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() */
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 */
34
#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
36
#include <stddef.h> /* NULL */
37
#include <string.h> /* strlen(), memcmp() */
38
#include <stdio.h> /* asprintf(), perror() */
39
#include <unistd.h> /* close(), write(), readlink(),
40
read(), STDOUT_FILENO, sleep(),
41
fork(), setuid(), geteuid(),
42
setsid(), chdir(), dup2(),
43
STDERR_FILENO, execv() */
44
#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
45
EXIT_SUCCESS, malloc(), _exit() */
46
#include <stdlib.h> /* getenv() */
47
#include <dirent.h> /* opendir(), readdir(), closedir() */
48
#include <inttypes.h> /* intmax_t, strtoimax() */
49
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
51
sig_atomic_t interrupted_by_signal = 0;
53
const char usplash_name[] = "/sbin/usplash";
55
static void termination_handler(int signum){
56
if(interrupted_by_signal){
59
interrupted_by_signal = 1;
60
signal_received = signum;
63
static bool usplash_write(int *fifo_fd_r,
64
const char *cmd, const char *arg){
66
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
67
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
73
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
82
char *cmd_line_alloc = NULL;
85
cmd_line_len = strlen(cmd) + 1;
88
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
91
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
96
cmd_line = cmd_line_alloc;
97
cmd_line_len = (size_t)ret + 1;
102
while(written < cmd_line_len){
103
sret = write(*fifo_fd_r, cmd_line + written,
104
cmd_line_len - written);
107
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
108
free(cmd_line_alloc);
112
written += (size_t)sret;
114
free(cmd_line_alloc);
119
/* Create prompt string */
120
char *makeprompt(void){
123
const char *const cryptsource = getenv("cryptsource");
124
const char *const crypttarget = getenv("crypttarget");
125
const char prompt_start[] = "Enter passphrase to unlock the disk";
127
if(cryptsource == NULL){
128
if(crypttarget == NULL){
129
ret = asprintf(&prompt, "%s: ", prompt_start);
131
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
135
if(crypttarget == NULL){
136
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
138
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
139
cryptsource, crypttarget);
148
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
151
char *cmdline = NULL;
152
size_t cmdline_len = 0;
153
DIR *proc_dir = opendir("/proc");
154
if(proc_dir == NULL){
159
for(struct dirent *proc_ent = readdir(proc_dir);
161
proc_ent = readdir(proc_dir)){
166
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
167
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
168
or tmpmax != (pid_t)tmpmax){
175
/* Find the executable name by doing readlink() on the
176
/proc/<pid>/exe link */
177
char exe_target[sizeof(usplash_name)];
179
/* create file name string */
181
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
184
goto fail_find_usplash;
187
/* Check that it refers to a symlink owned by root:root */
188
struct stat exe_stat;
189
ret = lstat(exe_link, &exe_stat);
197
goto fail_find_usplash;
199
if(not S_ISLNK(exe_stat.st_mode)
200
or exe_stat.st_uid != 0
201
or exe_stat.st_gid != 0){
206
sret = readlink(exe_link, exe_target, sizeof(exe_target));
209
/* Compare executable name */
210
if((sret != ((ssize_t)sizeof(exe_target)-1))
211
or (memcmp(usplash_name, exe_target,
212
sizeof(exe_target)-1) != 0)){
217
/* Read and save the command line of usplash in "cmdline" */
219
/* Open /proc/<pid>/cmdline */
222
char *cmdline_filename;
223
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
227
goto fail_find_usplash;
229
cl_fd = open(cmdline_filename, O_RDONLY);
230
free(cmdline_filename);
233
goto fail_find_usplash;
236
size_t cmdline_allocated = 0;
238
const size_t blocksize = 1024;
240
/* Allocate more space? */
241
if(cmdline_len + blocksize > cmdline_allocated){
242
tmp = realloc(cmdline, cmdline_allocated + blocksize);
246
goto fail_find_usplash;
249
cmdline_allocated += blocksize;
252
sret = read(cl_fd, cmdline + cmdline_len,
253
cmdline_allocated - cmdline_len);
257
goto fail_find_usplash;
259
cmdline_len += (size_t)sret;
264
goto fail_find_usplash;
267
/* Close directory */
268
ret = closedir(proc_dir);
271
goto fail_find_usplash;
274
*cmdline_r = cmdline;
275
*cmdline_len_r = cmdline_len;
282
if(proc_dir != NULL){
290
int main(__attribute__((unused))int argc,
291
__attribute__((unused))char **argv){
298
pid_t usplash_pid = -1;
299
bool usplash_accessed = false;
301
char *prompt = makeprompt();
306
/* Find usplash process */
307
char *cmdline = NULL;
308
size_t cmdline_len = 0;
309
usplash_pid = find_usplash(&cmdline, &cmdline_len);
310
if(usplash_pid == 0){
314
/* Set up the signal handler */
316
struct sigaction old_action,
317
new_action = { .sa_handler = termination_handler,
319
sigemptyset(&new_action.sa_mask);
320
ret = sigaddset(&new_action.sa_mask, SIGINT);
325
ret = sigaddset(&new_action.sa_mask, SIGHUP);
330
ret = sigaddset(&new_action.sa_mask, SIGTERM);
335
ret = sigaction(SIGINT, NULL, &old_action);
342
if(old_action.sa_handler != SIG_IGN){
343
ret = sigaction(SIGINT, &new_action, NULL);
351
ret = sigaction(SIGHUP, NULL, &old_action);
358
if(old_action.sa_handler != SIG_IGN){
359
ret = sigaction(SIGHUP, &new_action, NULL);
367
ret = sigaction(SIGTERM, NULL, &old_action);
374
if(old_action.sa_handler != SIG_IGN){
375
ret = sigaction(SIGTERM, &new_action, NULL);
385
usplash_accessed = true;
386
/* Write command to FIFO */
387
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
389
perror("usplash_write");
394
if(interrupted_by_signal){
398
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
400
perror("usplash_write");
405
if(interrupted_by_signal){
412
/* Read reply from usplash */
414
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
415
if(outfifo_fd == -1){
422
if(interrupted_by_signal){
427
size_t buf_allocated = 0;
428
const size_t blocksize = 1024;
430
/* Allocate more space */
431
if(buf_len + blocksize > buf_allocated){
432
char *tmp = realloc(buf, buf_allocated + blocksize);
440
buf_allocated += blocksize;
442
sret = read(outfifo_fd, buf + buf_len,
443
buf_allocated - buf_len);
448
TEMP_FAILURE_RETRY(close(outfifo_fd));
451
if(interrupted_by_signal){
455
buf_len += (size_t)sret;
457
ret = close(outfifo_fd);
466
if(interrupted_by_signal){
470
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
472
perror("usplash_write");
477
if(interrupted_by_signal){
481
ret = close(fifo_fd);
490
/* Print password to stdout */
492
while(written < buf_len){
494
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
503
if(interrupted_by_signal){
506
written += (size_t)sret;
511
if(interrupted_by_signal){
524
/* If usplash was never accessed, we can stop now */
525
if(not usplash_accessed){
531
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
532
if(ret == -1 and errno != EINTR){
538
/* Close output FIFO */
539
if(outfifo_fd != -1){
540
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
546
/* Create argc and argv for new usplash*/
547
int cmdline_argc = 0;
548
char **cmdline_argv = malloc(sizeof(char *));
551
while(position < cmdline_len){
552
char **tmp = realloc(cmdline_argv,
554
* (size_t)(cmdline_argc + 2)));
561
cmdline_argv[cmdline_argc] = cmdline + position;
563
position += strlen(cmdline + position) + 1;
565
cmdline_argv[cmdline_argc] = NULL;
567
/* Kill old usplash */
568
kill(usplash_pid, SIGTERM);
570
while(kill(usplash_pid, 0) == 0){
571
kill(usplash_pid, SIGKILL);
575
pid_t new_usplash_pid = fork();
576
if(new_usplash_pid == 0){
577
/* Child; will become new usplash process */
579
/* Make the effective user ID (root) the only user ID instead of
580
the real user ID (_mandos) */
581
ret = setuid(geteuid());
588
/* if(fork() != 0){ */
589
/* _exit(EXIT_SUCCESS); */
591
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
597
execv(usplash_name, cmdline_argv);
598
if(not interrupted_by_signal){
608
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
610
perror("usplash_write");
614
/* Close FIFO (again) */
616
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
617
if(ret == -1 and errno != EINTR){
623
if(interrupted_by_signal){
624
struct sigaction signal_action = { .sa_handler = SIG_DFL };
625
sigemptyset(&signal_action.sa_mask);
626
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
627
&signal_action, NULL));
632
ret = raise(signal_received);
633
} while(ret != 0 and errno == EINTR);
638
TEMP_FAILURE_RETRY(pause());
added
removed
plugins.d/usplash.c
