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@recompile.se>.
25
#define _GNU_SOURCE /* asprintf(), TEMP_FAILURE_RETRY() */
26
#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
37
#include <stddef.h> /* NULL */
38
#include <string.h> /* strlen(), memcmp(), strerror() */
39
#include <stdio.h> /* asprintf(), vasprintf(), vprintf(),
41
#include <unistd.h> /* close(), write(), readlink(),
42
read(), STDOUT_FILENO, sleep(),
43
fork(), setuid(), geteuid(),
44
setsid(), chdir(), dup2(),
45
STDERR_FILENO, execv() */
46
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
47
EXIT_SUCCESS, malloc(), _exit(),
49
#include <dirent.h> /* opendir(), readdir(), closedir() */
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(), ... */
56
sig_atomic_t interrupted_by_signal = 0;
58
const char usplash_name[] = "/sbin/usplash";
60
/* Function to use when printing errors */
61
void error_plus(int status, int errnum, const char *formatstring,
67
va_start(ap, formatstring);
68
ret = vasprintf(&text, formatstring, ap);
70
fprintf(stderr, "Mandos plugin %s: ",
71
program_invocation_short_name);
72
vfprintf(stderr, formatstring, ap);
73
fprintf(stderr, ": ");
74
fprintf(stderr, "%s\n", strerror(errnum));
75
error(status, errno, "vasprintf while printing error");
78
fprintf(stderr, "Mandos plugin ");
79
error(status, errnum, "%s", text);
83
static void termination_handler(int signum){
84
if(interrupted_by_signal){
87
interrupted_by_signal = 1;
88
signal_received = signum;
91
static bool usplash_write(int *fifo_fd_r,
92
const char *cmd, const char *arg){
94
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
95
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
100
if(*fifo_fd_r == -1){
101
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
108
const char *cmd_line;
110
char *cmd_line_alloc = NULL;
113
cmd_line_len = strlen(cmd) + 1;
116
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
119
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
124
cmd_line = cmd_line_alloc;
125
cmd_line_len = (size_t)ret + 1;
130
while(written < cmd_line_len){
131
sret = write(*fifo_fd_r, cmd_line + written,
132
cmd_line_len - written);
135
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
136
free(cmd_line_alloc);
140
written += (size_t)sret;
142
free(cmd_line_alloc);
147
/* Create prompt string */
148
char *makeprompt(void){
151
const char *const cryptsource = getenv("cryptsource");
152
const char *const crypttarget = getenv("crypttarget");
153
const char prompt_start[] = "Enter passphrase to unlock the disk";
155
if(cryptsource == NULL){
156
if(crypttarget == NULL){
157
ret = asprintf(&prompt, "%s: ", prompt_start);
159
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
163
if(crypttarget == NULL){
164
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
166
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
167
cryptsource, crypttarget);
176
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
179
char *cmdline = NULL;
180
size_t cmdline_len = 0;
181
DIR *proc_dir = opendir("/proc");
182
if(proc_dir == NULL){
183
error_plus(0, errno, "opendir");
187
for(struct dirent *proc_ent = readdir(proc_dir);
189
proc_ent = readdir(proc_dir)){
194
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
195
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
196
or tmpmax != (pid_t)tmpmax){
203
/* Find the executable name by doing readlink() on the
204
/proc/<pid>/exe link */
205
char exe_target[sizeof(usplash_name)];
207
/* create file name string */
209
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
211
error_plus(0, errno, "asprintf");
212
goto fail_find_usplash;
215
/* Check that it refers to a symlink owned by root:root */
216
struct stat exe_stat;
217
ret = lstat(exe_link, &exe_stat);
223
error_plus(0, errno, "lstat");
225
goto fail_find_usplash;
227
if(not S_ISLNK(exe_stat.st_mode)
228
or exe_stat.st_uid != 0
229
or exe_stat.st_gid != 0){
234
sret = readlink(exe_link, exe_target, sizeof(exe_target));
237
/* Compare executable name */
238
if((sret != ((ssize_t)sizeof(exe_target)-1))
239
or (memcmp(usplash_name, exe_target,
240
sizeof(exe_target)-1) != 0)){
245
/* Read and save the command line of usplash in "cmdline" */
247
/* Open /proc/<pid>/cmdline */
250
char *cmdline_filename;
251
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
254
error_plus(0, errno, "asprintf");
255
goto fail_find_usplash;
257
cl_fd = open(cmdline_filename, O_RDONLY);
258
free(cmdline_filename);
260
error_plus(0, errno, "open");
261
goto fail_find_usplash;
264
size_t cmdline_allocated = 0;
266
const size_t blocksize = 1024;
268
/* Allocate more space? */
269
if(cmdline_len + blocksize > cmdline_allocated){
270
tmp = realloc(cmdline, cmdline_allocated + blocksize);
272
error_plus(0, errno, "realloc");
274
goto fail_find_usplash;
277
cmdline_allocated += blocksize;
280
sret = read(cl_fd, cmdline + cmdline_len,
281
cmdline_allocated - cmdline_len);
283
error_plus(0, errno, "read");
285
goto fail_find_usplash;
287
cmdline_len += (size_t)sret;
291
error_plus(0, errno, "close");
292
goto fail_find_usplash;
295
/* Close directory */
296
ret = closedir(proc_dir);
298
error_plus(0, errno, "closedir");
299
goto fail_find_usplash;
302
*cmdline_r = cmdline;
303
*cmdline_len_r = cmdline_len;
310
if(proc_dir != NULL){
318
int main(__attribute__((unused))int argc,
319
__attribute__((unused))char **argv){
326
pid_t usplash_pid = -1;
327
bool usplash_accessed = false;
328
int status = EXIT_FAILURE; /* Default failure exit status */
330
char *prompt = makeprompt();
336
/* Find usplash process */
337
char *cmdline = NULL;
338
size_t cmdline_len = 0;
339
usplash_pid = find_usplash(&cmdline, &cmdline_len);
340
if(usplash_pid == 0){
341
status = EX_UNAVAILABLE;
345
/* Set up the signal handler */
347
struct sigaction old_action,
348
new_action = { .sa_handler = termination_handler,
350
sigemptyset(&new_action.sa_mask);
351
ret = sigaddset(&new_action.sa_mask, SIGINT);
353
error_plus(0, errno, "sigaddset");
357
ret = sigaddset(&new_action.sa_mask, SIGHUP);
359
error_plus(0, errno, "sigaddset");
363
ret = sigaddset(&new_action.sa_mask, SIGTERM);
365
error_plus(0, errno, "sigaddset");
369
ret = sigaction(SIGINT, NULL, &old_action);
372
error_plus(0, errno, "sigaction");
377
if(old_action.sa_handler != SIG_IGN){
378
ret = sigaction(SIGINT, &new_action, NULL);
381
error_plus(0, errno, "sigaction");
387
ret = sigaction(SIGHUP, NULL, &old_action);
390
error_plus(0, errno, "sigaction");
395
if(old_action.sa_handler != SIG_IGN){
396
ret = sigaction(SIGHUP, &new_action, NULL);
399
error_plus(0, errno, "sigaction");
405
ret = sigaction(SIGTERM, NULL, &old_action);
408
error_plus(0, errno, "sigaction");
413
if(old_action.sa_handler != SIG_IGN){
414
ret = sigaction(SIGTERM, &new_action, NULL);
417
error_plus(0, errno, "sigaction");
425
usplash_accessed = true;
426
/* Write command to FIFO */
427
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
429
error_plus(0, errno, "usplash_write");
435
if(interrupted_by_signal){
439
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
441
error_plus(0, errno, "usplash_write");
447
if(interrupted_by_signal){
454
/* Read reply from usplash */
456
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
457
if(outfifo_fd == -1){
459
error_plus(0, errno, "open");
465
if(interrupted_by_signal){
470
size_t buf_allocated = 0;
471
const size_t blocksize = 1024;
473
/* Allocate more space */
474
if(buf_len + blocksize > buf_allocated){
475
char *tmp = realloc(buf, buf_allocated + blocksize);
478
error_plus(0, errno, "realloc");
484
buf_allocated += blocksize;
486
sret = read(outfifo_fd, buf + buf_len,
487
buf_allocated - buf_len);
490
error_plus(0, errno, "read");
493
TEMP_FAILURE_RETRY(close(outfifo_fd));
496
if(interrupted_by_signal){
500
buf_len += (size_t)sret;
502
ret = close(outfifo_fd);
505
error_plus(0, errno, "close");
512
if(interrupted_by_signal){
516
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
518
error_plus(0, errno, "usplash_write");
524
if(interrupted_by_signal){
528
ret = close(fifo_fd);
531
error_plus(0, errno, "close");
538
/* Print password to stdout */
540
while(written < buf_len){
542
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
545
error_plus(0, errno, "write");
552
if(interrupted_by_signal){
555
written += (size_t)sret;
560
if(interrupted_by_signal){
573
/* If usplash was never accessed, we can stop now */
574
if(not usplash_accessed){
580
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
581
if(ret == -1 and errno != EINTR){
582
error_plus(0, errno, "close");
587
/* Close output FIFO */
588
if(outfifo_fd != -1){
589
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
591
error_plus(0, errno, "close");
595
/* Create argv for new usplash*/
596
char **cmdline_argv = malloc((argz_count(cmdline, cmdline_len) + 1)
597
* sizeof(char *)); /* Count args */
598
if(cmdline_argv == NULL){
599
error_plus(0, errno, "malloc");
602
argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
604
/* Kill old usplash */
605
kill(usplash_pid, SIGTERM);
607
while(kill(usplash_pid, 0) == 0){
608
kill(usplash_pid, SIGKILL);
612
pid_t new_usplash_pid = fork();
613
if(new_usplash_pid == 0){
614
/* Child; will become new usplash process */
616
/* Make the effective user ID (root) the only user ID instead of
617
the real user ID (_mandos) */
618
ret = setuid(geteuid());
620
error_plus(0, errno, "setuid");
626
error_plus(0, errno, "chdir");
629
/* if(fork() != 0){ */
630
/* _exit(EXIT_SUCCESS); */
632
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
634
error_plus(0, errno, "dup2");
638
execv(usplash_name, cmdline_argv);
639
if(not interrupted_by_signal){
640
error_plus(0, errno, "execv");
649
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
651
error_plus(0, errno, "usplash_write");
655
/* Close FIFO (again) */
657
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
658
if(ret == -1 and errno != EINTR){
659
error_plus(0, errno, "close");
664
if(interrupted_by_signal){
665
struct sigaction signal_action = { .sa_handler = SIG_DFL };
666
sigemptyset(&signal_action.sa_mask);
667
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
668
&signal_action, NULL));
670
error_plus(0, errno, "sigaction");
673
ret = raise(signal_received);
674
} while(ret != 0 and errno == EINTR);
676
error_plus(0, errno, "raise");
679
TEMP_FAILURE_RETRY(pause());
added
removed
plugins.d/usplash.c
