1
#define _GNU_SOURCE /* asprintf() */
1
/* -*- coding: utf-8 -*- */
3
* Usplash - Read a password from usplash and output it
5
* Copyright © 2008-2018 Teddy Hogeborn
6
* Copyright © 2008-2018 Björn Påhlsson
8
* This file is part of Mandos.
10
* Mandos is free software: you can redistribute it and/or modify it
11
* under the terms of the GNU General Public License as published by
12
* the Free Software Foundation, either version 3 of the License, or
13
* (at your option) any later version.
15
* Mandos is distributed in the hope that it will be useful, but
16
* WITHOUT ANY WARRANTY; without even the implied warranty of
17
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18
* General Public License for more details.
20
* You should have received a copy of the GNU General Public License
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
23
* Contact the authors at <mandos@recompile.se>.
26
#define _GNU_SOURCE /* asprintf(), TEMP_FAILURE_RETRY() */
2
27
#include <signal.h> /* sig_atomic_t, struct sigaction,
3
28
sigemptyset(), sigaddset(), SIGINT,
4
29
SIGHUP, SIGTERM, sigaction(),
5
30
SIG_IGN, kill(), SIGKILL */
6
31
#include <stdbool.h> /* bool, false, true */
7
32
#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
33
#include <iso646.h> /* and, or, not*/
8
34
#include <errno.h> /* errno, EINTR */
9
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR,
36
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
11
38
#include <stddef.h> /* NULL */
12
#include <string.h> /* strlen(), memcmp() */
13
#include <stdio.h> /* asprintf(), perror() */
39
#include <string.h> /* strlen(), memcmp(), strerror() */
40
#include <stdio.h> /* asprintf(), vasprintf(), vprintf(),
14
42
#include <unistd.h> /* close(), write(), readlink(),
15
43
read(), STDOUT_FILENO, sleep(),
16
44
fork(), setuid(), geteuid(),
17
45
setsid(), chdir(), dup2(),
18
46
STDERR_FILENO, execv() */
19
#include <stdlib.h> /* free(), EXIT_FAILURE, strtoul(),
20
realloc(), EXIT_SUCCESS, malloc(),
22
#include <stdlib.h> /* getenv() */
47
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
48
EXIT_SUCCESS, malloc(), _exit(),
23
50
#include <dirent.h> /* opendir(), readdir(), closedir() */
27
#include <iso646.h> /* and */
28
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
51
#include <inttypes.h> /* intmax_t, strtoimax() */
52
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
53
#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
54
#include <argz.h> /* argz_count(), argz_extract() */
55
#include <stdarg.h> /* va_list, va_start(), ... */
31
57
sig_atomic_t interrupted_by_signal = 0;
33
static void termination_handler(__attribute__((unused))int signum){
59
const char usplash_name[] = "/sbin/usplash";
61
/* Function to use when printing errors */
62
__attribute__((format (gnu_printf, 3, 4)))
63
void error_plus(int status, int errnum, const char *formatstring,
69
va_start(ap, formatstring);
70
ret = vasprintf(&text, formatstring, ap);
72
fprintf(stderr, "Mandos plugin %s: ",
73
program_invocation_short_name);
74
vfprintf(stderr, formatstring, ap);
75
fprintf(stderr, ": ");
76
fprintf(stderr, "%s\n", strerror(errnum));
77
error(status, errno, "vasprintf while printing error");
80
fprintf(stderr, "Mandos plugin ");
81
error(status, errnum, "%s", text);
85
static void termination_handler(int signum){
86
if(interrupted_by_signal){
34
89
interrupted_by_signal = 1;
90
signal_received = signum;
37
static bool usplash_write(const char *cmd, const char *arg){
93
static bool usplash_write(int *fifo_fd_r,
94
const char *cmd, const char *arg){
39
* usplash_write("TIMEOUT", "15"); -> "TIMEOUT 15\0"
40
* usplash_write("PULSATE", NULL); -> "PULSATE\0"
96
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
97
* 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)){
102
if(*fifo_fd_r == -1){
103
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
51
}while(fifo_fd == -1);
53
110
const char *cmd_line;
54
111
size_t cmd_line_len;
55
112
char *cmd_line_alloc = NULL;
58
cmd_line_len = strlen(cmd);
115
cmd_line_len = strlen(cmd) + 1;
61
118
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
62
if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
69
126
cmd_line = cmd_line_alloc;
70
127
cmd_line_len = (size_t)ret + 1;
73
130
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){
132
while(written < cmd_line_len){
133
sret = write(*fifo_fd_r, cmd_line + written,
134
cmd_line_len - written);
138
free(cmd_line_alloc);
88
written += (size_t)ret;
142
written += (size_t)sret;
90
144
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;
149
/* Create prompt string */
150
char *makeprompt(void){
153
const char *const cryptsource = getenv("cryptsource");
154
const char *const crypttarget = getenv("crypttarget");
155
const char prompt_start[] = "Enter passphrase to unlock the disk";
157
if(cryptsource == NULL){
158
if(crypttarget == NULL){
159
ret = asprintf(&prompt, "%s: ", prompt_start);
161
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
165
if(crypttarget == NULL){
166
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
168
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
169
cryptsource, crypttarget);
178
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
138
181
char *cmdline = NULL;
139
182
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);
183
DIR *proc_dir = opendir("/proc");
184
if(proc_dir == NULL){
185
error_plus(0, errno, "opendir");
189
for(struct dirent *proc_ent = readdir(proc_dir);
191
proc_ent = readdir(proc_dir)){
196
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
197
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
198
or tmpmax != (pid_t)tmpmax){
153
199
/* 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)];
205
/* Find the executable name by doing readlink() on the
206
/proc/<pid>/exe link */
207
char exe_target[sizeof(usplash_name)];
209
/* create file name string */
211
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
213
error_plus(0, errno, "asprintf");
214
goto fail_find_usplash;
217
/* Check that it refers to a symlink owned by root:root */
218
struct stat exe_stat;
219
ret = lstat(exe_link, &exe_stat);
225
error_plus(0, errno, "lstat");
227
goto fail_find_usplash;
229
if(not S_ISLNK(exe_stat.st_mode)
230
or exe_stat.st_uid != 0
231
or exe_stat.st_gid != 0){
236
sret = readlink(exe_link, exe_target, sizeof(exe_target));
239
/* Compare executable name */
240
if((sret != ((ssize_t)sizeof(exe_target)-1))
241
or (memcmp(usplash_name, exe_target,
242
sizeof(exe_target)-1) != 0)){
247
/* Read and save the command line of usplash in "cmdline" */
249
/* Open /proc/<pid>/cmdline */
161
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
252
char *cmdline_filename;
253
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
256
error_plus(0, errno, "asprintf");
257
goto fail_find_usplash;
168
sret = readlink(exe_link, exe_target, sizeof(exe_target));
259
cl_fd = open(cmdline_filename, O_RDONLY);
260
free(cmdline_filename);
262
error_plus(0, errno, "open");
263
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);
266
size_t cmdline_allocated = 0;
268
const size_t blocksize = 1024;
270
/* Allocate more space? */
271
if(cmdline_len + blocksize > cmdline_allocated){
272
tmp = realloc(cmdline, cmdline_allocated + blocksize);
274
error_plus(0, errno, "realloc");
276
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;
279
cmdline_allocated += blocksize;
282
sret = read(cl_fd, cmdline + cmdline_len,
283
cmdline_allocated - cmdline_len);
285
error_plus(0, errno, "read");
287
goto fail_find_usplash;
289
cmdline_len += (size_t)sret;
293
error_plus(0, errno, "close");
294
goto fail_find_usplash;
297
/* Close directory */
298
ret = closedir(proc_dir);
300
error_plus(0, errno, "closedir");
301
goto fail_find_usplash;
304
*cmdline_r = cmdline;
305
*cmdline_len_r = cmdline_len;
312
if(proc_dir != NULL){
234
314
closedir(proc_dir);
320
int main(__attribute__((unused))int argc,
321
__attribute__((unused))char **argv){
328
pid_t usplash_pid = -1;
329
bool usplash_accessed = false;
330
int status = EXIT_FAILURE; /* Default failure exit status */
332
char *prompt = makeprompt();
338
/* Find usplash process */
339
char *cmdline = NULL;
340
size_t cmdline_len = 0;
341
usplash_pid = find_usplash(&cmdline, &cmdline_len);
236
342
if(usplash_pid == 0){
343
status = EX_UNAVAILABLE;
241
347
/* Set up the signal handler */
244
350
new_action = { .sa_handler = termination_handler,
246
352
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);
353
ret = sigaddset(&new_action.sa_mask, SIGINT);
355
error_plus(0, errno, "sigaddset");
359
ret = sigaddset(&new_action.sa_mask, SIGHUP);
361
error_plus(0, errno, "sigaddset");
365
ret = sigaddset(&new_action.sa_mask, SIGTERM);
367
error_plus(0, errno, "sigaddset");
250
371
ret = sigaction(SIGINT, NULL, &old_action);
374
error_plus(0, errno, "sigaction");
256
if (old_action.sa_handler != SIG_IGN){
379
if(old_action.sa_handler != SIG_IGN){
257
380
ret = sigaction(SIGINT, &new_action, NULL);
383
error_plus(0, errno, "sigaction");
264
389
ret = sigaction(SIGHUP, NULL, &old_action);
392
error_plus(0, errno, "sigaction");
270
if (old_action.sa_handler != SIG_IGN){
397
if(old_action.sa_handler != SIG_IGN){
271
398
ret = sigaction(SIGHUP, &new_action, NULL);
401
error_plus(0, errno, "sigaction");
278
407
ret = sigaction(SIGTERM, NULL, &old_action);
410
error_plus(0, errno, "sigaction");
284
if (old_action.sa_handler != SIG_IGN){
415
if(old_action.sa_handler != SIG_IGN){
285
416
ret = sigaction(SIGTERM, &new_action, NULL);
419
error_plus(0, errno, "sigaction");
427
usplash_accessed = true;
294
428
/* 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;
429
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
431
error_plus(0, errno, "usplash_write");
437
if(interrupted_by_signal){
441
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
443
error_plus(0, errno, "usplash_write");
449
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)));
456
/* Read reply from usplash */
458
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
459
if(outfifo_fd == -1){
461
error_plus(0, errno, "open");
467
if(interrupted_by_signal){
472
size_t buf_allocated = 0;
473
const size_t blocksize = 1024;
475
/* Allocate more space */
476
if(buf_len + blocksize > buf_allocated){
477
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;
480
error_plus(0, errno, "realloc");
486
buf_allocated += blocksize;
488
sret = read(outfifo_fd, buf + buf_len,
489
buf_allocated - buf_len);
492
error_plus(0, errno, "read");
498
if(interrupted_by_signal){
502
buf_len += (size_t)sret;
504
ret = close(outfifo_fd);
507
error_plus(0, errno, "close");
514
if(interrupted_by_signal){
518
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
520
error_plus(0, errno, "usplash_write");
526
if(interrupted_by_signal){
530
ret = close(fifo_fd);
533
error_plus(0, errno, "close");
540
/* Print password to stdout */
542
while(written < buf_len){
544
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
547
error_plus(0, errno, "write");
554
if(interrupted_by_signal){
557
written += (size_t)sret;
562
if(interrupted_by_signal){
575
/* If usplash was never accessed, we can stop now */
576
if(not usplash_accessed){
582
ret = close(fifo_fd);
583
if(ret == -1 and errno != EINTR){
584
error_plus(0, errno, "close");
589
/* Close output FIFO */
590
if(outfifo_fd != -1){
591
ret = close(outfifo_fd);
593
error_plus(0, errno, "close");
597
/* Create argv for new usplash*/
598
char **cmdline_argv = malloc((argz_count(cmdline, cmdline_len) + 1)
599
* sizeof(char *)); /* Count args */
600
if(cmdline_argv == NULL){
601
error_plus(0, errno, "malloc");
604
argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
436
606
/* Kill old usplash */
437
kill(usplash_pid, SIGTERM);
607
kill(usplash_pid, SIGTERM);
439
609
while(kill(usplash_pid, 0) == 0){
440
610
kill(usplash_pid, SIGKILL);
443
614
pid_t new_usplash_pid = fork();
444
615
if(new_usplash_pid == 0){
445
616
/* Child; will become new usplash process */
447
618
/* Make the effective user ID (root) the only user ID instead of
448
the real user ID (mandos) */
619
the real user ID (_mandos) */
449
620
ret = setuid(geteuid());
622
error_plus(0, errno, "setuid");
455
626
ret = chdir("/");
628
error_plus(0, errno, "chdir");
456
631
/* if(fork() != 0){ */
457
632
/* _exit(EXIT_SUCCESS); */
459
634
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
636
error_plus(0, errno, "dup2");
465
640
execv(usplash_name, cmdline_argv);
641
if(not interrupted_by_signal){
642
error_plus(0, errno, "execv");
467
645
free(cmdline_argv);
470
649
free(cmdline_argv);
472
if(not usplash_write("PULSATE", NULL)
473
and (errno != EINTR)){
474
perror("usplash_write");
651
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
653
error_plus(0, errno, "usplash_write");
657
/* Close FIFO (again) */
659
ret = close(fifo_fd);
660
if(ret == -1 and errno != EINTR){
661
error_plus(0, errno, "close");
666
if(interrupted_by_signal){
667
struct sigaction signal_action = { .sa_handler = SIG_DFL };
668
sigemptyset(&signal_action.sa_mask);
669
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
670
&signal_action, NULL));
672
error_plus(0, errno, "sigaction");
675
ret = raise(signal_received);
676
} while(ret != 0 and errno == EINTR);
678
error_plus(0, errno, "raise");
681
TEMP_FAILURE_RETRY(pause());