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- Committer: Teddy Hogeborn
- Date: 2008-09-05 18:37:28 UTC
- Revision ID: teddy@fukt.bsnet.se-20080905183728-l0m8v3vqa302uwrw
* mandos (main): Use EAFP with pidfile.
- files added:
- plugins.d/usplash
- files removed:
- .bzr-builddeb
- debian
- debian/po
- debian/source
- network-hooks.d
- files renamed:
- plugins.d/mandos-client.c => plugins.d/password-request.c
- plugins.d/mandos-client.xml => plugins.d/password-request.xml
- files modified:
- .bzrignore
added
removed
plugins.d/splashy.c
1
/* -*- coding: utf-8 -*- */
2
/*
3
* Splashy - Read a password from splashy and output it
4
*
5
* Copyright © 2008-2012 Teddy Hogeborn
6
* Copyright © 2008-2012 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@recompile.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(), vasprintf(), vprintf(),
33
fprintf() */
34
#include <stdlib.h> /* EXIT_FAILURE, free(),
35
EXIT_SUCCESS */
36
#include <sys/types.h> /* pid_t, DIR, struct dirent,
37
ssize_t */
38
#include <dirent.h> /* opendir(), readdir(), closedir() */
39
#include <inttypes.h> /* intmax_t, strtoimax() */
40
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
41
#include <iso646.h> /* not, or, and */
42
#include <unistd.h> /* readlink(), fork(), execl(),
43
sleep(), dup2() STDERR_FILENO,
44
STDOUT_FILENO, _exit(),
45
pause() */
46
#include <string.h> /* memcmp(), strerror() */
47
#include <errno.h> /* errno, EACCES, ENOTDIR, ELOOP,
48
ENOENT, ENAMETOOLONG, EMFILE,
49
ENFILE, ENOMEM, ENOEXEC, EINVAL,
50
E2BIG, EFAULT, EIO, ETXTBSY,
51
EISDIR, ELIBBAD, EPERM, EINTR,
52
ECHILD */
53
#include <error.h> /* error() */
54
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
55
WEXITSTATUS() */
56
#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
57
EX_UNAVAILABLE */
58
#include <stdarg.h> /* va_list, va_start(), ... */
59
60
sig_atomic_t interrupted_by_signal = 0;
61
int signal_received;
62
63
/* Function to use when printing errors */
64
__attribute__((format (gnu_printf, 3, 4)))
65
void error_plus(int status, int errnum, const char *formatstring,
66
...){
67
va_list ap;
68
char *text;
69
int ret;
70
71
va_start(ap, formatstring);
72
ret = vasprintf(&text, formatstring, ap);
73
if (ret == -1){
74
fprintf(stderr, "Mandos plugin %s: ",
75
program_invocation_short_name);
76
vfprintf(stderr, formatstring, ap);
77
fprintf(stderr, ": ");
78
fprintf(stderr, "%s\n", strerror(errnum));
79
error(status, errno, "vasprintf while printing error");
80
return;
81
}
82
fprintf(stderr, "Mandos plugin ");
83
error(status, errnum, "%s", text);
84
free(text);
85
}
86
87
88
static void termination_handler(int signum){
89
if(interrupted_by_signal){
90
return;
91
}
92
interrupted_by_signal = 1;
93
signal_received = signum;
94
}
95
96
int main(__attribute__((unused))int argc,
97
__attribute__((unused))char **argv){
98
int ret = 0;
99
char *prompt = NULL;
100
DIR *proc_dir = NULL;
101
pid_t splashy_pid = 0;
102
pid_t splashy_command_pid = 0;
103
int exitstatus = EXIT_FAILURE;
104
105
/* Create prompt string */
106
{
107
const char *const cryptsource = getenv("cryptsource");
108
const char *const crypttarget = getenv("crypttarget");
109
const char *const prompt_start = "getpass "
110
"Enter passphrase to unlock the disk";
111
112
if(cryptsource == NULL){
113
if(crypttarget == NULL){
114
ret = asprintf(&prompt, "%s: ", prompt_start);
115
} else {
116
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
117
crypttarget);
118
}
119
} else {
120
if(crypttarget == NULL){
121
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
122
} else {
123
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
124
cryptsource, crypttarget);
125
}
126
}
127
if(ret == -1){
128
prompt = NULL;
129
exitstatus = EX_OSERR;
130
goto failure;
131
}
132
}
133
134
/* Find splashy process */
135
{
136
const char splashy_name[] = "/sbin/splashy";
137
proc_dir = opendir("/proc");
138
if(proc_dir == NULL){
139
int e = errno;
140
error_plus(0, errno, "opendir");
141
switch(e){
142
case EACCES:
143
case ENOTDIR:
144
case ELOOP:
145
case ENOENT:
146
default:
147
exitstatus = EX_OSFILE;
148
break;
149
case ENAMETOOLONG:
150
case EMFILE:
151
case ENFILE:
152
case ENOMEM:
153
exitstatus = EX_OSERR;
154
break;
155
}
156
goto failure;
157
}
158
for(struct dirent *proc_ent = readdir(proc_dir);
159
proc_ent != NULL;
160
proc_ent = readdir(proc_dir)){
161
pid_t pid;
162
{
163
intmax_t tmpmax;
164
char *tmp;
165
errno = 0;
166
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
167
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
168
or tmpmax != (pid_t)tmpmax){
169
/* Not a process */
170
continue;
171
}
172
pid = (pid_t)tmpmax;
173
}
174
/* Find the executable name by doing readlink() on the
175
/proc/<pid>/exe link */
176
char exe_target[sizeof(splashy_name)];
177
ssize_t sret;
178
{
179
char *exe_link;
180
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
181
if(ret == -1){
182
error_plus(0, errno, "asprintf");
183
exitstatus = EX_OSERR;
184
goto failure;
185
}
186
187
/* Check that it refers to a symlink owned by root:root */
188
struct stat exe_stat;
189
ret = lstat(exe_link, &exe_stat);
190
if(ret == -1){
191
if(errno == ENOENT){
192
free(exe_link);
193
continue;
194
}
195
int e = errno;
196
error_plus(0, errno, "lstat");
197
free(exe_link);
198
switch(e){
199
case EACCES:
200
case ENOTDIR:
201
case ELOOP:
202
default:
203
exitstatus = EX_OSFILE;
204
break;
205
case ENAMETOOLONG:
206
exitstatus = EX_OSERR;
207
break;
208
}
209
goto failure;
210
}
211
if(not S_ISLNK(exe_stat.st_mode)
212
or exe_stat.st_uid != 0
213
or exe_stat.st_gid != 0){
214
free(exe_link);
215
continue;
216
}
217
218
sret = readlink(exe_link, exe_target, sizeof(exe_target));
219
free(exe_link);
220
}
221
if((sret == ((ssize_t)sizeof(exe_target)-1))
222
and (memcmp(splashy_name, exe_target,
223
sizeof(exe_target)-1) == 0)){
224
splashy_pid = pid;
225
break;
226
}
227
}
228
closedir(proc_dir);
229
proc_dir = NULL;
230
}
231
if(splashy_pid == 0){
232
exitstatus = EX_UNAVAILABLE;
233
goto failure;
234
}
235
236
/* Set up the signal handler */
237
{
238
struct sigaction old_action,
239
new_action = { .sa_handler = termination_handler,
240
.sa_flags = 0 };
241
sigemptyset(&new_action.sa_mask);
242
ret = sigaddset(&new_action.sa_mask, SIGINT);
243
if(ret == -1){
244
error_plus(0, errno, "sigaddset");
245
exitstatus = EX_OSERR;
246
goto failure;
247
}
248
ret = sigaddset(&new_action.sa_mask, SIGHUP);
249
if(ret == -1){
250
error_plus(0, errno, "sigaddset");
251
exitstatus = EX_OSERR;
252
goto failure;
253
}
254
ret = sigaddset(&new_action.sa_mask, SIGTERM);
255
if(ret == -1){
256
error_plus(0, errno, "sigaddset");
257
exitstatus = EX_OSERR;
258
goto failure;
259
}
260
ret = sigaction(SIGINT, NULL, &old_action);
261
if(ret == -1){
262
error_plus(0, errno, "sigaction");
263
exitstatus = EX_OSERR;
264
goto failure;
265
}
266
if(old_action.sa_handler != SIG_IGN){
267
ret = sigaction(SIGINT, &new_action, NULL);
268
if(ret == -1){
269
error_plus(0, errno, "sigaction");
270
exitstatus = EX_OSERR;
271
goto failure;
272
}
273
}
274
ret = sigaction(SIGHUP, NULL, &old_action);
275
if(ret == -1){
276
error_plus(0, errno, "sigaction");
277
exitstatus = EX_OSERR;
278
goto failure;
279
}
280
if(old_action.sa_handler != SIG_IGN){
281
ret = sigaction(SIGHUP, &new_action, NULL);
282
if(ret == -1){
283
error_plus(0, errno, "sigaction");
284
exitstatus = EX_OSERR;
285
goto failure;
286
}
287
}
288
ret = sigaction(SIGTERM, NULL, &old_action);
289
if(ret == -1){
290
error_plus(0, errno, "sigaction");
291
exitstatus = EX_OSERR;
292
goto failure;
293
}
294
if(old_action.sa_handler != SIG_IGN){
295
ret = sigaction(SIGTERM, &new_action, NULL);
296
if(ret == -1){
297
error_plus(0, errno, "sigaction");
298
exitstatus = EX_OSERR;
299
goto failure;
300
}
301
}
302
}
303
304
if(interrupted_by_signal){
305
goto failure;
306
}
307
308
/* Fork off the splashy command to prompt for password */
309
splashy_command_pid = fork();
310
if(splashy_command_pid != 0 and interrupted_by_signal){
311
goto failure;
312
}
313
if(splashy_command_pid == -1){
314
error_plus(0, errno, "fork");
315
exitstatus = EX_OSERR;
316
goto failure;
317
}
318
/* Child */
319
if(splashy_command_pid == 0){
320
if(not interrupted_by_signal){
321
const char splashy_command[] = "/sbin/splashy_update";
322
execl(splashy_command, splashy_command, prompt, (char *)NULL);
323
int e = errno;
324
error_plus(0, errno, "execl");
325
switch(e){
326
case EACCES:
327
case ENOENT:
328
case ENOEXEC:
329
case EINVAL:
330
_exit(EX_UNAVAILABLE);
331
case ENAMETOOLONG:
332
case E2BIG:
333
case ENOMEM:
334
case EFAULT:
335
case EIO:
336
case EMFILE:
337
case ENFILE:
338
case ETXTBSY:
339
default:
340
_exit(EX_OSERR);
341
case ENOTDIR:
342
case ELOOP:
343
case EISDIR:
344
#ifdef ELIBBAD
345
case ELIBBAD: /* Linux only */
346
#endif
347
case EPERM:
348
_exit(EX_OSFILE);
349
}
350
}
351
free(prompt);
352
_exit(EXIT_FAILURE);
353
}
354
355
/* Parent */
356
free(prompt);
357
prompt = NULL;
358
359
if(interrupted_by_signal){
360
goto failure;
361
}
362
363
/* Wait for command to complete */
364
{
365
int status;
366
do {
367
ret = waitpid(splashy_command_pid, &status, 0);
368
} while(ret == -1 and errno == EINTR
369
and not interrupted_by_signal);
370
if(interrupted_by_signal){
371
goto failure;
372
}
373
if(ret == -1){
374
error_plus(0, errno, "waitpid");
375
if(errno == ECHILD){
376
splashy_command_pid = 0;
377
}
378
} else {
379
/* The child process has exited */
380
splashy_command_pid = 0;
381
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
382
return EXIT_SUCCESS;
383
}
384
}
385
}
386
387
failure:
388
389
free(prompt);
390
391
if(proc_dir != NULL){
392
TEMP_FAILURE_RETRY(closedir(proc_dir));
393
}
394
395
if(splashy_command_pid != 0){
396
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
397
398
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
399
sleep(2);
400
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
401
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
402
sleep(1);
403
}
404
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
405
if(new_splashy_pid == 0){
406
/* Child; will become new splashy process */
407
408
/* Make the effective user ID (root) the only user ID instead of
409
the real user ID (_mandos) */
410
ret = setuid(geteuid());
411
if(ret == -1){
412
error_plus(0, errno, "setuid");
413
}
414
415
setsid();
416
ret = chdir("/");
417
if(ret == -1){
418
error_plus(0, errno, "chdir");
419
}
420
/* if(fork() != 0){ */
421
/* _exit(EXIT_SUCCESS); */
422
/* } */
423
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
424
if(ret == -1){
425
error_plus(0, errno, "dup2");
426
_exit(EX_OSERR);
427
}
428
429
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
430
{
431
int e = errno;
432
error_plus(0, errno, "execl");
433
switch(e){
434
case EACCES:
435
case ENOENT:
436
case ENOEXEC:
437
default:
438
_exit(EX_UNAVAILABLE);
439
case ENAMETOOLONG:
440
case E2BIG:
441
case ENOMEM:
442
_exit(EX_OSERR);
443
case ENOTDIR:
444
case ELOOP:
445
_exit(EX_OSFILE);
446
}
447
}
448
}
449
}
450
451
if(interrupted_by_signal){
452
struct sigaction signal_action;
453
sigemptyset(&signal_action.sa_mask);
454
signal_action.sa_handler = SIG_DFL;
455
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
456
&signal_action, NULL));
457
if(ret == -1){
458
error_plus(0, errno, "sigaction");
459
}
460
do {
461
ret = raise(signal_received);
462
} while(ret != 0 and errno == EINTR);
463
if(ret != 0){
464
error_plus(0, errno, "raise");
465
abort();
466
}
467
TEMP_FAILURE_RETRY(pause());
468
}
469
470
return exitstatus;
471
}
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