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- Committer: Björn Påhlsson
- Date: 2008-09-19 20:42:17 UTC
- mto: (237.7.1 mandos) (24.1.154 mandos)
- mto: This revision was merged to the branch mainline in revision 203.
- Revision ID: belorn@braxen-20080919204217-q6q70pvgybph0ekd
changed 2007-2008 copyright notice to 2008
- files added:
- etc-plugins.d-README
- files removed:
- NEWS
- 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
#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
51
52
sig_atomic_t interrupted_by_signal = 0;
53
int signal_received;
54
const char usplash_name[] = "/sbin/usplash";
55
56
static void termination_handler(int signum){
57
if(interrupted_by_signal){
58
return;
59
}
60
interrupted_by_signal = 1;
61
signal_received = signum;
62
}
63
64
static bool usplash_write(int *fifo_fd_r,
65
const char *cmd, const char *arg){
66
/*
67
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
68
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
69
* SEE ALSO
70
* usplash_write(8)
71
*/
72
int ret;
73
if(*fifo_fd_r == -1){
74
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
75
if(ret == -1){
76
return false;
77
}
78
*fifo_fd_r = ret;
79
}
80
81
const char *cmd_line;
82
size_t cmd_line_len;
83
char *cmd_line_alloc = NULL;
84
if(arg == NULL){
85
cmd_line = cmd;
86
cmd_line_len = strlen(cmd) + 1;
87
} else {
88
do {
89
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
90
if(ret == -1){
91
int e = errno;
92
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
93
errno = e;
94
return false;
95
}
96
} while(ret == -1);
97
cmd_line = cmd_line_alloc;
98
cmd_line_len = (size_t)ret + 1;
99
}
100
101
size_t written = 0;
102
ssize_t sret = 0;
103
while(written < cmd_line_len){
104
sret = write(*fifo_fd_r, cmd_line + written,
105
cmd_line_len - written);
106
if(sret == -1){
107
int e = errno;
108
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
109
free(cmd_line_alloc);
110
errno = e;
111
return false;
112
}
113
written += (size_t)sret;
114
}
115
free(cmd_line_alloc);
116
117
return true;
118
}
119
120
/* Create prompt string */
121
char *makeprompt(void){
122
int ret = 0;
123
char *prompt;
124
const char *const cryptsource = getenv("cryptsource");
125
const char *const crypttarget = getenv("crypttarget");
126
const char prompt_start[] = "Enter passphrase to unlock the disk";
127
128
if(cryptsource == NULL){
129
if(crypttarget == NULL){
130
ret = asprintf(&prompt, "%s: ", prompt_start);
131
} else {
132
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
133
crypttarget);
134
}
135
} else {
136
if(crypttarget == NULL){
137
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
138
} else {
139
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
140
cryptsource, crypttarget);
141
}
142
}
143
if(ret == -1){
144
return NULL;
145
}
146
return prompt;
147
}
148
149
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
150
int ret = 0;
151
ssize_t sret = 0;
152
char *cmdline = NULL;
153
size_t cmdline_len = 0;
154
DIR *proc_dir = opendir("/proc");
155
if(proc_dir == NULL){
156
perror("opendir");
157
return -1;
158
}
159
errno = 0;
160
for(struct dirent *proc_ent = readdir(proc_dir);
161
proc_ent != NULL;
162
proc_ent = readdir(proc_dir)){
163
pid_t pid;
164
{
165
intmax_t tmpmax;
166
char *tmp;
167
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
168
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
169
or tmpmax != (pid_t)tmpmax){
170
/* Not a process */
171
errno = 0;
172
continue;
173
}
174
pid = (pid_t)tmpmax;
175
}
176
/* Find the executable name by doing readlink() on the
177
/proc/<pid>/exe link */
178
char exe_target[sizeof(usplash_name)];
179
{
180
/* create file name string */
181
char *exe_link;
182
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
183
if(ret == -1){
184
perror("asprintf");
185
goto fail_find_usplash;
186
}
187
188
/* Check that it refers to a symlink owned by root:root */
189
struct stat exe_stat;
190
ret = lstat(exe_link, &exe_stat);
191
if(ret == -1){
192
if(errno == ENOENT){
193
free(exe_link);
194
continue;
195
}
196
perror("lstat");
197
free(exe_link);
198
goto fail_find_usplash;
199
}
200
if(not S_ISLNK(exe_stat.st_mode)
201
or exe_stat.st_uid != 0
202
or exe_stat.st_gid != 0){
203
free(exe_link);
204
continue;
205
}
206
207
sret = readlink(exe_link, exe_target, sizeof(exe_target));
208
free(exe_link);
209
}
210
/* Compare executable name */
211
if((sret != ((ssize_t)sizeof(exe_target)-1))
212
or (memcmp(usplash_name, exe_target,
213
sizeof(exe_target)-1) != 0)){
214
/* Not it */
215
continue;
216
}
217
/* Found usplash */
218
/* Read and save the command line of usplash in "cmdline" */
219
{
220
/* Open /proc/<pid>/cmdline */
221
int cl_fd;
222
{
223
char *cmdline_filename;
224
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
225
proc_ent->d_name);
226
if(ret == -1){
227
perror("asprintf");
228
goto fail_find_usplash;
229
}
230
cl_fd = open(cmdline_filename, O_RDONLY);
231
free(cmdline_filename);
232
if(cl_fd == -1){
233
perror("open");
234
goto fail_find_usplash;
235
}
236
}
237
size_t cmdline_allocated = 0;
238
char *tmp;
239
const size_t blocksize = 1024;
240
do {
241
/* Allocate more space? */
242
if(cmdline_len + blocksize > cmdline_allocated){
243
tmp = realloc(cmdline, cmdline_allocated + blocksize);
244
if(tmp == NULL){
245
perror("realloc");
246
close(cl_fd);
247
goto fail_find_usplash;
248
}
249
cmdline = tmp;
250
cmdline_allocated += blocksize;
251
}
252
/* Read data */
253
sret = read(cl_fd, cmdline + cmdline_len,
254
cmdline_allocated - cmdline_len);
255
if(sret == -1){
256
perror("read");
257
close(cl_fd);
258
goto fail_find_usplash;
259
}
260
cmdline_len += (size_t)sret;
261
} while(sret != 0);
262
ret = close(cl_fd);
263
if(ret == -1){
264
perror("close");
265
goto fail_find_usplash;
266
}
267
}
268
/* Close directory */
269
ret = closedir(proc_dir);
270
if(ret == -1){
271
perror("closedir");
272
goto fail_find_usplash;
273
}
274
/* Success */
275
*cmdline_r = cmdline;
276
*cmdline_len_r = cmdline_len;
277
return pid;
278
}
279
280
fail_find_usplash:
281
282
free(cmdline);
283
if(proc_dir != NULL){
284
int e = errno;
285
closedir(proc_dir);
286
errno = e;
287
}
288
return 0;
289
}
290
291
int main(__attribute__((unused))int argc,
292
__attribute__((unused))char **argv){
293
int ret = 0;
294
ssize_t sret;
295
int fifo_fd = -1;
296
int outfifo_fd = -1;
297
char *buf = NULL;
298
size_t buf_len = 0;
299
pid_t usplash_pid = -1;
300
bool usplash_accessed = false;
301
int status = EXIT_FAILURE; /* Default failure exit status */
302
303
char *prompt = makeprompt();
304
if(prompt == NULL){
305
status = EX_OSERR;
306
goto failure;
307
}
308
309
/* Find usplash process */
310
char *cmdline = NULL;
311
size_t cmdline_len = 0;
312
usplash_pid = find_usplash(&cmdline, &cmdline_len);
313
if(usplash_pid == 0){
314
status = EX_UNAVAILABLE;
315
goto failure;
316
}
317
318
/* Set up the signal handler */
319
{
320
struct sigaction old_action,
321
new_action = { .sa_handler = termination_handler,
322
.sa_flags = 0 };
323
sigemptyset(&new_action.sa_mask);
324
ret = sigaddset(&new_action.sa_mask, SIGINT);
325
if(ret == -1){
326
perror("sigaddset");
327
status = EX_OSERR;
328
goto failure;
329
}
330
ret = sigaddset(&new_action.sa_mask, SIGHUP);
331
if(ret == -1){
332
perror("sigaddset");
333
status = EX_OSERR;
334
goto failure;
335
}
336
ret = sigaddset(&new_action.sa_mask, SIGTERM);
337
if(ret == -1){
338
perror("sigaddset");
339
status = EX_OSERR;
340
goto failure;
341
}
342
ret = sigaction(SIGINT, NULL, &old_action);
343
if(ret == -1){
344
if(errno != EINTR){
345
perror("sigaction");
346
status = EX_OSERR;
347
}
348
goto failure;
349
}
350
if(old_action.sa_handler != SIG_IGN){
351
ret = sigaction(SIGINT, &new_action, NULL);
352
if(ret == -1){
353
if(errno != EINTR){
354
perror("sigaction");
355
status = EX_OSERR;
356
}
357
goto failure;
358
}
359
}
360
ret = sigaction(SIGHUP, NULL, &old_action);
361
if(ret == -1){
362
if(errno != EINTR){
363
perror("sigaction");
364
status = EX_OSERR;
365
}
366
goto failure;
367
}
368
if(old_action.sa_handler != SIG_IGN){
369
ret = sigaction(SIGHUP, &new_action, NULL);
370
if(ret == -1){
371
if(errno != EINTR){
372
perror("sigaction");
373
status = EX_OSERR;
374
}
375
goto failure;
376
}
377
}
378
ret = sigaction(SIGTERM, NULL, &old_action);
379
if(ret == -1){
380
if(errno != EINTR){
381
perror("sigaction");
382
status = EX_OSERR;
383
}
384
goto failure;
385
}
386
if(old_action.sa_handler != SIG_IGN){
387
ret = sigaction(SIGTERM, &new_action, NULL);
388
if(ret == -1){
389
if(errno != EINTR){
390
perror("sigaction");
391
status = EX_OSERR;
392
}
393
goto failure;
394
}
395
}
396
}
397
398
usplash_accessed = true;
399
/* Write command to FIFO */
400
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
401
if(errno != EINTR){
402
perror("usplash_write");
403
status = EX_OSERR;
404
}
405
goto failure;
406
}
407
408
if(interrupted_by_signal){
409
goto failure;
410
}
411
412
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
413
if(errno != EINTR){
414
perror("usplash_write");
415
status = EX_OSERR;
416
}
417
goto failure;
418
}
419
420
if(interrupted_by_signal){
421
goto failure;
422
}
423
424
free(prompt);
425
prompt = NULL;
426
427
/* Read reply from usplash */
428
/* Open FIFO */
429
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
430
if(outfifo_fd == -1){
431
if(errno != EINTR){
432
perror("open");
433
status = EX_OSERR;
434
}
435
goto failure;
436
}
437
438
if(interrupted_by_signal){
439
goto failure;
440
}
441
442
/* Read from FIFO */
443
size_t buf_allocated = 0;
444
const size_t blocksize = 1024;
445
do {
446
/* Allocate more space */
447
if(buf_len + blocksize > buf_allocated){
448
char *tmp = realloc(buf, buf_allocated + blocksize);
449
if(tmp == NULL){
450
if(errno != EINTR){
451
perror("realloc");
452
status = EX_OSERR;
453
}
454
goto failure;
455
}
456
buf = tmp;
457
buf_allocated += blocksize;
458
}
459
sret = read(outfifo_fd, buf + buf_len,
460
buf_allocated - buf_len);
461
if(sret == -1){
462
if(errno != EINTR){
463
perror("read");
464
status = EX_OSERR;
465
}
466
TEMP_FAILURE_RETRY(close(outfifo_fd));
467
goto failure;
468
}
469
if(interrupted_by_signal){
470
break;
471
}
472
473
buf_len += (size_t)sret;
474
} while(sret != 0);
475
ret = close(outfifo_fd);
476
if(ret == -1){
477
if(errno != EINTR){
478
perror("close");
479
status = EX_OSERR;
480
}
481
goto failure;
482
}
483
outfifo_fd = -1;
484
485
if(interrupted_by_signal){
486
goto failure;
487
}
488
489
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
490
if(errno != EINTR){
491
perror("usplash_write");
492
status = EX_OSERR;
493
}
494
goto failure;
495
}
496
497
if(interrupted_by_signal){
498
goto failure;
499
}
500
501
ret = close(fifo_fd);
502
if(ret == -1){
503
if(errno != EINTR){
504
perror("close");
505
status = EX_OSERR;
506
}
507
goto failure;
508
}
509
fifo_fd = -1;
510
511
/* Print password to stdout */
512
size_t written = 0;
513
while(written < buf_len){
514
do {
515
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
516
if(sret == -1){
517
if(errno != EINTR){
518
perror("write");
519
status = EX_OSERR;
520
}
521
goto failure;
522
}
523
} while(sret == -1);
524
525
if(interrupted_by_signal){
526
goto failure;
527
}
528
written += (size_t)sret;
529
}
530
free(buf);
531
buf = NULL;
532
533
if(interrupted_by_signal){
534
goto failure;
535
}
536
537
free(cmdline);
538
return EXIT_SUCCESS;
539
540
failure:
541
542
free(buf);
543
544
free(prompt);
545
546
/* If usplash was never accessed, we can stop now */
547
if(not usplash_accessed){
548
return status;
549
}
550
551
/* Close FIFO */
552
if(fifo_fd != -1){
553
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
554
if(ret == -1 and errno != EINTR){
555
perror("close");
556
}
557
fifo_fd = -1;
558
}
559
560
/* Close output FIFO */
561
if(outfifo_fd != -1){
562
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
563
if(ret == -1){
564
perror("close");
565
}
566
}
567
568
/* Create argc and argv for new usplash*/
569
int cmdline_argc = 0;
570
char **cmdline_argv = malloc(sizeof(char *));
571
{
572
size_t position = 0;
573
while(position < cmdline_len){
574
char **tmp = realloc(cmdline_argv,
575
(sizeof(char *)
576
* (size_t)(cmdline_argc + 2)));
577
if(tmp == NULL){
578
perror("realloc");
579
free(cmdline_argv);
580
return status;
581
}
582
cmdline_argv = tmp;
583
cmdline_argv[cmdline_argc] = cmdline + position;
584
cmdline_argc++;
585
position += strlen(cmdline + position) + 1;
586
}
587
cmdline_argv[cmdline_argc] = NULL;
588
}
589
/* Kill old usplash */
590
kill(usplash_pid, SIGTERM);
591
sleep(2);
592
while(kill(usplash_pid, 0) == 0){
593
kill(usplash_pid, SIGKILL);
594
sleep(1);
595
}
596
597
pid_t new_usplash_pid = fork();
598
if(new_usplash_pid == 0){
599
/* Child; will become new usplash process */
600
601
/* Make the effective user ID (root) the only user ID instead of
602
the real user ID (_mandos) */
603
ret = setuid(geteuid());
604
if(ret == -1){
605
perror("setuid");
606
}
607
608
setsid();
609
ret = chdir("/");
610
/* if(fork() != 0){ */
611
/* _exit(EXIT_SUCCESS); */
612
/* } */
613
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
614
if(ret == -1){
615
perror("dup2");
616
_exit(EX_OSERR);
617
}
618
619
execv(usplash_name, cmdline_argv);
620
if(not interrupted_by_signal){
621
perror("execv");
622
}
623
free(cmdline);
624
free(cmdline_argv);
625
_exit(EX_OSERR);
626
}
627
free(cmdline);
628
free(cmdline_argv);
629
sleep(2);
630
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
631
if(errno != EINTR){
632
perror("usplash_write");
633
}
634
}
635
636
/* Close FIFO (again) */
637
if(fifo_fd != -1){
638
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
639
if(ret == -1 and errno != EINTR){
640
perror("close");
641
}
642
fifo_fd = -1;
643
}
644
645
if(interrupted_by_signal){
646
struct sigaction signal_action = { .sa_handler = SIG_DFL };
647
sigemptyset(&signal_action.sa_mask);
648
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
649
&signal_action, NULL));
650
if(ret == -1){
651
perror("sigaction");
652
}
653
do {
654
ret = raise(signal_received);
655
} while(ret != 0 and errno == EINTR);
656
if(ret != 0){
657
perror("raise");
658
abort();
659
}
660
TEMP_FAILURE_RETRY(pause());
661
}
662
663
return status;
664
}
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