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         else
 154                 fprintf(f,
 155                         "RequiresMountsFor=%s\n",
 156                         u);
 157
 158         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 159         if (r < 0)
 160                 return r;
 161
 162         fprintf(f,
 163                 "\n[Service]\n"
 164                 "Type=oneshot\n"
 165                 "RemainAfterExit=yes\n"
 166                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 167                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 168                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 169                 name, u, strempty(password), strempty(filtered),
 170                 name);
 171
 172         if (tmp)
 173                 fprintf(f,
 174                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 175                         name);
 176
 177         if (swap)
 178                 fprintf(f,
 179                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 180                         name);
 181
 182         r = fflush_and_check(f);
 183         if (r < 0)
 184                 return log_error_errno(r, "Failed to write file %s: %m", p);
 185
 186         from = strjoina("../", n);
 187
 188         if (!noauto) {
 189
 190                 to = strjoin(arg_dest, "/", d, ".wants/", n);
 191                 if (!to)
 192                         return log_oom();
 193
 194                 mkdir_parents_label(to, 0755);
 195                 if (symlink(from, to) < 0)
 196                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 197
 198                 free(to);
 199                 if (!nofail)
 200                         to = strjoin(arg_dest, "/cryptsetup.target.requires/", n);
 201                 else
 202                         to = strjoin(arg_dest, "/cryptsetup.target.wants/", n);
 203                 if (!to)
 204                         return log_oom();
 205
 206                 mkdir_parents_label(to, 0755);
 207                 if (symlink(from, to) < 0)
 208                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 209         }
 210
 211         free(to);
 212         to = strjoin(arg_dest, "/dev-mapper-", e, ".device.requires/", n);
 213         if (!to)
 214                 return log_oom();
 215
 216         mkdir_parents_label(to, 0755);
 217         if (symlink(from, to) < 0)
 218                 return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 219
 220         if (!noauto && !nofail) {
 221                 _cleanup_free_ char *dmname;
 222                 dmname = strjoin("dev-mapper-", e, ".device");
 223                 if (!dmname)
 224                         return log_oom();
 225
 226                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 227                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 228                                   "[Unit]\nJobTimeoutSec=0");
 229                 if (r < 0)
 230                         return log_error_errno(r, "Failed to write device drop-in: %m");
 231         }
 232
 233         return 0;
 234 }
 235
 236 static void free_arg_disks(void) {
 237         crypto_device *d;
 238
 239         while ((d = hashmap_steal_first(arg_disks))) {
 240                 free(d->uuid);
 241                 free(d->keyfile);
 242                 free(d->name);
 243                 free(d->options);
 244                 free(d);
 245         }
 246
 247         hashmap_free(arg_disks);
 248 }
 249
 250 static crypto_device *get_crypto_device(const char *uuid) {
 251         int r;
 252         crypto_device *d;
 253
 254         assert(uuid);
 255
 256         d = hashmap_get(arg_disks, uuid);
 257         if (!d) {
 258                 d = new0(struct crypto_device, 1);
 259                 if (!d)
 260                         return NULL;
 261
 262                 d->create = false;
 263                 d->keyfile = d->options = d->name = NULL;
 264
 265                 d->uuid = strdup(uuid);
 266                 if (!d->uuid)
 267                         return mfree(d);
 268
 269                 r = hashmap_put(arg_disks, d->uuid, d);
 270                 if (r < 0) {
 271                         free(d->uuid);
 272                         return mfree(d);
 273                 }
 274         }
 275
 276         return d;
 277 }
 278
 279 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 280         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 281         crypto_device *d;
 282         int r;
 283
 284         if (streq(key, "luks")) {
 285
 286                 r = value ? parse_boolean(value) : 1;
 287                 if (r < 0)
 288                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 289                 else
 290                         arg_enabled = r;
 291
 292         } else if (streq(key, "luks.crypttab")) {
 293
 294                 r = value ? parse_boolean(value) : 1;
 295                 if (r < 0)
 296                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 297                 else
 298                         arg_read_crypttab = r;
 299
 300         } else if (streq(key, "luks.uuid")) {
 301
 302                 if (proc_cmdline_value_missing(key, value))
 303                         return 0;
 304
 305                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 306                 if (!d)
 307                         return log_oom();
 308
 309                 d->create = arg_whitelist = true;
 310
 311         } else if (streq(key, "luks.options")) {
 312
 313                 if (proc_cmdline_value_missing(key, value))
 314                         return 0;
 315
 316                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 317                 if (r == 2) {
 318                         d = get_crypto_device(uuid);
 319                         if (!d)
 320                                 return log_oom();
 321
 322                         free_and_replace(d->options, uuid_value);
 323                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 324                         return log_oom();
 325
 326         } else if (streq(key, "luks.key")) {
 327
 328                 if (proc_cmdline_value_missing(key, value))
 329                         return 0;
 330
 331                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 332                 if (r == 2) {
 333                         d = get_crypto_device(uuid);
 334                         if (!d)
 335                                 return log_oom();
 336
 337                         free_and_replace(d->keyfile, uuid_value);
 338                 } else if (free_and_strdup(&arg_default_keyfile, value) < 0)
 339                         return log_oom();
 340
 341         } else if (streq(key, "luks.name")) {
 342
 343                 if (proc_cmdline_value_missing(key, value))
 344                         return 0;
 345
 346                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 347                 if (r == 2) {
 348                         d = get_crypto_device(uuid);
 349                         if (!d)
 350                                 return log_oom();
 351
 352                         d->create = arg_whitelist = true;
 353
 354                         free(d->name);
 355                         d->name = uuid_value;
 356                         uuid_value = NULL;
 357                 } else
 358                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 359         }
 360
 361         return 0;
 362 }
 363
 364 static int add_crypttab_devices(void) {
 365         struct stat st;
 366         unsigned crypttab_line = 0;
 367         _cleanup_fclose_ FILE *f = NULL;
 368
 369         if (!arg_read_crypttab)
 370                 return 0;
 371
 372         f = fopen("/etc/crypttab", "re");
 373         if (!f) {
 374                 if (errno != ENOENT)
 375                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 376                 return 0;
 377         }
 378
 379         if (fstat(fileno(f), &st) < 0) {
 380                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 381                 return 0;
 382         }
 383
 384         for (;;) {
 385                 int r, k;
 386                 char line[LINE_MAX], *l, *uuid;
 387                 crypto_device *d = NULL;
 388                 _cleanup_free_ char *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 389
 390                 if (!fgets(line, sizeof(line), f))
 391                         break;
 392
 393                 crypttab_line++;
 394
 395                 l = strstrip(line);
 396                 if (*l == '#' || *l == 0)
 397                         continue;
 398
 399                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 400                 if (k < 2 || k > 4) {
 401                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 402                         continue;
 403                 }
 404
 405                 uuid = startswith(device, "UUID=");
 406                 if (!uuid)
 407                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 408                 if (!uuid)
 409                         uuid = startswith(name, "luks-");
 410                 if (uuid)
 411                         d = hashmap_get(arg_disks, uuid);
 412
 413                 if (arg_whitelist && !d) {
 414                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 415                         continue;
 416                 }
 417
 418                 r = create_disk(name, device, keyfile, (d && d->options) ? d->options : options);
 419                 if (r < 0)
 420                         return r;
 421
 422                 if (d)
 423                         d->create = false;
 424         }
 425
 426         return 0;
 427 }
 428
 429 static int add_proc_cmdline_devices(void) {
 430         int r;
 431         Iterator i;
 432         crypto_device *d;
 433
 434         HASHMAP_FOREACH(d, arg_disks, i) {
 435                 const char *options;
 436                 _cleanup_free_ char *device = NULL;
 437
 438                 if (!d->create)
 439                         continue;
 440
 441                 if (!d->name) {
 442                         d->name = strappend("luks-", d->uuid);
 443                         if (!d->name)
 444                                 return log_oom();
 445                 }
 446
 447                 device = strappend("UUID=", d->uuid);
 448                 if (!device)
 449                         return log_oom();
 450
 451                 if (d->options)
 452                         options = d->options;
 453                 else if (arg_default_options)
 454                         options = arg_default_options;
 455                 else
 456                         options = "timeout=0";
 457
 458                 r = create_disk(d->name, device, d->keyfile ?: arg_default_keyfile, options);
 459                 if (r < 0)
 460                         return r;
 461         }
 462
 463         return 0;
 464 }
 465
 466 int main(int argc, char *argv[]) {
 467         int r;
 468
 469         if (argc > 1 && argc != 4) {
 470                 log_error("This program takes three or no arguments.");
 471                 return EXIT_FAILURE;
 472         }
 473
 474         if (argc > 1)
 475                 arg_dest = argv[1];
 476
 477         log_set_target(LOG_TARGET_SAFE);
 478         log_parse_environment();
 479         log_open();
 480
 481         umask(0022);
 482
 483         arg_disks = hashmap_new(&string_hash_ops);
 484         if (!arg_disks) {
 485                 r = log_oom();
 486                 goto finish;
 487         }
 488
 489         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
 490         if (r < 0) {
 491                 log_warning_errno(r, "Failed to parse kernel command line: %m");
 492                 goto finish;
 493         }
 494
 495         if (!arg_enabled) {
 496                 r = 0;
 497                 goto finish;
 498         }
 499
 500         r = add_crypttab_devices();
 501         if (r < 0)
 502                 goto finish;
 503
 504         r = add_proc_cmdline_devices();
 505         if (r < 0)
 506                 goto finish;
 507
 508         r = 0;
 509
 510 finish:
 511         free_arg_disks();
 512         free(arg_default_options);
 513         free(arg_default_keyfile);
 514
 515         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 516 }