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-fs-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                 "KeyringMode=shared\n" /* make sure we can share cached keys among instances */
 174                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 175                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 176                 name, u, strempty(password), strempty(filtered),
 177                 name);
 178
 179         if (tmp)
 180                 fprintf(f,
 181                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 182                         name);
 183
 184         if (swap)
 185                 fprintf(f,
 186                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 187                         name);
 188
 189         r = fflush_and_check(f);
 190         if (r < 0)
 191                 return log_error_errno(r, "Failed to write file %s: %m", p);
 192
 193         if (!noauto) {
 194                 r = generator_add_symlink(arg_dest, d, "wants", n);
 195                 if (r < 0)
 196                         return r;
 197
 198                 r = generator_add_symlink(arg_dest,
 199                                           netdev ? "remote-cryptsetup.target" : "cryptsetup.target",
 200                                           nofail ? "wants" : "requires", n);
 201                 if (r < 0)
 202                         return r;
 203         }
 204
 205         dmname = strjoina("dev-mapper-", e, ".device");
 206         r = generator_add_symlink(arg_dest, dmname, "requires", n);
 207         if (r < 0)
 208                 return r;
 209
 210         if (!noauto && !nofail) {
 211                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 212                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 213                                   "[Unit]\nJobTimeoutSec=0");
 214                 if (r < 0)
 215                         return log_error_errno(r, "Failed to write device drop-in: %m");
 216         }
 217
 218         return 0;
 219 }
 220
 221 static void free_arg_disks(void) {
 222         crypto_device *d;
 223
 224         while ((d = hashmap_steal_first(arg_disks))) {
 225                 free(d->uuid);
 226                 free(d->keyfile);
 227                 free(d->name);
 228                 free(d->options);
 229                 free(d);
 230         }
 231
 232         hashmap_free(arg_disks);
 233 }
 234
 235 static crypto_device *get_crypto_device(const char *uuid) {
 236         int r;
 237         crypto_device *d;
 238
 239         assert(uuid);
 240
 241         d = hashmap_get(arg_disks, uuid);
 242         if (!d) {
 243                 d = new0(struct crypto_device, 1);
 244                 if (!d)
 245                         return NULL;
 246
 247                 d->create = false;
 248                 d->keyfile = d->options = d->name = NULL;
 249
 250                 d->uuid = strdup(uuid);
 251                 if (!d->uuid)
 252                         return mfree(d);
 253
 254                 r = hashmap_put(arg_disks, d->uuid, d);
 255                 if (r < 0) {
 256                         free(d->uuid);
 257                         return mfree(d);
 258                 }
 259         }
 260
 261         return d;
 262 }
 263
 264 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 265         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 266         crypto_device *d;
 267         int r;
 268
 269         if (streq(key, "luks")) {
 270
 271                 r = value ? parse_boolean(value) : 1;
 272                 if (r < 0)
 273                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 274                 else
 275                         arg_enabled = r;
 276
 277         } else if (streq(key, "luks.crypttab")) {
 278
 279                 r = value ? parse_boolean(value) : 1;
 280                 if (r < 0)
 281                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 282                 else
 283                         arg_read_crypttab = r;
 284
 285         } else if (streq(key, "luks.uuid")) {
 286
 287                 if (proc_cmdline_value_missing(key, value))
 288                         return 0;
 289
 290                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 291                 if (!d)
 292                         return log_oom();
 293
 294                 d->create = arg_whitelist = true;
 295
 296         } else if (streq(key, "luks.options")) {
 297
 298                 if (proc_cmdline_value_missing(key, value))
 299                         return 0;
 300
 301                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 302                 if (r == 2) {
 303                         d = get_crypto_device(uuid);
 304                         if (!d)
 305                                 return log_oom();
 306
 307                         free_and_replace(d->options, uuid_value);
 308                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 309                         return log_oom();
 310
 311         } else if (streq(key, "luks.key")) {
 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->keyfile, uuid_value);
 323                 } else if (free_and_strdup(&arg_default_keyfile, value) < 0)
 324                         return log_oom();
 325
 326         } else if (streq(key, "luks.name")) {
 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                         d->create = arg_whitelist = true;
 338
 339                         free(d->name);
 340                         d->name = uuid_value;
 341                         uuid_value = NULL;
 342                 } else
 343                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 344         }
 345
 346         return 0;
 347 }
 348
 349 static int add_crypttab_devices(void) {
 350         struct stat st;
 351         unsigned crypttab_line = 0;
 352         _cleanup_fclose_ FILE *f = NULL;
 353
 354         if (!arg_read_crypttab)
 355                 return 0;
 356
 357         f = fopen("/etc/crypttab", "re");
 358         if (!f) {
 359                 if (errno != ENOENT)
 360                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 361                 return 0;
 362         }
 363
 364         if (fstat(fileno(f), &st) < 0) {
 365                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 366                 return 0;
 367         }
 368
 369         for (;;) {
 370                 int r, k;
 371                 char line[LINE_MAX], *l, *uuid;
 372                 crypto_device *d = NULL;
 373                 _cleanup_free_ char *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 374
 375                 if (!fgets(line, sizeof(line), f))
 376                         break;
 377
 378                 crypttab_line++;
 379
 380                 l = strstrip(line);
 381                 if (IN_SET(*l, 0, '#'))
 382                         continue;
 383
 384                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 385                 if (k < 2 || k > 4) {
 386                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 387                         continue;
 388                 }
 389
 390                 uuid = startswith(device, "UUID=");
 391                 if (!uuid)
 392                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 393                 if (!uuid)
 394                         uuid = startswith(name, "luks-");
 395                 if (uuid)
 396                         d = hashmap_get(arg_disks, uuid);
 397
 398                 if (arg_whitelist && !d) {
 399                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 400                         continue;
 401                 }
 402
 403                 r = create_disk(name, device, keyfile, (d && d->options) ? d->options : options);
 404                 if (r < 0)
 405                         return r;
 406
 407                 if (d)
 408                         d->create = false;
 409         }
 410
 411         return 0;
 412 }
 413
 414 static int add_proc_cmdline_devices(void) {
 415         int r;
 416         Iterator i;
 417         crypto_device *d;
 418
 419         HASHMAP_FOREACH(d, arg_disks, i) {
 420                 const char *options;
 421                 _cleanup_free_ char *device = NULL;
 422
 423                 if (!d->create)
 424                         continue;
 425
 426                 if (!d->name) {
 427                         d->name = strappend("luks-", d->uuid);
 428                         if (!d->name)
 429                                 return log_oom();
 430                 }
 431
 432                 device = strappend("UUID=", d->uuid);
 433                 if (!device)
 434                         return log_oom();
 435
 436                 if (d->options)
 437                         options = d->options;
 438                 else if (arg_default_options)
 439                         options = arg_default_options;
 440                 else
 441                         options = "timeout=0";
 442
 443                 r = create_disk(d->name, device, d->keyfile ?: arg_default_keyfile, options);
 444                 if (r < 0)
 445                         return r;
 446         }
 447
 448         return 0;
 449 }
 450
 451 int main(int argc, char *argv[]) {
 452         int r;
 453
 454         if (argc > 1 && argc != 4) {
 455                 log_error("This program takes three or no arguments.");
 456                 return EXIT_FAILURE;
 457         }
 458
 459         if (argc > 1)
 460                 arg_dest = argv[1];
 461
 462         log_set_target(LOG_TARGET_SAFE);
 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         free_arg_disks();
 497         free(arg_default_options);
 498         free(arg_default_keyfile);
 499
 500         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 501 }