1
/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
3
* Password-prompt - Read a password from the terminal and print it
5
* Copyright © 2008-2016 Teddy Hogeborn
6
* Copyright © 2008-2016 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 /* getline(), asprintf() */
27
#include <termios.h> /* struct termios, tcsetattr(),
1
#define _GNU_SOURCE /* getline() */
2
#define _FORTIFY_SOURCE 2
3
#include <termios.h> /* struct termios, tcsetattr(),
28
4
TCSAFLUSH, tcgetattr(), ECHO */
29
5
#include <unistd.h> /* struct termios, tcsetattr(),
30
6
STDIN_FILENO, TCSAFLUSH,
31
tcgetattr(), ECHO, readlink() */
32
8
#include <signal.h> /* sig_atomic_t, raise(), struct
33
9
sigaction, sigemptyset(),
34
10
sigaction(), sigaddset(), SIGINT,
35
SIGQUIT, SIGHUP, SIGTERM,
37
#include <stddef.h> /* NULL, size_t, ssize_t */
38
#include <sys/types.h> /* ssize_t, struct dirent, pid_t,
11
SIGQUIT, SIGHUP, SIGTERM */
12
#include <stddef.h> /* NULL, size_t */
13
#include <sys/types.h> /* ssize_t */
40
14
#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE,
42
#include <dirent.h> /* scandir(), alphasort() */
43
16
#include <stdio.h> /* fprintf(), stderr, getline(),
44
stdin, feof(), fputc(), vfprintf(),
46
#include <errno.h> /* errno, EBADF, ENOTTY, EINVAL,
47
EFAULT, EFBIG, EIO, ENOSPC, EINTR
49
#include <error.h> /* error() */
17
stdin, feof(), perror(), fputc(),
18
stdout, getopt_long */
19
#include <errno.h> /* errno, EINVAL */
50
20
#include <iso646.h> /* or, not */
51
21
#include <stdbool.h> /* bool, false, true */
52
#include <inttypes.h> /* strtoumax() */
53
#include <sys/stat.h> /* struct stat, lstat(), open() */
54
#include <string.h> /* strlen, rindex, memcmp, strerror()
56
#include <argp.h> /* struct argp_option, struct
57
argp_state, struct argp,
58
argp_parse(), error_t,
59
ARGP_KEY_ARG, ARGP_KEY_END,
61
#include <sysexits.h> /* EX_SOFTWARE, EX_OSERR,
62
EX_UNAVAILABLE, EX_IOERR, EX_OK */
63
#include <fcntl.h> /* open() */
64
#include <stdarg.h> /* va_list, va_start(), ... */
22
#include <string.h> /* strlen, rindex, strncmp, strcmp */
23
#include <getopt.h> /* getopt_long */
66
volatile sig_atomic_t quit_now = 0;
25
volatile bool quit_now = false;
68
26
bool debug = false;
69
const char *argp_program_version = "password-prompt " VERSION;
70
const char *argp_program_bug_address = "<mandos@recompile.se>";
72
/* Needed for conflict resolution */
73
const char plymouth_name[] = "plymouthd";
75
/* Function to use when printing errors */
76
__attribute__((format (gnu_printf, 3, 4)))
77
void error_plus(int status, int errnum, const char *formatstring,
83
va_start(ap, formatstring);
84
ret = vasprintf(&text, formatstring, ap);
86
fprintf(stderr, "Mandos plugin %s: ",
87
program_invocation_short_name);
88
vfprintf(stderr, formatstring, ap);
89
fprintf(stderr, ": %s\n", strerror(errnum));
90
error(status, errno, "vasprintf while printing error");
93
fprintf(stderr, "Mandos plugin ");
94
error(status, errnum, "%s", text);
98
static void termination_handler(int signum){
103
signal_received = signum;
106
bool conflict_detection(void){
108
/* plymouth conflicts with password-prompt since both want to read
109
from the terminal. Password-prompt will exit if it detects
110
plymouth since plymouth performs the same functionality.
112
__attribute__((nonnull))
113
int is_plymouth(const struct dirent *proc_entry){
120
proc_id = strtoumax(proc_entry->d_name, &tmp, 10);
122
if(errno != 0 or *tmp != '\0'
123
or proc_id != (uintmax_t)((pid_t)proc_id)){
128
char *cmdline_filename;
129
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
132
error_plus(0, errno, "asprintf");
136
/* Open /proc/<pid>/cmdline */
137
cl_fd = open(cmdline_filename, O_RDONLY);
138
free(cmdline_filename);
141
error_plus(0, errno, "open");
146
char *cmdline = NULL;
148
size_t cmdline_len = 0;
149
size_t cmdline_allocated = 0;
151
const size_t blocksize = 1024;
154
/* Allocate more space? */
155
if(cmdline_len + blocksize + 1 > cmdline_allocated){
156
tmp = realloc(cmdline, cmdline_allocated + blocksize + 1);
158
error_plus(0, errno, "realloc");
164
cmdline_allocated += blocksize;
168
sret = read(cl_fd, cmdline + cmdline_len,
169
cmdline_allocated - cmdline_len);
171
error_plus(0, errno, "read");
176
cmdline_len += (size_t)sret;
180
error_plus(0, errno, "close");
184
cmdline[cmdline_len] = '\0'; /* Make sure it is terminated */
186
/* we now have cmdline */
189
char *cmdline_base = strrchr(cmdline, '/');
190
if(cmdline_base != NULL){
191
cmdline_base += 1; /* skip the slash */
193
cmdline_base = cmdline;
196
if(strcmp(cmdline_base, plymouth_name) != 0){
198
fprintf(stderr, "\"%s\" is not \"%s\"\n", cmdline_base,
205
fprintf(stderr, "\"%s\" equals \"%s\"\n", cmdline_base,
212
struct dirent **direntries = NULL;
214
ret = scandir("/proc", &direntries, is_plymouth, alphasort);
216
error_plus(1, errno, "scandir");
28
void termination_handler(int signum){
223
32
int main(int argc, char **argv){
227
35
struct termios t_new, t_old;
228
36
char *buffer = NULL;
231
39
struct sigaction old_action,
232
40
new_action = { .sa_handler = termination_handler,
235
struct argp_option options[] = {
236
{ .name = "prefix", .key = 'p',
237
.arg = "PREFIX", .flags = 0,
238
.doc = "Prefix shown before the prompt", .group = 2 },
239
{ .name = "debug", .key = 128,
240
.doc = "Debug mode", .group = 3 },
242
* These reproduce what we would get without ARGP_NO_HELP
244
{ .name = "help", .key = '?',
245
.doc = "Give this help list", .group = -1 },
246
{ .name = "usage", .key = -3,
247
.doc = "Give a short usage message", .group = -1 },
248
{ .name = "version", .key = 'V',
249
.doc = "Print program version", .group = -1 },
253
__attribute__((nonnull(3)))
254
error_t parse_opt (int key, char *arg, struct argp_state *state){
264
* These reproduce what we would get without ARGP_NO_HELP
266
case '?': /* --help */
267
argp_state_help(state, state->out_stream,
268
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
269
& ~(unsigned int)ARGP_HELP_EXIT_OK);
270
case -3: /* --usage */
271
argp_state_help(state, state->out_stream,
272
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
273
case 'V': /* --version */
274
fprintf(state->out_stream, "%s\n", argp_program_version);
275
exit(argp_err_exit_status);
278
return ARGP_ERR_UNKNOWN;
44
static struct option long_options[] = {
45
{"debug", no_argument, (int *)&debug, 1},
46
{"prefix", required_argument, 0, 'p'},
50
ret = getopt_long (argc, argv, "p:", long_options, &option_index);
283
struct argp argp = { .options = options, .parser = parse_opt,
285
.doc = "Mandos password-prompt -- Read and"
286
" output a password" };
287
ret = argp_parse(&argp, argc, argv,
288
ARGP_IN_ORDER | ARGP_NO_HELP, NULL, NULL);
295
error_plus(0, errno, "argp_parse");
63
fprintf(stderr, "bad arguments\n");
303
69
fprintf(stderr, "Starting %s\n", argv[0]);
306
if(conflict_detection()){
308
fprintf(stderr, "Stopping %s because of conflict\n", argv[0]);
314
72
fprintf(stderr, "Storing current terminal attributes\n");
317
if(tcgetattr(STDIN_FILENO, &t_old) != 0){
319
error_plus(0, errno, "tcgetattr");
323
return EX_UNAVAILABLE;
75
if (tcgetattr(STDIN_FILENO, &t_old) != 0){
329
79
sigemptyset(&new_action.sa_mask);
330
ret = sigaddset(&new_action.sa_mask, SIGINT);
332
error_plus(0, errno, "sigaddset");
335
ret = sigaddset(&new_action.sa_mask, SIGHUP);
337
error_plus(0, errno, "sigaddset");
340
ret = sigaddset(&new_action.sa_mask, SIGTERM);
342
error_plus(0, errno, "sigaddset");
345
/* Need to check if the handler is SIG_IGN before handling:
346
| [[info:libc:Initial Signal Actions]] |
347
| [[info:libc:Basic Signal Handling]] |
349
ret = sigaction(SIGINT, NULL, &old_action);
351
error_plus(0, errno, "sigaction");
354
if(old_action.sa_handler != SIG_IGN){
355
ret = sigaction(SIGINT, &new_action, NULL);
357
error_plus(0, errno, "sigaction");
361
ret = sigaction(SIGHUP, NULL, &old_action);
363
error_plus(0, errno, "sigaction");
366
if(old_action.sa_handler != SIG_IGN){
367
ret = sigaction(SIGHUP, &new_action, NULL);
369
error_plus(0, errno, "sigaction");
373
ret = sigaction(SIGTERM, NULL, &old_action);
375
error_plus(0, errno, "sigaction");
378
if(old_action.sa_handler != SIG_IGN){
379
ret = sigaction(SIGTERM, &new_action, NULL);
381
error_plus(0, errno, "sigaction");
80
sigaddset(&new_action.sa_mask, SIGINT);
81
sigaddset(&new_action.sa_mask, SIGQUIT);
82
sigaddset(&new_action.sa_mask, SIGHUP);
83
sigaddset(&new_action.sa_mask, SIGTERM);
84
sigaction(SIGINT, NULL, &old_action);
85
if (old_action.sa_handler != SIG_IGN)
86
sigaction(SIGINT, &new_action, NULL);
87
sigaction(SIGQUIT, NULL, &old_action);
88
if (old_action.sa_handler != SIG_IGN)
89
sigaction(SIGQUIT, &new_action, NULL);
90
sigaction(SIGHUP, NULL, &old_action);
91
if (old_action.sa_handler != SIG_IGN)
92
sigaction(SIGHUP, &new_action, NULL);
93
sigaction(SIGTERM, NULL, &old_action);
94
if (old_action.sa_handler != SIG_IGN)
95
sigaction(SIGTERM, &new_action, NULL);
388
99
fprintf(stderr, "Removing echo flag from terminal attributes\n");
392
t_new.c_lflag &= ~(tcflag_t)ECHO;
393
if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
395
error_plus(0, errno, "tcsetattr-echo");
399
return EX_UNAVAILABLE;
103
t_new.c_lflag &= ~ECHO;
104
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
105
perror("tcsetattr-echo");
407
110
fprintf(stderr, "Waiting for input from stdin \n");
412
fprintf(stderr, "Interrupted by signal, exiting.\n");
414
114
status = EXIT_FAILURE;
419
fprintf(stderr, "%s ", prefix);
422
const char *cryptsource = getenv("CRYPTTAB_SOURCE");
423
const char *crypttarget = getenv("CRYPTTAB_NAME");
424
/* Before cryptsetup 1.1.0~rc2 */
425
if(cryptsource == NULL){
426
cryptsource = getenv("cryptsource");
428
if(crypttarget == NULL){
429
crypttarget = getenv("crypttarget");
431
const char *const prompt1 = "Unlocking the disk";
432
const char *const prompt2 = "Enter passphrase";
433
if(cryptsource == NULL){
434
if(crypttarget == NULL){
435
fprintf(stderr, "%s to unlock the disk: ", prompt2);
437
fprintf(stderr, "%s (%s)\n%s: ", prompt1, crypttarget,
441
if(crypttarget == NULL){
442
fprintf(stderr, "%s %s\n%s: ", prompt1, cryptsource,
445
fprintf(stderr, "%s %s (%s)\n%s: ", prompt1, cryptsource,
446
crypttarget, prompt2);
450
sret = getline(&buffer, &n, stdin);
119
fprintf(stderr, "%s Password: ", prefix);
121
fprintf(stderr, "Password: ");
123
ret = getline(&buffer, &n, stdin);
125
fprintf(stdout, "%s", buffer);
452
126
status = EXIT_SUCCESS;
453
/* Make n = data size instead of allocated buffer size */
455
/* Strip final newline */
456
if(n > 0 and buffer[n-1] == '\n'){
457
buffer[n-1] = '\0'; /* not strictly necessary */
462
sret = write(STDOUT_FILENO, buffer + written, n - written);
465
error_plus(0, errno, "write");
477
status = EXIT_FAILURE;
482
written += (size_t)sret;
484
sret = close(STDOUT_FILENO);
487
error_plus(0, errno, "close");
502
if(errno != EINTR and not feof(stdin)){
503
error_plus(0, errno, "getline");
506
status = EX_UNAVAILABLE;
129
// ret == 0 makes no other sence than to retry to read from stdin
131
if (errno != EINTR and not feof(stdin)){
133
status = EXIT_FAILURE;
517
/* if(sret == 0), then the only sensible thing to do is to retry
518
to read from stdin */
519
137
fputc('\n', stderr);
520
if(debug and not quit_now){
521
/* If quit_now is nonzero, we were interrupted by a signal, and
522
will print that later, so no need to show this too. */
523
fprintf(stderr, "getline() returned 0, retrying.\n");
530
141
fprintf(stderr, "Restoring terminal attributes\n");
532
if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
533
error_plus(0, errno, "tcsetattr+echo");
537
sigemptyset(&old_action.sa_mask);
538
old_action.sa_handler = SIG_DFL;
539
ret = sigaction(signal_received, &old_action, NULL);
541
error_plus(0, errno, "sigaction");
543
raise(signal_received);
547
fprintf(stderr, "%s is exiting with status %d\n", argv[0],
550
if(status == EXIT_SUCCESS or status == EX_OK){
143
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
144
perror("tcsetattr+echo");
148
fprintf(stderr, "%s is exiting\n", argv[0]);