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, *e = NULL,
  62                 *filtered = NULL;
  63         _cleanup_fclose_ FILE *f = NULL;
  64         const char *dmname;
  65         bool noauto, nofail, tmp, swap, netdev;
  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         netdev = fstab_test_option(options, "_netdev\0");
  76
  77         if (tmp && swap) {
  78                 log_error("Device '%s' cannot be both 'tmp' and 'swap'. Ignoring.", name);
  79                 return -EINVAL;
  80         }
  81
  82         e = unit_name_escape(name);
  83         if (!e)
  84                 return log_oom();
  85
  86         r = unit_name_build("systemd-cryptsetup", e, ".service", &n);
  87         if (r < 0)
  88                 return log_error_errno(r, "Failed to generate unit name: %m");
  89
  90         p = strjoin(arg_dest, "/", n);
  91         if (!p)
  92                 return log_oom();
  93
  94         u = fstab_node_to_udev_node(device);
  95         if (!u)
  96                 return log_oom();
  97
  98         r = unit_name_from_path(u, ".device", &d);
  99         if (r < 0)
 100                 return log_error_errno(r, "Failed to generate unit name: %m");
 101
 102         f = fopen(p, "wxe");
 103         if (!f)
 104                 return log_error_errno(errno, "Failed to create unit file %s: %m", p);
 105
 106         fprintf(f,
 107                 "# Automatically generated by systemd-cryptsetup-generator\n\n"
 108                 "[Unit]\n"
 109                 "Description=Cryptography Setup for %%I\n"
 110                 "Documentation=man:crypttab(5) man:systemd-cryptsetup-generator(8) man:systemd-cryptsetup@.service(8)\n"
 111                 "SourcePath=/etc/crypttab\n"
 112                 "DefaultDependencies=no\n"
 113                 "Conflicts=umount.target\n"
 114                 "IgnoreOnIsolate=true\n"
 115                 "After=%s\n",
 116                 netdev ? "remote-cryptsetup-pre.target" : "cryptsetup-pre.target");
 117
 118         if (!nofail)
 119                 fprintf(f,
 120                         "Before=%s\n",
 121                         netdev ? "remote-cryptsetup.target" : "cryptsetup.target");
 122
 123         if (password) {
 124                 if (STR_IN_SET(password, "/dev/urandom", "/dev/random", "/dev/hw_random"))
 125                         fputs_unlocked("After=systemd-random-seed.service\n", f);
 126                 else if (!STR_IN_SET(password, "-", "none")) {
 127                         _cleanup_free_ char *uu;
 128
 129                         uu = fstab_node_to_udev_node(password);
 130                         if (!uu)
 131                                 return log_oom();
 132
 133                         if (!path_equal(uu, "/dev/null")) {
 134
 135                                 if (path_startswith(uu, "/dev/")) {
 136                                         _cleanup_free_ char *dd = NULL;
 137
 138                                         r = unit_name_from_path(uu, ".device", &dd);
 139                                         if (r < 0)
 140                                                 return log_error_errno(r, "Failed to generate unit name: %m");
 141
 142                                         fprintf(f, "After=%1$s\nRequires=%1$s\n", dd);
 143                                 } else
 144                                         fprintf(f, "RequiresMountsFor=%s\n", password);
 145                         }
 146                 }
 147         }
 148
 149         if (path_startswith(u, "/dev/")) {
 150                 fprintf(f,
 151                         "BindsTo=%s\n"
 152                         "After=%s\n"
 153                         "Before=umount.target\n",
 154                         d, d);
 155
 156                 if (swap)
 157                         fputs_unlocked("Before=dev-mapper-%i.swap\n",
 158                                        f);
 159         } else
 160                 fprintf(f,
 161                         "RequiresMountsFor=%s\n",
 162                         u);
 163
 164         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 165         if (r < 0)
 166                 return r;
 167
 168         fprintf(f,
 169                 "\n[Service]\n"
 170                 "Type=oneshot\n"
 171                 "RemainAfterExit=yes\n"
 172                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 173                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 174                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 175                 name, u, strempty(password), strempty(filtered),
 176                 name);
 177
 178         if (tmp)
 179                 fprintf(f,
 180                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 181                         name);
 182
 183         if (swap)
 184                 fprintf(f,
 185                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 186                         name);
 187
 188         r = fflush_and_check(f);
 189         if (r < 0)
 190                 return log_error_errno(r, "Failed to write file %s: %m", p);
 191
 192         if (!noauto) {
 193                 r = generator_add_symlink(arg_dest, d, "wants", n);
 194                 if (r < 0)
 195                         return r;
 196
 197                 r = generator_add_symlink(arg_dest,
 198                                           netdev ? "remote-cryptsetup.target" : "cryptsetup.target",
 199                                           nofail ? "wants" : "requires", n);
 200                 if (r < 0)
 201                         return r;
 202         }
 203
 204         dmname = strjoina("dev-mapper-", e, ".device");
 205         r = generator_add_symlink(arg_dest, dmname, "requires", n);
 206         if (r < 0)
 207                 return r;
 208
 209         if (!noauto && !nofail) {
 210                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 211                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 212                                   "[Unit]\nJobTimeoutSec=0");
 213                 if (r < 0)
 214                         return log_error_errno(r, "Failed to write device drop-in: %m");
 215         }
 216
 217         return 0;
 218 }
 219
 220 static void free_arg_disks(void) {
 221         crypto_device *d;
 222
 223         while ((d = hashmap_steal_first(arg_disks))) {
 224                 free(d->uuid);
 225                 free(d->keyfile);
 226                 free(d->name);
 227                 free(d->options);
 228                 free(d);
 229         }
 230
 231         hashmap_free(arg_disks);
 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(d->name);
 339                         d->name = uuid_value;
 340                         uuid_value = NULL;
 341                 } else
 342                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 343         }
 344
 345         return 0;
 346 }
 347
 348 static int add_crypttab_devices(void) {
 349         struct stat st;
 350         unsigned crypttab_line = 0;
 351         _cleanup_fclose_ FILE *f = NULL;
 352
 353         if (!arg_read_crypttab)
 354                 return 0;
 355
 356         f = fopen("/etc/crypttab", "re");
 357         if (!f) {
 358                 if (errno != ENOENT)
 359                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 360                 return 0;
 361         }
 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 (*l == '#' || *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_target(LOG_TARGET_SAFE);
 462         log_parse_environment();
 463         log_open();
 464
 465         umask(0022);
 466
 467         arg_disks = hashmap_new(&string_hash_ops);
 468         if (!arg_disks) {
 469                 r = log_oom();
 470                 goto finish;
 471         }
 472
 473         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
 474         if (r < 0) {
 475                 log_warning_errno(r, "Failed to parse kernel command line: %m");
 476                 goto finish;
 477         }
 478
 479         if (!arg_enabled) {
 480                 r = 0;
 481                 goto finish;
 482         }
 483
 484         r = add_crypttab_devices();
 485         if (r < 0)
 486                 goto finish;
 487
 488         r = add_proc_cmdline_devices();
 489         if (r < 0)
 490                 goto finish;
 491
 492         r = 0;
 493
 494 finish:
 495         free_arg_disks();
 496         free(arg_default_options);
 497         free(arg_default_keyfile);
 498
 499         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 500 }