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- Committer: Teddy Hogeborn
- Date: 2008-09-21 12:20:55 UTC
- Revision ID: teddy@fukt.bsnet.se-20080921122055-vrs4tmw1az0yr92u
* mandos.xml (SECURITY): Minor wording improvement.
- files added:
- debian/mandos-client.config
- files removed:
- NEWS
- 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 <https://www.fukt.bsnet.se/~belorn/> and
23
* <https://www.fukt.bsnet.se/~teddy/>.
24
*/
25
26
#define _GNU_SOURCE /* asprintf() */
27
#include <signal.h> /* sig_atomic_t, struct sigaction,
28
sigemptyset(), sigaddset(), SIGINT,
29
SIGHUP, SIGTERM, sigaction(),
30
SIG_IGN, kill(), SIGKILL */
31
#include <stdbool.h> /* bool, false, true */
32
#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
33
#include <iso646.h> /* and, or, not*/
34
#include <errno.h> /* errno, EINTR */
35
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
36
dirent */
37
#include <stddef.h> /* NULL */
38
#include <string.h> /* strlen(), memcmp() */
39
#include <stdio.h> /* asprintf(), perror(), sscanf() */
40
#include <unistd.h> /* close(), write(), readlink(),
41
read(), STDOUT_FILENO, sleep(),
42
fork(), setuid(), geteuid(),
43
setsid(), chdir(), dup2(),
44
STDERR_FILENO, execv() */
45
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
46
EXIT_SUCCESS, malloc(), _exit() */
47
#include <stdlib.h> /* getenv() */
48
#include <dirent.h> /* opendir(), readdir(), closedir() */
49
#include <inttypes.h> /* intmax_t, SCNdMAX */
50
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
51
52
sig_atomic_t interrupted_by_signal = 0;
53
54
static void termination_handler(__attribute__((unused))int signum){
55
interrupted_by_signal = 1;
56
}
57
58
static bool usplash_write(const char *cmd, const char *arg){
59
/*
60
* usplash_write("TIMEOUT", "15") will write "TIMEOUT 15\0"
61
* usplash_write("PULSATE", NULL) will write "PULSATE\0"
62
* SEE ALSO
63
* usplash_write(8)
64
*/
65
int ret;
66
int fifo_fd;
67
do{
68
fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
69
if(fifo_fd == -1 and (errno != EINTR or interrupted_by_signal)){
70
return false;
71
}
72
}while(fifo_fd == -1);
73
74
const char *cmd_line;
75
size_t cmd_line_len;
76
char *cmd_line_alloc = NULL;
77
if(arg == NULL){
78
cmd_line = cmd;
79
cmd_line_len = strlen(cmd);
80
}else{
81
do{
82
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
83
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
84
int e = errno;
85
close(fifo_fd);
86
errno = e;
87
return false;
88
}
89
}while(ret == -1);
90
cmd_line = cmd_line_alloc;
91
cmd_line_len = (size_t)ret + 1;
92
}
93
94
size_t written = 0;
95
ssize_t sret = 0;
96
while(not interrupted_by_signal and written < cmd_line_len){
97
sret = write(fifo_fd, cmd_line + written,
98
cmd_line_len - written);
99
if(sret == -1){
100
if(errno != EINTR or interrupted_by_signal){
101
int e = errno;
102
close(fifo_fd);
103
free(cmd_line_alloc);
104
errno = e;
105
return false;
106
} else {
107
continue;
108
}
109
}
110
written += (size_t)sret;
111
}
112
free(cmd_line_alloc);
113
do{
114
ret = close(fifo_fd);
115
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
116
return false;
117
}
118
}while(ret == -1);
119
if(interrupted_by_signal){
120
return false;
121
}
122
return true;
123
}
124
125
int main(__attribute__((unused))int argc,
126
__attribute__((unused))char **argv){
127
int ret = 0;
128
ssize_t sret;
129
bool an_error_occured = false;
130
131
/* Create prompt string */
132
char *prompt = NULL;
133
{
134
const char *const cryptsource = getenv("cryptsource");
135
const char *const crypttarget = getenv("crypttarget");
136
const char prompt_start[] = "Enter passphrase to unlock the disk";
137
138
if(cryptsource == NULL){
139
if(crypttarget == NULL){
140
ret = asprintf(&prompt, "%s: ", prompt_start);
141
} else {
142
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
143
crypttarget);
144
}
145
} else {
146
if(crypttarget == NULL){
147
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
148
} else {
149
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
150
cryptsource, crypttarget);
151
}
152
}
153
if(ret == -1){
154
return EXIT_FAILURE;
155
}
156
}
157
158
/* Find usplash process */
159
pid_t usplash_pid = 0;
160
char *cmdline = NULL;
161
size_t cmdline_len = 0;
162
const char usplash_name[] = "/sbin/usplash";
163
{
164
DIR *proc_dir = opendir("/proc");
165
if(proc_dir == NULL){
166
free(prompt);
167
perror("opendir");
168
return EXIT_FAILURE;
169
}
170
for(struct dirent *proc_ent = readdir(proc_dir);
171
proc_ent != NULL;
172
proc_ent = readdir(proc_dir)){
173
pid_t pid;
174
{
175
intmax_t tmpmax;
176
int numchars;
177
ret = sscanf(proc_ent->d_name, "%" SCNdMAX "%n", &tmpmax,
178
&numchars);
179
if(ret < 1 or tmpmax != (pid_t)tmpmax
180
or proc_ent->d_name[numchars] != '\0'){
181
/* Not a process */
182
continue;
183
}
184
pid = (pid_t)tmpmax;
185
}
186
/* Find the executable name by doing readlink() on the
187
/proc/<pid>/exe link */
188
char exe_target[sizeof(usplash_name)];
189
{
190
/* create file name string */
191
char *exe_link;
192
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
193
if(ret == -1){
194
perror("asprintf");
195
free(prompt);
196
closedir(proc_dir);
197
return EXIT_FAILURE;
198
}
199
200
/* Check that it refers to a symlink owned by root:root */
201
struct stat exe_stat;
202
ret = lstat(exe_link, &exe_stat);
203
if(ret == -1){
204
if(errno == ENOENT){
205
free(exe_link);
206
continue;
207
}
208
perror("lstat");
209
free(exe_link);
210
free(prompt);
211
closedir(proc_dir);
212
return EXIT_FAILURE;
213
}
214
if(not S_ISLNK(exe_stat.st_mode)
215
or exe_stat.st_uid != 0
216
or exe_stat.st_gid != 0){
217
free(exe_link);
218
continue;
219
}
220
221
sret = readlink(exe_link, exe_target, sizeof(exe_target));
222
free(exe_link);
223
}
224
if((sret == ((ssize_t)sizeof(exe_target)-1))
225
and (memcmp(usplash_name, exe_target,
226
sizeof(exe_target)-1) == 0)){
227
usplash_pid = pid;
228
/* Read and save the command line of usplash in "cmdline" */
229
{
230
/* Open /proc/<pid>/cmdline */
231
int cl_fd;
232
{
233
char *cmdline_filename;
234
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
235
proc_ent->d_name);
236
if(ret == -1){
237
perror("asprintf");
238
free(prompt);
239
closedir(proc_dir);
240
return EXIT_FAILURE;
241
}
242
cl_fd = open(cmdline_filename, O_RDONLY);
243
if(cl_fd == -1){
244
perror("open");
245
free(cmdline_filename);
246
free(prompt);
247
closedir(proc_dir);
248
return EXIT_FAILURE;
249
}
250
free(cmdline_filename);
251
}
252
size_t cmdline_allocated = 0;
253
char *tmp;
254
const size_t blocksize = 1024;
255
do{
256
if(cmdline_len + blocksize > cmdline_allocated){
257
tmp = realloc(cmdline, cmdline_allocated + blocksize);
258
if(tmp == NULL){
259
perror("realloc");
260
free(cmdline);
261
free(prompt);
262
closedir(proc_dir);
263
return EXIT_FAILURE;
264
}
265
cmdline = tmp;
266
cmdline_allocated += blocksize;
267
}
268
sret = read(cl_fd, cmdline + cmdline_len,
269
cmdline_allocated - cmdline_len);
270
if(sret == -1){
271
perror("read");
272
free(cmdline);
273
free(prompt);
274
closedir(proc_dir);
275
return EXIT_FAILURE;
276
}
277
cmdline_len += (size_t)sret;
278
} while(sret != 0);
279
close(cl_fd);
280
}
281
break;
282
}
283
}
284
closedir(proc_dir);
285
}
286
if(usplash_pid == 0){
287
free(prompt);
288
return EXIT_FAILURE;
289
}
290
291
/* Set up the signal handler */
292
{
293
struct sigaction old_action,
294
new_action = { .sa_handler = termination_handler,
295
.sa_flags = 0 };
296
sigemptyset(&new_action.sa_mask);
297
sigaddset(&new_action.sa_mask, SIGINT);
298
sigaddset(&new_action.sa_mask, SIGHUP);
299
sigaddset(&new_action.sa_mask, SIGTERM);
300
ret = sigaction(SIGINT, NULL, &old_action);
301
if(ret == -1){
302
perror("sigaction");
303
free(prompt);
304
return EXIT_FAILURE;
305
}
306
if(old_action.sa_handler != SIG_IGN){
307
ret = sigaction(SIGINT, &new_action, NULL);
308
if(ret == -1){
309
perror("sigaction");
310
free(prompt);
311
return EXIT_FAILURE;
312
}
313
}
314
ret = sigaction(SIGHUP, NULL, &old_action);
315
if(ret == -1){
316
perror("sigaction");
317
free(prompt);
318
return EXIT_FAILURE;
319
}
320
if(old_action.sa_handler != SIG_IGN){
321
ret = sigaction(SIGHUP, &new_action, NULL);
322
if(ret == -1){
323
perror("sigaction");
324
free(prompt);
325
return EXIT_FAILURE;
326
}
327
}
328
ret = sigaction(SIGTERM, NULL, &old_action);
329
if(ret == -1){
330
perror("sigaction");
331
free(prompt);
332
return EXIT_FAILURE;
333
}
334
if(old_action.sa_handler != SIG_IGN){
335
ret = sigaction(SIGTERM, &new_action, NULL);
336
if(ret == -1){
337
perror("sigaction");
338
free(prompt);
339
return EXIT_FAILURE;
340
}
341
}
342
}
343
344
/* Write command to FIFO */
345
if(not interrupted_by_signal){
346
if(not usplash_write("TIMEOUT", "0")
347
and (errno != EINTR)){
348
perror("usplash_write");
349
an_error_occured = true;
350
}
351
}
352
if(not interrupted_by_signal and not an_error_occured){
353
if(not usplash_write("INPUTQUIET", prompt)
354
and (errno != EINTR)){
355
perror("usplash_write");
356
an_error_occured = true;
357
}
358
}
359
free(prompt);
360
361
/* This is not really a loop; while() is used to be able to "break"
362
out of it; those breaks are marked "Big" */
363
while(not interrupted_by_signal and not an_error_occured){
364
char *buf = NULL;
365
size_t buf_len = 0;
366
367
/* Open FIFO */
368
int fifo_fd;
369
do{
370
fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
371
if(fifo_fd == -1){
372
if(errno != EINTR){
373
perror("open");
374
an_error_occured = true;
375
break;
376
}
377
if(interrupted_by_signal){
378
break;
379
}
380
}
381
}while(fifo_fd == -1);
382
if(interrupted_by_signal or an_error_occured){
383
break; /* Big */
384
}
385
386
/* Read from FIFO */
387
size_t buf_allocated = 0;
388
const size_t blocksize = 1024;
389
do{
390
if(buf_len + blocksize > buf_allocated){
391
char *tmp = realloc(buf, buf_allocated + blocksize);
392
if(tmp == NULL){
393
perror("realloc");
394
an_error_occured = true;
395
break;
396
}
397
buf = tmp;
398
buf_allocated += blocksize;
399
}
400
do{
401
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
402
if(sret == -1){
403
if(errno != EINTR){
404
perror("read");
405
an_error_occured = true;
406
break;
407
}
408
if(interrupted_by_signal){
409
break;
410
}
411
}
412
}while(sret == -1);
413
if(interrupted_by_signal or an_error_occured){
414
break;
415
}
416
417
buf_len += (size_t)sret;
418
}while(sret != 0);
419
close(fifo_fd);
420
if(interrupted_by_signal or an_error_occured){
421
break; /* Big */
422
}
423
424
if(not usplash_write("TIMEOUT", "15")
425
and (errno != EINTR)){
426
perror("usplash_write");
427
an_error_occured = true;
428
}
429
if(interrupted_by_signal or an_error_occured){
430
break; /* Big */
431
}
432
433
/* Print password to stdout */
434
size_t written = 0;
435
while(written < buf_len){
436
do{
437
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
438
if(sret == -1){
439
if(errno != EINTR){
440
perror("write");
441
an_error_occured = true;
442
break;
443
}
444
if(interrupted_by_signal){
445
break;
446
}
447
}
448
}while(sret == -1);
449
if(interrupted_by_signal or an_error_occured){
450
break;
451
}
452
written += (size_t)sret;
453
}
454
free(buf);
455
if(not interrupted_by_signal and not an_error_occured){
456
free(cmdline);
457
return EXIT_SUCCESS;
458
}
459
break; /* Big */
460
} /* end of non-loop while() */
461
462
/* If we got here, an error or interrupt must have happened */
463
464
/* Create argc and argv for new usplash*/
465
int cmdline_argc = 0;
466
char **cmdline_argv = malloc(sizeof(char *));
467
{
468
size_t position = 0;
469
while(position < cmdline_len){
470
char **tmp = realloc(cmdline_argv,
471
(sizeof(char *)
472
* (size_t)(cmdline_argc + 2)));
473
if(tmp == NULL){
474
perror("realloc");
475
free(cmdline_argv);
476
return EXIT_FAILURE;
477
}
478
cmdline_argv = tmp;
479
cmdline_argv[cmdline_argc] = cmdline + position;
480
cmdline_argc++;
481
position += strlen(cmdline + position) + 1;
482
}
483
cmdline_argv[cmdline_argc] = NULL;
484
}
485
/* Kill old usplash */
486
kill(usplash_pid, SIGTERM);
487
sleep(2);
488
while(kill(usplash_pid, 0) == 0){
489
kill(usplash_pid, SIGKILL);
490
sleep(1);
491
}
492
pid_t new_usplash_pid = fork();
493
if(new_usplash_pid == 0){
494
/* Child; will become new usplash process */
495
496
/* Make the effective user ID (root) the only user ID instead of
497
the real user ID (_mandos) */
498
ret = setuid(geteuid());
499
if(ret == -1){
500
perror("setuid");
501
}
502
503
setsid();
504
ret = chdir("/");
505
/* if(fork() != 0){ */
506
/* _exit(EXIT_SUCCESS); */
507
/* } */
508
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
509
if(ret == -1){
510
perror("dup2");
511
_exit(EXIT_FAILURE);
512
}
513
514
execv(usplash_name, cmdline_argv);
515
if(not interrupted_by_signal){
516
perror("execv");
517
}
518
free(cmdline);
519
free(cmdline_argv);
520
_exit(EXIT_FAILURE);
521
}
522
free(cmdline);
523
free(cmdline_argv);
524
sleep(2);
525
if(not usplash_write("PULSATE", NULL)
526
and (errno != EINTR)){
527
perror("usplash_write");
528
}
529
530
return EXIT_FAILURE;
531
}
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