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 */
50
#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
52
sig_atomic_t interrupted_by_signal = 0;
54
const char usplash_name[] = "/sbin/usplash";
56
static void termination_handler(int signum){
57
if(interrupted_by_signal){
60
interrupted_by_signal = 1;
61
signal_received = signum;
64
static bool usplash_write(int *fifo_fd_r,
65
const char *cmd, const char *arg){
67
* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
68
* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
74
ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
83
char *cmd_line_alloc = NULL;
86
cmd_line_len = strlen(cmd) + 1;
89
ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
92
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
97
cmd_line = cmd_line_alloc;
98
cmd_line_len = (size_t)ret + 1;
103
while(written < cmd_line_len){
104
sret = write(*fifo_fd_r, cmd_line + written,
105
cmd_line_len - written);
108
TEMP_FAILURE_RETRY(close(*fifo_fd_r));
109
free(cmd_line_alloc);
113
written += (size_t)sret;
115
free(cmd_line_alloc);
120
/* Create prompt string */
121
char *makeprompt(void){
124
const char *const cryptsource = getenv("cryptsource");
125
const char *const crypttarget = getenv("crypttarget");
126
const char prompt_start[] = "Enter passphrase to unlock the disk";
128
if(cryptsource == NULL){
129
if(crypttarget == NULL){
130
ret = asprintf(&prompt, "%s: ", prompt_start);
132
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
136
if(crypttarget == NULL){
137
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
139
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
140
cryptsource, crypttarget);
149
pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
152
char *cmdline = NULL;
153
size_t cmdline_len = 0;
154
DIR *proc_dir = opendir("/proc");
155
if(proc_dir == NULL){
160
for(struct dirent *proc_ent = readdir(proc_dir);
162
proc_ent = readdir(proc_dir)){
167
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
168
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
169
or tmpmax != (pid_t)tmpmax){
176
/* Find the executable name by doing readlink() on the
177
/proc/<pid>/exe link */
178
char exe_target[sizeof(usplash_name)];
180
/* create file name string */
182
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
185
goto fail_find_usplash;
188
/* Check that it refers to a symlink owned by root:root */
189
struct stat exe_stat;
190
ret = lstat(exe_link, &exe_stat);
198
goto fail_find_usplash;
200
if(not S_ISLNK(exe_stat.st_mode)
201
or exe_stat.st_uid != 0
202
or exe_stat.st_gid != 0){
207
sret = readlink(exe_link, exe_target, sizeof(exe_target));
210
/* Compare executable name */
211
if((sret != ((ssize_t)sizeof(exe_target)-1))
212
or (memcmp(usplash_name, exe_target,
213
sizeof(exe_target)-1) != 0)){
218
/* Read and save the command line of usplash in "cmdline" */
220
/* Open /proc/<pid>/cmdline */
223
char *cmdline_filename;
224
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
228
goto fail_find_usplash;
230
cl_fd = open(cmdline_filename, O_RDONLY);
231
free(cmdline_filename);
234
goto fail_find_usplash;
237
size_t cmdline_allocated = 0;
239
const size_t blocksize = 1024;
241
/* Allocate more space? */
242
if(cmdline_len + blocksize > cmdline_allocated){
243
tmp = realloc(cmdline, cmdline_allocated + blocksize);
247
goto fail_find_usplash;
250
cmdline_allocated += blocksize;
253
sret = read(cl_fd, cmdline + cmdline_len,
254
cmdline_allocated - cmdline_len);
258
goto fail_find_usplash;
260
cmdline_len += (size_t)sret;
265
goto fail_find_usplash;
268
/* Close directory */
269
ret = closedir(proc_dir);
272
goto fail_find_usplash;
275
*cmdline_r = cmdline;
276
*cmdline_len_r = cmdline_len;
283
if(proc_dir != NULL){
291
int main(__attribute__((unused))int argc,
292
__attribute__((unused))char **argv){
299
pid_t usplash_pid = -1;
300
bool usplash_accessed = false;
301
int status = EXIT_FAILURE; /* Default failure exit status */
303
char *prompt = makeprompt();
309
/* Find usplash process */
310
char *cmdline = NULL;
311
size_t cmdline_len = 0;
312
usplash_pid = find_usplash(&cmdline, &cmdline_len);
313
if(usplash_pid == 0){
314
status = EX_UNAVAILABLE;
318
/* Set up the signal handler */
320
struct sigaction old_action,
321
new_action = { .sa_handler = termination_handler,
323
sigemptyset(&new_action.sa_mask);
324
ret = sigaddset(&new_action.sa_mask, SIGINT);
330
ret = sigaddset(&new_action.sa_mask, SIGHUP);
336
ret = sigaddset(&new_action.sa_mask, SIGTERM);
342
ret = sigaction(SIGINT, NULL, &old_action);
350
if(old_action.sa_handler != SIG_IGN){
351
ret = sigaction(SIGINT, &new_action, NULL);
360
ret = sigaction(SIGHUP, NULL, &old_action);
368
if(old_action.sa_handler != SIG_IGN){
369
ret = sigaction(SIGHUP, &new_action, NULL);
378
ret = sigaction(SIGTERM, NULL, &old_action);
386
if(old_action.sa_handler != SIG_IGN){
387
ret = sigaction(SIGTERM, &new_action, NULL);
398
usplash_accessed = true;
399
/* Write command to FIFO */
400
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
402
perror("usplash_write");
408
if(interrupted_by_signal){
412
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
414
perror("usplash_write");
420
if(interrupted_by_signal){
427
/* Read reply from usplash */
429
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
430
if(outfifo_fd == -1){
438
if(interrupted_by_signal){
443
size_t buf_allocated = 0;
444
const size_t blocksize = 1024;
446
/* Allocate more space */
447
if(buf_len + blocksize > buf_allocated){
448
char *tmp = realloc(buf, buf_allocated + blocksize);
457
buf_allocated += blocksize;
459
sret = read(outfifo_fd, buf + buf_len,
460
buf_allocated - buf_len);
466
TEMP_FAILURE_RETRY(close(outfifo_fd));
469
if(interrupted_by_signal){
473
buf_len += (size_t)sret;
475
ret = close(outfifo_fd);
485
if(interrupted_by_signal){
489
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
491
perror("usplash_write");
497
if(interrupted_by_signal){
501
ret = close(fifo_fd);
511
/* Print password to stdout */
513
while(written < buf_len){
515
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
525
if(interrupted_by_signal){
528
written += (size_t)sret;
533
if(interrupted_by_signal){
546
/* If usplash was never accessed, we can stop now */
547
if(not usplash_accessed){
553
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
554
if(ret == -1 and errno != EINTR){
560
/* Close output FIFO */
561
if(outfifo_fd != -1){
562
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
568
/* Create argc and argv for new usplash*/
569
int cmdline_argc = 0;
570
char **cmdline_argv = malloc(sizeof(char *));
573
while(position < cmdline_len){
574
char **tmp = realloc(cmdline_argv,
576
* (size_t)(cmdline_argc + 2)));
583
cmdline_argv[cmdline_argc] = cmdline + position;
585
position += strlen(cmdline + position) + 1;
587
cmdline_argv[cmdline_argc] = NULL;
589
/* Kill old usplash */
590
kill(usplash_pid, SIGTERM);
592
while(kill(usplash_pid, 0) == 0){
593
kill(usplash_pid, SIGKILL);
597
pid_t new_usplash_pid = fork();
598
if(new_usplash_pid == 0){
599
/* Child; will become new usplash process */
601
/* Make the effective user ID (root) the only user ID instead of
602
the real user ID (_mandos) */
603
ret = setuid(geteuid());
610
/* if(fork() != 0){ */
611
/* _exit(EXIT_SUCCESS); */
613
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
619
execv(usplash_name, cmdline_argv);
620
if(not interrupted_by_signal){
630
if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
632
perror("usplash_write");
636
/* Close FIFO (again) */
638
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
639
if(ret == -1 and errno != EINTR){
645
if(interrupted_by_signal){
646
struct sigaction signal_action = { .sa_handler = SIG_DFL };
647
sigemptyset(&signal_action.sa_mask);
648
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
649
&signal_action, NULL));
654
ret = raise(signal_received);
655
} while(ret != 0 and errno == EINTR);
660
TEMP_FAILURE_RETRY(pause());
added
removed
plugins.d/usplash.c
