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 #include "def.h"
  35
  36 static const char *opt_type = NULL; /* LUKS1 or PLAIN */
  37 static char *opt_cipher = NULL;
  38 static unsigned opt_key_size = 0;
  39 static char *opt_hash = NULL;
  40 static unsigned opt_tries = 0;
  41 static bool opt_readonly = false;
  42 static bool opt_verify = false;
  43 static usec_t opt_timeout = 0;
  44
  45 /* Options Debian's crypttab knows we don't:
  46
  47     offset=
  48     skip=
  49     precheck=
  50     check=
  51     checkargs=
  52     noearly=
  53     loud=
  54     keyscript=
  55 */
  56
  57 static int parse_one_option(const char *option) {
  58         assert(option);
  59
  60         /* Handled outside of this tool */
  61         if (streq(option, "noauto"))
  62                 return 0;
  63
  64         if (startswith(option, "cipher=")) {
  65                 char *t;
  66
  67                 if (!(t = strdup(option+7)))
  68                         return -ENOMEM;
  69
  70                 free(opt_cipher);
  71                 opt_cipher = t;
  72
  73         } else if (startswith(option, "size=")) {
  74
  75                 if (safe_atou(option+5, &opt_key_size) < 0) {
  76                         log_error("size= parse failure, ignoring.");
  77                         return 0;
  78                 }
  79
  80         } else if (startswith(option, "hash=")) {
  81                 char *t;
  82
  83                 if (!(t = strdup(option+5)))
  84                         return -ENOMEM;
  85
  86                 free(opt_hash);
  87                 opt_hash = t;
  88
  89         } else if (startswith(option, "tries=")) {
  90
  91                 if (safe_atou(option+6, &opt_tries) < 0) {
  92                         log_error("tries= parse failure, ignoring.");
  93                         return 0;
  94                 }
  95
  96         } else if (streq(option, "readonly"))
  97                 opt_readonly = true;
  98         else if (streq(option, "verify"))
  99                 opt_verify = true;
 100         else if (streq(option, "luks"))
 101                 opt_type = CRYPT_LUKS1;
 102         else if (streq(option, "plain") ||
 103                  streq(option, "swap") ||
 104                  streq(option, "tmp"))
 105                 opt_type = CRYPT_PLAIN;
 106         else if (startswith(option, "timeout=")) {
 107
 108                 if (parse_usec(option+8, &opt_timeout) < 0) {
 109                         log_error("timeout= parse failure, ignoring.");
 110                         return 0;
 111                 }
 112
 113         } else
 114                 log_error("Encountered unknown /etc/crypttab option '%s', ignoring.", option);
 115
 116         return 0;
 117 }
 118
 119 static int parse_options(const char *options) {
 120         char *state;
 121         char *w;
 122         size_t l;
 123
 124         assert(options);
 125
 126         FOREACH_WORD_SEPARATOR(w, l, options, ",", state) {
 127                 char *o;
 128                 int r;
 129
 130                 if (!(o = strndup(w, l)))
 131                         return -ENOMEM;
 132
 133                 r = parse_one_option(o);
 134                 free(o);
 135
 136                 if (r < 0)
 137                         return r;
 138         }
 139
 140         return 0;
 141 }
 142
 143 static void log_glue(int level, const char *msg, void *usrptr) {
 144         log_debug("%s", msg);
 145 }
 146
 147 static char *disk_description(const char *path) {
 148         struct udev *udev = NULL;
 149         struct udev_device *device = NULL;
 150         struct stat st;
 151         char *description = NULL;
 152         const char *model;
 153
 154         assert(path);
 155
 156         if (stat(path, &st) < 0)
 157                 return NULL;
 158
 159         if (!S_ISBLK(st.st_mode))
 160                 return NULL;
 161
 162         if (!(udev = udev_new()))
 163                 return NULL;
 164
 165         if (!(device = udev_device_new_from_devnum(udev, 'b', st.st_rdev)))
 166                 goto finish;
 167
 168         if ((model = udev_device_get_property_value(device, "ID_MODEL_FROM_DATABASE")) ||
 169             (model = udev_device_get_property_value(device, "ID_MODEL")) ||
 170             (model = udev_device_get_property_value(device, "DM_NAME")))
 171                 description = strdup(model);
 172
 173 finish:
 174         if (device)
 175                 udev_device_unref(device);
 176
 177         if (udev)
 178                 udev_unref(udev);
 179
 180         return description;
 181 }
 182
 183 static char *disk_mount_point(const char *label) {
 184         char *mp = NULL, *device = NULL;
 185         FILE *f = NULL;
 186         struct mntent *m;
 187
 188         /* Yeah, we don't support native systemd unit files here for now */
 189
 190         if (asprintf(&device, "/dev/mapper/%s", label) < 0)
 191                 goto finish;
 192
 193         if (!(f = setmntent("/etc/fstab", "r")))
 194                 goto finish;
 195
 196         while ((m = getmntent(f)))
 197                 if (path_equal(m->mnt_fsname, device)) {
 198                         mp = strdup(m->mnt_dir);
 199                         break;
 200                 }
 201
 202 finish:
 203         if (f)
 204                 endmntent(f);
 205
 206         free(device);
 207
 208         return mp;
 209 }
 210
 211 static int help(void) {
 212
 213         printf("%s attach VOLUME SOURCEDEVICE [PASSWORD] [OPTIONS]\n"
 214                "%s detach VOLUME\n\n"
 215                "Attaches or detaches an encrypted block device.\n",
 216                program_invocation_short_name,
 217                program_invocation_short_name);
 218
 219         return 0;
 220 }
 221
 222 int main(int argc, char *argv[]) {
 223         int r = EXIT_FAILURE;
 224         struct crypt_device *cd = NULL;
 225         char **passwords = NULL, *truncated_cipher = NULL;
 226         const char *cipher = NULL, *cipher_mode = NULL, *hash = NULL, *name = NULL;
 227         char *description = NULL, *name_buffer = NULL, *mount_point = NULL;
 228
 229         if (argc <= 1) {
 230                 help();
 231                 return EXIT_SUCCESS;
 232         }
 233
 234         if (argc < 3) {
 235                 log_error("This program requires at least two arguments.");
 236                 return EXIT_FAILURE;
 237         }
 238
 239         log_set_target(LOG_TARGET_AUTO);
 240         log_parse_environment();
 241         log_open();
 242
 243         if (streq(argv[1], "attach")) {
 244                 uint32_t flags = 0;
 245                 int k;
 246                 unsigned try;
 247                 const char *key_file = NULL;
 248                 usec_t until;
 249                 crypt_status_info status;
 250
 251                 /* Arguments: systemd-cryptsetup attach VOLUME SOURCE-DEVICE [PASSWORD] [OPTIONS] */
 252
 253                 if (argc < 4) {
 254                         log_error("attach requires at least two arguments.");
 255                         goto finish;
 256                 }
 257
 258                 if (argc >= 5 &&
 259                     argv[4][0] &&
 260                     !streq(argv[4], "-") &&
 261                     !streq(argv[4], "none")) {
 262
 263                         if (!path_is_absolute(argv[4]))
 264                                 log_error("Password file path %s is not absolute. Ignoring.", argv[4]);
 265                         else
 266                                 key_file = argv[4];
 267                 }
 268
 269                 if (argc >= 6 && argv[5][0] && !streq(argv[5], "-"))
 270                         parse_options(argv[5]);
 271
 272                 /* A delicious drop of snake oil */
 273                 mlockall(MCL_FUTURE);
 274
 275                 description = disk_description(argv[3]);
 276                 mount_point = disk_mount_point(argv[2]);
 277
 278                 if (description && streq(argv[2], description)) {
 279                         /* If the description string is simply the
 280                          * volume name, then let's not show this
 281                          * twice */
 282                         free(description);
 283                         description = NULL;
 284                 }
 285
 286                 if (mount_point && description)
 287                         asprintf(&name_buffer, "%s (%s) on %s", description, argv[2], mount_point);
 288                 else if (mount_point)
 289                         asprintf(&name_buffer, "%s on %s", argv[2], mount_point);
 290                 else if (description)
 291                         asprintf(&name_buffer, "%s (%s)", description, argv[2]);
 292
 293                 name = name_buffer ? name_buffer : argv[2];
 294
 295                 if ((k = crypt_init(&cd, argv[3]))) {
 296                         log_error("crypt_init() failed: %s", strerror(-k));
 297                         goto finish;
 298                 }
 299
 300                 crypt_set_log_callback(cd, log_glue, NULL);
 301
 302                 status = crypt_status(cd, argv[2]);
 303                 if (status == CRYPT_ACTIVE || status == CRYPT_BUSY) {
 304                         log_info("Volume %s already active.", argv[2]);
 305                         r = EXIT_SUCCESS;
 306                         goto finish;
 307                 }
 308
 309                 if (opt_readonly)
 310                         flags |= CRYPT_ACTIVATE_READONLY;
 311
 312                 if (opt_timeout > 0)
 313                         until = now(CLOCK_MONOTONIC) + opt_timeout;
 314                 else
 315                         until = 0;
 316
 317                 opt_tries = opt_tries > 0 ? opt_tries : 3;
 318                 opt_key_size = (opt_key_size > 0 ? opt_key_size : 256);
 319                 hash = opt_hash ? opt_hash : "ripemd160";
 320
 321                 if (opt_cipher) {
 322                         size_t l;
 323
 324                         l = strcspn(opt_cipher, "-");
 325
 326                         if (!(truncated_cipher = strndup(opt_cipher, l))) {
 327                                 log_error("Out of memory");
 328                                 goto finish;
 329                         }
 330
 331                         cipher = truncated_cipher;
 332                         cipher_mode = opt_cipher[l] ? opt_cipher+l+1 : "plain";
 333                 } else {
 334                         cipher = "aes";
 335                         cipher_mode = "cbc-essiv:sha256";
 336                 }
 337
 338                 for (try = 0; try < opt_tries; try++) {
 339                         bool pass_volume_key = false;
 340
 341                         strv_free(passwords);
 342                         passwords = NULL;
 343
 344                         if (!key_file) {
 345                                 char *text;
 346                                 char **p;
 347
 348                                 if (asprintf(&text, "Please enter passphrase for disk %s!", name) < 0) {
 349                                         log_error("Out of memory");
 350                                         goto finish;
 351                                 }
 352
 353                                 k = ask_password_auto(text, "drive-harddisk", until, try == 0 && !opt_verify, &passwords);
 354                                 free(text);
 355
 356                                 if (k < 0) {
 357                                         log_error("Failed to query password: %s", strerror(-k));
 358                                         goto finish;
 359                                 }
 360
 361                                 if (opt_verify) {
 362                                         char **passwords2 = NULL;
 363
 364                                         assert(strv_length(passwords) == 1);
 365
 366                                         if (asprintf(&text, "Please enter passphrase for disk %s! (verification)", name) < 0) {
 367                                                 log_error("Out of memory");
 368                                                 goto finish;
 369                                         }
 370
 371                                         k = ask_password_auto(text, "drive-harddisk", until, false, &passwords2);
 372                                         free(text);
 373
 374                                         if (k < 0) {
 375                                                 log_error("Failed to query verification password: %s", strerror(-k));
 376                                                 goto finish;
 377                                         }
 378
 379                                         assert(strv_length(passwords2) == 1);
 380
 381                                         if (!streq(passwords[0], passwords2[0])) {
 382                                                 log_warning("Passwords did not match, retrying.");
 383                                                 strv_free(passwords2);
 384                                                 continue;
 385                                         }
 386
 387                                         strv_free(passwords2);
 388                                 }
 389
 390                                 strv_uniq(passwords);
 391
 392                                 STRV_FOREACH(p, passwords) {
 393                                         char *c;
 394
 395                                         if (strlen(*p)+1 >= opt_key_size)
 396                                                 continue;
 397
 398                                         /* Pad password if necessary */
 399                                         if (!(c = new(char, opt_key_size))) {
 400                                                 log_error("Out of memory.");
 401                                                 goto finish;
 402                                         }
 403
 404                                         strncpy(c, *p, opt_key_size);
 405                                         free(*p);
 406                                         *p = c;
 407                                 }
 408                         }
 409
 410                         k = 0;
 411
 412                         if (!opt_type || streq(opt_type, CRYPT_LUKS1))
 413                                 k = crypt_load(cd, CRYPT_LUKS1, NULL);
 414
 415                         if ((!opt_type && k < 0) || streq_ptr(opt_type, CRYPT_PLAIN)) {
 416                                 struct crypt_params_plain params;
 417
 418                                 zero(params);
 419                                 params.hash = hash;
 420
 421                                 /* In contrast to what the name
 422                                  * crypt_setup() might suggest this
 423                                  * doesn't actually format anything,
 424                                  * it just configures encryption
 425                                  * parameters when used for plain
 426                                  * mode. */
 427                                 k = crypt_format(cd, CRYPT_PLAIN,
 428                                                  cipher,
 429                                                  cipher_mode,
 430                                                  NULL,
 431                                                  NULL,
 432                                                  opt_key_size / 8,
 433                                                  &params);
 434
 435                                 pass_volume_key = streq(hash, "plain");
 436                         }
 437
 438                         if (k < 0) {
 439                                 log_error("Loading of cryptographic parameters failed: %s", strerror(-k));
 440                                 goto finish;
 441                         }
 442
 443                         log_info("Set cipher %s, mode %s, key size %i bits for device %s.",
 444                                  crypt_get_cipher(cd),
 445                                  crypt_get_cipher_mode(cd),
 446                                  crypt_get_volume_key_size(cd)*8,
 447                                  argv[3]);
 448
 449                         if (key_file)
 450                                 k = crypt_activate_by_keyfile(cd, argv[2], CRYPT_ANY_SLOT, key_file, opt_key_size, flags);
 451                         else {
 452                                 char **p;
 453
 454                                 STRV_FOREACH(p, passwords) {
 455
 456                                         if (pass_volume_key)
 457                                                 k = crypt_activate_by_volume_key(cd, argv[2], *p, opt_key_size, flags);
 458                                         else
 459                                                 k = crypt_activate_by_passphrase(cd, argv[2], CRYPT_ANY_SLOT, *p, strlen(*p), flags);
 460
 461                                         if (k >= 0)
 462                                                 break;
 463                                 }
 464                         }
 465
 466                         if (k >= 0)
 467                                 break;
 468
 469                         if (k != -EPERM) {
 470                                 log_error("Failed to activate: %s", strerror(-k));
 471                                 goto finish;
 472                         }
 473
 474                         log_warning("Invalid passphrase.");
 475                 }
 476
 477                 if (try >= opt_tries) {
 478                         log_error("Too many attempts.");
 479                         r = EXIT_FAILURE;
 480                         goto finish;
 481                 }
 482
 483         } else if (streq(argv[1], "detach")) {
 484                 int k;
 485
 486                 if ((k = crypt_init_by_name(&cd, argv[2]))) {
 487                         log_error("crypt_init() failed: %s", strerror(-k));
 488                         goto finish;
 489                 }
 490
 491                 crypt_set_log_callback(cd, log_glue, NULL);
 492
 493                 if ((k = crypt_deactivate(cd, argv[2])) < 0) {
 494                         log_error("Failed to deactivate: %s", strerror(-k));
 495                         goto finish;
 496                 }
 497
 498         } else {
 499                 log_error("Unknown verb %s.", argv[1]);
 500                 goto finish;
 501         }
 502
 503         r = EXIT_SUCCESS;
 504
 505 finish:
 506
 507         if (cd)
 508                 crypt_free(cd);
 509
 510         free(opt_cipher);
 511         free(opt_hash);
 512
 513         free(truncated_cipher);
 514
 515         strv_free(passwords);
 516
 517         free(description);
 518         free(mount_point);
 519         free(name_buffer);
 520
 521         return r;
 522 }