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(
 106                 "# Automatically generated by systemd-cryptsetup-generator\n\n"
 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                 "BindsTo=dev-mapper-%i.device\n"
 114                 "IgnoreOnIsolate=true\n"
 115                 "After=cryptsetup-pre.target\n",
 116                 f);
 117
 118         if (!nofail)
 119                 fprintf(f,
 120                         "Before=cryptsetup.target\n");
 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 (!streq(password, "-") && !streq(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 (is_device_path(uu)) {
 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);
 144                         }
 145                 }
 146         }
 147
 148         if (is_device_path(u))
 149                 fprintf(f,
 150                         "BindsTo=%s\n"
 151                         "After=%s\n"
 152                         "Before=umount.target\n",
 153                         d, d);
 154         else
 155                 fprintf(f,
 156                         "RequiresMountsFor=%s\n",
 157                         u);
 158
 159         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 160         if (r < 0)
 161                 return r;
 162
 163         fprintf(f,
 164                 "\n[Service]\n"
 165                 "Type=oneshot\n"
 166                 "RemainAfterExit=yes\n"
 167                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 168                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 169                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 170                 name, u, strempty(password), strempty(filtered),
 171                 name);
 172
 173         if (tmp)
 174                 fprintf(f,
 175                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 176                         name);
 177
 178         if (swap)
 179                 fprintf(f,
 180                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 181                         name);
 182
 183         r = fflush_and_check(f);
 184         if (r < 0)
 185                 return log_error_errno(r, "Failed to write file %s: %m", p);
 186
 187         from = strjoina("../", n);
 188
 189         if (!noauto) {
 190
 191                 to = strjoin(arg_dest, "/", d, ".wants/", n);
 192                 if (!to)
 193                         return log_oom();
 194
 195                 mkdir_parents_label(to, 0755);
 196                 if (symlink(from, to) < 0)
 197                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 198
 199                 free(to);
 200                 if (!nofail)
 201                         to = strjoin(arg_dest, "/cryptsetup.target.requires/", n);
 202                 else
 203                         to = strjoin(arg_dest, "/cryptsetup.target.wants/", n);
 204                 if (!to)
 205                         return log_oom();
 206
 207                 mkdir_parents_label(to, 0755);
 208                 if (symlink(from, to) < 0)
 209                         return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 210         }
 211
 212         free(to);
 213         to = strjoin(arg_dest, "/dev-mapper-", e, ".device.requires/", n);
 214         if (!to)
 215                 return log_oom();
 216
 217         mkdir_parents_label(to, 0755);
 218         if (symlink(from, to) < 0)
 219                 return log_error_errno(errno, "Failed to create symlink %s: %m", to);
 220
 221         if (!noauto && !nofail) {
 222                 _cleanup_free_ char *dmname;
 223                 dmname = strjoin("dev-mapper-", e, ".device");
 224                 if (!dmname)
 225                         return log_oom();
 226
 227                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 228                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 229                                   "[Unit]\nJobTimeoutSec=0");
 230                 if (r < 0)
 231                         return log_error_errno(r, "Failed to write device drop-in: %m");
 232         }
 233
 234         return 0;
 235 }
 236
 237 static void free_arg_disks(void) {
 238         crypto_device *d;
 239
 240         while ((d = hashmap_steal_first(arg_disks))) {
 241                 free(d->uuid);
 242                 free(d->keyfile);
 243                 free(d->name);
 244                 free(d->options);
 245                 free(d);
 246         }
 247
 248         hashmap_free(arg_disks);
 249 }
 250
 251 static crypto_device *get_crypto_device(const char *uuid) {
 252         int r;
 253         crypto_device *d;
 254
 255         assert(uuid);
 256
 257         d = hashmap_get(arg_disks, uuid);
 258         if (!d) {
 259                 d = new0(struct crypto_device, 1);
 260                 if (!d)
 261                         return NULL;
 262
 263                 d->create = false;
 264                 d->keyfile = d->options = d->name = NULL;
 265
 266                 d->uuid = strdup(uuid);
 267                 if (!d->uuid)
 268                         return mfree(d);
 269
 270                 r = hashmap_put(arg_disks, d->uuid, d);
 271                 if (r < 0) {
 272                         free(d->uuid);
 273                         return mfree(d);
 274                 }
 275         }
 276
 277         return d;
 278 }
 279
 280 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 281         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 282         crypto_device *d;
 283         int r;
 284
 285         if (streq(key, "luks")) {
 286
 287                 r = value ? parse_boolean(value) : 1;
 288                 if (r < 0)
 289                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 290                 else
 291                         arg_enabled = r;
 292
 293         } else if (streq(key, "luks.crypttab")) {
 294
 295                 r = value ? parse_boolean(value) : 1;
 296                 if (r < 0)
 297                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 298                 else
 299                         arg_read_crypttab = r;
 300
 301         } else if (streq(key, "luks.uuid")) {
 302
 303                 if (proc_cmdline_value_missing(key, value))
 304                         return 0;
 305
 306                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 307                 if (!d)
 308                         return log_oom();
 309
 310                 d->create = arg_whitelist = true;
 311
 312         } else if (streq(key, "luks.options")) {
 313
 314                 if (proc_cmdline_value_missing(key, value))
 315                         return 0;
 316
 317                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 318                 if (r == 2) {
 319                         d = get_crypto_device(uuid);
 320                         if (!d)
 321                                 return log_oom();
 322
 323                         free_and_replace(d->options, uuid_value);
 324                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 325                         return log_oom();
 326
 327         } else if (streq(key, "luks.key")) {
 328
 329                 if (proc_cmdline_value_missing(key, value))
 330                         return 0;
 331
 332                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 333                 if (r == 2) {
 334                         d = get_crypto_device(uuid);
 335                         if (!d)
 336                                 return log_oom();
 337
 338                         free_and_replace(d->keyfile, uuid_value);
 339                 } else if (free_and_strdup(&arg_default_keyfile, value) < 0)
 340                         return log_oom();
 341
 342         } else if (streq(key, "luks.name")) {
 343
 344                 if (proc_cmdline_value_missing(key, value))
 345                         return 0;
 346
 347                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 348                 if (r == 2) {
 349                         d = get_crypto_device(uuid);
 350                         if (!d)
 351                                 return log_oom();
 352
 353                         d->create = arg_whitelist = true;
 354
 355                         free(d->name);
 356                         d->name = uuid_value;
 357                         uuid_value = NULL;
 358                 } else
 359                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 360
 361         }
 362
 363         return 0;
 364 }
 365
 366 static int add_crypttab_devices(void) {
 367         struct stat st;
 368         unsigned crypttab_line = 0;
 369         _cleanup_fclose_ FILE *f = NULL;
 370
 371         if (!arg_read_crypttab)
 372                 return 0;
 373
 374         f = fopen("/etc/crypttab", "re");
 375         if (!f) {
 376                 if (errno != ENOENT)
 377                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 378                 return 0;
 379         }
 380
 381         if (fstat(fileno(f), &st) < 0) {
 382                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 383                 return 0;
 384         }
 385
 386         for (;;) {
 387                 int r, k;
 388                 char line[LINE_MAX], *l, *uuid;
 389                 crypto_device *d = NULL;
 390                 _cleanup_free_ char *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 391
 392                 if (!fgets(line, sizeof(line), f))
 393                         break;
 394
 395                 crypttab_line++;
 396
 397                 l = strstrip(line);
 398                 if (*l == '#' || *l == 0)
 399                         continue;
 400
 401                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 402                 if (k < 2 || k > 4) {
 403                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 404                         continue;
 405                 }
 406
 407                 uuid = startswith(device, "UUID=");
 408                 if (!uuid)
 409                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 410                 if (!uuid)
 411                         uuid = startswith(name, "luks-");
 412                 if (uuid)
 413                         d = hashmap_get(arg_disks, uuid);
 414
 415                 if (arg_whitelist && !d) {
 416                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 417                         continue;
 418                 }
 419
 420                 r = create_disk(name, device, keyfile, (d && d->options) ? d->options : options);
 421                 if (r < 0)
 422                         return r;
 423
 424                 if (d)
 425                         d->create = false;
 426         }
 427
 428         return 0;
 429 }
 430
 431 static int add_proc_cmdline_devices(void) {
 432         int r;
 433         Iterator i;
 434         crypto_device *d;
 435
 436         HASHMAP_FOREACH(d, arg_disks, i) {
 437                 const char *options;
 438                 _cleanup_free_ char *device = NULL;
 439
 440                 if (!d->create)
 441                         continue;
 442
 443                 if (!d->name) {
 444                         d->name = strappend("luks-", d->uuid);
 445                         if (!d->name)
 446                                 return log_oom();
 447                 }
 448
 449                 device = strappend("UUID=", d->uuid);
 450                 if (!device)
 451                         return log_oom();
 452
 453                 if (d->options)
 454                         options = d->options;
 455                 else if (arg_default_options)
 456                         options = arg_default_options;
 457                 else
 458                         options = "timeout=0";
 459
 460                 r = create_disk(d->name, device, d->keyfile ?: arg_default_keyfile, options);
 461                 if (r < 0)
 462                         return r;
 463         }
 464
 465         return 0;
 466 }
 467
 468 int main(int argc, char *argv[]) {
 469         int r = EXIT_FAILURE;
 470
 471         if (argc > 1 && argc != 4) {
 472                 log_error("This program takes three or no arguments.");
 473                 return EXIT_FAILURE;
 474         }
 475
 476         if (argc > 1)
 477                 arg_dest = argv[1];
 478
 479         log_set_target(LOG_TARGET_SAFE);
 480         log_parse_environment();
 481         log_open();
 482
 483         umask(0022);
 484
 485         arg_disks = hashmap_new(&string_hash_ops);
 486         if (!arg_disks)
 487                 goto cleanup;
 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, ignoring: %m");
 492                 r = EXIT_FAILURE;
 493         }
 494
 495         if (!arg_enabled) {
 496                 r = EXIT_SUCCESS;
 497                 goto cleanup;
 498         }
 499
 500         if (add_crypttab_devices() < 0)
 501                 goto cleanup;
 502
 503         if (add_proc_cmdline_devices() < 0)
 504                 goto cleanup;
 505
 506         r = EXIT_SUCCESS;
 507
 508 cleanup:
 509         free_arg_disks();
 510         free(arg_default_options);
 511         free(arg_default_keyfile);
 512
 513         return r;
 514 }