src/cryptsetup/cryptsetup-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <stdio_ext.h>
   6 #include <sys/stat.h>
   7 #include <sys/types.h>
   8
   9 #include "alloc-util.h"
  10 #include "dropin.h"
  11 #include "escape.h"
  12 #include "fd-util.h"
  13 #include "fileio.h"
  14 #include "fstab-util.h"
  15 #include "generator.h"
  16 #include "hashmap.h"
  17 #include "id128-util.h"
  18 #include "log.h"
  19 #include "mkdir.h"
  20 #include "parse-util.h"
  21 #include "path-util.h"
  22 #include "proc-cmdline.h"
  23 #include "specifier.h"
  24 #include "string-util.h"
  25 #include "strv.h"
  26 #include "unit-name.h"
  27 #include "util.h"
  28
  29 typedef struct crypto_device {
  30         char *uuid;
  31         char *keyfile;
  32         char *keydev;
  33         char *name;
  34         char *options;
  35         bool create;
  36 } crypto_device;
  37
  38 static const char *arg_dest = NULL;
  39 static bool arg_enabled = true;
  40 static bool arg_read_crypttab = true;
  41 static bool arg_whitelist = false;
  42 static Hashmap *arg_disks = NULL;
  43 static char *arg_default_options = NULL;
  44 static char *arg_default_keyfile = NULL;
  45
  46 STATIC_DESTRUCTOR_REGISTER(arg_disks, hashmap_freep);
  47 STATIC_DESTRUCTOR_REGISTER(arg_default_options, freep);
  48 STATIC_DESTRUCTOR_REGISTER(arg_default_keyfile, freep);
  49
  50 static int generate_keydev_mount(const char *name, const char *keydev, char **unit, char **mount) {
  51         _cleanup_free_ char *u = NULL, *what = NULL, *where = NULL, *name_escaped = NULL;
  52         _cleanup_fclose_ FILE *f = NULL;
  53         int r;
  54
  55         assert(name);
  56         assert(keydev);
  57         assert(unit);
  58         assert(mount);
  59
  60         r = mkdir_parents("/run/systemd/cryptsetup", 0755);
  61         if (r < 0)
  62                 return r;
  63
  64         r = mkdir("/run/systemd/cryptsetup", 0700);
  65         if (r < 0 && errno != EEXIST)
  66                 return -errno;
  67
  68         name_escaped = cescape(name);
  69         if (!name_escaped)
  70                 return -ENOMEM;
  71
  72         where = strjoin("/run/systemd/cryptsetup/keydev-", name_escaped);
  73         if (!where)
  74                 return -ENOMEM;
  75
  76         r = mkdir(where, 0700);
  77         if (r < 0 && errno != EEXIST)
  78                 return -errno;
  79
  80         r = unit_name_from_path(where, ".mount", &u);
  81         if (r < 0)
  82                 return r;
  83
  84         r = generator_open_unit_file(arg_dest, NULL, u, &f);
  85         if (r < 0)
  86                 return r;
  87
  88         what = fstab_node_to_udev_node(keydev);
  89         if (!what)
  90                 return -ENOMEM;
  91
  92         fprintf(f,
  93                 "[Unit]\n"
  94                 "DefaultDependencies=no\n\n"
  95                 "[Mount]\n"
  96                 "What=%s\n"
  97                 "Where=%s\n"
  98                 "Options=ro\n", what, where);
  99
 100         r = fflush_and_check(f);
 101         if (r < 0)
 102                 return r;
 103
 104         *unit = TAKE_PTR(u);
 105         *mount = TAKE_PTR(where);
 106
 107         return 0;
 108 }
 109
 110 static int create_disk(
 111                 const char *name,
 112                 const char *device,
 113                 const char *keydev,
 114                 const char *password,
 115                 const char *options) {
 116
 117         _cleanup_free_ char *n = NULL, *d = NULL, *u = NULL, *e = NULL,
 118                 *filtered = NULL, *u_escaped = NULL, *password_escaped = NULL, *filtered_escaped = NULL, *name_escaped = NULL, *keydev_mount = NULL;
 119         _cleanup_fclose_ FILE *f = NULL;
 120         const char *dmname;
 121         bool noauto, nofail, tmp, swap, netdev;
 122         int r;
 123
 124         assert(name);
 125         assert(device);
 126
 127         noauto = fstab_test_yes_no_option(options, "noauto\0" "auto\0");
 128         nofail = fstab_test_yes_no_option(options, "nofail\0" "fail\0");
 129         tmp = fstab_test_option(options, "tmp\0");
 130         swap = fstab_test_option(options, "swap\0");
 131         netdev = fstab_test_option(options, "_netdev\0");
 132
 133         if (tmp && swap)
 134                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 135                                        "Device '%s' cannot be both 'tmp' and 'swap'. Ignoring.",
 136                                        name);
 137
 138         name_escaped = specifier_escape(name);
 139         if (!name_escaped)
 140                 return log_oom();
 141
 142         e = unit_name_escape(name);
 143         if (!e)
 144                 return log_oom();
 145
 146         u = fstab_node_to_udev_node(device);
 147         if (!u)
 148                 return log_oom();
 149
 150         r = unit_name_build("systemd-cryptsetup", e, ".service", &n);
 151         if (r < 0)
 152                 return log_error_errno(r, "Failed to generate unit name: %m");
 153
 154         u_escaped = specifier_escape(u);
 155         if (!u_escaped)
 156                 return log_oom();
 157
 158         r = unit_name_from_path(u, ".device", &d);
 159         if (r < 0)
 160                 return log_error_errno(r, "Failed to generate unit name: %m");
 161
 162         if (password) {
 163                 password_escaped = specifier_escape(password);
 164                 if (!password_escaped)
 165                         return log_oom();
 166         }
 167
 168         if (keydev && !password)
 169                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 170                                        "Key device is specified, but path to the password file is missing.");
 171
 172         r = generator_open_unit_file(arg_dest, NULL, n, &f);
 173         if (r < 0)
 174                 return r;
 175
 176         fprintf(f,
 177                 "[Unit]\n"
 178                 "Description=Cryptography Setup for %%I\n"
 179                 "Documentation=man:crypttab(5) man:systemd-cryptsetup-generator(8) man:systemd-cryptsetup@.service(8)\n"
 180                 "SourcePath=/etc/crypttab\n"
 181                 "DefaultDependencies=no\n"
 182                 "Conflicts=umount.target\n"
 183                 "IgnoreOnIsolate=true\n"
 184                 "After=%s\n",
 185                 netdev ? "remote-fs-pre.target" : "cryptsetup-pre.target");
 186
 187         if (keydev) {
 188                 _cleanup_free_ char *unit = NULL, *p = NULL;
 189
 190                 r = generate_keydev_mount(name, keydev, &unit, &keydev_mount);
 191                 if (r < 0)
 192                         return log_error_errno(r, "Failed to generate keydev mount unit: %m");
 193
 194                 p = prefix_root(keydev_mount, password_escaped);
 195                 if (!p)
 196                         return log_oom();
 197
 198                 free_and_replace(password_escaped, p);
 199         }
 200
 201         if (!nofail)
 202                 fprintf(f,
 203                         "Before=%s\n",
 204                         netdev ? "remote-cryptsetup.target" : "cryptsetup.target");
 205
 206         if (password) {
 207                 if (PATH_IN_SET(password, "/dev/urandom", "/dev/random", "/dev/hw_random"))
 208                         fputs("After=systemd-random-seed.service\n", f);
 209                 else if (!STR_IN_SET(password, "-", "none")) {
 210                         _cleanup_free_ char *uu;
 211
 212                         uu = fstab_node_to_udev_node(password);
 213                         if (!uu)
 214                                 return log_oom();
 215
 216                         if (!path_equal(uu, "/dev/null")) {
 217
 218                                 if (path_startswith(uu, "/dev/")) {
 219                                         _cleanup_free_ char *dd = NULL;
 220
 221                                         r = unit_name_from_path(uu, ".device", &dd);
 222                                         if (r < 0)
 223                                                 return log_error_errno(r, "Failed to generate unit name: %m");
 224
 225                                         fprintf(f, "After=%1$s\nRequires=%1$s\n", dd);
 226                                 } else
 227                                         fprintf(f, "RequiresMountsFor=%s\n", password_escaped);
 228                         }
 229                 }
 230         }
 231
 232         if (path_startswith(u, "/dev/")) {
 233                 fprintf(f,
 234                         "BindsTo=%s\n"
 235                         "After=%s\n"
 236                         "Before=umount.target\n",
 237                         d, d);
 238
 239                 if (swap)
 240                         fputs("Before=dev-mapper-%i.swap\n",
 241                               f);
 242         } else
 243                 /* For loopback devices, add systemd-tmpfiles-setup-dev.service
 244                    dependency to ensure that loopback support is available in
 245                    the kernel (/dev/loop-control needs to exist) */
 246                 fprintf(f,
 247                         "RequiresMountsFor=%s\n"
 248                         "Requires=systemd-tmpfiles-setup-dev.service\n"
 249                         "After=systemd-tmpfiles-setup-dev.service\n",
 250                         u_escaped);
 251
 252         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 253         if (r < 0)
 254                 return r;
 255
 256         if (filtered) {
 257                 filtered_escaped = specifier_escape(filtered);
 258                 if (!filtered_escaped)
 259                         return log_oom();
 260         }
 261
 262         fprintf(f,
 263                 "\n[Service]\n"
 264                 "Type=oneshot\n"
 265                 "RemainAfterExit=yes\n"
 266                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 267                 "KeyringMode=shared\n" /* make sure we can share cached keys among instances */
 268                 "OOMScoreAdjust=500\n" /* unlocking can allocate a lot of memory if Argon2 is used */
 269                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 270                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 271                 name_escaped, u_escaped, strempty(password_escaped), strempty(filtered_escaped),
 272                 name_escaped);
 273
 274         if (tmp)
 275                 fprintf(f,
 276                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 277                         name_escaped);
 278
 279         if (swap)
 280                 fprintf(f,
 281                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 282                         name_escaped);
 283
 284         if (keydev)
 285                 fprintf(f,
 286                         "ExecStartPost=" UMOUNT_PATH " %s\n\n",
 287                         keydev_mount);
 288
 289         r = fflush_and_check(f);
 290         if (r < 0)
 291                 return log_error_errno(r, "Failed to write unit file %s: %m", n);
 292
 293         if (!noauto) {
 294                 r = generator_add_symlink(arg_dest,
 295                                           netdev ? "remote-cryptsetup.target" : "cryptsetup.target",
 296                                           nofail ? "wants" : "requires", n);
 297                 if (r < 0)
 298                         return r;
 299         }
 300
 301         dmname = strjoina("dev-mapper-", e, ".device");
 302         r = generator_add_symlink(arg_dest, dmname, "requires", n);
 303         if (r < 0)
 304                 return r;
 305
 306         if (!noauto && !nofail) {
 307                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 308                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 309                                   "[Unit]\nJobTimeoutSec=0");
 310                 if (r < 0)
 311                         return log_error_errno(r, "Failed to write device drop-in: %m");
 312         }
 313
 314         return 0;
 315 }
 316
 317 static crypto_device* crypt_device_free(crypto_device *d) {
 318         if (!d)
 319                 return NULL;
 320
 321         free(d->uuid);
 322         free(d->keyfile);
 323         free(d->keydev);
 324         free(d->name);
 325         free(d->options);
 326         return mfree(d);
 327 }
 328
 329 static crypto_device *get_crypto_device(const char *uuid) {
 330         int r;
 331         crypto_device *d;
 332
 333         assert(uuid);
 334
 335         d = hashmap_get(arg_disks, uuid);
 336         if (!d) {
 337                 d = new0(struct crypto_device, 1);
 338                 if (!d)
 339                         return NULL;
 340
 341                 d->create = false;
 342                 d->keyfile = d->options = d->name = NULL;
 343
 344                 d->uuid = strdup(uuid);
 345                 if (!d->uuid)
 346                         return mfree(d);
 347
 348                 r = hashmap_put(arg_disks, d->uuid, d);
 349                 if (r < 0) {
 350                         free(d->uuid);
 351                         return mfree(d);
 352                 }
 353         }
 354
 355         return d;
 356 }
 357
 358 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 359         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 360         crypto_device *d;
 361         int r;
 362
 363         if (streq(key, "luks")) {
 364
 365                 r = value ? parse_boolean(value) : 1;
 366                 if (r < 0)
 367                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 368                 else
 369                         arg_enabled = r;
 370
 371         } else if (streq(key, "luks.crypttab")) {
 372
 373                 r = value ? parse_boolean(value) : 1;
 374                 if (r < 0)
 375                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 376                 else
 377                         arg_read_crypttab = r;
 378
 379         } else if (streq(key, "luks.uuid")) {
 380
 381                 if (proc_cmdline_value_missing(key, value))
 382                         return 0;
 383
 384                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 385                 if (!d)
 386                         return log_oom();
 387
 388                 d->create = arg_whitelist = true;
 389
 390         } else if (streq(key, "luks.options")) {
 391
 392                 if (proc_cmdline_value_missing(key, value))
 393                         return 0;
 394
 395                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 396                 if (r == 2) {
 397                         d = get_crypto_device(uuid);
 398                         if (!d)
 399                                 return log_oom();
 400
 401                         free_and_replace(d->options, uuid_value);
 402                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 403                         return log_oom();
 404
 405         } else if (streq(key, "luks.key")) {
 406                 size_t n;
 407                 _cleanup_free_ char *keyfile = NULL, *keydev = NULL;
 408                 char *c;
 409                 const char *keyspec;
 410
 411                 if (proc_cmdline_value_missing(key, value))
 412                         return 0;
 413
 414                 n = strspn(value, LETTERS DIGITS "-");
 415                 if (value[n] != '=') {
 416                         if (free_and_strdup(&arg_default_keyfile, value) < 0)
 417                                  return log_oom();
 418                         return 0;
 419                 }
 420
 421                 uuid = strndup(value, n);
 422                 if (!uuid)
 423                         return log_oom();
 424
 425                 if (!id128_is_valid(uuid)) {
 426                         log_warning("Failed to parse luks.key= kernel command line switch. UUID is invalid, ignoring.");
 427                         return 0;
 428                 }
 429
 430                 d = get_crypto_device(uuid);
 431                 if (!d)
 432                         return log_oom();
 433
 434                 keyspec = value + n + 1;
 435                 c = strrchr(keyspec, ':');
 436                 if (c) {
 437                          *c = '\0';
 438                         keyfile = strdup(keyspec);
 439                         keydev = strdup(c + 1);
 440
 441                         if (!keyfile || !keydev)
 442                                 return log_oom();
 443                 } else {
 444                         /* No keydev specified */
 445                         keyfile = strdup(keyspec);
 446                         if (!keyfile)
 447                                 return log_oom();
 448                 }
 449
 450                 free_and_replace(d->keyfile, keyfile);
 451                 free_and_replace(d->keydev, keydev);
 452         } else if (streq(key, "luks.name")) {
 453
 454                 if (proc_cmdline_value_missing(key, value))
 455                         return 0;
 456
 457                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 458                 if (r == 2) {
 459                         d = get_crypto_device(uuid);
 460                         if (!d)
 461                                 return log_oom();
 462
 463                         d->create = arg_whitelist = true;
 464
 465                         free_and_replace(d->name, uuid_value);
 466                 } else
 467                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 468         }
 469
 470         return 0;
 471 }
 472
 473 static int add_crypttab_devices(void) {
 474         _cleanup_fclose_ FILE *f = NULL;
 475         unsigned crypttab_line = 0;
 476         struct stat st;
 477         int r;
 478
 479         if (!arg_read_crypttab)
 480                 return 0;
 481
 482         f = fopen("/etc/crypttab", "re");
 483         if (!f) {
 484                 if (errno != ENOENT)
 485                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 486                 return 0;
 487         }
 488
 489         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 490
 491         if (fstat(fileno(f), &st) < 0) {
 492                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 493                 return 0;
 494         }
 495
 496         for (;;) {
 497                 _cleanup_free_ char *line = NULL, *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 498                 crypto_device *d = NULL;
 499                 char *l, *uuid;
 500                 int k;
 501
 502                 r = read_line(f, LONG_LINE_MAX, &line);
 503                 if (r < 0)
 504                         return log_error_errno(r, "Failed to read /etc/crypttab: %m");
 505                 if (r == 0)
 506                         break;
 507
 508                 crypttab_line++;
 509
 510                 l = strstrip(line);
 511                 if (IN_SET(l[0], 0, '#'))
 512                         continue;
 513
 514                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 515                 if (k < 2 || k > 4) {
 516                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 517                         continue;
 518                 }
 519
 520                 uuid = STARTSWITH_SET(device, "UUID=", "luks-");
 521                 if (!uuid)
 522                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 523                 if (uuid)
 524                         d = hashmap_get(arg_disks, uuid);
 525
 526                 if (arg_whitelist && !d) {
 527                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 528                         continue;
 529                 }
 530
 531                 r = create_disk(name, device, NULL, keyfile, (d && d->options) ? d->options : options);
 532                 if (r < 0)
 533                         return r;
 534
 535                 if (d)
 536                         d->create = false;
 537         }
 538
 539         return 0;
 540 }
 541
 542 static int add_proc_cmdline_devices(void) {
 543         int r;
 544         Iterator i;
 545         crypto_device *d;
 546
 547         HASHMAP_FOREACH(d, arg_disks, i) {
 548                 const char *options;
 549                 _cleanup_free_ char *device = NULL;
 550
 551                 if (!d->create)
 552                         continue;
 553
 554                 if (!d->name) {
 555                         d->name = strappend("luks-", d->uuid);
 556                         if (!d->name)
 557                                 return log_oom();
 558                 }
 559
 560                 device = strappend("UUID=", d->uuid);
 561                 if (!device)
 562                         return log_oom();
 563
 564                 if (d->options)
 565                         options = d->options;
 566                 else if (arg_default_options)
 567                         options = arg_default_options;
 568                 else
 569                         options = "timeout=0";
 570
 571                 r = create_disk(d->name, device, d->keydev, d->keyfile ?: arg_default_keyfile, options);
 572                 if (r < 0)
 573                         return r;
 574         }
 575
 576         return 0;
 577 }
 578
 579 DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(crypt_device_hash_ops, char, string_hash_func, string_compare_func,
 580                                               crypto_device, crypt_device_free);
 581
 582 static int run(const char *dest, const char *dest_early, const char *dest_late) {
 583         int r;
 584
 585         assert_se(arg_dest = dest);
 586
 587         arg_disks = hashmap_new(&crypt_device_hash_ops);
 588         if (!arg_disks)
 589                 return log_oom();
 590
 591         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
 592         if (r < 0)
 593                 return log_warning_errno(r, "Failed to parse kernel command line: %m");
 594
 595         if (!arg_enabled)
 596                 return 0;
 597
 598         r = add_crypttab_devices();
 599         if (r < 0)
 600                 return r;
 601
 602         r = add_proc_cmdline_devices();
 603         if (r < 0)
 604                 return r;
 605
 606         return 0;
 607 }
 608
 609 DEFINE_MAIN_GENERATOR_FUNCTION(run);