/mandos/release

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/release
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/*  -*- coding: utf-8 -*- */
/*
 * Plymouth - Read a password from Plymouth and output it
 * 
 * Copyright © 2010-2017 Teddy Hogeborn
 * Copyright © 2010-2017 Björn Påhlsson
 * 
 * This file is part of Mandos.
 * 
 * Mandos is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Mandos is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Mandos.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contact the authors at <mandos@recompile.se>.
 */

#define _GNU_SOURCE		/* asprintf(), TEMP_FAILURE_RETRY() */
#include <signal.h>		/* sig_atomic_t, struct sigaction,
				   sigemptyset(), sigaddset(), SIGINT,
				   SIGHUP, SIGTERM, sigaction(),
				   kill(), SIG_IGN */
#include <stdbool.h>		/* bool, false, true */
#include <fcntl.h>		/* open(), O_RDONLY */
#include <iso646.h>		/* and, or, not*/
#include <sys/types.h>		/* size_t, ssize_t, pid_t, struct
				   dirent, waitpid() */
#include <sys/wait.h>		/* waitpid() */
#include <stddef.h>		/* NULL */
#include <string.h>		/* strchr(), memcmp() */
#include <stdio.h>		/* asprintf(), perror(), fopen(),
				   fscanf(), vasprintf(), fprintf(),
				   vfprintf() */
#include <unistd.h>		/* close(), readlink(), read(),
				   fork(), setsid(), chdir(), dup2(),
				   STDERR_FILENO, execv(), access() */
#include <stdlib.h>		/* free(), EXIT_FAILURE, realloc(),
				   EXIT_SUCCESS, malloc(), _exit(),
				   getenv() */
#include <dirent.h>		/* scandir(), alphasort() */
#include <inttypes.h>		/* intmax_t, strtoumax(), SCNuMAX */
#include <sys/stat.h>		/* struct stat, lstat() */
#include <sysexits.h>		/* EX_OSERR, EX_UNAVAILABLE */
#include <error.h>		/* error() */
#include <errno.h>		/* TEMP_FAILURE_RETRY */
#include <argz.h>		/* argz_count(), argz_extract() */
#include <stdarg.h>		/* va_list, va_start(), ... */

sig_atomic_t interrupted_by_signal = 0;

/* Used by Ubuntu 11.04 (Natty Narwahl) */
const char plymouth_old_pid[] = "/dev/.initramfs/plymouth.pid";
/* Used by Ubuntu 11.10 (Oneiric Ocelot) */
const char plymouth_pid[] = "/run/initramfs/plymouth.pid";

const char plymouth_path[] = "/bin/plymouth";
const char plymouthd_path[] = "/sbin/plymouthd";
const char *plymouthd_default_argv[] = {"/sbin/plymouthd",
					"--mode=boot",
					"--attach-to-session",
					NULL };

static void termination_handler(__attribute__((unused))int signum){
  if(interrupted_by_signal){
    return;
  }
  interrupted_by_signal = 1;
}

/* Function to use when printing errors */
__attribute__((format (gnu_printf, 3, 4)))
void error_plus(int status, int errnum, const char *formatstring,
		...){
  va_list ap;
  char *text;
  int ret;
  
  va_start(ap, formatstring);
  ret = vasprintf(&text, formatstring, ap);
  if(ret == -1){
    fprintf(stderr, "Mandos plugin %s: ",
	    program_invocation_short_name);
    vfprintf(stderr, formatstring, ap);
    fprintf(stderr, ": ");
    fprintf(stderr, "%s\n", strerror(errnum));
    error(status, errno, "vasprintf while printing error");
    return;
  }
  fprintf(stderr, "Mandos plugin ");
  error(status, errnum, "%s", text);
  free(text);
}

/* Create prompt string */
char *makeprompt(void){
  int ret = 0;
  char *prompt;
  const char *const cryptsource = getenv("cryptsource");
  const char *const crypttarget = getenv("crypttarget");
  const char prompt_start[] = "Unlocking the disk";
  const char prompt_end[] = "Enter passphrase";
  
  if(cryptsource == NULL){
    if(crypttarget == NULL){
      ret = asprintf(&prompt, "%s\n%s", prompt_start, prompt_end);
    } else {
      ret = asprintf(&prompt, "%s (%s)\n%s", prompt_start,
		     crypttarget, prompt_end);
    }
  } else {
    if(crypttarget == NULL){
      ret = asprintf(&prompt, "%s %s\n%s", prompt_start, cryptsource,
		     prompt_end);
    } else {
      ret = asprintf(&prompt, "%s %s (%s)\n%s", prompt_start,
		     cryptsource, crypttarget, prompt_end);
    }
  }
  if(ret == -1){
    return NULL;
  }
  return prompt;
}

void kill_and_wait(pid_t pid){
  TEMP_FAILURE_RETRY(kill(pid, SIGTERM));
  TEMP_FAILURE_RETRY(waitpid(pid, NULL, 0));
}

bool become_a_daemon(void){
  int ret = setuid(geteuid());
  if(ret == -1){
    error_plus(0, errno, "setuid");
  }
    
  setsid();
  ret = chdir("/");
  if(ret == -1){
    error_plus(0, errno, "chdir");
    return false;
  }
  ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
  if(ret == -1){
    error_plus(0, errno, "dup2");
    return false;
  }
  return true;
}

__attribute__((nonnull (2, 3)))
bool exec_and_wait(pid_t *pid_return, const char *path,
		   const char * const *argv, bool interruptable,
		   bool daemonize){
  int status;
  int ret;
  pid_t pid;
  pid = fork();
  if(pid == -1){
    error_plus(0, errno, "fork");
    return false;
  }
  if(pid == 0){
    /* Child */
    if(daemonize){
      if(not become_a_daemon()){
	_exit(EX_OSERR);
      }
    }
    
    char **new_argv = malloc(sizeof(const char *));
    if(new_argv == NULL){
      error_plus(0, errno, "malloc");
      _exit(EX_OSERR);
    }
    char **tmp;
    int i = 0;
    for (; argv[i] != NULL; i++){
      tmp = realloc(new_argv, sizeof(const char *) * ((size_t)i + 2));
      if(tmp == NULL){
	error_plus(0, errno, "realloc");
	free(new_argv);
	_exit(EX_OSERR);
      }
      new_argv = tmp;
      new_argv[i] = strdup(argv[i]);
    }
    new_argv[i] = NULL;
    
    execv(path, (char *const *)new_argv);
    error_plus(0, errno, "execv");
    _exit(EXIT_FAILURE);
  }
  if(pid_return != NULL){
    *pid_return = pid;
  }
  do {
    ret = waitpid(pid, &status, 0);
  } while(ret == -1 and errno == EINTR
	  and ((not interrupted_by_signal)
	       or (not interruptable)));
  if(interrupted_by_signal and interruptable){
    return false;
  }
  if(ret == -1){
    error_plus(0, errno, "waitpid");
    return false;
  }
  if(WIFEXITED(status) and (WEXITSTATUS(status) == 0)){
    return true;
  }
  return false;
}

__attribute__((nonnull))
int is_plymouth(const struct dirent *proc_entry){
  int ret;
  {
    uintmax_t proc_id;
    char *tmp;
    errno = 0;
    proc_id = strtoumax(proc_entry->d_name, &tmp, 10);

    if(errno != 0 or *tmp != '\0'
       or proc_id != (uintmax_t)((pid_t)proc_id)){
      return 0;
    }
  }
  char exe_target[sizeof(plymouthd_path)];
  char *exe_link;
  ret = asprintf(&exe_link, "/proc/%s/exe", proc_entry->d_name);
  if(ret == -1){
    error_plus(0, errno, "asprintf");
    return 0;
  }
  
  struct stat exe_stat;
  ret = lstat(exe_link, &exe_stat);
  if(ret == -1){
    free(exe_link);
    if(errno != ENOENT){
      error_plus(0, errno, "lstat");
    }
    return 0;
  }
  
  if(not S_ISLNK(exe_stat.st_mode)
     or exe_stat.st_uid != 0
     or exe_stat.st_gid != 0){
    free(exe_link);
    return 0;
  }
  
  ssize_t sret = readlink(exe_link, exe_target, sizeof(exe_target));
  free(exe_link);
  if((sret != (ssize_t)sizeof(plymouthd_path)-1) or
      (memcmp(plymouthd_path, exe_target,
	      sizeof(plymouthd_path)-1) != 0)){
    return 0;
  }
  return 1;
}

pid_t get_pid(void){
  int ret;
  uintmax_t proc_id = 0;
  FILE *pidfile = fopen(plymouth_pid, "r");
  /* Try the new pid file location */
  if(pidfile != NULL){
    ret = fscanf(pidfile, "%" SCNuMAX, &proc_id);
    if(ret != 1){
      proc_id = 0;
    }
    fclose(pidfile);
  }
  /* Try the old pid file location */
  if(proc_id == 0){
    pidfile = fopen(plymouth_pid, "r");
    if(pidfile != NULL){
      ret = fscanf(pidfile, "%" SCNuMAX, &proc_id);
      if(ret != 1){
	proc_id = 0;
      }
      fclose(pidfile);
    }
  }
  /* Look for a plymouth process */
  if(proc_id == 0){
    struct dirent **direntries = NULL;
    ret = scandir("/proc", &direntries, is_plymouth, alphasort);
    if(ret == -1){
      error_plus(0, errno, "scandir");
    }
    if(ret > 0){
      ret = sscanf(direntries[0]->d_name, "%" SCNuMAX, &proc_id);
      if(ret < 0){
	error_plus(0, errno, "sscanf");
      }
    }
    /* scandir might preallocate for this variable (man page unclear).
       even if ret == 0, therefore we need to free it. */
    free(direntries);
  }
  pid_t pid;
  pid = (pid_t)proc_id;
  if((uintmax_t)pid == proc_id){
    return pid;
  }
  
  return 0;
}

char **getargv(pid_t pid){
  int cl_fd;
  char *cmdline_filename;
  ssize_t sret;
  int ret;
  
  ret = asprintf(&cmdline_filename, "/proc/%" PRIuMAX "/cmdline",
		 (uintmax_t)pid);
  if(ret == -1){
    error_plus(0, errno, "asprintf");
    return NULL;
  }
  
  /* Open /proc/<pid>/cmdline  */
  cl_fd = open(cmdline_filename, O_RDONLY);
  free(cmdline_filename);
  if(cl_fd == -1){
    error_plus(0, errno, "open");
    return NULL;
  }
  
  size_t cmdline_allocated = 0;
  size_t cmdline_len = 0;
  char *cmdline = NULL;
  char *tmp;
  const size_t blocksize = 1024;
  do {
    /* Allocate more space? */
    if(cmdline_len + blocksize > cmdline_allocated){
      tmp = realloc(cmdline, cmdline_allocated + blocksize);
      if(tmp == NULL){
	error_plus(0, errno, "realloc");
	free(cmdline);
	close(cl_fd);
	return NULL;
      }
      cmdline = tmp;
      cmdline_allocated += blocksize;
    }
    
    /* Read data */
    sret = read(cl_fd, cmdline + cmdline_len,
		cmdline_allocated - cmdline_len);
    if(sret == -1){
      error_plus(0, errno, "read");
      free(cmdline);
      close(cl_fd);
      return NULL;
    }
    cmdline_len += (size_t)sret;
  } while(sret != 0);
  ret = close(cl_fd);
  if(ret == -1){
    error_plus(0, errno, "close");
    free(cmdline);
    return NULL;
  }
  
  /* we got cmdline and cmdline_len, ignore rest... */
  char **argv = malloc((argz_count(cmdline, cmdline_len) + 1)
		       * sizeof(char *)); /* Get number of args */
  if(argv == NULL){
    error_plus(0, errno, "argv = malloc()");
    free(cmdline);
    return NULL;
  }
  argz_extract(cmdline, cmdline_len, argv); /* Create argv */
  return argv;
}

int main(__attribute__((unused))int argc,
	 __attribute__((unused))char **argv){
  char *prompt;
  char *prompt_arg;
  pid_t plymouth_command_pid;
  int ret;
  bool bret;

  /* test -x /bin/plymouth */
  ret = access(plymouth_path, X_OK);
  if(ret == -1){
    /* Plymouth is probably not installed.  Don't print an error
       message, just exit. */
    exit(EX_UNAVAILABLE);
  }
  
  { /* Add signal handlers */
    struct sigaction old_action,
      new_action = { .sa_handler = termination_handler,
		     .sa_flags = 0 };
    sigemptyset(&new_action.sa_mask);
    for(int *sig = (int[]){ SIGINT, SIGHUP, SIGTERM, 0 };
	*sig != 0; sig++){
      ret = sigaddset(&new_action.sa_mask, *sig);
      if(ret == -1){
	error_plus(EX_OSERR, errno, "sigaddset");
      }
      ret = sigaction(*sig, NULL, &old_action);
      if(ret == -1){
	error_plus(EX_OSERR, errno, "sigaction");
      }
      if(old_action.sa_handler != SIG_IGN){
	ret = sigaction(*sig, &new_action, NULL);
	if(ret == -1){
	  error_plus(EX_OSERR, errno, "sigaction");
	}
      }
    }
  }
  
  /* plymouth --ping */
  bret = exec_and_wait(&plymouth_command_pid, plymouth_path,
		       (const char *[])
		       { plymouth_path, "--ping", NULL },
		       true, false);
  if(not bret){
    if(interrupted_by_signal){
      kill_and_wait(plymouth_command_pid);
      exit(EXIT_FAILURE);
    }
    /* Plymouth is probably not running.  Don't print an error
       message, just exit. */
    exit(EX_UNAVAILABLE);
  }
  
  prompt = makeprompt();
  ret = asprintf(&prompt_arg, "--prompt=%s", prompt);
  free(prompt);
  if(ret == -1){
    error_plus(EX_OSERR, errno, "asprintf");
  }
  
  /* plymouth ask-for-password --prompt="$prompt" */
  bret = exec_and_wait(&plymouth_command_pid,
		       plymouth_path, (const char *[])
		       { plymouth_path, "ask-for-password",
			   prompt_arg, NULL },
		       true, false);
  free(prompt_arg);
  if(bret){
    exit(EXIT_SUCCESS);
  }
  if(not interrupted_by_signal){
    /* exec_and_wait failed for some other reason */
    exit(EXIT_FAILURE);
  }
  kill_and_wait(plymouth_command_pid);
  
  char **plymouthd_argv = NULL;
  pid_t pid = get_pid();
  if(pid == 0){
    error_plus(0, 0, "plymouthd pid not found");
  } else {
    plymouthd_argv = getargv(pid);
  }
  
  bret = exec_and_wait(NULL, plymouth_path, (const char *[])
		       { plymouth_path, "quit", NULL },
		       false, false);
  if(not bret){
    if(plymouthd_argv != NULL){
      free(*plymouthd_argv);
      free(plymouthd_argv);
    }
    exit(EXIT_FAILURE);
  }
  bret = exec_and_wait(NULL, plymouthd_path,
		       (plymouthd_argv != NULL)
		       ? (const char * const *)plymouthd_argv
		       : plymouthd_default_argv,
		       false, true);
  if(plymouthd_argv != NULL){
    free(*plymouthd_argv);
    free(plymouthd_argv);
  }
  if(not bret){
    exit(EXIT_FAILURE);
  }
  exec_and_wait(NULL, plymouth_path, (const char *[])
		{ plymouth_path, "show-splash", NULL },
		false, false);
  exit(EXIT_FAILURE);
}