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- Committer: Björn Påhlsson
- Date: 2008-07-20 03:51:41 UTC
- Revision ID: belorn@braxen-20080720035141-ta0y0be7fotdm4ks
Fixed a overbufferflow bug, thanks to a forgotten \0
- files added:
- ca.pem
- files removed:
- .bzr-builddeb
- debian
- debian/po
- debian/source
- files renamed:
- clients.conf => mandos-clients.conf
- plugin-runner.c => plugbasedclient.c
- plugins.d/mandos-client.c => plugins.d/mandosclient.c
- plugins.d/password-prompt.c => plugins.d/passprompt.c
- mandos => server.py
- files modified:
- Makefile
added
removed
plugins.d/splashy.c
1
/* -*- coding: utf-8 -*- */
2
/*
3
* Splashy - Read a password from splashy and output it
4
*
5
* Copyright © 2008-2010 Teddy Hogeborn
6
* Copyright © 2008-2010 Björn Påhlsson
7
*
8
* This program is free software: you can redistribute it and/or
9
* modify it under the terms of the GNU General Public License as
10
* published by the Free Software Foundation, either version 3 of the
11
* License, or (at your option) any later version.
12
*
13
* This program is distributed in the hope that it will be useful, but
14
* WITHOUT ANY WARRANTY; without even the implied warranty of
15
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16
* General Public License for more details.
17
*
18
* You should have received a copy of the GNU General Public License
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
21
*
22
* Contact the authors at <mandos@fukt.bsnet.se>.
23
*/
24
25
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
27
sigemptyset(), sigaddset(), SIGINT,
28
SIGHUP, SIGTERM, sigaction,
29
SIG_IGN, kill(), SIGKILL */
30
#include <stddef.h> /* NULL */
31
#include <stdlib.h> /* getenv() */
32
#include <stdio.h> /* asprintf() */
33
#include <stdlib.h> /* EXIT_FAILURE, free(),
34
EXIT_SUCCESS */
35
#include <sys/types.h> /* pid_t, DIR, struct dirent,
36
ssize_t */
37
#include <dirent.h> /* opendir(), readdir(), closedir() */
38
#include <inttypes.h> /* intmax_t, strtoimax() */
39
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
40
#include <iso646.h> /* not, or, and */
41
#include <unistd.h> /* readlink(), fork(), execl(),
42
sleep(), dup2() STDERR_FILENO,
43
STDOUT_FILENO, _exit(),
44
pause() */
45
#include <string.h> /* memcmp() */
46
#include <errno.h> /* errno, EACCES, ENOTDIR, ELOOP,
47
ENOENT, ENAMETOOLONG, EMFILE,
48
ENFILE, ENOMEM, ENOEXEC, EINVAL,
49
E2BIG, EFAULT, EIO, ETXTBSY,
50
EISDIR, ELIBBAD, EPERM, EINTR,
51
ECHILD */
52
#include <error.h> /* error() */
53
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
54
WEXITSTATUS() */
55
#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
56
EX_UNAVAILABLE */
57
58
sig_atomic_t interrupted_by_signal = 0;
59
int signal_received;
60
61
static void termination_handler(int signum){
62
if(interrupted_by_signal){
63
return;
64
}
65
interrupted_by_signal = 1;
66
signal_received = signum;
67
}
68
69
int main(__attribute__((unused))int argc,
70
__attribute__((unused))char **argv){
71
int ret = 0;
72
char *prompt = NULL;
73
DIR *proc_dir = NULL;
74
pid_t splashy_pid = 0;
75
pid_t splashy_command_pid = 0;
76
int exitstatus = EXIT_FAILURE;
77
78
/* Create prompt string */
79
{
80
const char *const cryptsource = getenv("cryptsource");
81
const char *const crypttarget = getenv("crypttarget");
82
const char *const prompt_start = "getpass "
83
"Enter passphrase to unlock the disk";
84
85
if(cryptsource == NULL){
86
if(crypttarget == NULL){
87
ret = asprintf(&prompt, "%s: ", prompt_start);
88
} else {
89
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
90
crypttarget);
91
}
92
} else {
93
if(crypttarget == NULL){
94
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
95
} else {
96
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
97
cryptsource, crypttarget);
98
}
99
}
100
if(ret == -1){
101
prompt = NULL;
102
exitstatus = EX_OSERR;
103
goto failure;
104
}
105
}
106
107
/* Find splashy process */
108
{
109
const char splashy_name[] = "/sbin/splashy";
110
proc_dir = opendir("/proc");
111
if(proc_dir == NULL){
112
int e = errno;
113
error(0, errno, "opendir");
114
switch(e){
115
case EACCES:
116
case ENOTDIR:
117
case ELOOP:
118
case ENOENT:
119
default:
120
exitstatus = EX_OSFILE;
121
break;
122
case ENAMETOOLONG:
123
case EMFILE:
124
case ENFILE:
125
case ENOMEM:
126
exitstatus = EX_OSERR;
127
break;
128
}
129
goto failure;
130
}
131
for(struct dirent *proc_ent = readdir(proc_dir);
132
proc_ent != NULL;
133
proc_ent = readdir(proc_dir)){
134
pid_t pid;
135
{
136
intmax_t tmpmax;
137
char *tmp;
138
errno = 0;
139
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
140
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
141
or tmpmax != (pid_t)tmpmax){
142
/* Not a process */
143
continue;
144
}
145
pid = (pid_t)tmpmax;
146
}
147
/* Find the executable name by doing readlink() on the
148
/proc/<pid>/exe link */
149
char exe_target[sizeof(splashy_name)];
150
ssize_t sret;
151
{
152
char *exe_link;
153
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
154
if(ret == -1){
155
error(0, errno, "asprintf");
156
exitstatus = EX_OSERR;
157
goto failure;
158
}
159
160
/* Check that it refers to a symlink owned by root:root */
161
struct stat exe_stat;
162
ret = lstat(exe_link, &exe_stat);
163
if(ret == -1){
164
if(errno == ENOENT){
165
free(exe_link);
166
continue;
167
}
168
int e = errno;
169
error(0, errno, "lstat");
170
free(exe_link);
171
switch(e){
172
case EACCES:
173
case ENOTDIR:
174
case ELOOP:
175
default:
176
exitstatus = EX_OSFILE;
177
break;
178
case ENAMETOOLONG:
179
exitstatus = EX_OSERR;
180
break;
181
}
182
goto failure;
183
}
184
if(not S_ISLNK(exe_stat.st_mode)
185
or exe_stat.st_uid != 0
186
or exe_stat.st_gid != 0){
187
free(exe_link);
188
continue;
189
}
190
191
sret = readlink(exe_link, exe_target, sizeof(exe_target));
192
free(exe_link);
193
}
194
if((sret == ((ssize_t)sizeof(exe_target)-1))
195
and (memcmp(splashy_name, exe_target,
196
sizeof(exe_target)-1) == 0)){
197
splashy_pid = pid;
198
break;
199
}
200
}
201
closedir(proc_dir);
202
proc_dir = NULL;
203
}
204
if(splashy_pid == 0){
205
exitstatus = EX_UNAVAILABLE;
206
goto failure;
207
}
208
209
/* Set up the signal handler */
210
{
211
struct sigaction old_action,
212
new_action = { .sa_handler = termination_handler,
213
.sa_flags = 0 };
214
sigemptyset(&new_action.sa_mask);
215
ret = sigaddset(&new_action.sa_mask, SIGINT);
216
if(ret == -1){
217
error(0, errno, "sigaddset");
218
exitstatus = EX_OSERR;
219
goto failure;
220
}
221
ret = sigaddset(&new_action.sa_mask, SIGHUP);
222
if(ret == -1){
223
error(0, errno, "sigaddset");
224
exitstatus = EX_OSERR;
225
goto failure;
226
}
227
ret = sigaddset(&new_action.sa_mask, SIGTERM);
228
if(ret == -1){
229
error(0, errno, "sigaddset");
230
exitstatus = EX_OSERR;
231
goto failure;
232
}
233
ret = sigaction(SIGINT, NULL, &old_action);
234
if(ret == -1){
235
error(0, errno, "sigaction");
236
exitstatus = EX_OSERR;
237
goto failure;
238
}
239
if(old_action.sa_handler != SIG_IGN){
240
ret = sigaction(SIGINT, &new_action, NULL);
241
if(ret == -1){
242
error(0, errno, "sigaction");
243
exitstatus = EX_OSERR;
244
goto failure;
245
}
246
}
247
ret = sigaction(SIGHUP, NULL, &old_action);
248
if(ret == -1){
249
error(0, errno, "sigaction");
250
exitstatus = EX_OSERR;
251
goto failure;
252
}
253
if(old_action.sa_handler != SIG_IGN){
254
ret = sigaction(SIGHUP, &new_action, NULL);
255
if(ret == -1){
256
error(0, errno, "sigaction");
257
exitstatus = EX_OSERR;
258
goto failure;
259
}
260
}
261
ret = sigaction(SIGTERM, NULL, &old_action);
262
if(ret == -1){
263
error(0, errno, "sigaction");
264
exitstatus = EX_OSERR;
265
goto failure;
266
}
267
if(old_action.sa_handler != SIG_IGN){
268
ret = sigaction(SIGTERM, &new_action, NULL);
269
if(ret == -1){
270
error(0, errno, "sigaction");
271
exitstatus = EX_OSERR;
272
goto failure;
273
}
274
}
275
}
276
277
if(interrupted_by_signal){
278
goto failure;
279
}
280
281
/* Fork off the splashy command to prompt for password */
282
splashy_command_pid = fork();
283
if(splashy_command_pid != 0 and interrupted_by_signal){
284
goto failure;
285
}
286
if(splashy_command_pid == -1){
287
error(0, errno, "fork");
288
exitstatus = EX_OSERR;
289
goto failure;
290
}
291
/* Child */
292
if(splashy_command_pid == 0){
293
if(not interrupted_by_signal){
294
const char splashy_command[] = "/sbin/splashy_update";
295
execl(splashy_command, splashy_command, prompt, (char *)NULL);
296
int e = errno;
297
error(0, errno, "execl");
298
switch(e){
299
case EACCES:
300
case ENOENT:
301
case ENOEXEC:
302
case EINVAL:
303
_exit(EX_UNAVAILABLE);
304
case ENAMETOOLONG:
305
case E2BIG:
306
case ENOMEM:
307
case EFAULT:
308
case EIO:
309
case EMFILE:
310
case ENFILE:
311
case ETXTBSY:
312
default:
313
_exit(EX_OSERR);
314
case ENOTDIR:
315
case ELOOP:
316
case EISDIR:
317
#ifdef ELIBBAD
318
case ELIBBAD: /* Linux only */
319
#endif
320
case EPERM:
321
_exit(EX_OSFILE);
322
}
323
}
324
free(prompt);
325
_exit(EXIT_FAILURE);
326
}
327
328
/* Parent */
329
free(prompt);
330
prompt = NULL;
331
332
if(interrupted_by_signal){
333
goto failure;
334
}
335
336
/* Wait for command to complete */
337
{
338
int status;
339
do {
340
ret = waitpid(splashy_command_pid, &status, 0);
341
} while(ret == -1 and errno == EINTR
342
and not interrupted_by_signal);
343
if(interrupted_by_signal){
344
goto failure;
345
}
346
if(ret == -1){
347
error(0, errno, "waitpid");
348
if(errno == ECHILD){
349
splashy_command_pid = 0;
350
}
351
} else {
352
/* The child process has exited */
353
splashy_command_pid = 0;
354
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
355
return EXIT_SUCCESS;
356
}
357
}
358
}
359
360
failure:
361
362
free(prompt);
363
364
if(proc_dir != NULL){
365
TEMP_FAILURE_RETRY(closedir(proc_dir));
366
}
367
368
if(splashy_command_pid != 0){
369
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
370
371
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
372
sleep(2);
373
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
374
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
375
sleep(1);
376
}
377
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
378
if(new_splashy_pid == 0){
379
/* Child; will become new splashy process */
380
381
/* Make the effective user ID (root) the only user ID instead of
382
the real user ID (_mandos) */
383
ret = setuid(geteuid());
384
if(ret == -1){
385
error(0, errno, "setuid");
386
}
387
388
setsid();
389
ret = chdir("/");
390
if(ret == -1){
391
error(0, errno, "chdir");
392
}
393
/* if(fork() != 0){ */
394
/* _exit(EXIT_SUCCESS); */
395
/* } */
396
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
397
if(ret == -1){
398
error(0, errno, "dup2");
399
_exit(EX_OSERR);
400
}
401
402
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
403
{
404
int e = errno;
405
error(0, errno, "execl");
406
switch(e){
407
case EACCES:
408
case ENOENT:
409
case ENOEXEC:
410
default:
411
_exit(EX_UNAVAILABLE);
412
case ENAMETOOLONG:
413
case E2BIG:
414
case ENOMEM:
415
_exit(EX_OSERR);
416
case ENOTDIR:
417
case ELOOP:
418
_exit(EX_OSFILE);
419
}
420
}
421
}
422
}
423
424
if(interrupted_by_signal){
425
struct sigaction signal_action;
426
sigemptyset(&signal_action.sa_mask);
427
signal_action.sa_handler = SIG_DFL;
428
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
429
&signal_action, NULL));
430
if(ret == -1){
431
error(0, errno, "sigaction");
432
}
433
do {
434
ret = raise(signal_received);
435
} while(ret != 0 and errno == EINTR);
436
if(ret != 0){
437
error(0, errno, "raise");
438
abort();
439
}
440
TEMP_FAILURE_RETRY(pause());
441
}
442
443
return exitstatus;
444
}
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