]>
Commit | Line | Data |
---|---|---|
0d55f4d0 | 1 | /* Stack protector support. |
fbd26352 | 2 | Copyright (C) 2005-2019 Free Software Foundation, Inc. |
0d55f4d0 | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
6bc9506f | 8 | Software Foundation; either version 3, or (at your option) any later |
0d55f4d0 | 9 | version. |
10 | ||
11 | In addition to the permissions in the GNU General Public License, the | |
12 | Free Software Foundation gives you unlimited permission to link the | |
13 | compiled version of this file into combinations with other programs, | |
14 | and to distribute those combinations without any restriction coming | |
15 | from the use of this file. (The General Public License restrictions | |
16 | do apply in other respects; for example, they cover modification of | |
17 | the file, and distribution when not linked into a combine | |
18 | executable.) | |
19 | ||
20 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
21 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
22 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
23 | for more details. | |
24 | ||
6bc9506f | 25 | Under Section 7 of GPL version 3, you are granted additional |
26 | permissions described in the GCC Runtime Library Exception, version | |
27 | 3.1, as published by the Free Software Foundation. | |
28 | ||
29 | You should have received a copy of the GNU General Public License and | |
30 | a copy of the GCC Runtime Library Exception along with this program; | |
31 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
32 | <http://www.gnu.org/licenses/>. */ | |
0d55f4d0 | 33 | |
0d55f4d0 | 34 | |
35 | #include "config.h" | |
36 | #ifdef HAVE_ALLOCA_H | |
37 | # include <alloca.h> | |
38 | #endif | |
724518ff | 39 | #ifdef HAVE_MALLOC_H |
40 | # include <malloc.h> | |
41 | #endif | |
0d55f4d0 | 42 | #ifdef HAVE_STRING_H |
43 | # include <string.h> | |
44 | #endif | |
45 | #ifdef HAVE_UNISTD_H | |
46 | # include <unistd.h> | |
47 | #endif | |
48 | #ifdef HAVE_FCNTL_H | |
49 | # include <fcntl.h> | |
50 | #endif | |
51 | #ifdef HAVE_PATHS_H | |
52 | # include <paths.h> | |
53 | #endif | |
54 | #ifndef _PATH_TTY | |
1070c6bd | 55 | /* Native win32 apps don't know about /dev/tty but can print directly |
56 | to the console using "CONOUT$" */ | |
57 | #if defined (_WIN32) && !defined (__CYGWIN__) | |
19fef163 | 58 | #include <windows.h> |
4f6f2923 | 59 | #include <wincrypt.h> |
1070c6bd | 60 | # define _PATH_TTY "CONOUT$" |
61 | #else | |
0d55f4d0 | 62 | # define _PATH_TTY "/dev/tty" |
63 | #endif | |
1070c6bd | 64 | #endif |
0d55f4d0 | 65 | #ifdef HAVE_SYSLOG_H |
66 | # include <syslog.h> | |
67 | #endif | |
68 | ||
69 | void *__stack_chk_guard = 0; | |
70 | ||
71 | static void __attribute__ ((constructor)) | |
72 | __guard_setup (void) | |
73 | { | |
74 | unsigned char *p; | |
0d55f4d0 | 75 | |
76 | if (__stack_chk_guard != 0) | |
77 | return; | |
78 | ||
19fef163 | 79 | #if defined (_WIN32) && !defined (__CYGWIN__) |
80 | HCRYPTPROV hprovider = 0; | |
81 | if (CryptAcquireContext(&hprovider, NULL, NULL, PROV_RSA_FULL, | |
82 | CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) | |
83 | { | |
84 | if (CryptGenRandom(hprovider, sizeof (__stack_chk_guard), | |
85 | (BYTE *)&__stack_chk_guard) && __stack_chk_guard != 0) | |
86 | { | |
87 | CryptReleaseContext(hprovider, 0); | |
88 | return; | |
89 | } | |
90 | CryptReleaseContext(hprovider, 0); | |
91 | } | |
92 | #else | |
7714131b | 93 | int fd = open ("/dev/urandom", O_RDONLY); |
0d55f4d0 | 94 | if (fd != -1) |
95 | { | |
96 | ssize_t size = read (fd, &__stack_chk_guard, | |
97 | sizeof (__stack_chk_guard)); | |
98 | close (fd); | |
99 | if (size == sizeof(__stack_chk_guard) && __stack_chk_guard != 0) | |
100 | return; | |
101 | } | |
102 | ||
19fef163 | 103 | #endif |
0d55f4d0 | 104 | /* If a random generator can't be used, the protector switches the guard |
105 | to the "terminator canary". */ | |
106 | p = (unsigned char *) &__stack_chk_guard; | |
107 | p[sizeof(__stack_chk_guard)-1] = 255; | |
108 | p[sizeof(__stack_chk_guard)-2] = '\n'; | |
109 | p[0] = 0; | |
110 | } | |
111 | ||
112 | static void | |
113 | fail (const char *msg1, size_t msg1len, const char *msg3) | |
114 | { | |
115 | #ifdef __GNU_LIBRARY__ | |
116 | extern char * __progname; | |
117 | #else | |
118 | static const char __progname[] = ""; | |
119 | #endif | |
120 | int fd; | |
121 | ||
122 | /* Print error message directly to the tty. This avoids Bad Things | |
123 | happening if stderr is redirected. */ | |
124 | fd = open (_PATH_TTY, O_WRONLY); | |
125 | if (fd != -1) | |
126 | { | |
127 | static const char msg2[] = " terminated\n"; | |
128 | size_t progname_len, len; | |
129 | char *buf, *p; | |
130 | ||
131 | progname_len = strlen (__progname); | |
132 | len = msg1len + progname_len + sizeof(msg2)-1 + 1; | |
133 | p = buf = alloca (len); | |
134 | ||
135 | memcpy (p, msg1, msg1len); | |
136 | p += msg1len; | |
137 | memcpy (p, __progname, progname_len); | |
138 | p += progname_len; | |
139 | memcpy (p, msg2, sizeof(msg2)); | |
140 | ||
141 | while (len > 0) | |
142 | { | |
143 | ssize_t wrote = write (fd, buf, len); | |
144 | if (wrote < 0) | |
145 | break; | |
146 | buf += wrote; | |
147 | len -= wrote; | |
148 | } | |
149 | close (fd); | |
150 | } | |
151 | ||
152 | #ifdef HAVE_SYSLOG_H | |
153 | /* Only send the error to syslog if there was no tty available. */ | |
154 | else | |
08edd07c | 155 | syslog (LOG_CRIT, "%s", msg3); |
0d55f4d0 | 156 | #endif /* HAVE_SYSLOG_H */ |
157 | ||
158 | /* Try very hard to exit. Note that signals may be blocked preventing | |
159 | the first two options from working. The use of volatile is here to | |
160 | prevent optimizers from "knowing" that __builtin_trap is called first, | |
161 | and that it doesn't return, and so "obviously" the rest of the code | |
162 | is dead. */ | |
163 | { | |
164 | volatile int state; | |
165 | for (state = 0; ; state++) | |
166 | switch (state) | |
167 | { | |
168 | case 0: | |
169 | __builtin_trap (); | |
170 | break; | |
171 | case 1: | |
172 | *(volatile int *)-1L = 0; | |
173 | break; | |
174 | case 2: | |
175 | _exit (127); | |
176 | break; | |
177 | } | |
178 | } | |
179 | } | |
180 | ||
181 | void | |
182 | __stack_chk_fail (void) | |
183 | { | |
184 | const char *msg = "*** stack smashing detected ***: "; | |
185 | fail (msg, strlen (msg), "stack smashing detected: terminated"); | |
186 | } | |
187 | ||
188 | void | |
189 | __chk_fail (void) | |
190 | { | |
191 | const char *msg = "*** buffer overflow detected ***: "; | |
192 | fail (msg, strlen (msg), "buffer overflow detected: terminated"); | |
193 | } | |
194 | ||
195 | #ifdef HAVE_HIDDEN_VISIBILITY | |
196 | void | |
197 | __attribute__((visibility ("hidden"))) | |
198 | __stack_chk_fail_local (void) | |
199 | { | |
200 | __stack_chk_fail (); | |
201 | } | |
202 | #endif |