1
#define _GNU_SOURCE /* asprintf() */
1
/* -*- coding: utf-8 -*- */
3
* Usplash - Read a password from usplash and output it
5
* Copyright © 2008-2017 Teddy Hogeborn
6
* Copyright © 2008-2017 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@recompile.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
#include <string.h> /* strlen(), memcmp() */
13
#include <stdio.h> /* asprintf(), perror() */
38
#include <string.h> /* strlen(), memcmp(), strerror() */
39
#include <stdio.h> /* asprintf(), vasprintf(), vprintf(),
14
41
#include <unistd.h> /* close(), write(), readlink(),
15
42
read(), STDOUT_FILENO, sleep(),
16
43
fork(), setuid(), geteuid(),
17
44
setsid(), chdir(), dup2(),
18
45
STDERR_FILENO, execv() */
19
#include <stdlib.h> /* free(), EXIT_FAILURE, strtoul(),
20
realloc(), EXIT_SUCCESS, malloc(),
22
#include <stdlib.h> /* getenv() */
46
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
47
EXIT_SUCCESS, malloc(), _exit(),
23
49
#include <dirent.h> /* opendir(), readdir(), closedir() */
27
#include <iso646.h> /* and */
28
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
50
#include <inttypes.h> /* intmax_t, strtoimax() */
51
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
52
#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
53
#include <argz.h> /* argz_count(), argz_extract() */
54
#include <stdarg.h> /* va_list, va_start(), ... */
31
56
sig_atomic_t interrupted_by_signal = 0;
33
static void termination_handler(__attribute__((unused))int signum){
58
const char usplash_name[] = "/sbin/usplash";
60
/* Function to use when printing errors */
61
__attribute__((format (gnu_printf, 3, 4)))
62
void error_plus(int status, int errnum, const char *formatstring,
68
va_start(ap, formatstring);
69
ret = vasprintf(&text, formatstring, ap);
71
fprintf(stderr, "Mandos plugin %s: ",
72
program_invocation_short_name);
73
vfprintf(stderr, formatstring, ap);
74
fprintf(stderr, ": ");
75
fprintf(stderr, "%s\n", strerror(errnum));
76
error(status, errno, "vasprintf while printing error");
79
fprintf(stderr, "Mandos plugin ");
80
error(status, errnum, "%s", text);
84
static void termination_handler(int signum){
85
if(interrupted_by_signal){
34
88
interrupted_by_signal = 1;
89
signal_received = signum;
37
static bool usplash_write(const char *cmd, const char *arg){
92
static bool usplash_write(int *fifo_fd_r,
93
const char *cmd, const char *arg){
39
* usplash_write("TIMEOUT", "15"); -> "TIMEOUT 15\0"
40
* usplash_write("PULSATE", NULL); -> "PULSATE\0"
95
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
96
* 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)){
101
if(*fifo_fd_r == -1){
102
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
51
}while(fifo_fd == -1);
53
109
const char *cmd_line;
54
110
size_t cmd_line_len;
55
111
char *cmd_line_alloc = NULL;
58
cmd_line_len = strlen(cmd);
114
cmd_line_len = strlen(cmd) + 1;
61
117
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
62
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
69
125
cmd_line = cmd_line_alloc;
70
126
cmd_line_len = (size_t)ret + 1;
73
129
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){
131
while(written < cmd_line_len){
132
sret = write(*fifo_fd_r, cmd_line + written,
133
cmd_line_len - written);
137
free(cmd_line_alloc);
88
written += (size_t)ret;
141
written += (size_t)sret;
90
143
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;
148
/* Create prompt string */
149
char *makeprompt(void){
152
const char *const cryptsource = getenv("cryptsource");
153
const char *const crypttarget = getenv("crypttarget");
154
const char prompt_start[] = "Enter passphrase to unlock the disk";
156
if(cryptsource == NULL){
157
if(crypttarget == NULL){
158
ret = asprintf(&prompt, "%s: ", prompt_start);
160
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
164
if(crypttarget == NULL){
165
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
167
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
168
cryptsource, crypttarget);
177
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
138
180
char *cmdline = NULL;
139
181
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);
182
DIR *proc_dir = opendir("/proc");
183
if(proc_dir == NULL){
184
error_plus(0, errno, "opendir");
188
for(struct dirent *proc_ent = readdir(proc_dir);
190
proc_ent = readdir(proc_dir)){
195
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
196
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
197
or tmpmax != (pid_t)tmpmax){
153
198
/* 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)];
204
/* Find the executable name by doing readlink() on the
205
/proc/<pid>/exe link */
206
char exe_target[sizeof(usplash_name)];
208
/* create file name string */
210
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
212
error_plus(0, errno, "asprintf");
213
goto fail_find_usplash;
216
/* Check that it refers to a symlink owned by root:root */
217
struct stat exe_stat;
218
ret = lstat(exe_link, &exe_stat);
224
error_plus(0, errno, "lstat");
226
goto fail_find_usplash;
228
if(not S_ISLNK(exe_stat.st_mode)
229
or exe_stat.st_uid != 0
230
or exe_stat.st_gid != 0){
235
sret = readlink(exe_link, exe_target, sizeof(exe_target));
238
/* Compare executable name */
239
if((sret != ((ssize_t)sizeof(exe_target)-1))
240
or (memcmp(usplash_name, exe_target,
241
sizeof(exe_target)-1) != 0)){
246
/* Read and save the command line of usplash in "cmdline" */
248
/* Open /proc/<pid>/cmdline */
161
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
251
char *cmdline_filename;
252
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
255
error_plus(0, errno, "asprintf");
256
goto fail_find_usplash;
168
sret = readlink(exe_link, exe_target, sizeof(exe_target));
258
cl_fd = open(cmdline_filename, O_RDONLY);
259
free(cmdline_filename);
261
error_plus(0, errno, "open");
262
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",
192
cl_fd = open(cmdline_filename, O_RDONLY);
195
free(cmdline_filename);
200
free(cmdline_filename);
265
size_t cmdline_allocated = 0;
267
const size_t blocksize = 1024;
269
/* Allocate more space? */
270
if(cmdline_len + blocksize > cmdline_allocated){
271
tmp = realloc(cmdline, cmdline_allocated + blocksize);
273
error_plus(0, errno, "realloc");
275
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,
219
cmdline_allocated - cmdline_len);
227
cmdline_len += (size_t)sret;
278
cmdline_allocated += blocksize;
281
sret = read(cl_fd, cmdline + cmdline_len,
282
cmdline_allocated - cmdline_len);
284
error_plus(0, errno, "read");
286
goto fail_find_usplash;
288
cmdline_len += (size_t)sret;
292
error_plus(0, errno, "close");
293
goto fail_find_usplash;
296
/* Close directory */
297
ret = closedir(proc_dir);
299
error_plus(0, errno, "closedir");
300
goto fail_find_usplash;
303
*cmdline_r = cmdline;
304
*cmdline_len_r = cmdline_len;
311
if(proc_dir != NULL){
234
313
closedir(proc_dir);
319
int main(__attribute__((unused))int argc,
320
__attribute__((unused))char **argv){
327
pid_t usplash_pid = -1;
328
bool usplash_accessed = false;
329
int status = EXIT_FAILURE; /* Default failure exit status */
331
char *prompt = makeprompt();
337
/* Find usplash process */
338
char *cmdline = NULL;
339
size_t cmdline_len = 0;
340
usplash_pid = find_usplash(&cmdline, &cmdline_len);
236
341
if(usplash_pid == 0){
342
status = EX_UNAVAILABLE;
241
346
/* Set up the signal handler */
244
349
new_action = { .sa_handler = termination_handler,
246
351
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);
352
ret = sigaddset(&new_action.sa_mask, SIGINT);
354
error_plus(0, errno, "sigaddset");
358
ret = sigaddset(&new_action.sa_mask, SIGHUP);
360
error_plus(0, errno, "sigaddset");
364
ret = sigaddset(&new_action.sa_mask, SIGTERM);
366
error_plus(0, errno, "sigaddset");
250
370
ret = sigaction(SIGINT, NULL, &old_action);
373
error_plus(0, errno, "sigaction");
256
if (old_action.sa_handler != SIG_IGN){
378
if(old_action.sa_handler != SIG_IGN){
257
379
ret = sigaction(SIGINT, &new_action, NULL);
382
error_plus(0, errno, "sigaction");
264
388
ret = sigaction(SIGHUP, NULL, &old_action);
391
error_plus(0, errno, "sigaction");
270
if (old_action.sa_handler != SIG_IGN){
396
if(old_action.sa_handler != SIG_IGN){
271
397
ret = sigaction(SIGHUP, &new_action, NULL);
400
error_plus(0, errno, "sigaction");
278
406
ret = sigaction(SIGTERM, NULL, &old_action);
409
error_plus(0, errno, "sigaction");
284
if (old_action.sa_handler != SIG_IGN){
414
if(old_action.sa_handler != SIG_IGN){
285
415
ret = sigaction(SIGTERM, &new_action, NULL);
418
error_plus(0, errno, "sigaction");
426
usplash_accessed = true;
294
427
/* 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;
428
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
430
error_plus(0, errno, "usplash_write");
436
if(interrupted_by_signal){
440
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
442
error_plus(0, errno, "usplash_write");
448
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)));
455
/* Read reply from usplash */
457
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
458
if(outfifo_fd == -1){
460
error_plus(0, errno, "open");
466
if(interrupted_by_signal){
471
size_t buf_allocated = 0;
472
const size_t blocksize = 1024;
474
/* Allocate more space */
475
if(buf_len + blocksize > buf_allocated){
476
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;
479
error_plus(0, errno, "realloc");
485
buf_allocated += blocksize;
487
sret = read(outfifo_fd, buf + buf_len,
488
buf_allocated - buf_len);
491
error_plus(0, errno, "read");
497
if(interrupted_by_signal){
501
buf_len += (size_t)sret;
503
ret = close(outfifo_fd);
506
error_plus(0, errno, "close");
513
if(interrupted_by_signal){
517
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
519
error_plus(0, errno, "usplash_write");
525
if(interrupted_by_signal){
529
ret = close(fifo_fd);
532
error_plus(0, errno, "close");
539
/* Print password to stdout */
541
while(written < buf_len){
543
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
546
error_plus(0, errno, "write");
553
if(interrupted_by_signal){
556
written += (size_t)sret;
561
if(interrupted_by_signal){
574
/* If usplash was never accessed, we can stop now */
575
if(not usplash_accessed){
581
ret = close(fifo_fd);
582
if(ret == -1 and errno != EINTR){
583
error_plus(0, errno, "close");
588
/* Close output FIFO */
589
if(outfifo_fd != -1){
590
ret = close(outfifo_fd);
592
error_plus(0, errno, "close");
596
/* Create argv for new usplash*/
597
char **cmdline_argv = malloc((argz_count(cmdline, cmdline_len) + 1)
598
* sizeof(char *)); /* Count args */
599
if(cmdline_argv == NULL){
600
error_plus(0, errno, "malloc");
603
argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
436
605
/* Kill old usplash */
437
kill(usplash_pid, SIGTERM);
606
kill(usplash_pid, SIGTERM);
439
608
while(kill(usplash_pid, 0) == 0){
440
609
kill(usplash_pid, SIGKILL);
443
613
pid_t new_usplash_pid = fork();
444
614
if(new_usplash_pid == 0){
445
615
/* Child; will become new usplash process */
447
617
/* Make the effective user ID (root) the only user ID instead of
448
the real user ID (mandos) */
618
the real user ID (_mandos) */
449
619
ret = setuid(geteuid());
621
error_plus(0, errno, "setuid");
455
625
ret = chdir("/");
627
error_plus(0, errno, "chdir");
456
630
/* if(fork() != 0){ */
457
631
/* _exit(EXIT_SUCCESS); */
459
633
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
635
error_plus(0, errno, "dup2");
465
639
execv(usplash_name, cmdline_argv);
640
if(not interrupted_by_signal){
641
error_plus(0, errno, "execv");
467
644
free(cmdline_argv);
470
648
free(cmdline_argv);
472
if(not usplash_write("PULSATE", NULL)
473
and (errno != EINTR)){
474
perror("usplash_write");
650
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
652
error_plus(0, errno, "usplash_write");
656
/* Close FIFO (again) */
658
ret = close(fifo_fd);
659
if(ret == -1 and errno != EINTR){
660
error_plus(0, errno, "close");
665
if(interrupted_by_signal){
666
struct sigaction signal_action = { .sa_handler = SIG_DFL };
667
sigemptyset(&signal_action.sa_mask);
668
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
669
&signal_action, NULL));
671
error_plus(0, errno, "sigaction");
674
ret = raise(signal_received);
675
} while(ret != 0 and errno == EINTR);
677
error_plus(0, errno, "raise");
680
TEMP_FAILURE_RETRY(pause());