141 | system (command: command); |
142 | exit (0); |
143 | } |
144 | |
145 | close (fd: fds[1]); |
146 | |
147 | if (TEMP_FAILURE_RETRY (read (fds[0], &child_stack_chk_guards[i], |
148 | sizeof (uintptr_t))) != sizeof (uintptr_t)) |
149 | { |
150 | puts (s: "could not read stack_chk_guard value from child" ); |
151 | return 1; |
152 | } |
153 | |
154 | close (fd: fds[0]); |
155 | |
156 | pid_t termpid; |
157 | int status; |
158 | termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)); |
159 | if (termpid == -1) |
160 | { |
161 | printf (format: "waitpid failed: %m\n" ); |
162 | return 1; |
163 | } |
164 | else if (termpid != pid) |
165 | { |
166 | printf (format: "waitpid returned %ld != %ld\n" , |
167 | (long int) termpid, (long int) pid); |
168 | return 1; |
169 | } |
170 | else if (!WIFEXITED (status) || WEXITSTATUS (status)) |
171 | { |
172 | puts (s: "child hasn't exited with exit status 0" ); |
173 | return 1; |
174 | } |
175 | } |
176 | |
177 | qsort (child_stack_chk_guards, N + 1, sizeof (uintptr_t), uintptr_t_cmp); |
178 | |
179 | uintptr_t default_guard = 0; |
180 | unsigned char *p = (unsigned char *) &default_guard; |
181 | p[sizeof (uintptr_t) - 1] = 255; |
182 | p[sizeof (uintptr_t) - 2] = '\n'; |
183 | p[0] = 0; |
184 | |
185 | /* Test if the stack guard canaries are either randomized, |
186 | or equal to the default stack guard canary value. |
187 | Even with randomized stack guards it might happen |
188 | that the random number generator generates the same |
189 | values, but if that happens in more than half from |
190 | the 16 runs, something is very wrong. */ |
191 | int ndifferences = 0; |
192 | int ndefaults = 0; |
193 | for (i = 0; i < N; ++i) |
194 | { |
195 | if (child_stack_chk_guards[i] != child_stack_chk_guards[i+1]) |
196 | ndifferences++; |
197 | else if (child_stack_chk_guards[i] == default_guard) |
198 | ndefaults++; |
199 | } |
200 | |
201 | printf (format: "differences %d defaults %d\n" , ndifferences, ndefaults); |
202 | |
203 | if (ndifferences < N / 2 && ndefaults < N / 2) |
204 | { |
205 | puts (s: "stack guard canaries are not randomized enough" ); |
206 | puts (s: "nor equal to the default canary value" ); |
207 | return 1; |
208 | } |
209 | |
210 | return 0; |
211 | } |
212 | |
213 | #define OPT_COMMAND 10000 |
214 | #define OPT_CHILD 10001 |
215 | #define CMDLINE_OPTIONS \ |
216 | { "command", required_argument, NULL, OPT_COMMAND }, \ |
217 | { "child", no_argument, NULL, OPT_CHILD }, |
218 | #define CMDLINE_PROCESS \ |
219 | case OPT_COMMAND: \ |
220 | command = optarg; \ |
221 | break; \ |
222 | case OPT_CHILD: \ |
223 | child = true; \ |
224 | break; |
225 | #define TEST_FUNCTION do_test () |
226 | #include "../test-skeleton.c" |
227 | |