1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
|
/* Copyright (C) 2005 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* Copyright (C) 2006-2007 Gentoo Foundation Inc.
* License terms as above.
*
* Hardened Gentoo SSP handler
*
* An SSP failure handler that does not use functions from the rest of
* glibc; it uses the INTERNAL_SYSCALL methods directly. This ensures
* no possibility of recursion into the handler.
*
* Direct all bug reports to http://bugs.gentoo.org/
*
* Re-written from the glibc-2.3 Hardened Gentoo SSP handler
* by Kevin F. Quinn - <kevquinn[@]gentoo.org>
*
* The following people contributed to the glibc-2.3 Hardened
* Gentoo SSP handler, from which this implementation draws much:
*
* Ned Ludd - <solar[@]gentoo.org>
* Alexander Gabert - <pappy[@]gentoo.org>
* The PaX Team - <pageexec[@]freemail.hu>
* Peter S. Mazinger - <ps.m[@]gmx.net>
* Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
* Robert Connolly - <robert[@]linuxfromscratch.org>
* Cory Visi <cory[@]visi.name>
* Mike Frysinger <vapier[@]gentoo.org>
*/
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#include <bp-checks.h>
#include <kernel-features.h>
#include <alloca.h>
/* from sysdeps */
#include <socketcall.h>
/* for the stuff in bits/socket.h */
#include <sys/socket.h>
#include <sys/un.h>
/* Sanity check on SYSCALL macro names - force compilation
* failure if the names used here do not exist
*/
#if !defined __NR_socketcall && !defined __NR_socket
# error Cannot do syscall socket or socketcall
#endif
#if !defined __NR_socketcall && !defined __NR_connect
# error Cannot do syscall connect or socketcall
#endif
#ifndef __NR_write
# error Cannot do syscall write
#endif
#ifndef __NR_close
# error Cannot do syscall close
#endif
#ifndef __NR_getpid
# error Cannot do syscall getpid
#endif
#ifndef __NR_kill
# error Cannot do syscall kill
#endif
#ifndef __NR_exit
# error Cannot do syscall exit
#endif
#ifdef SSP_SMASH_DUMPS_CORE
# define ENABLE_SSP_SMASH_DUMPS_CORE 1
# if !defined _KERNEL_NSIG && !defined _NSIG
# error No _NSIG or _KERNEL_NSIG for rt_sigaction
# endif
# if !defined __NR_sigaction && !defined __NR_rt_sigaction
# error Cannot do syscall sigaction or rt_sigaction
# endif
/* Although rt_sigaction expects sizeof(sigset_t) - it expects the size
* of the _kernel_ sigset_t which is not the same as the user sigset_t.
* Most arches have this as _NSIG bits - mips has _KERNEL_NSIG bits for
* some reason.
*/
# ifdef _KERNEL_NSIG
# define _SSP_NSIG _KERNEL_NSIG
# else
# define _SSP_NSIG _NSIG
# endif
#else
# define _SSP_NSIG 0
# define ENABLE_SSP_SMASH_DUMPS_CORE 0
#endif
/* Define DO_SIGACTION - default to newer rt signal interface but
* fallback to old as needed.
*/
#ifdef __NR_rt_sigaction
# define DO_SIGACTION(signum, act, oldact) \
INLINE_SYSCALL(rt_sigaction, 4, signum, act, oldact, _SSP_NSIG/8)
#else
# define DO_SIGACTION(signum, act, oldact) \
INLINE_SYSCALL(sigaction, 3, signum, act, oldact)
#endif
/* Define DO_SOCKET/DO_CONNECT functions to deal with socketcall vs socket/connect */
#if defined(__NR_socket) && defined(__NR_connect)
# define USE_OLD_SOCKETCALL 0
#else
# define USE_OLD_SOCKETCALL 1
#endif
/* stub out the __NR_'s so we can let gcc optimize away dead code */
#ifndef __NR_socketcall
# define __NR_socketcall 0
#endif
#ifndef __NR_socket
# define __NR_socket 0
#endif
#ifndef __NR_connect
# define __NR_connect 0
#endif
#define DO_SOCKET(result, domain, type, protocol) \
do { \
if (USE_OLD_SOCKETCALL) { \
socketargs[0] = domain; \
socketargs[1] = type; \
socketargs[2] = protocol; \
socketargs[3] = 0; \
result = INLINE_SYSCALL(socketcall, 2, SOCKOP_socket, socketargs); \
} else \
result = INLINE_SYSCALL(socket, 3, domain, type, protocol); \
} while (0)
#define DO_CONNECT(result, sockfd, serv_addr, addrlen) \
do { \
if (USE_OLD_SOCKETCALL) { \
socketargs[0] = sockfd; \
socketargs[1] = (unsigned long int)serv_addr; \
socketargs[2] = addrlen; \
socketargs[3] = 0; \
result = INLINE_SYSCALL(socketcall, 2, SOCKOP_connect, socketargs); \
} else \
result = INLINE_SYSCALL(connect, 3, sockfd, serv_addr, addrlen); \
} while (0)
#ifndef _PATH_LOG
# define _PATH_LOG "/dev/log"
#endif
static const char path_log[] = _PATH_LOG;
/* For building glibc with SSP switched on, define __progname to a
* constant if building for the run-time loader, to avoid pulling
* in more of libc.so into ld.so
*/
#ifdef IS_IN_rtld
static char *__progname = "<rtld>";
#else
extern char *__progname;
#endif
/* Common handler code, used by stack_chk_fail and __stack_smash_handler
* Inlined to ensure no self-references to the handler within itself.
* Data static to avoid putting more than necessary on the stack,
* to aid core debugging.
*/
__attribute__ ((__noreturn__ , __always_inline__))
static inline void
__hardened_gentoo_stack_chk_fail(char func[], int damaged)
{
#define MESSAGE_BUFSIZ 256
static pid_t pid;
static int plen, i;
static char message[MESSAGE_BUFSIZ];
static const char msg_ssa[] = ": stack smashing attack";
static const char msg_inf[] = " in function ";
static const char msg_ssd[] = "*** stack smashing detected ***: ";
static const char msg_terminated[] = " - terminated\n";
static const char msg_report[] = "Report to http://bugs.gentoo.org/\n";
static const char msg_unknown[] = "<unknown>";
static int log_socket, connect_result;
static struct sockaddr_un sock;
static unsigned long int socketargs[4];
/* Build socket address
*/
sock.sun_family = AF_UNIX;
i = 0;
while ((path_log[i] != '\0') && (i<(sizeof(sock.sun_path)-1))) {
sock.sun_path[i] = path_log[i];
i++;
}
sock.sun_path[i] = '\0';
/* Try SOCK_DGRAM connection to syslog */
connect_result = -1;
DO_SOCKET(log_socket, AF_UNIX, SOCK_DGRAM, 0);
if (log_socket != -1)
DO_CONNECT(connect_result, log_socket, &sock, sizeof(sock));
if (connect_result == -1) {
if (log_socket != -1)
INLINE_SYSCALL(close, 1, log_socket);
/* Try SOCK_STREAM connection to syslog */
DO_SOCKET(log_socket, AF_UNIX, SOCK_STREAM, 0);
if (log_socket != -1)
DO_CONNECT(connect_result, log_socket, &sock, sizeof(sock));
}
/* Build message. Messages are generated both in the old style and new style,
* so that log watchers that are configured for the old-style message continue
* to work.
*/
#define strconcat(str) \
{i=0; while ((str[i] != '\0') && ((i+plen)<(MESSAGE_BUFSIZ-1))) \
{\
message[plen+i]=str[i];\
i++;\
}\
plen+=i;}
/* R.Henderson post-gcc-4 style message */
plen = 0;
strconcat(msg_ssd);
if (__progname != (char *)0)
strconcat(__progname)
else
strconcat(msg_unknown);
strconcat(msg_terminated);
/* Write out error message to STDERR, to syslog if open */
INLINE_SYSCALL(write, 3, STDERR_FILENO, message, plen);
if (connect_result != -1)
INLINE_SYSCALL(write, 3, log_socket, message, plen);
/* Dr. Etoh pre-gcc-4 style message */
plen = 0;
if (__progname != (char *)0)
strconcat(__progname)
else
strconcat(msg_unknown);
strconcat(msg_ssa);
strconcat(msg_inf);
if (func != NULL)
strconcat(func)
else
strconcat(msg_unknown);
strconcat(msg_terminated);
/* Write out error message to STDERR, to syslog if open */
INLINE_SYSCALL(write, 3, STDERR_FILENO, message, plen);
if (connect_result != -1)
INLINE_SYSCALL(write, 3, log_socket, message, plen);
/* Direct reports to bugs.gentoo.org */
plen=0;
strconcat(msg_report);
message[plen++]='\0';
/* Write out error message to STDERR, to syslog if open */
INLINE_SYSCALL(write, 3, STDERR_FILENO, message, plen);
if (connect_result != -1)
INLINE_SYSCALL(write, 3, log_socket, message, plen);
if (log_socket != -1)
INLINE_SYSCALL(close, 1, log_socket);
/* Suicide */
pid = INLINE_SYSCALL(getpid, 0);
if (ENABLE_SSP_SMASH_DUMPS_CORE) {
static struct sigaction default_abort_act;
/* Remove any user-supplied handler for SIGABRT, before using it */
default_abort_act.sa_handler = SIG_DFL;
default_abort_act.sa_sigaction = NULL;
__sigfillset(&default_abort_act.sa_mask);
default_abort_act.sa_flags = 0;
if (DO_SIGACTION(SIGABRT, &default_abort_act, NULL) == 0)
INLINE_SYSCALL(kill, 2, pid, SIGABRT);
}
/* Note; actions cannot be added to SIGKILL */
INLINE_SYSCALL(kill, 2, pid, SIGKILL);
/* In case the kill didn't work, exit anyway
* The loop prevents gcc thinking this routine returns
*/
while (1)
INLINE_SYSCALL(exit, 0);
}
__attribute__ ((__noreturn__))
void __stack_chk_fail(void)
{
__hardened_gentoo_stack_chk_fail(NULL, 0);
}
#ifdef ENABLE_OLD_SSP_COMPAT
__attribute__ ((__noreturn__))
void __stack_smash_handler(char func[], int damaged)
{
__hardened_gentoo_stack_chk_fail(func, damaged);
}
#endif
|
