src/cryptsetup/cryptsetup-generator.c

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