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 = DEFAULT_TIMEOUT_USEC;
  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         unsigned keyfile_size = 0;
 229
 230         if (argc <= 1) {
 231                 help();
 232                 return EXIT_SUCCESS;
 233         }
 234
 235         if (argc < 3) {
 236                 log_error("This program requires at least two arguments.");
 237                 return EXIT_FAILURE;
 238         }
 239
 240         log_set_target(LOG_TARGET_AUTO);
 241         log_parse_environment();
 242         log_open();
 243
 244         if (streq(argv[1], "attach")) {
 245                 uint32_t flags = 0;
 246                 int k;
 247                 unsigned try;
 248                 const char *key_file = NULL;
 249                 usec_t until;
 250                 crypt_status_info status;
 251
 252                 /* Arguments: systemd-cryptsetup attach VOLUME SOURCE-DEVICE [PASSWORD] [OPTIONS] */
 253
 254                 if (argc < 4) {
 255                         log_error("attach requires at least two arguments.");
 256                         goto finish;
 257                 }
 258
 259                 if (argc >= 5 &&
 260                     argv[4][0] &&
 261                     !streq(argv[4], "-") &&
 262                     !streq(argv[4], "none")) {
 263
 264                         if (!path_is_absolute(argv[4]))
 265                                 log_error("Password file path %s is not absolute. Ignoring.", argv[4]);
 266                         else
 267                                 key_file = argv[4];
 268                 }
 269
 270                 if (argc >= 6 && argv[5][0] && !streq(argv[5], "-"))
 271                         parse_options(argv[5]);
 272
 273                 /* A delicious drop of snake oil */
 274                 mlockall(MCL_FUTURE);
 275
 276                 description = disk_description(argv[3]);
 277                 mount_point = disk_mount_point(argv[2]);
 278
 279                 if (description && streq(argv[2], description)) {
 280                         /* If the description string is simply the
 281                          * volume name, then let's not show this
 282                          * twice */
 283                         free(description);
 284                         description = NULL;
 285                 }
 286
 287                 if (mount_point && description)
 288                         asprintf(&name_buffer, "%s (%s) on %s", description, argv[2], mount_point);
 289                 else if (mount_point)
 290                         asprintf(&name_buffer, "%s on %s", argv[2], mount_point);
 291                 else if (description)
 292                         asprintf(&name_buffer, "%s (%s)", description, argv[2]);
 293
 294                 name = name_buffer ? name_buffer : argv[2];
 295
 296                 if ((k = crypt_init(&cd, argv[3]))) {
 297                         log_error("crypt_init() failed: %s", strerror(-k));
 298                         goto finish;
 299                 }
 300
 301                 crypt_set_log_callback(cd, log_glue, NULL);
 302
 303                 status = crypt_status(cd, argv[2]);
 304                 if (status == CRYPT_ACTIVE || status == CRYPT_BUSY) {
 305                         log_info("Volume %s already active.", argv[2]);
 306                         r = EXIT_SUCCESS;
 307                         goto finish;
 308                 }
 309
 310                 if (opt_readonly)
 311                         flags |= CRYPT_ACTIVATE_READONLY;
 312
 313                 if (opt_timeout > 0)
 314                         until = now(CLOCK_MONOTONIC) + opt_timeout;
 315                 else
 316                         until = 0;
 317
 318                 opt_tries = opt_tries > 0 ? opt_tries : 3;
 319                 opt_key_size = (opt_key_size > 0 ? opt_key_size : 256);
 320                 hash = opt_hash ? opt_hash : "ripemd160";
 321
 322                 if (opt_cipher) {
 323                         size_t l;
 324
 325                         l = strcspn(opt_cipher, "-");
 326
 327                         if (!(truncated_cipher = strndup(opt_cipher, l))) {
 328                                 log_error("Out of memory");
 329                                 goto finish;
 330                         }
 331
 332                         cipher = truncated_cipher;
 333                         cipher_mode = opt_cipher[l] ? opt_cipher+l+1 : "plain";
 334                 } else {
 335                         cipher = "aes";
 336                         cipher_mode = "cbc-essiv:sha256";
 337                 }
 338
 339                 for (try = 0; try < opt_tries; try++) {
 340                         bool pass_volume_key = false;
 341
 342                         strv_free(passwords);
 343                         passwords = NULL;
 344
 345                         if (!key_file) {
 346                                 char *text;
 347                                 char **p;
 348
 349                                 if (asprintf(&text, "Please enter passphrase for disk %s!", name) < 0) {
 350                                         log_error("Out of memory");
 351                                         goto finish;
 352                                 }
 353
 354                                 k = ask_password_auto(text, "drive-harddisk", until, try == 0 && !opt_verify, &passwords);
 355                                 free(text);
 356
 357                                 if (k < 0) {
 358                                         log_error("Failed to query password: %s", strerror(-k));
 359                                         goto finish;
 360                                 }
 361
 362                                 if (opt_verify) {
 363                                         char **passwords2 = NULL;
 364
 365                                         assert(strv_length(passwords) == 1);
 366
 367                                         if (asprintf(&text, "Please enter passphrase for disk %s! (verification)", name) < 0) {
 368                                                 log_error("Out of memory");
 369                                                 goto finish;
 370                                         }
 371
 372                                         k = ask_password_auto(text, "drive-harddisk", until, false, &passwords2);
 373                                         free(text);
 374
 375                                         if (k < 0) {
 376                                                 log_error("Failed to query verification password: %s", strerror(-k));
 377                                                 goto finish;
 378                                         }
 379
 380                                         assert(strv_length(passwords2) == 1);
 381
 382                                         if (!streq(passwords[0], passwords2[0])) {
 383                                                 log_warning("Passwords did not match, retrying.");
 384                                                 strv_free(passwords2);
 385                                                 continue;
 386                                         }
 387
 388                                         strv_free(passwords2);
 389                                 }
 390
 391                                 strv_uniq(passwords);
 392
 393                                 STRV_FOREACH(p, passwords) {
 394                                         char *c;
 395
 396                                         if (strlen(*p)+1 >= opt_key_size)
 397                                                 continue;
 398
 399                                         /* Pad password if necessary */
 400                                         if (!(c = new(char, opt_key_size))) {
 401                                                 log_error("Out of memory.");
 402                                                 goto finish;
 403                                         }
 404
 405                                         strncpy(c, *p, opt_key_size);
 406                                         free(*p);
 407                                         *p = c;
 408                                 }
 409                         }
 410
 411                         k = 0;
 412
 413                         if (!opt_type || streq(opt_type, CRYPT_LUKS1))
 414                                 k = crypt_load(cd, CRYPT_LUKS1, NULL);
 415
 416                         if ((!opt_type && k < 0) || streq_ptr(opt_type, CRYPT_PLAIN)) {
 417                                 struct crypt_params_plain params;
 418
 419                                 zero(params);
 420                                 params.hash = hash;
 421
 422                                 /* In contrast to what the name
 423                                  * crypt_setup() might suggest this
 424                                  * doesn't actually format anything,
 425                                  * it just configures encryption
 426                                  * parameters when used for plain
 427                                  * mode. */
 428                                 k = crypt_format(cd, CRYPT_PLAIN,
 429                                                  cipher,
 430                                                  cipher_mode,
 431                                                  NULL,
 432                                                  NULL,
 433                                                  opt_key_size / 8,
 434                                                  &params);
 435
 436                                 pass_volume_key = streq(hash, "plain");
 437
 438                                /* for CRYPT_PLAIN limit reads
 439                                 * from keyfile to key length */
 440                                 keyfile_size = opt_key_size / 8;
 441                         }
 442
 443                         if (k < 0) {
 444                                 log_error("Loading of cryptographic parameters failed: %s", strerror(-k));
 445                                 goto finish;
 446                         }
 447
 448                         log_info("Set cipher %s, mode %s, key size %i bits for device %s.",
 449                                  crypt_get_cipher(cd),
 450                                  crypt_get_cipher_mode(cd),
 451                                  crypt_get_volume_key_size(cd)*8,
 452                                  argv[3]);
 453
 454                         if (key_file)
 455                                 k = crypt_activate_by_keyfile(cd, argv[2], CRYPT_ANY_SLOT, key_file, keyfile_size, flags);
 456                         else {
 457                                 char **p;
 458
 459                                 STRV_FOREACH(p, passwords) {
 460
 461                                         if (pass_volume_key)
 462                                                 k = crypt_activate_by_volume_key(cd, argv[2], *p, opt_key_size, flags);
 463                                         else
 464                                                 k = crypt_activate_by_passphrase(cd, argv[2], CRYPT_ANY_SLOT, *p, strlen(*p), flags);
 465
 466                                         if (k >= 0)
 467                                                 break;
 468                                 }
 469                         }
 470
 471                         if (k >= 0)
 472                                 break;
 473
 474                         if (k != -EPERM) {
 475                                 log_error("Failed to activate: %s", strerror(-k));
 476                                 goto finish;
 477                         }
 478
 479                         log_warning("Invalid passphrase.");
 480                 }
 481
 482                 if (try >= opt_tries) {
 483                         log_error("Too many attempts.");
 484                         r = EXIT_FAILURE;
 485                         goto finish;
 486                 }
 487
 488         } else if (streq(argv[1], "detach")) {
 489                 int k;
 490
 491                 if ((k = crypt_init_by_name(&cd, argv[2]))) {
 492                         log_error("crypt_init() failed: %s", strerror(-k));
 493                         goto finish;
 494                 }
 495
 496                 crypt_set_log_callback(cd, log_glue, NULL);
 497
 498                 if ((k = crypt_deactivate(cd, argv[2])) < 0) {
 499                         log_error("Failed to deactivate: %s", strerror(-k));
 500                         goto finish;
 501                 }
 502
 503         } else {
 504                 log_error("Unknown verb %s.", argv[1]);
 505                 goto finish;
 506         }
 507
 508         r = EXIT_SUCCESS;
 509
 510 finish:
 511
 512         if (cd)
 513                 crypt_free(cd);
 514
 515         free(opt_cipher);
 516         free(opt_hash);
 517
 518         free(truncated_cipher);
 519
 520         strv_free(passwords);
 521
 522         free(description);
 523         free(mount_point);
 524         free(name_buffer);
 525
 526         return r;
 527 }