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- Committer: Teddy Hogeborn
- Date: 2008-09-06 16:33:54 UTC
- Revision ID: teddy@fukt.bsnet.se-20080906163354-x2l238fvbs2xashj
* .bzrignore: Rename "password-request" to "mandos-client".
- files added:
- etc-plugins.d-README
- files removed:
- .bzr-builddeb
- debian
- debian/po
- files modified:
- .bzrignore
added
removed
plugins.d/usplash.c
1
/* -*- coding: utf-8 -*- */
2
/*
3
* Usplash - Read a password from usplash and output it
4
*
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 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 /* asprintf(), TEMP_FAILURE_RETRY() */
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
27
sigemptyset(), sigaddset(), SIGINT,
28
SIGHUP, SIGTERM, sigaction(),
29
SIG_IGN, kill(), SIGKILL */
30
#include <stdbool.h> /* bool, false, true */
31
#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
32
#include <iso646.h> /* and, or, not*/
33
#include <errno.h> /* errno, EINTR */
34
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
35
dirent */
36
#include <stddef.h> /* NULL */
37
#include <string.h> /* strlen(), memcmp() */
38
#include <stdio.h> /* asprintf(), perror() */
39
#include <unistd.h> /* close(), write(), readlink(),
40
read(), STDOUT_FILENO, sleep(),
41
fork(), setuid(), geteuid(),
42
setsid(), chdir(), dup2(),
43
STDERR_FILENO, execv() */
44
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
45
EXIT_SUCCESS, malloc(), _exit() */
46
#include <stdlib.h> /* getenv() */
47
#include <dirent.h> /* opendir(), readdir(), closedir() */
48
#include <inttypes.h> /* intmax_t, strtoimax() */
49
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
50
51
sig_atomic_t interrupted_by_signal = 0;
52
int signal_received;
53
const char usplash_name[] = "/sbin/usplash";
54
55
static void termination_handler(int signum){
56
if(interrupted_by_signal){
57
return;
58
}
59
interrupted_by_signal = 1;
60
signal_received = signum;
61
}
62
63
static bool usplash_write(int *fifo_fd_r,
64
const char *cmd, const char *arg){
65
/*
66
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
67
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
68
* SEE ALSO
69
* usplash_write(8)
70
*/
71
int ret;
72
if(*fifo_fd_r == -1){
73
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
74
if(ret == -1){
75
return false;
76
}
77
*fifo_fd_r = ret;
78
}
79
80
const char *cmd_line;
81
size_t cmd_line_len;
82
char *cmd_line_alloc = NULL;
83
if(arg == NULL){
84
cmd_line = cmd;
85
cmd_line_len = strlen(cmd) + 1;
86
} else {
87
do {
88
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
89
if(ret == -1){
90
int e = errno;
91
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
92
errno = e;
93
return false;
94
}
95
} while(ret == -1);
96
cmd_line = cmd_line_alloc;
97
cmd_line_len = (size_t)ret + 1;
98
}
99
100
size_t written = 0;
101
ssize_t sret = 0;
102
while(written < cmd_line_len){
103
sret = write(*fifo_fd_r, cmd_line + written,
104
cmd_line_len - written);
105
if(sret == -1){
106
int e = errno;
107
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
108
free(cmd_line_alloc);
109
errno = e;
110
return false;
111
}
112
written += (size_t)sret;
113
}
114
free(cmd_line_alloc);
115
116
return true;
117
}
118
119
/* Create prompt string */
120
char *makeprompt(void){
121
int ret = 0;
122
char *prompt;
123
const char *const cryptsource = getenv("cryptsource");
124
const char *const crypttarget = getenv("crypttarget");
125
const char prompt_start[] = "Enter passphrase to unlock the disk";
126
127
if(cryptsource == NULL){
128
if(crypttarget == NULL){
129
ret = asprintf(&prompt, "%s: ", prompt_start);
130
} else {
131
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
132
crypttarget);
133
}
134
} else {
135
if(crypttarget == NULL){
136
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
137
} else {
138
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
139
cryptsource, crypttarget);
140
}
141
}
142
if(ret == -1){
143
return NULL;
144
}
145
return prompt;
146
}
147
148
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
149
int ret = 0;
150
ssize_t sret = 0;
151
char *cmdline = NULL;
152
size_t cmdline_len = 0;
153
DIR *proc_dir = opendir("/proc");
154
if(proc_dir == NULL){
155
perror("opendir");
156
return -1;
157
}
158
errno = 0;
159
for(struct dirent *proc_ent = readdir(proc_dir);
160
proc_ent != NULL;
161
proc_ent = readdir(proc_dir)){
162
pid_t pid;
163
{
164
intmax_t tmpmax;
165
char *tmp;
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
errno = 0;
171
continue;
172
}
173
pid = (pid_t)tmpmax;
174
}
175
/* Find the executable name by doing readlink() on the
176
/proc/<pid>/exe link */
177
char exe_target[sizeof(usplash_name)];
178
{
179
/* create file name string */
180
char *exe_link;
181
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
182
if(ret == -1){
183
perror("asprintf");
184
goto fail_find_usplash;
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
perror("lstat");
196
free(exe_link);
197
goto fail_find_usplash;
198
}
199
if(not S_ISLNK(exe_stat.st_mode)
200
or exe_stat.st_uid != 0
201
or exe_stat.st_gid != 0){
202
free(exe_link);
203
continue;
204
}
205
206
sret = readlink(exe_link, exe_target, sizeof(exe_target));
207
free(exe_link);
208
}
209
/* Compare executable name */
210
if((sret != ((ssize_t)sizeof(exe_target)-1))
211
or (memcmp(usplash_name, exe_target,
212
sizeof(exe_target)-1) != 0)){
213
/* Not it */
214
continue;
215
}
216
/* Found usplash */
217
/* Read and save the command line of usplash in "cmdline" */
218
{
219
/* Open /proc/<pid>/cmdline */
220
int cl_fd;
221
{
222
char *cmdline_filename;
223
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
224
proc_ent->d_name);
225
if(ret == -1){
226
perror("asprintf");
227
goto fail_find_usplash;
228
}
229
cl_fd = open(cmdline_filename, O_RDONLY);
230
free(cmdline_filename);
231
if(cl_fd == -1){
232
perror("open");
233
goto fail_find_usplash;
234
}
235
}
236
size_t cmdline_allocated = 0;
237
char *tmp;
238
const size_t blocksize = 1024;
239
do {
240
/* Allocate more space? */
241
if(cmdline_len + blocksize > cmdline_allocated){
242
tmp = realloc(cmdline, cmdline_allocated + blocksize);
243
if(tmp == NULL){
244
perror("realloc");
245
close(cl_fd);
246
goto fail_find_usplash;
247
}
248
cmdline = tmp;
249
cmdline_allocated += blocksize;
250
}
251
/* Read data */
252
sret = read(cl_fd, cmdline + cmdline_len,
253
cmdline_allocated - cmdline_len);
254
if(sret == -1){
255
perror("read");
256
close(cl_fd);
257
goto fail_find_usplash;
258
}
259
cmdline_len += (size_t)sret;
260
} while(sret != 0);
261
ret = close(cl_fd);
262
if(ret == -1){
263
perror("close");
264
goto fail_find_usplash;
265
}
266
}
267
/* Close directory */
268
ret = closedir(proc_dir);
269
if(ret == -1){
270
perror("closedir");
271
goto fail_find_usplash;
272
}
273
/* Success */
274
*cmdline_r = cmdline;
275
*cmdline_len_r = cmdline_len;
276
return pid;
277
}
278
279
fail_find_usplash:
280
281
free(cmdline);
282
if(proc_dir != NULL){
283
int e = errno;
284
closedir(proc_dir);
285
errno = e;
286
}
287
return 0;
288
}
289
290
int main(__attribute__((unused))int argc,
291
__attribute__((unused))char **argv){
292
int ret = 0;
293
ssize_t sret;
294
int fifo_fd = -1;
295
int outfifo_fd = -1;
296
char *buf = NULL;
297
size_t buf_len = 0;
298
pid_t usplash_pid = -1;
299
bool usplash_accessed = false;
300
301
char *prompt = makeprompt();
302
if(prompt == NULL){
303
goto failure;
304
}
305
306
/* Find usplash process */
307
char *cmdline = NULL;
308
size_t cmdline_len = 0;
309
usplash_pid = find_usplash(&cmdline, &cmdline_len);
310
if(usplash_pid == 0){
311
goto failure;
312
}
313
314
/* Set up the signal handler */
315
{
316
struct sigaction old_action,
317
new_action = { .sa_handler = termination_handler,
318
.sa_flags = 0 };
319
sigemptyset(&new_action.sa_mask);
320
ret = sigaddset(&new_action.sa_mask, SIGINT);
321
if(ret == -1){
322
perror("sigaddset");
323
goto failure;
324
}
325
ret = sigaddset(&new_action.sa_mask, SIGHUP);
326
if(ret == -1){
327
perror("sigaddset");
328
goto failure;
329
}
330
ret = sigaddset(&new_action.sa_mask, SIGTERM);
331
if(ret == -1){
332
perror("sigaddset");
333
goto failure;
334
}
335
ret = sigaction(SIGINT, NULL, &old_action);
336
if(ret == -1){
337
if(errno != EINTR){
338
perror("sigaction");
339
}
340
goto failure;
341
}
342
if(old_action.sa_handler != SIG_IGN){
343
ret = sigaction(SIGINT, &new_action, NULL);
344
if(ret == -1){
345
if(errno != EINTR){
346
perror("sigaction");
347
}
348
goto failure;
349
}
350
}
351
ret = sigaction(SIGHUP, NULL, &old_action);
352
if(ret == -1){
353
if(errno != EINTR){
354
perror("sigaction");
355
}
356
goto failure;
357
}
358
if(old_action.sa_handler != SIG_IGN){
359
ret = sigaction(SIGHUP, &new_action, NULL);
360
if(ret == -1){
361
if(errno != EINTR){
362
perror("sigaction");
363
}
364
goto failure;
365
}
366
}
367
ret = sigaction(SIGTERM, NULL, &old_action);
368
if(ret == -1){
369
if(errno != EINTR){
370
perror("sigaction");
371
}
372
goto failure;
373
}
374
if(old_action.sa_handler != SIG_IGN){
375
ret = sigaction(SIGTERM, &new_action, NULL);
376
if(ret == -1){
377
if(errno != EINTR){
378
perror("sigaction");
379
}
380
goto failure;
381
}
382
}
383
}
384
385
usplash_accessed = true;
386
/* Write command to FIFO */
387
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
388
if(errno != EINTR){
389
perror("usplash_write");
390
}
391
goto failure;
392
}
393
394
if(interrupted_by_signal){
395
goto failure;
396
}
397
398
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
399
if(errno != EINTR){
400
perror("usplash_write");
401
}
402
goto failure;
403
}
404
405
if(interrupted_by_signal){
406
goto failure;
407
}
408
409
free(prompt);
410
prompt = NULL;
411
412
/* Read reply from usplash */
413
/* Open FIFO */
414
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
415
if(outfifo_fd == -1){
416
if(errno != EINTR){
417
perror("open");
418
}
419
goto failure;
420
}
421
422
if(interrupted_by_signal){
423
goto failure;
424
}
425
426
/* Read from FIFO */
427
size_t buf_allocated = 0;
428
const size_t blocksize = 1024;
429
do {
430
/* Allocate more space */
431
if(buf_len + blocksize > buf_allocated){
432
char *tmp = realloc(buf, buf_allocated + blocksize);
433
if(tmp == NULL){
434
if(errno != EINTR){
435
perror("realloc");
436
}
437
goto failure;
438
}
439
buf = tmp;
440
buf_allocated += blocksize;
441
}
442
sret = read(outfifo_fd, buf + buf_len,
443
buf_allocated - buf_len);
444
if(sret == -1){
445
if(errno != EINTR){
446
perror("read");
447
}
448
TEMP_FAILURE_RETRY(close(outfifo_fd));
449
goto failure;
450
}
451
if(interrupted_by_signal){
452
break;
453
}
454
455
buf_len += (size_t)sret;
456
} while(sret != 0);
457
ret = close(outfifo_fd);
458
if(ret == -1){
459
if(errno != EINTR){
460
perror("close");
461
}
462
goto failure;
463
}
464
outfifo_fd = -1;
465
466
if(interrupted_by_signal){
467
goto failure;
468
}
469
470
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
471
if(errno != EINTR){
472
perror("usplash_write");
473
}
474
goto failure;
475
}
476
477
if(interrupted_by_signal){
478
goto failure;
479
}
480
481
ret = close(fifo_fd);
482
if(ret == -1){
483
if(errno != EINTR){
484
perror("close");
485
}
486
goto failure;
487
}
488
fifo_fd = -1;
489
490
/* Print password to stdout */
491
size_t written = 0;
492
while(written < buf_len){
493
do {
494
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
495
if(sret == -1){
496
if(errno != EINTR){
497
perror("write");
498
}
499
goto failure;
500
}
501
} while(sret == -1);
502
503
if(interrupted_by_signal){
504
goto failure;
505
}
506
written += (size_t)sret;
507
}
508
free(buf);
509
buf = NULL;
510
511
if(interrupted_by_signal){
512
goto failure;
513
}
514
515
free(cmdline);
516
return EXIT_SUCCESS;
517
518
failure:
519
520
free(buf);
521
522
free(prompt);
523
524
/* If usplash was never accessed, we can stop now */
525
if(not usplash_accessed){
526
return EXIT_FAILURE;
527
}
528
529
/* Close FIFO */
530
if(fifo_fd != -1){
531
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
532
if(ret == -1 and errno != EINTR){
533
perror("close");
534
}
535
fifo_fd = -1;
536
}
537
538
/* Close output FIFO */
539
if(outfifo_fd != -1){
540
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
541
if(ret == -1){
542
perror("close");
543
}
544
}
545
546
/* Create argc and argv for new usplash*/
547
int cmdline_argc = 0;
548
char **cmdline_argv = malloc(sizeof(char *));
549
{
550
size_t position = 0;
551
while(position < cmdline_len){
552
char **tmp = realloc(cmdline_argv,
553
(sizeof(char *)
554
* (size_t)(cmdline_argc + 2)));
555
if(tmp == NULL){
556
perror("realloc");
557
free(cmdline_argv);
558
return EXIT_FAILURE;
559
}
560
cmdline_argv = tmp;
561
cmdline_argv[cmdline_argc] = cmdline + position;
562
cmdline_argc++;
563
position += strlen(cmdline + position) + 1;
564
}
565
cmdline_argv[cmdline_argc] = NULL;
566
}
567
/* Kill old usplash */
568
kill(usplash_pid, SIGTERM);
569
sleep(2);
570
while(kill(usplash_pid, 0) == 0){
571
kill(usplash_pid, SIGKILL);
572
sleep(1);
573
}
574
575
pid_t new_usplash_pid = fork();
576
if(new_usplash_pid == 0){
577
/* Child; will become new usplash process */
578
579
/* Make the effective user ID (root) the only user ID instead of
580
the real user ID (_mandos) */
581
ret = setuid(geteuid());
582
if(ret == -1){
583
perror("setuid");
584
}
585
586
setsid();
587
ret = chdir("/");
588
/* if(fork() != 0){ */
589
/* _exit(EXIT_SUCCESS); */
590
/* } */
591
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
592
if(ret == -1){
593
perror("dup2");
594
_exit(EXIT_FAILURE);
595
}
596
597
execv(usplash_name, cmdline_argv);
598
if(not interrupted_by_signal){
599
perror("execv");
600
}
601
free(cmdline);
602
free(cmdline_argv);
603
_exit(EXIT_FAILURE);
604
}
605
free(cmdline);
606
free(cmdline_argv);
607
sleep(2);
608
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
609
if(errno != EINTR){
610
perror("usplash_write");
611
}
612
}
613
614
/* Close FIFO (again) */
615
if(fifo_fd != -1){
616
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
617
if(ret == -1 and errno != EINTR){
618
perror("close");
619
}
620
fifo_fd = -1;
621
}
622
623
if(interrupted_by_signal){
624
struct sigaction signal_action = { .sa_handler = SIG_DFL };
625
sigemptyset(&signal_action.sa_mask);
626
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
627
&signal_action, NULL));
628
if(ret == -1){
629
perror("sigaction");
630
}
631
do {
632
ret = raise(signal_received);
633
} while(ret != 0 and errno == EINTR);
634
if(ret != 0){
635
perror("raise");
636
abort();
637
}
638
TEMP_FAILURE_RETRY(pause());
639
}
640
641
return EXIT_FAILURE;
642
}
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