1
#define _GNU_SOURCE /* asprintf() */
1
/* -*- coding: utf-8 -*- */
3
* Usplash - Read a password from usplash and output it
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 Björn Påhlsson
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.
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.
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/>.
22
* Contact the authors at <mandos@fukt.bsnet.se>.
25
#define _GNU_SOURCE /* asprintf(), TEMP_FAILURE_RETRY() */
2
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
3
27
sigemptyset(), sigaddset(), SIGINT,
4
28
SIGHUP, SIGTERM, sigaction(),
5
29
SIG_IGN, kill(), SIGKILL */
6
30
#include <stdbool.h> /* bool, false, true */
7
31
#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
32
#include <iso646.h> /* and, or, not*/
8
33
#include <errno.h> /* errno, EINTR */
9
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR,
35
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
11
37
#include <stddef.h> /* NULL */
12
38
#include <string.h> /* strlen(), memcmp() */
13
#include <stdio.h> /* asprintf(), perror() */
39
#include <stdio.h> /* asprintf()*/
14
40
#include <unistd.h> /* close(), write(), readlink(),
15
41
read(), STDOUT_FILENO, sleep(),
16
42
fork(), setuid(), geteuid(),
17
43
setsid(), chdir(), dup2(),
18
44
STDERR_FILENO, execv() */
19
#include <stdlib.h> /* free(), EXIT_FAILURE, strtoul(),
20
realloc(), EXIT_SUCCESS, malloc(),
22
#include <stdlib.h> /* getenv() */
45
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
46
EXIT_SUCCESS, malloc(), _exit(),
23
48
#include <dirent.h> /* opendir(), readdir(), closedir() */
27
#include <iso646.h> /* and */
28
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
49
#include <inttypes.h> /* intmax_t, strtoimax() */
50
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
51
#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
52
#include <argz.h> /* argz_count(), argz_extract() */
31
54
sig_atomic_t interrupted_by_signal = 0;
56
const char usplash_name[] = "/sbin/usplash";
33
static void termination_handler(__attribute__((unused))int signum){
58
static void termination_handler(int signum){
59
if(interrupted_by_signal){
34
62
interrupted_by_signal = 1;
63
signal_received = signum;
37
static bool usplash_write(const char *cmd, const char *arg){
66
static bool usplash_write(int *fifo_fd_r,
67
const char *cmd, const char *arg){
39
* usplash_write("TIMEOUT", "15"); -> "TIMEOUT 15\0"
40
* usplash_write("PULSATE", NULL); -> "PULSATE\0"
69
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
70
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
47
fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
48
if(fifo_fd == -1 and (errno != EINTR or interrupted_by_signal)){
76
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
51
}while(fifo_fd == -1);
53
83
const char *cmd_line;
54
84
size_t cmd_line_len;
55
85
char *cmd_line_alloc = NULL;
58
cmd_line_len = strlen(cmd);
88
cmd_line_len = strlen(cmd) + 1;
61
91
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
62
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
94
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
69
99
cmd_line = cmd_line_alloc;
70
100
cmd_line_len = (size_t)ret + 1;
73
103
size_t written = 0;
74
while(not interrupted_by_signal and written < cmd_line_len){
75
ret = write(fifo_fd, cmd_line + written,
76
cmd_line_len - written);
78
if(errno != EINTR or interrupted_by_signal){
105
while(written < cmd_line_len){
106
sret = write(*fifo_fd_r, cmd_line + written,
107
cmd_line_len - written);
110
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
111
free(cmd_line_alloc);
88
written += (size_t)ret;
115
written += (size_t)sret;
90
117
free(cmd_line_alloc);
93
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
97
if(interrupted_by_signal){
103
int main(__attribute__((unused))int argc,
104
__attribute__((unused))char **argv){
107
bool an_error_occured = false;
109
/* Create prompt string */
112
const char *const cryptsource = getenv("cryptsource");
113
const char *const crypttarget = getenv("crypttarget");
114
const char prompt_start[] = "Enter passphrase to unlock the disk";
116
if(cryptsource == NULL){
117
if(crypttarget == NULL){
118
ret = asprintf(&prompt, "%s: ", prompt_start);
120
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
124
if(crypttarget == NULL){
125
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
127
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
128
cryptsource, crypttarget);
136
/* Find usplash process */
137
pid_t usplash_pid = 0;
122
/* Create prompt string */
123
char *makeprompt(void){
126
const char *const cryptsource = getenv("cryptsource");
127
const char *const crypttarget = getenv("crypttarget");
128
const char prompt_start[] = "Enter passphrase to unlock the disk";
130
if(cryptsource == NULL){
131
if(crypttarget == NULL){
132
ret = asprintf(&prompt, "%s: ", prompt_start);
134
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
138
if(crypttarget == NULL){
139
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
141
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
142
cryptsource, crypttarget);
151
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
138
154
char *cmdline = NULL;
139
155
size_t cmdline_len = 0;
140
const char usplash_name[] = "/sbin/usplash";
142
DIR *proc_dir = opendir("/proc");
143
if(proc_dir == NULL){
148
for(struct dirent *proc_ent = readdir(proc_dir);
150
proc_ent = readdir(proc_dir)){
151
pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
156
DIR *proc_dir = opendir("/proc");
157
if(proc_dir == NULL){
158
error(0, errno, "opendir");
162
for(struct dirent *proc_ent = readdir(proc_dir);
164
proc_ent = readdir(proc_dir)){
169
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
170
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
171
or tmpmax != (pid_t)tmpmax){
153
172
/* Not a process */
156
/* Find the executable name by doing readlink() on the
157
/proc/<pid>/exe link */
158
char exe_target[sizeof(usplash_name)];
178
/* Find the executable name by doing readlink() on the
179
/proc/<pid>/exe link */
180
char exe_target[sizeof(usplash_name)];
182
/* create file name string */
184
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
186
error(0, errno, "asprintf");
187
goto fail_find_usplash;
190
/* Check that it refers to a symlink owned by root:root */
191
struct stat exe_stat;
192
ret = lstat(exe_link, &exe_stat);
198
error(0, errno, "lstat");
200
goto fail_find_usplash;
202
if(not S_ISLNK(exe_stat.st_mode)
203
or exe_stat.st_uid != 0
204
or exe_stat.st_gid != 0){
209
sret = readlink(exe_link, exe_target, sizeof(exe_target));
212
/* Compare executable name */
213
if((sret != ((ssize_t)sizeof(exe_target)-1))
214
or (memcmp(usplash_name, exe_target,
215
sizeof(exe_target)-1) != 0)){
220
/* Read and save the command line of usplash in "cmdline" */
222
/* Open /proc/<pid>/cmdline */
161
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
225
char *cmdline_filename;
226
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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error(0, errno, "asprintf");
230
goto fail_find_usplash;
168
sret = readlink(exe_link, exe_target, sizeof(exe_target));
232
cl_fd = open(cmdline_filename, O_RDONLY);
233
free(cmdline_filename);
235
error(0, errno, "open");
236
goto fail_find_usplash;
174
if((sret == ((ssize_t)sizeof(exe_target)-1))
175
and (memcmp(usplash_name, exe_target,
176
sizeof(exe_target)-1) == 0)){
178
/* Read and save the command line of usplash in "cmdline" */
180
/* Open /proc/<pid>/cmdline */
183
char *cmdline_filename;
184
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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cl_fd = open(cmdline_filename, O_RDONLY);
195
free(cmdline_filename);
200
free(cmdline_filename);
239
size_t cmdline_allocated = 0;
241
const size_t blocksize = 1024;
243
/* Allocate more space? */
244
if(cmdline_len + blocksize > cmdline_allocated){
245
tmp = realloc(cmdline, cmdline_allocated + blocksize);
247
error(0, errno, "realloc");
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goto fail_find_usplash;
202
size_t cmdline_allocated = 0;
204
const size_t blocksize = 1024;
206
if(cmdline_len + blocksize > cmdline_allocated){
207
tmp = realloc(cmdline, cmdline_allocated + blocksize);
216
cmdline_allocated += blocksize;
218
sret = read(cl_fd, cmdline + cmdline_len,
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cmdline_allocated - cmdline_len);
227
cmdline_len += (size_t)sret;
252
cmdline_allocated += blocksize;
255
sret = read(cl_fd, cmdline + cmdline_len,
256
cmdline_allocated - cmdline_len);
258
error(0, errno, "read");
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goto fail_find_usplash;
262
cmdline_len += (size_t)sret;
266
error(0, errno, "close");
267
goto fail_find_usplash;
270
/* Close directory */
271
ret = closedir(proc_dir);
273
error(0, errno, "closedir");
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goto fail_find_usplash;
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*cmdline_r = cmdline;
278
*cmdline_len_r = cmdline_len;
285
if(proc_dir != NULL){
234
287
closedir(proc_dir);
293
int main(__attribute__((unused))int argc,
294
__attribute__((unused))char **argv){
301
pid_t usplash_pid = -1;
302
bool usplash_accessed = false;
303
int status = EXIT_FAILURE; /* Default failure exit status */
305
char *prompt = makeprompt();
311
/* Find usplash process */
312
char *cmdline = NULL;
313
size_t cmdline_len = 0;
314
usplash_pid = find_usplash(&cmdline, &cmdline_len);
236
315
if(usplash_pid == 0){
316
status = EX_UNAVAILABLE;
241
320
/* Set up the signal handler */
244
323
new_action = { .sa_handler = termination_handler,
246
325
sigemptyset(&new_action.sa_mask);
247
sigaddset(&new_action.sa_mask, SIGINT);
248
sigaddset(&new_action.sa_mask, SIGHUP);
249
sigaddset(&new_action.sa_mask, SIGTERM);
326
ret = sigaddset(&new_action.sa_mask, SIGINT);
328
error(0, errno, "sigaddset");
332
ret = sigaddset(&new_action.sa_mask, SIGHUP);
334
error(0, errno, "sigaddset");
338
ret = sigaddset(&new_action.sa_mask, SIGTERM);
340
error(0, errno, "sigaddset");
250
344
ret = sigaction(SIGINT, NULL, &old_action);
347
error(0, errno, "sigaction");
256
if (old_action.sa_handler != SIG_IGN){
352
if(old_action.sa_handler != SIG_IGN){
257
353
ret = sigaction(SIGINT, &new_action, NULL);
356
error(0, errno, "sigaction");
264
362
ret = sigaction(SIGHUP, NULL, &old_action);
365
error(0, errno, "sigaction");
270
if (old_action.sa_handler != SIG_IGN){
370
if(old_action.sa_handler != SIG_IGN){
271
371
ret = sigaction(SIGHUP, &new_action, NULL);
374
error(0, errno, "sigaction");
278
380
ret = sigaction(SIGTERM, NULL, &old_action);
383
error(0, errno, "sigaction");
284
if (old_action.sa_handler != SIG_IGN){
388
if(old_action.sa_handler != SIG_IGN){
285
389
ret = sigaction(SIGTERM, &new_action, NULL);
392
error(0, errno, "sigaction");
400
usplash_accessed = true;
294
401
/* Write command to FIFO */
295
if(not interrupted_by_signal){
296
if(not usplash_write("TIMEOUT", "0")
297
and (errno != EINTR)){
298
perror("usplash_write");
299
an_error_occured = true;
302
if(not interrupted_by_signal and not an_error_occured){
303
if(not usplash_write("INPUTQUIET", prompt)
304
and (errno != EINTR)){
305
perror("usplash_write");
306
an_error_occured = true;
402
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
404
error(0, errno, "usplash_write");
410
if(interrupted_by_signal){
414
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
416
error(0, errno, "usplash_write");
422
if(interrupted_by_signal){
311
/* This is not really a loop; while() is used to be able to "break"
312
out of it; those breaks are marked "Big" */
313
while(not interrupted_by_signal and not an_error_occured){
320
fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
324
an_error_occured = true;
327
if(interrupted_by_signal){
331
}while(fifo_fd == -1);
332
if(interrupted_by_signal or an_error_occured){
337
size_t buf_allocated = 0;
338
const size_t blocksize = 1024;
340
if(buf_len + blocksize > buf_allocated){
341
char *tmp = realloc(buf, buf_allocated + blocksize);
344
an_error_occured = true;
348
buf_allocated += blocksize;
351
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
355
an_error_occured = true;
358
if(interrupted_by_signal){
363
if(interrupted_by_signal or an_error_occured){
367
buf_len += (size_t)sret;
370
if(interrupted_by_signal or an_error_occured){
374
if(not usplash_write("TIMEOUT", "15")
375
and (errno != EINTR)){
376
perror("usplash_write");
377
an_error_occured = true;
379
if(interrupted_by_signal or an_error_occured){
383
/* Print password to stdout */
385
while(written < buf_len){
387
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
391
an_error_occured = true;
394
if(interrupted_by_signal){
399
if(interrupted_by_signal or an_error_occured){
402
written += (size_t)sret;
405
if(not interrupted_by_signal and not an_error_occured){
412
/* If we got here, an error or interrupt must have happened */
414
int cmdline_argc = 0;
415
char **cmdline_argv = malloc(sizeof(char *));
416
/* Create argv and argc for new usplash*/
419
while(position < cmdline_len){
420
char **tmp = realloc(cmdline_argv,
422
* (size_t)(cmdline_argc + 2)));
429
/* Read reply from usplash */
431
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
432
if(outfifo_fd == -1){
434
error(0, errno, "open");
440
if(interrupted_by_signal){
445
size_t buf_allocated = 0;
446
const size_t blocksize = 1024;
448
/* Allocate more space */
449
if(buf_len + blocksize > buf_allocated){
450
char *tmp = realloc(buf, buf_allocated + blocksize);
429
cmdline_argv[cmdline_argc] = cmdline + position;
431
position += strlen(cmdline + position) + 1;
433
cmdline_argv[cmdline_argc] = NULL;
453
error(0, errno, "realloc");
459
buf_allocated += blocksize;
461
sret = read(outfifo_fd, buf + buf_len,
462
buf_allocated - buf_len);
465
error(0, errno, "read");
468
TEMP_FAILURE_RETRY(close(outfifo_fd));
471
if(interrupted_by_signal){
475
buf_len += (size_t)sret;
477
ret = close(outfifo_fd);
480
error(0, errno, "close");
487
if(interrupted_by_signal){
491
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
493
error(0, errno, "usplash_write");
499
if(interrupted_by_signal){
503
ret = close(fifo_fd);
506
error(0, errno, "close");
513
/* Print password to stdout */
515
while(written < buf_len){
517
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
520
error(0, errno, "write");
527
if(interrupted_by_signal){
530
written += (size_t)sret;
535
if(interrupted_by_signal){
548
/* If usplash was never accessed, we can stop now */
549
if(not usplash_accessed){
555
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
556
if(ret == -1 and errno != EINTR){
557
error(0, errno, "close");
562
/* Close output FIFO */
563
if(outfifo_fd != -1){
564
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
566
error(0, errno, "close");
570
/* Create argv for new usplash*/
571
char **cmdline_argv = malloc(argz_count(cmdline, cmdline_len)
572
* sizeof(char *)); /* Count args */
573
if(cmdline_argv == NULL){
574
error(0, errno, "malloc");
577
argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
435
579
/* Kill old usplash */
436
kill(usplash_pid, SIGTERM);
580
kill(usplash_pid, SIGTERM);
438
582
while(kill(usplash_pid, 0) == 0){
439
583
kill(usplash_pid, SIGKILL);
442
587
pid_t new_usplash_pid = fork();
443
588
if(new_usplash_pid == 0){
444
589
/* Child; will become new usplash process */
446
591
/* Make the effective user ID (root) the only user ID instead of
447
the real user ID (mandos) */
592
the real user ID (_mandos) */
448
593
ret = setuid(geteuid());
595
error(0, errno, "setuid");
454
599
ret = chdir("/");
601
error(0, errno, "chdir");
455
604
/* if(fork() != 0){ */
456
605
/* _exit(EXIT_SUCCESS); */
458
607
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
609
error(0, errno, "dup2");
464
613
execv(usplash_name, cmdline_argv);
614
if(not interrupted_by_signal){
615
error(0, errno, "execv");
467
618
free(cmdline_argv);
471
622
free(cmdline_argv);
473
if(not usplash_write("PULSATE", NULL)
474
and (errno != EINTR)){
475
perror("usplash_write");
624
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
626
error(0, errno, "usplash_write");
630
/* Close FIFO (again) */
632
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
633
if(ret == -1 and errno != EINTR){
634
error(0, errno, "close");
639
if(interrupted_by_signal){
640
struct sigaction signal_action = { .sa_handler = SIG_DFL };
641
sigemptyset(&signal_action.sa_mask);
642
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
643
&signal_action, NULL));
645
error(0, errno, "sigaction");
648
ret = raise(signal_received);
649
} while(ret != 0 and errno == EINTR);
651
error(0, errno, "raise");
654
TEMP_FAILURE_RETRY(pause());