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- Committer: Teddy Hogeborn
- Date: 2008-09-08 18:54:47 UTC
- Revision ID: teddy@fukt.bsnet.se-20080908185447-dm2ertwxa20qbckf
* INSTALL: Even better text.
- files added:
- etc-plugins.d-README
- files removed:
- .bzr-builddeb
- debian
- debian/po
- debian/source
- 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 © 2008-2011 Teddy Hogeborn
6
* Copyright © 2008-2011 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(), 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
void error_plus(int status, int errnum, const char *formatstring,
65
...){
66
va_list ap;
67
char *text;
68
int ret;
69
70
va_start(ap, formatstring);
71
ret = vasprintf(&text, formatstring, ap);
72
if (ret == -1){
73
fprintf(stderr, "Mandos plugin %s: ",
74
program_invocation_short_name);
75
vfprintf(stderr, formatstring, ap);
76
fprintf(stderr, ": ");
77
fprintf(stderr, "%s\n", strerror(errnum));
78
error(status, errno, "vasprintf while printing error");
79
return;
80
}
81
fprintf(stderr, "Mandos plugin ");
82
error(status, errnum, "%s", text);
83
free(text);
84
}
85
86
87
static void termination_handler(int signum){
88
if(interrupted_by_signal){
89
return;
90
}
91
interrupted_by_signal = 1;
92
signal_received = signum;
93
}
94
95
int main(__attribute__((unused))int argc,
96
__attribute__((unused))char **argv){
97
int ret = 0;
98
char *prompt = NULL;
99
DIR *proc_dir = NULL;
100
pid_t splashy_pid = 0;
101
pid_t splashy_command_pid = 0;
102
int exitstatus = EXIT_FAILURE;
103
104
/* Create prompt string */
105
{
106
const char *const cryptsource = getenv("cryptsource");
107
const char *const crypttarget = getenv("crypttarget");
108
const char *const prompt_start = "getpass "
109
"Enter passphrase to unlock the disk";
110
111
if(cryptsource == NULL){
112
if(crypttarget == NULL){
113
ret = asprintf(&prompt, "%s: ", prompt_start);
114
} else {
115
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
116
crypttarget);
117
}
118
} else {
119
if(crypttarget == NULL){
120
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
121
} else {
122
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
123
cryptsource, crypttarget);
124
}
125
}
126
if(ret == -1){
127
prompt = NULL;
128
exitstatus = EX_OSERR;
129
goto failure;
130
}
131
}
132
133
/* Find splashy process */
134
{
135
const char splashy_name[] = "/sbin/splashy";
136
proc_dir = opendir("/proc");
137
if(proc_dir == NULL){
138
int e = errno;
139
error_plus(0, errno, "opendir");
140
switch(e){
141
case EACCES:
142
case ENOTDIR:
143
case ELOOP:
144
case ENOENT:
145
default:
146
exitstatus = EX_OSFILE;
147
break;
148
case ENAMETOOLONG:
149
case EMFILE:
150
case ENFILE:
151
case ENOMEM:
152
exitstatus = EX_OSERR;
153
break;
154
}
155
goto failure;
156
}
157
for(struct dirent *proc_ent = readdir(proc_dir);
158
proc_ent != NULL;
159
proc_ent = readdir(proc_dir)){
160
pid_t pid;
161
{
162
intmax_t tmpmax;
163
char *tmp;
164
errno = 0;
165
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
166
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
167
or tmpmax != (pid_t)tmpmax){
168
/* Not a process */
169
continue;
170
}
171
pid = (pid_t)tmpmax;
172
}
173
/* Find the executable name by doing readlink() on the
174
/proc/<pid>/exe link */
175
char exe_target[sizeof(splashy_name)];
176
ssize_t sret;
177
{
178
char *exe_link;
179
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
180
if(ret == -1){
181
error_plus(0, errno, "asprintf");
182
exitstatus = EX_OSERR;
183
goto failure;
184
}
185
186
/* Check that it refers to a symlink owned by root:root */
187
struct stat exe_stat;
188
ret = lstat(exe_link, &exe_stat);
189
if(ret == -1){
190
if(errno == ENOENT){
191
free(exe_link);
192
continue;
193
}
194
int e = errno;
195
error_plus(0, errno, "lstat");
196
free(exe_link);
197
switch(e){
198
case EACCES:
199
case ENOTDIR:
200
case ELOOP:
201
default:
202
exitstatus = EX_OSFILE;
203
break;
204
case ENAMETOOLONG:
205
exitstatus = EX_OSERR;
206
break;
207
}
208
goto failure;
209
}
210
if(not S_ISLNK(exe_stat.st_mode)
211
or exe_stat.st_uid != 0
212
or exe_stat.st_gid != 0){
213
free(exe_link);
214
continue;
215
}
216
217
sret = readlink(exe_link, exe_target, sizeof(exe_target));
218
free(exe_link);
219
}
220
if((sret == ((ssize_t)sizeof(exe_target)-1))
221
and (memcmp(splashy_name, exe_target,
222
sizeof(exe_target)-1) == 0)){
223
splashy_pid = pid;
224
break;
225
}
226
}
227
closedir(proc_dir);
228
proc_dir = NULL;
229
}
230
if(splashy_pid == 0){
231
exitstatus = EX_UNAVAILABLE;
232
goto failure;
233
}
234
235
/* Set up the signal handler */
236
{
237
struct sigaction old_action,
238
new_action = { .sa_handler = termination_handler,
239
.sa_flags = 0 };
240
sigemptyset(&new_action.sa_mask);
241
ret = sigaddset(&new_action.sa_mask, SIGINT);
242
if(ret == -1){
243
error_plus(0, errno, "sigaddset");
244
exitstatus = EX_OSERR;
245
goto failure;
246
}
247
ret = sigaddset(&new_action.sa_mask, SIGHUP);
248
if(ret == -1){
249
error_plus(0, errno, "sigaddset");
250
exitstatus = EX_OSERR;
251
goto failure;
252
}
253
ret = sigaddset(&new_action.sa_mask, SIGTERM);
254
if(ret == -1){
255
error_plus(0, errno, "sigaddset");
256
exitstatus = EX_OSERR;
257
goto failure;
258
}
259
ret = sigaction(SIGINT, NULL, &old_action);
260
if(ret == -1){
261
error_plus(0, errno, "sigaction");
262
exitstatus = EX_OSERR;
263
goto failure;
264
}
265
if(old_action.sa_handler != SIG_IGN){
266
ret = sigaction(SIGINT, &new_action, NULL);
267
if(ret == -1){
268
error_plus(0, errno, "sigaction");
269
exitstatus = EX_OSERR;
270
goto failure;
271
}
272
}
273
ret = sigaction(SIGHUP, NULL, &old_action);
274
if(ret == -1){
275
error_plus(0, errno, "sigaction");
276
exitstatus = EX_OSERR;
277
goto failure;
278
}
279
if(old_action.sa_handler != SIG_IGN){
280
ret = sigaction(SIGHUP, &new_action, NULL);
281
if(ret == -1){
282
error_plus(0, errno, "sigaction");
283
exitstatus = EX_OSERR;
284
goto failure;
285
}
286
}
287
ret = sigaction(SIGTERM, NULL, &old_action);
288
if(ret == -1){
289
error_plus(0, errno, "sigaction");
290
exitstatus = EX_OSERR;
291
goto failure;
292
}
293
if(old_action.sa_handler != SIG_IGN){
294
ret = sigaction(SIGTERM, &new_action, NULL);
295
if(ret == -1){
296
error_plus(0, errno, "sigaction");
297
exitstatus = EX_OSERR;
298
goto failure;
299
}
300
}
301
}
302
303
if(interrupted_by_signal){
304
goto failure;
305
}
306
307
/* Fork off the splashy command to prompt for password */
308
splashy_command_pid = fork();
309
if(splashy_command_pid != 0 and interrupted_by_signal){
310
goto failure;
311
}
312
if(splashy_command_pid == -1){
313
error_plus(0, errno, "fork");
314
exitstatus = EX_OSERR;
315
goto failure;
316
}
317
/* Child */
318
if(splashy_command_pid == 0){
319
if(not interrupted_by_signal){
320
const char splashy_command[] = "/sbin/splashy_update";
321
execl(splashy_command, splashy_command, prompt, (char *)NULL);
322
int e = errno;
323
error_plus(0, errno, "execl");
324
switch(e){
325
case EACCES:
326
case ENOENT:
327
case ENOEXEC:
328
case EINVAL:
329
_exit(EX_UNAVAILABLE);
330
case ENAMETOOLONG:
331
case E2BIG:
332
case ENOMEM:
333
case EFAULT:
334
case EIO:
335
case EMFILE:
336
case ENFILE:
337
case ETXTBSY:
338
default:
339
_exit(EX_OSERR);
340
case ENOTDIR:
341
case ELOOP:
342
case EISDIR:
343
#ifdef ELIBBAD
344
case ELIBBAD: /* Linux only */
345
#endif
346
case EPERM:
347
_exit(EX_OSFILE);
348
}
349
}
350
free(prompt);
351
_exit(EXIT_FAILURE);
352
}
353
354
/* Parent */
355
free(prompt);
356
prompt = NULL;
357
358
if(interrupted_by_signal){
359
goto failure;
360
}
361
362
/* Wait for command to complete */
363
{
364
int status;
365
do {
366
ret = waitpid(splashy_command_pid, &status, 0);
367
} while(ret == -1 and errno == EINTR
368
and not interrupted_by_signal);
369
if(interrupted_by_signal){
370
goto failure;
371
}
372
if(ret == -1){
373
error_plus(0, errno, "waitpid");
374
if(errno == ECHILD){
375
splashy_command_pid = 0;
376
}
377
} else {
378
/* The child process has exited */
379
splashy_command_pid = 0;
380
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
381
return EXIT_SUCCESS;
382
}
383
}
384
}
385
386
failure:
387
388
free(prompt);
389
390
if(proc_dir != NULL){
391
TEMP_FAILURE_RETRY(closedir(proc_dir));
392
}
393
394
if(splashy_command_pid != 0){
395
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
396
397
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
398
sleep(2);
399
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
400
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
401
sleep(1);
402
}
403
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
404
if(new_splashy_pid == 0){
405
/* Child; will become new splashy process */
406
407
/* Make the effective user ID (root) the only user ID instead of
408
the real user ID (_mandos) */
409
ret = setuid(geteuid());
410
if(ret == -1){
411
error_plus(0, errno, "setuid");
412
}
413
414
setsid();
415
ret = chdir("/");
416
if(ret == -1){
417
error_plus(0, errno, "chdir");
418
}
419
/* if(fork() != 0){ */
420
/* _exit(EXIT_SUCCESS); */
421
/* } */
422
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
423
if(ret == -1){
424
error_plus(0, errno, "dup2");
425
_exit(EX_OSERR);
426
}
427
428
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
429
{
430
int e = errno;
431
error_plus(0, errno, "execl");
432
switch(e){
433
case EACCES:
434
case ENOENT:
435
case ENOEXEC:
436
default:
437
_exit(EX_UNAVAILABLE);
438
case ENAMETOOLONG:
439
case E2BIG:
440
case ENOMEM:
441
_exit(EX_OSERR);
442
case ENOTDIR:
443
case ELOOP:
444
_exit(EX_OSFILE);
445
}
446
}
447
}
448
}
449
450
if(interrupted_by_signal){
451
struct sigaction signal_action;
452
sigemptyset(&signal_action.sa_mask);
453
signal_action.sa_handler = SIG_DFL;
454
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
455
&signal_action, NULL));
456
if(ret == -1){
457
error_plus(0, errno, "sigaction");
458
}
459
do {
460
ret = raise(signal_received);
461
} while(ret != 0 and errno == EINTR);
462
if(ret != 0){
463
error_plus(0, errno, "raise");
464
abort();
465
}
466
TEMP_FAILURE_RETRY(pause());
467
}
468
469
return exitstatus;
470
}
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