src/cryptsetup.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd 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.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <sys/mman.h>
  25 #include <mntent.h>
  26
  27 #include <libcryptsetup.h>
  28 #include <libudev.h>
  29
  30 #include "log.h"
  31 #include "util.h"
  32 #include "strv.h"
  33 #include "ask-password-api.h"
  34
  35 static const char *opt_type = NULL; /* LUKS1 or PLAIN */
  36 static char *opt_cipher = NULL;
  37 static unsigned opt_key_size = 0;
  38 static char *opt_hash = NULL;
  39 static unsigned opt_tries = 0;
  40 static bool opt_readonly = false;
  41 static bool opt_verify = false;
  42 static usec_t opt_timeout = 0;
  43
  44 /* Options Debian's crypttab knows we don't:
  45
  46     offset=
  47     skip=
  48     precheck=
  49     check=
  50     checkargs=
  51     noearly=
  52     loud=
  53     keyscript=
  54 */
  55
  56 static int parse_one_option(const char *option) {
  57         assert(option);
  58
  59         /* Handled outside of this tool */
  60         if (streq(option, "noauto"))
  61                 return 0;
  62
  63         if (startswith(option, "cipher=")) {
  64                 char *t;
  65
  66                 if (!(t = strdup(option+7)))
  67                         return -ENOMEM;
  68
  69                 free(opt_cipher);
  70                 opt_cipher = t;
  71
  72         } else if (startswith(option, "size=")) {
  73
  74                 if (safe_atou(option+5, &opt_key_size) < 0) {
  75                         log_error("size= parse failure, ignoring.");
  76                         return 0;
  77                 }
  78
  79         } else if (startswith(option, "hash=")) {
  80                 char *t;
  81
  82                 if (!(t = strdup(option+5)))
  83                         return -ENOMEM;
  84
  85                 free(opt_hash);
  86                 opt_hash = t;
  87
  88         } else if (startswith(option, "tries=")) {
  89
  90                 if (safe_atou(option+6, &opt_tries) < 0) {
  91                         log_error("tries= parse failure, ignoring.");
  92                         return 0;
  93                 }
  94
  95         } else if (streq(option, "readonly"))
  96                 opt_readonly = true;
  97         else if (streq(option, "verify"))
  98                 opt_verify = true;
  99         else if (streq(option, "luks"))
 100                 opt_type = CRYPT_LUKS1;
 101         else if (streq(option, "plain") ||
 102                  streq(option, "swap") ||
 103                  streq(option, "tmp"))
 104                 opt_type = CRYPT_PLAIN;
 105         else if (startswith(option, "timeout=")) {
 106
 107                 if (parse_usec(option+8, &opt_timeout) < 0) {
 108                         log_error("timeout= parse failure, ignoring.");
 109                         return 0;
 110                 }
 111
 112         } else
 113                 log_error("Encountered unknown /etc/crypttab option '%s', ignoring.", option);
 114
 115         return 0;
 116 }
 117
 118 static int parse_options(const char *options) {
 119         char *state;
 120         char *w;
 121         size_t l;
 122
 123         assert(options);
 124
 125         FOREACH_WORD_SEPARATOR(w, l, options, ",", state) {
 126                 char *o;
 127                 int r;
 128
 129                 if (!(o = strndup(w, l)))
 130                         return -ENOMEM;
 131
 132                 r = parse_one_option(o);
 133                 free(o);
 134
 135                 if (r < 0)
 136                         return r;
 137         }
 138
 139         return 0;
 140 }
 141
 142 static void log_glue(int level, const char *msg, void *usrptr) {
 143         log_debug("%s", msg);
 144 }
 145
 146 static char *disk_description(const char *path) {
 147         struct udev *udev = NULL;
 148         struct udev_device *device = NULL;
 149         struct stat st;
 150         char *description = NULL;
 151         const char *model;
 152
 153         assert(path);
 154
 155         if (stat(path, &st) < 0)
 156                 return NULL;
 157
 158         if (!S_ISBLK(st.st_mode))
 159                 return NULL;
 160
 161         if (!(udev = udev_new()))
 162                 return NULL;
 163
 164         if (!(device = udev_device_new_from_devnum(udev, 'b', st.st_rdev)))
 165                 goto finish;
 166
 167         if ((model = udev_device_get_property_value(device, "ID_MODEL_FROM_DATABASE")) ||
 168             (model = udev_device_get_property_value(device, "ID_MODEL")) ||
 169             (model = udev_device_get_property_value(device, "DM_NAME")))
 170                 description = strdup(model);
 171
 172 finish:
 173         if (device)
 174                 udev_device_unref(device);
 175
 176         if (udev)
 177                 udev_unref(udev);
 178
 179         return description;
 180 }
 181
 182 static char *disk_mount_point(const char *label) {
 183         char *mp = NULL, *device = NULL;
 184         FILE *f = NULL;
 185         struct mntent *m;
 186
 187         /* Yeah, we don't support native systemd unit files here for now */
 188
 189         if (asprintf(&device, "/dev/mapper/%s", label) < 0)
 190                 goto finish;
 191
 192         if (!(f = setmntent("/etc/fstab", "r")))
 193                 goto finish;
 194
 195         while ((m = getmntent(f)))
 196                 if (path_equal(m->mnt_fsname, device)) {
 197                         mp = strdup(m->mnt_dir);
 198                         break;
 199                 }
 200
 201 finish:
 202         if (f)
 203                 endmntent(f);
 204
 205         free(device);
 206
 207         return mp;
 208 }
 209
 210 static int help(void) {
 211
 212         printf("%s attach VOLUME SOURCEDEVICE [PASSWORD] [OPTIONS]\n"
 213                "%s detach VOLUME\n\n"
 214                "Attaches or detaches an encrypted block device.\n",
 215                program_invocation_short_name,
 216                program_invocation_short_name);
 217
 218         return 0;
 219 }
 220
 221 int main(int argc, char *argv[]) {
 222         int r = EXIT_FAILURE;
 223         struct crypt_device *cd = NULL;
 224         char **passwords = NULL, *truncated_cipher = NULL;
 225         const char *cipher = NULL, *cipher_mode = NULL, *hash = NULL, *name = NULL;
 226         char *description = NULL, *name_buffer = NULL, *mount_point = NULL;
 227
 228         if (argc <= 1) {
 229                 help();
 230                 return EXIT_SUCCESS;
 231         }
 232
 233         if (argc < 3) {
 234                 log_error("This program requires at least two arguments.");
 235                 return EXIT_FAILURE;
 236         }
 237
 238         log_set_target(LOG_TARGET_AUTO);
 239         log_parse_environment();
 240         log_open();
 241
 242         if (streq(argv[1], "attach")) {
 243                 uint32_t flags = 0;
 244                 int k;
 245                 unsigned try;
 246                 const char *key_file = NULL;
 247                 usec_t until;
 248                 crypt_status_info status;
 249
 250                 /* Arguments: systemd-cryptsetup attach VOLUME SOURCE-DEVICE [PASSWORD] [OPTIONS] */
 251
 252                 if (argc < 4) {
 253                         log_error("attach requires at least two arguments.");
 254                         goto finish;
 255                 }
 256
 257                 if (argc >= 5 &&
 258                     argv[4][0] &&
 259                     !streq(argv[4], "-") &&
 260                     !streq(argv[4], "none")) {
 261
 262                         if (!path_is_absolute(argv[4]))
 263                                 log_error("Password file path %s is not absolute. Ignoring.", argv[4]);
 264                         else
 265                                 key_file = argv[4];
 266                 }
 267
 268                 if (argc >= 6 && argv[5][0] && !streq(argv[5], "-"))
 269                         parse_options(argv[5]);
 270
 271                 /* A delicious drop of snake oil */
 272                 mlockall(MCL_FUTURE);
 273
 274                 description = disk_description(argv[3]);
 275                 mount_point = disk_mount_point(argv[2]);
 276
 277                 if (description && streq(argv[2], description)) {
 278                         /* If the description string is simply the
 279                          * volume name, then let's not show this
 280                          * twice */
 281                         free(description);
 282                         description = NULL;
 283                 }
 284
 285                 if (mount_point && description)
 286                         asprintf(&name_buffer, "%s (%s) on %s", description, argv[2], mount_point);
 287                 else if (mount_point)
 288                         asprintf(&name_buffer, "%s on %s", argv[2], mount_point);
 289                 else if (description)
 290                         asprintf(&name_buffer, "%s (%s)", description, argv[2]);
 291
 292                 name = name_buffer ? name_buffer : argv[2];
 293
 294                 if ((k = crypt_init(&cd, argv[3]))) {
 295                         log_error("crypt_init() failed: %s", strerror(-k));
 296                         goto finish;
 297                 }
 298
 299                 crypt_set_log_callback(cd, log_glue, NULL);
 300
 301                 status = crypt_status(cd, argv[2]);
 302                 if (status == CRYPT_ACTIVE || status == CRYPT_BUSY) {
 303                         log_info("Volume %s already active.", argv[2]);
 304                         r = EXIT_SUCCESS;
 305                         goto finish;
 306                 }
 307
 308                 if (opt_readonly)
 309                         flags |= CRYPT_ACTIVATE_READONLY;
 310
 311                 until = now(CLOCK_MONOTONIC) + (opt_timeout > 0 ? opt_timeout : 60 * USEC_PER_SEC);
 312
 313                 opt_tries = opt_tries > 0 ? opt_tries : 3;
 314                 opt_key_size = (opt_key_size > 0 ? opt_key_size : 256);
 315                 hash = opt_hash ? opt_hash : "ripemd160";
 316
 317                 if (opt_cipher) {
 318                         size_t l;
 319
 320                         l = strcspn(opt_cipher, "-");
 321
 322                         if (!(truncated_cipher = strndup(opt_cipher, l))) {
 323                                 log_error("Out of memory");
 324                                 goto finish;
 325                         }
 326
 327                         cipher = truncated_cipher;
 328                         cipher_mode = opt_cipher[l] ? opt_cipher+l+1 : "plain";
 329                 } else {
 330                         cipher = "aes";
 331                         cipher_mode = "cbc-essiv:sha256";
 332                 }
 333
 334                 for (try = 0; try < opt_tries; try++) {
 335                         bool pass_volume_key = false;
 336
 337                         strv_free(passwords);
 338                         passwords = NULL;
 339
 340                         if (!key_file) {
 341                                 char *text;
 342                                 char **p;
 343
 344                                 if (asprintf(&text, "Please enter passphrase for disk %s!", name) < 0) {
 345                                         log_error("Out of memory");
 346                                         goto finish;
 347                                 }
 348
 349                                 k = ask_password_auto(text, "drive-harddisk", until, try == 0 && !opt_verify, &passwords);
 350                                 free(text);
 351
 352                                 if (k < 0) {
 353                                         log_error("Failed to query password: %s", strerror(-k));
 354                                         goto finish;
 355                                 }
 356
 357                                 if (opt_verify) {
 358                                         char **passwords2 = NULL;
 359
 360                                         assert(strv_length(passwords) == 1);
 361
 362                                         if (asprintf(&text, "Please enter passphrase for disk %s! (verification)", name) < 0) {
 363                                                 log_error("Out of memory");
 364                                                 goto finish;
 365                                         }
 366
 367                                         k = ask_password_auto(text, "drive-harddisk", until, false, &passwords2);
 368                                         free(text);
 369
 370                                         if (k < 0) {
 371                                                 log_error("Failed to query verification password: %s", strerror(-k));
 372                                                 goto finish;
 373                                         }
 374
 375                                         assert(strv_length(passwords2) == 1);
 376
 377                                         if (!streq(passwords[0], passwords2[0])) {
 378                                                 log_warning("Passwords did not match, retrying.");
 379                                                 strv_free(passwords2);
 380                                                 continue;
 381                                         }
 382
 383                                         strv_free(passwords2);
 384                                 }
 385
 386                                 strv_uniq(passwords);
 387
 388                                 STRV_FOREACH(p, passwords) {
 389                                         char *c;
 390
 391                                         if (strlen(*p)+1 >= opt_key_size)
 392                                                 continue;
 393
 394                                         /* Pad password if necessary */
 395                                         if (!(c = new(char, opt_key_size))) {
 396                                                 log_error("Out of memory.");
 397                                                 goto finish;
 398                                         }
 399
 400                                         strncpy(c, *p, opt_key_size);
 401                                         free(*p);
 402                                         *p = c;
 403                                 }
 404                         }
 405
 406                         if (!opt_type || streq(opt_type, CRYPT_LUKS1))
 407                                 k = crypt_load(cd, CRYPT_LUKS1, NULL);
 408
 409                         if ((!opt_type && k < 0) || streq_ptr(opt_type, CRYPT_PLAIN)) {
 410                                 struct crypt_params_plain params;
 411
 412                                 zero(params);
 413                                 params.hash = hash;
 414
 415                                 /* In contrast to what the name
 416                                  * crypt_setup() might suggest this
 417                                  * doesn't actually format anything,
 418                                  * it just configures encryption
 419                                  * parameters when used for plain
 420                                  * mode. */
 421                                 k = crypt_format(cd, CRYPT_PLAIN,
 422                                                  cipher,
 423                                                  cipher_mode,
 424                                                  NULL,
 425                                                  NULL,
 426                                                  opt_key_size / 8,
 427                                                  &params);
 428
 429                                 pass_volume_key = streq(hash, "plain");
 430                         }
 431
 432                         if (k < 0) {
 433                                 log_error("Loading of cryptographic parameters failed: %s", strerror(-k));
 434                                 goto finish;
 435                         }
 436
 437                         log_info("Set cipher %s, mode %s, key size %i bits for device %s.",
 438                                  crypt_get_cipher(cd),
 439                                  crypt_get_cipher_mode(cd),
 440                                  crypt_get_volume_key_size(cd)*8,
 441                                  argv[3]);
 442
 443                         if (key_file)
 444                                 k = crypt_activate_by_keyfile(cd, argv[2], CRYPT_ANY_SLOT, key_file, opt_key_size, flags);
 445                         else {
 446                                 char **p;
 447
 448                                 STRV_FOREACH(p, passwords) {
 449
 450                                         if (pass_volume_key)
 451                                                 k = crypt_activate_by_volume_key(cd, argv[2], *p, opt_key_size, flags);
 452                                         else
 453                                                 k = crypt_activate_by_passphrase(cd, argv[2], CRYPT_ANY_SLOT, *p, strlen(*p), flags);
 454
 455                                         if (k >= 0)
 456                                                 break;
 457                                 }
 458                         }
 459
 460                         if (k >= 0)
 461                                 break;
 462
 463                         if (k != -EPERM) {
 464                                 log_error("Failed to activate: %s", strerror(-k));
 465                                 goto finish;
 466                         }
 467
 468                         log_warning("Invalid passphrase.");
 469                 }
 470
 471                 if (try >= opt_tries) {
 472                         log_error("Too many attempts.");
 473                         r = EXIT_FAILURE;
 474                         goto finish;
 475                 }
 476
 477         } else if (streq(argv[1], "detach")) {
 478                 int k;
 479
 480                 if ((k = crypt_init_by_name(&cd, argv[2]))) {
 481                         log_error("crypt_init() failed: %s", strerror(-k));
 482                         goto finish;
 483                 }
 484
 485                 crypt_set_log_callback(cd, log_glue, NULL);
 486
 487                 if ((k = crypt_deactivate(cd, argv[2])) < 0) {
 488                         log_error("Failed to deactivate: %s", strerror(-k));
 489                         goto finish;
 490                 }
 491
 492         } else {
 493                 log_error("Unknown verb %s.", argv[1]);
 494                 goto finish;
 495         }
 496
 497         r = EXIT_SUCCESS;
 498
 499 finish:
 500
 501         if (cd)
 502                 crypt_free(cd);
 503
 504         free(opt_cipher);
 505         free(opt_hash);
 506
 507         free(truncated_cipher);
 508
 509         strv_free(passwords);
 510
 511         free(description);
 512         free(mount_point);
 513         free(name_buffer);
 514
 515         return r;
 516 }