1
/* -*- coding: utf-8 -*- */
3
* Usplash - Read a password from usplash and output it
5
* Copyright © 2008-2011 Teddy Hogeborn
6
* Copyright © 2008-2011 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() */
1
#define _GNU_SOURCE /* asprintf() */
26
2
#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 */
35
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
3
sigemptyset(), sigaddset(),
4
sigaction, SIGINT, SIG_IGN, SIGHUP,
5
SIGTERM, kill(), SIGKILL */
37
6
#include <stddef.h> /* NULL */
38
#include <string.h> /* strlen(), memcmp(), strerror() */
39
#include <stdio.h> /* asprintf(), vasprintf(), vprintf(), fprintf() */
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(),
7
#include <stdlib.h> /* getenv() */
8
#include <stdio.h> /* asprintf(), perror() */
9
#include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS,
11
#include <sys/types.h> /* pid_t, DIR, struct dirent,
48
13
#include <dirent.h> /* opendir(), readdir(), closedir() */
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() */
53
#include <stdarg.h> /* va_list, va_start(), ... */
14
#include <unistd.h> /* readlink(), fork(), execl(),
16
#include <string.h> /* memcmp() */
17
#include <iso646.h> /* and */
18
#include <stdbool.h> /* bool, false, true */
19
#include <errno.h> /* errno */
20
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
22
#include <fcntl.h> /* open(), O_RDONLY */
55
24
sig_atomic_t interrupted_by_signal = 0;
57
const char usplash_name[] = "/sbin/usplash";
59
/* Function to use when printing errors */
60
void error_plus(int status, int errnum, const char *formatstring, ...){
65
va_start(ap, formatstring);
66
ret = vasprintf(&text, formatstring, ap);
68
fprintf(stderr, "Mandos plugin %s: ", program_invocation_short_name);
69
vfprintf(stderr, formatstring, ap);
70
fprintf(stderr, ": ");
71
fprintf(stderr, "%s\n", strerror(errnum));
72
error(status, errno, "vasprintf while printing error");
75
fprintf(stderr, "Mandos plugin ");
76
error(status, errnum, "%s", text);
80
static void termination_handler(int signum){
81
if(interrupted_by_signal){
26
static void termination_handler(__attribute__((unused))int signum){
84
27
interrupted_by_signal = 1;
85
signal_received = signum;
88
static bool usplash_write(int *fifo_fd_r,
89
const char *cmd, const char *arg){
30
static bool usplash_write(const char *cmd, const char *arg){
91
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
92
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
32
* usplash_write("TIMEOUT", "15"); -> "TIMEOUT 15\0"
33
* usplash_write("PULSATE", NULL); -> "PULSATE\0"
98
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
40
fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
41
if(fifo_fd == -1 and (errno != EINTR or interrupted_by_signal)){
44
}while(fifo_fd == -1);
105
46
const char *cmd_line;
107
47
char *cmd_line_alloc = NULL;
110
cmd_line_len = strlen(cmd) + 1;
50
ret = (int)strlen(cmd);
113
53
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
54
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
116
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
121
61
cmd_line = cmd_line_alloc;
122
cmd_line_len = (size_t)ret + 1;
64
size_t cmd_line_len = (size_t)ret + 1;
125
65
size_t written = 0;
127
while(written < cmd_line_len){
128
sret = write(*fifo_fd_r, cmd_line + written,
129
cmd_line_len - written);
132
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
133
free(cmd_line_alloc);
66
while(not interrupted_by_signal and written < cmd_line_len){
67
ret = write(fifo_fd, cmd_line + written,
68
cmd_line_len - written);
70
if(errno != EINTR or interrupted_by_signal){
137
written += (size_t)sret;
80
written += (size_t)ret;
139
82
free(cmd_line_alloc);
85
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
89
if(interrupted_by_signal){
144
/* Create prompt string */
145
char *makeprompt(void){
148
const char *const cryptsource = getenv("cryptsource");
149
const char *const crypttarget = getenv("crypttarget");
150
const char prompt_start[] = "Enter passphrase to unlock the disk";
152
if(cryptsource == NULL){
153
if(crypttarget == NULL){
154
ret = asprintf(&prompt, "%s: ", prompt_start);
156
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
160
if(crypttarget == NULL){
161
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
163
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
164
cryptsource, crypttarget);
173
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
95
int main(__attribute__((unused))int argc,
96
__attribute__((unused))char **argv){
99
bool an_error_occured = false;
101
/* Create prompt string */
104
const char *const cryptsource = getenv("cryptsource");
105
const char *const crypttarget = getenv("crypttarget");
106
const char *const prompt_start = "Enter passphrase to unlock the disk";
108
if(cryptsource == NULL){
109
if(crypttarget == NULL){
110
ret = asprintf(&prompt, "%s: ", prompt_start);
112
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
116
if(crypttarget == NULL){
117
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
119
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
120
cryptsource, crypttarget);
128
/* Find usplash process */
129
pid_t usplash_pid = 0;
176
130
char *cmdline = NULL;
177
131
size_t cmdline_len = 0;
178
DIR *proc_dir = opendir("/proc");
179
if(proc_dir == NULL){
180
error_plus(0, errno, "opendir");
184
for(struct dirent *proc_ent = readdir(proc_dir);
186
proc_ent = readdir(proc_dir)){
191
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
192
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
193
or tmpmax != (pid_t)tmpmax){
132
const char usplash_name[] = "/sbin/usplash";
134
DIR *proc_dir = opendir("/proc");
135
if(proc_dir == NULL){
140
for(struct dirent *proc_ent = readdir(proc_dir);
142
proc_ent = readdir(proc_dir)){
143
pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
194
145
/* Not a process */
200
/* Find the executable name by doing readlink() on the
201
/proc/<pid>/exe link */
202
char exe_target[sizeof(usplash_name)];
204
/* create file name string */
206
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
208
error_plus(0, errno, "asprintf");
209
goto fail_find_usplash;
212
/* Check that it refers to a symlink owned by root:root */
213
struct stat exe_stat;
214
ret = lstat(exe_link, &exe_stat);
220
error_plus(0, errno, "lstat");
222
goto fail_find_usplash;
224
if(not S_ISLNK(exe_stat.st_mode)
225
or exe_stat.st_uid != 0
226
or exe_stat.st_gid != 0){
231
sret = readlink(exe_link, exe_target, sizeof(exe_target));
234
/* Compare executable name */
235
if((sret != ((ssize_t)sizeof(exe_target)-1))
236
or (memcmp(usplash_name, exe_target,
237
sizeof(exe_target)-1) != 0)){
242
/* Read and save the command line of usplash in "cmdline" */
244
/* Open /proc/<pid>/cmdline */
148
/* Find the executable name by doing readlink() on the
149
/proc/<pid>/exe link */
150
char exe_target[sizeof(usplash_name)];
247
char *cmdline_filename;
248
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
153
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
251
error_plus(0, errno, "asprintf");
252
goto fail_find_usplash;
254
cl_fd = open(cmdline_filename, O_RDONLY);
255
free(cmdline_filename);
257
error_plus(0, errno, "open");
258
goto fail_find_usplash;
160
sret = readlink(exe_link, exe_target, sizeof(exe_target));
261
size_t cmdline_allocated = 0;
263
const size_t blocksize = 1024;
265
/* Allocate more space? */
266
if(cmdline_len + blocksize > cmdline_allocated){
267
tmp = realloc(cmdline, cmdline_allocated + blocksize);
269
error_plus(0, errno, "realloc");
271
goto fail_find_usplash;
163
if((sret == ((ssize_t)sizeof(exe_target)-1))
164
and (memcmp(usplash_name, exe_target,
165
sizeof(exe_target)-1) == 0)){
167
/* Read and save the command line of usplash in "cmdline" */
169
/* Open /proc/<pid>/cmdline */
172
char *cmdline_filename;
173
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
181
cl_fd = open(cmdline_filename, O_RDONLY);
184
free(cmdline_filename);
189
free(cmdline_filename);
274
cmdline_allocated += blocksize;
277
sret = read(cl_fd, cmdline + cmdline_len,
278
cmdline_allocated - cmdline_len);
280
error_plus(0, errno, "read");
191
size_t cmdline_allocated = 0;
193
const size_t blocksize = 1024;
195
if(cmdline_len + blocksize > cmdline_allocated){
196
tmp = realloc(cmdline, cmdline_allocated + blocksize);
205
cmdline_allocated += blocksize;
207
sret = read(cl_fd, cmdline + cmdline_len,
208
cmdline_allocated - cmdline_len);
216
cmdline_len += (size_t)sret;
282
goto fail_find_usplash;
284
cmdline_len += (size_t)sret;
288
error_plus(0, errno, "close");
289
goto fail_find_usplash;
292
/* Close directory */
293
ret = closedir(proc_dir);
295
error_plus(0, errno, "closedir");
296
goto fail_find_usplash;
299
*cmdline_r = cmdline;
300
*cmdline_len_r = cmdline_len;
307
if(proc_dir != NULL){
309
223
closedir(proc_dir);
315
int main(__attribute__((unused))int argc,
316
__attribute__((unused))char **argv){
323
pid_t usplash_pid = -1;
324
bool usplash_accessed = false;
325
int status = EXIT_FAILURE; /* Default failure exit status */
327
char *prompt = makeprompt();
333
/* Find usplash process */
334
char *cmdline = NULL;
335
size_t cmdline_len = 0;
336
usplash_pid = find_usplash(&cmdline, &cmdline_len);
337
225
if(usplash_pid == 0){
338
status = EX_UNAVAILABLE;
342
230
/* Set up the signal handler */
345
233
new_action = { .sa_handler = termination_handler,
347
235
sigemptyset(&new_action.sa_mask);
348
ret = sigaddset(&new_action.sa_mask, SIGINT);
350
error_plus(0, errno, "sigaddset");
354
ret = sigaddset(&new_action.sa_mask, SIGHUP);
356
error_plus(0, errno, "sigaddset");
360
ret = sigaddset(&new_action.sa_mask, SIGTERM);
362
error_plus(0, errno, "sigaddset");
236
sigaddset(&new_action.sa_mask, SIGINT);
237
sigaddset(&new_action.sa_mask, SIGHUP);
238
sigaddset(&new_action.sa_mask, SIGTERM);
366
239
ret = sigaction(SIGINT, NULL, &old_action);
369
error_plus(0, errno, "sigaction");
374
if(old_action.sa_handler != SIG_IGN){
245
if (old_action.sa_handler != SIG_IGN){
375
246
ret = sigaction(SIGINT, &new_action, NULL);
378
error_plus(0, errno, "sigaction");
384
253
ret = sigaction(SIGHUP, NULL, &old_action);
387
error_plus(0, errno, "sigaction");
392
if(old_action.sa_handler != SIG_IGN){
259
if (old_action.sa_handler != SIG_IGN){
393
260
ret = sigaction(SIGHUP, &new_action, NULL);
396
error_plus(0, errno, "sigaction");
402
267
ret = sigaction(SIGTERM, NULL, &old_action);
405
error_plus(0, errno, "sigaction");
410
if(old_action.sa_handler != SIG_IGN){
273
if (old_action.sa_handler != SIG_IGN){
411
274
ret = sigaction(SIGTERM, &new_action, NULL);
414
error_plus(0, errno, "sigaction");
422
usplash_accessed = true;
423
283
/* Write command to FIFO */
424
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
426
error_plus(0, errno, "usplash_write");
432
if(interrupted_by_signal){
436
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
438
error_plus(0, errno, "usplash_write");
444
if(interrupted_by_signal){
284
if(not interrupted_by_signal){
285
if(not usplash_write("TIMEOUT", "0")
286
and (errno != EINTR)){
287
perror("usplash_write");
288
an_error_occured = true;
291
if(not interrupted_by_signal and not an_error_occured){
292
if(not usplash_write("INPUTQUIET", prompt)
293
and (errno != EINTR)){
294
perror("usplash_write");
295
an_error_occured = true;
451
/* Read reply from usplash */
453
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
454
if(outfifo_fd == -1){
456
error_plus(0, errno, "open");
462
if(interrupted_by_signal){
467
size_t buf_allocated = 0;
468
const size_t blocksize = 1024;
470
/* Allocate more space */
471
if(buf_len + blocksize > buf_allocated){
472
char *tmp = realloc(buf, buf_allocated + blocksize);
300
/* This is not really a loop; while() is used to be able to "break"
301
out of it; those breaks are marked "Big" */
302
while(not interrupted_by_signal and not an_error_occured){
309
fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
313
an_error_occured = true;
316
if(interrupted_by_signal){
320
}while(fifo_fd == -1);
321
if(interrupted_by_signal or an_error_occured){
326
size_t buf_allocated = 0;
327
const size_t blocksize = 1024;
329
if(buf_len + blocksize > buf_allocated){
330
char *tmp = realloc(buf, buf_allocated + blocksize);
333
an_error_occured = true;
337
buf_allocated += blocksize;
340
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
344
an_error_occured = true;
347
if(interrupted_by_signal){
352
if(interrupted_by_signal or an_error_occured){
356
buf_len += (size_t)sret;
359
if(interrupted_by_signal or an_error_occured){
363
if(not usplash_write("TIMEOUT", "15")
364
and (errno != EINTR)){
365
perror("usplash_write");
366
an_error_occured = true;
368
if(interrupted_by_signal or an_error_occured){
372
/* Print password to stdout */
376
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
380
an_error_occured = true;
383
if(interrupted_by_signal){
388
if(interrupted_by_signal or an_error_occured){
392
written += (size_t)sret;
393
}while(written < buf_len);
394
if(not interrupted_by_signal and not an_error_occured){
400
/* If we got here, an error or interrupt must have happened */
402
int cmdline_argc = 0;
403
char **cmdline_argv = malloc(sizeof(char *));
404
/* Create argv and argc for new usplash*/
407
while(position < cmdline_len){
408
char **tmp = realloc(cmdline_argv,
409
(sizeof(char *) * (size_t)(cmdline_argc + 2)));
475
error_plus(0, errno, "realloc");
481
buf_allocated += blocksize;
483
sret = read(outfifo_fd, buf + buf_len,
484
buf_allocated - buf_len);
487
error_plus(0, errno, "read");
490
TEMP_FAILURE_RETRY(close(outfifo_fd));
493
if(interrupted_by_signal){
497
buf_len += (size_t)sret;
499
ret = close(outfifo_fd);
502
error_plus(0, errno, "close");
509
if(interrupted_by_signal){
513
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
515
error_plus(0, errno, "usplash_write");
521
if(interrupted_by_signal){
525
ret = close(fifo_fd);
528
error_plus(0, errno, "close");
535
/* Print password to stdout */
537
while(written < buf_len){
539
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
542
error_plus(0, errno, "write");
549
if(interrupted_by_signal){
552
written += (size_t)sret;
557
if(interrupted_by_signal){
570
/* If usplash was never accessed, we can stop now */
571
if(not usplash_accessed){
577
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
578
if(ret == -1 and errno != EINTR){
579
error_plus(0, errno, "close");
584
/* Close output FIFO */
585
if(outfifo_fd != -1){
586
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
588
error_plus(0, errno, "close");
592
/* Create argv for new usplash*/
593
char **cmdline_argv = malloc((argz_count(cmdline, cmdline_len) + 1)
594
* sizeof(char *)); /* Count args */
595
if(cmdline_argv == NULL){
596
error_plus(0, errno, "malloc");
599
argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
416
cmdline_argv[cmdline_argc] = cmdline + position;
418
position += strlen(cmdline + position) + 1;
420
cmdline_argv[cmdline_argc] = NULL;
601
422
/* Kill old usplash */
602
kill(usplash_pid, SIGTERM);
423
kill(usplash_pid, SIGTERM);
604
425
while(kill(usplash_pid, 0) == 0){
605
426
kill(usplash_pid, SIGKILL);
609
429
pid_t new_usplash_pid = fork();
610
430
if(new_usplash_pid == 0){
611
431
/* Child; will become new usplash process */
613
433
/* Make the effective user ID (root) the only user ID instead of
614
the real user ID (_mandos) */
434
the real user ID (mandos) */
615
435
ret = setuid(geteuid());
617
error_plus(0, errno, "setuid");
621
441
ret = chdir("/");
623
error_plus(0, errno, "chdir");
626
442
/* if(fork() != 0){ */
627
443
/* _exit(EXIT_SUCCESS); */
629
445
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
631
error_plus(0, errno, "dup2");
635
451
execv(usplash_name, cmdline_argv);
636
if(not interrupted_by_signal){
637
error_plus(0, errno, "execv");
646
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
648
error_plus(0, errno, "usplash_write");
652
/* Close FIFO (again) */
654
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
655
if(ret == -1 and errno != EINTR){
656
error_plus(0, errno, "close");
661
if(interrupted_by_signal){
662
struct sigaction signal_action = { .sa_handler = SIG_DFL };
663
sigemptyset(&signal_action.sa_mask);
664
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
665
&signal_action, NULL));
667
error_plus(0, errno, "sigaction");
670
ret = raise(signal_received);
671
} while(ret != 0 and errno == EINTR);
673
error_plus(0, errno, "raise");
676
TEMP_FAILURE_RETRY(pause());
454
if(not usplash_write("PULSATE", NULL)
455
and (errno != EINTR)){
456
perror("usplash_write");