src/cryptsetup/cryptsetup-generator.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21
  22 #include "alloc-util.h"
  23 #include "dropin.h"
  24 #include "fd-util.h"
  25 #include "fileio.h"
  26 #include "fstab-util.h"
  27 #include "generator.h"
  28 #include "hashmap.h"
  29 #include "log.h"
  30 #include "mkdir.h"
  31 #include "parse-util.h"
  32 #include "path-util.h"
  33 #include "proc-cmdline.h"
  34 #include "string-util.h"
  35 #include "strv.h"
  36 #include "unit-name.h"
  37 #include "util.h"
  38
  39 typedef struct crypto_device {
  40         char *uuid;
  41         char *keyfile;
  42         char *name;
  43         char *options;
  44         bool create;
  45 } crypto_device;
  46
  47 static const char *arg_dest = "/tmp";
  48 static bool arg_enabled = true;
  49 static bool arg_read_crypttab = true;
  50 static bool arg_whitelist = false;
  51 static Hashmap *arg_disks = NULL;
  52 static char *arg_default_options = NULL;
  53 static char *arg_default_keyfile = NULL;
  54
  55 static int create_disk(
  56                 const char *name,
  57                 const char *device,
  58                 const char *password,
  59                 const char *options) {
  60
  61         _cleanup_free_ char *p = NULL, *n = NULL, *d = NULL, *u = NULL, *to = NULL, *e = NULL,
  62                 *filtered = NULL;
  63         _cleanup_fclose_ FILE *f = NULL;
  64         bool noauto, nofail, tmp, swap;
  65         char *from;
  66         int r;
  67
  68         assert(name);
  69         assert(device);
  70
  71         noauto = fstab_test_yes_no_option(options, "noauto\0" "auto\0");
  72         nofail = fstab_test_yes_no_option(options, "nofail\0" "fail\0");
  73         tmp = fstab_test_option(options, "tmp\0");
  74         swap = fstab_test_option(options, "swap\0");
  75
  76         if (tmp && swap) {
  77                 log_error("Device '%s' cannot be both 'tmp' and 'swap'. Ignoring.", name);
  78                 return -EINVAL;
  79         }
  80
  81         e = unit_name_escape(name);
  82         if (!e)
  83                 return log_oom();
  84
  85         r = unit_name_build("systemd-cryptsetup", e, ".service", &n);
  86         if (r < 0)
  87                 return log_error_errno(r, "Failed to generate unit name: %m");
  88
  89         p = strjoin(arg_dest, "/", n);
  90         if (!p)
  91                 return log_oom();
  92
  93         u = fstab_node_to_udev_node(device);
  94         if (!u)
  95                 return log_oom();
  96
  97         r = unit_name_from_path(u, ".device", &d);
  98         if (r < 0)
  99                 return log_error_errno(r, "Failed to generate unit name: %m");
 100
 101         f = fopen(p, "wxe");
 102         if (!f)
 103                 return log_error_errno(errno, "Failed to create unit file %s: %m", p);
 104
 105         fputs("# Automatically generated by systemd-cryptsetup-generator\n\n"
 106               "[Unit]\n"
 107               "Description=Cryptography Setup for %I\n"
 108               "Documentation=man:crypttab(5) man:systemd-cryptsetup-generator(8) man:systemd-cryptsetup@.service(8)\n"
 109               "SourcePath=/etc/crypttab\n"
 110               "DefaultDependencies=no\n"
 111               "Conflicts=umount.target\n"
 112               "BindsTo=dev-mapper-%i.device\n"
 113               "IgnoreOnIsolate=true\n"
 114               "After=cryptsetup-pre.target\n",
 115               f);
 116
 117         if (!nofail)
 118                 fprintf(f,
 119                         "Before=cryptsetup.target\n");
 120
 121         if (password) {
 122                 if (STR_IN_SET(password, "/dev/urandom", "/dev/random", "/dev/hw_random"))
 123                         fputs("After=systemd-random-seed.service\n", f);
 124                 else if (!streq(password, "-") && !streq(password, "none")) {
 125                         _cleanup_free_ char *uu;
 126
 127                         uu = fstab_node_to_udev_node(password);
 128                         if (!uu)
 129                                 return log_oom();
 130
 131                         if (!path_equal(uu, "/dev/null")) {
 132
 133                                 if (is_device_path(uu)) {
 134                                         _cleanup_free_ char *dd = NULL;
 135
 136                                         r = unit_name_from_path(uu, ".device", &dd);
 137                                         if (r < 0)
 138                                                 return log_error_errno(r, "Failed to generate unit name: %m");
 139
 140                                         fprintf(f, "After=%1$s\nRequires=%1$s\n", dd);
 141                                 } else
 142                                         fprintf(f, "RequiresMountsFor=%s\n", password);
 143                         }
 144                 }
 145         }
 146
 147         if (is_device_path(u)) {
 148                 fprintf(f,
 149                         "BindsTo=%s\n"
 150                         "After=%s\n"
 151                         "Before=umount.target\n",
 152                         d, d);
 153
 154                 if (swap)
 155                         fputs("Before=dev-mapper-%i.swap\n",
 156                               f);
 157         } else
 158                 fprintf(f,
 159                         "RequiresMountsFor=%s\n",
 160                         u);
 161
 162         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 163         if (r < 0)
 164                 return r;
 165
 166         fprintf(f,
 167                 "\n[Service]\n"
 168                 "Type=oneshot\n"
 169                 "RemainAfterExit=yes\n"
 170                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 171                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 172                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 173                 name, u, strempty(password), strempty(filtered),
 174                 name);
 175
 176         if (tmp)
 177                 fprintf(f,
 178                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 179                         name);
 180
 181         if (swap)
 182                 fprintf(f,
 183                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 184                         name);
 185
 186         r = fflush_and_check(f);
 187         if (r < 0)
 188                 return log_error_errno(r, "Failed to write file %s: %m", p);
 189
 190         from = strjoina("../", n);
 191
 192         if (!noauto) {
 193
 194                 to = strjoin(arg_dest, "/", d, ".wants/", n);
 195                 if (!to)
 196                         return log_oom();
 197
 198                 mkdir_parents_label(to, 0755);
 199                 if (symlink(from, to) < 0)
 200                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 201
 202                 free(to);
 203                 if (!nofail)
 204                         to = strjoin(arg_dest, "/cryptsetup.target.requires/", n);
 205                 else
 206                         to = strjoin(arg_dest, "/cryptsetup.target.wants/", n);
 207                 if (!to)
 208                         return log_oom();
 209
 210                 mkdir_parents_label(to, 0755);
 211                 if (symlink(from, to) < 0)
 212                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 213         }
 214
 215         free(to);
 216         to = strjoin(arg_dest, "/dev-mapper-", e, ".device.requires/", n);
 217         if (!to)
 218                 return log_oom();
 219
 220         mkdir_parents_label(to, 0755);
 221         if (symlink(from, to) < 0)
 222                 return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 223
 224         if (!noauto && !nofail) {
 225                 _cleanup_free_ char *dmname;
 226                 dmname = strjoin("dev-mapper-", e, ".device");
 227                 if (!dmname)
 228                         return log_oom();
 229
 230                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 231                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 232                                   "[Unit]\nJobTimeoutSec=0");
 233                 if (r < 0)
 234                         return log_error_errno(r, "Failed to write device drop-in: %m");
 235         }
 236
 237         return 0;
 238 }
 239
 240 static void free_arg_disks(void) {
 241         crypto_device *d;
 242
 243         while ((d = hashmap_steal_first(arg_disks))) {
 244                 free(d->uuid);
 245                 free(d->keyfile);
 246                 free(d->name);
 247                 free(d->options);
 248                 free(d);
 249         }
 250
 251         hashmap_free(arg_disks);
 252 }
 253
 254 static crypto_device *get_crypto_device(const char *uuid) {
 255         int r;
 256         crypto_device *d;
 257
 258         assert(uuid);
 259
 260         d = hashmap_get(arg_disks, uuid);
 261         if (!d) {
 262                 d = new0(struct crypto_device, 1);
 263                 if (!d)
 264                         return NULL;
 265
 266                 d->create = false;
 267                 d->keyfile = d->options = d->name = NULL;
 268
 269                 d->uuid = strdup(uuid);
 270                 if (!d->uuid)
 271                         return mfree(d);
 272
 273                 r = hashmap_put(arg_disks, d->uuid, d);
 274                 if (r < 0) {
 275                         free(d->uuid);
 276                         return mfree(d);
 277                 }
 278         }
 279
 280         return d;
 281 }
 282
 283 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 284         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 285         crypto_device *d;
 286         int r;
 287
 288         if (streq(key, "luks")) {
 289
 290                 r = value ? parse_boolean(value) : 1;
 291                 if (r < 0)
 292                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 293                 else
 294                         arg_enabled = r;
 295
 296         } else if (streq(key, "luks.crypttab")) {
 297
 298                 r = value ? parse_boolean(value) : 1;
 299                 if (r < 0)
 300                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 301                 else
 302                         arg_read_crypttab = r;
 303
 304         } else if (streq(key, "luks.uuid")) {
 305
 306                 if (proc_cmdline_value_missing(key, value))
 307                         return 0;
 308
 309                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 310                 if (!d)
 311                         return log_oom();
 312
 313                 d->create = arg_whitelist = true;
 314
 315         } else if (streq(key, "luks.options")) {
 316
 317                 if (proc_cmdline_value_missing(key, value))
 318                         return 0;
 319
 320                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 321                 if (r == 2) {
 322                         d = get_crypto_device(uuid);
 323                         if (!d)
 324                                 return log_oom();
 325
 326                         free_and_replace(d->options, uuid_value);
 327                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 328                         return log_oom();
 329
 330         } else if (streq(key, "luks.key")) {
 331
 332                 if (proc_cmdline_value_missing(key, value))
 333                         return 0;
 334
 335                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 336                 if (r == 2) {
 337                         d = get_crypto_device(uuid);
 338                         if (!d)
 339                                 return log_oom();
 340
 341                         free_and_replace(d->keyfile, uuid_value);
 342                 } else if (free_and_strdup(&arg_default_keyfile, value) < 0)
 343                         return log_oom();
 344
 345         } else if (streq(key, "luks.name")) {
 346
 347                 if (proc_cmdline_value_missing(key, value))
 348                         return 0;
 349
 350                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 351                 if (r == 2) {
 352                         d = get_crypto_device(uuid);
 353                         if (!d)
 354                                 return log_oom();
 355
 356                         d->create = arg_whitelist = true;
 357
 358                         free(d->name);
 359                         d->name = uuid_value;
 360                         uuid_value = NULL;
 361                 } else
 362                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 363         }
 364
 365         return 0;
 366 }
 367
 368 static int add_crypttab_devices(void) {
 369         struct stat st;
 370         unsigned crypttab_line = 0;
 371         _cleanup_fclose_ FILE *f = NULL;
 372
 373         if (!arg_read_crypttab)
 374                 return 0;
 375
 376         f = fopen("/etc/crypttab", "re");
 377         if (!f) {
 378                 if (errno != ENOENT)
 379                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 380                 return 0;
 381         }
 382
 383         if (fstat(fileno(f), &st) < 0) {
 384                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 385                 return 0;
 386         }
 387
 388         for (;;) {
 389                 int r, k;
 390                 char line[LINE_MAX], *l, *uuid;
 391                 crypto_device *d = NULL;
 392                 _cleanup_free_ char *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 393
 394                 if (!fgets(line, sizeof(line), f))
 395                         break;
 396
 397                 crypttab_line++;
 398
 399                 l = strstrip(line);
 400                 if (*l == '#' || *l == 0)
 401                         continue;
 402
 403                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 404                 if (k < 2 || k > 4) {
 405                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 406                         continue;
 407                 }
 408
 409                 uuid = startswith(device, "UUID=");
 410                 if (!uuid)
 411                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 412                 if (!uuid)
 413                         uuid = startswith(name, "luks-");
 414                 if (uuid)
 415                         d = hashmap_get(arg_disks, uuid);
 416
 417                 if (arg_whitelist && !d) {
 418                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 419                         continue;
 420                 }
 421
 422                 r = create_disk(name, device, keyfile, (d && d->options) ? d->options : options);
 423                 if (r < 0)
 424                         return r;
 425
 426                 if (d)
 427                         d->create = false;
 428         }
 429
 430         return 0;
 431 }
 432
 433 static int add_proc_cmdline_devices(void) {
 434         int r;
 435         Iterator i;
 436         crypto_device *d;
 437
 438         HASHMAP_FOREACH(d, arg_disks, i) {
 439                 const char *options;
 440                 _cleanup_free_ char *device = NULL;
 441
 442                 if (!d->create)
 443                         continue;
 444
 445                 if (!d->name) {
 446                         d->name = strappend("luks-", d->uuid);
 447                         if (!d->name)
 448                                 return log_oom();
 449                 }
 450
 451                 device = strappend("UUID=", d->uuid);
 452                 if (!device)
 453                         return log_oom();
 454
 455                 if (d->options)
 456                         options = d->options;
 457                 else if (arg_default_options)
 458                         options = arg_default_options;
 459                 else
 460                         options = "timeout=0";
 461
 462                 r = create_disk(d->name, device, d->keyfile ?: arg_default_keyfile, options);
 463                 if (r < 0)
 464                         return r;
 465         }
 466
 467         return 0;
 468 }
 469
 470 int main(int argc, char *argv[]) {
 471         int r;
 472
 473         if (argc > 1 && argc != 4) {
 474                 log_error("This program takes three or no arguments.");
 475                 return EXIT_FAILURE;
 476         }
 477
 478         if (argc > 1)
 479                 arg_dest = argv[1];
 480
 481         log_set_target(LOG_TARGET_SAFE);
 482         log_parse_environment();
 483         log_open();
 484
 485         umask(0022);
 486
 487         arg_disks = hashmap_new(&string_hash_ops);
 488         if (!arg_disks) {
 489                 r = log_oom();
 490                 goto finish;
 491         }
 492
 493         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
 494         if (r < 0) {
 495                 log_warning_errno(r, "Failed to parse kernel command line: %m");
 496                 goto finish;
 497         }
 498
 499         if (!arg_enabled) {
 500                 r = 0;
 501                 goto finish;
 502         }
 503
 504         r = add_crypttab_devices();
 505         if (r < 0)
 506                 goto finish;
 507
 508         r = add_proc_cmdline_devices();
 509         if (r < 0)
 510                 goto finish;
 511
 512         r = 0;
 513
 514 finish:
 515         free_arg_disks();
 516         free(arg_default_options);
 517         free(arg_default_keyfile);
 518
 519         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 520 }