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;
  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_unlocked("# 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                        "IgnoreOnIsolate=true\n"
 113                        "After=cryptsetup-pre.target\n",
 114                        f);
 115
 116         if (!nofail)
 117                 fprintf(f,
 118                         "Before=cryptsetup.target\n");
 119
 120         if (password) {
 121                 if (STR_IN_SET(password, "/dev/urandom", "/dev/random", "/dev/hw_random"))
 122                         fputs_unlocked("After=systemd-random-seed.service\n", f);
 123                 else if (!STR_IN_SET(password, "-", "none")) {
 124                         _cleanup_free_ char *uu;
 125
 126                         uu = fstab_node_to_udev_node(password);
 127                         if (!uu)
 128                                 return log_oom();
 129
 130                         if (!path_equal(uu, "/dev/null")) {
 131
 132                                 if (is_device_path(uu)) {
 133                                         _cleanup_free_ char *dd = NULL;
 134
 135                                         r = unit_name_from_path(uu, ".device", &dd);
 136                                         if (r < 0)
 137                                                 return log_error_errno(r, "Failed to generate unit name: %m");
 138
 139                                         fprintf(f, "After=%1$s\nRequires=%1$s\n", dd);
 140                                 } else
 141                                         fprintf(f, "RequiresMountsFor=%s\n", password);
 142                         }
 143                 }
 144         }
 145
 146         if (is_device_path(u)) {
 147                 fprintf(f,
 148                         "BindsTo=%s\n"
 149                         "After=%s\n"
 150                         "Before=umount.target\n",
 151                         d, d);
 152
 153                 if (swap)
 154                         fputs_unlocked("Before=dev-mapper-%i.swap\n",
 155                                        f);
 156         } else
 157                 fprintf(f,
 158                         "RequiresMountsFor=%s\n",
 159                         u);
 160
 161         r = generator_write_timeouts(arg_dest, device, name, options, &filtered);
 162         if (r < 0)
 163                 return r;
 164
 165         fprintf(f,
 166                 "\n[Service]\n"
 167                 "Type=oneshot\n"
 168                 "RemainAfterExit=yes\n"
 169                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
 170                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n"
 171                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
 172                 name, u, strempty(password), strempty(filtered),
 173                 name);
 174
 175         if (tmp)
 176                 fprintf(f,
 177                         "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n",
 178                         name);
 179
 180         if (swap)
 181                 fprintf(f,
 182                         "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n",
 183                         name);
 184
 185         r = fflush_and_check(f);
 186         if (r < 0)
 187                 return log_error_errno(r, "Failed to write file %s: %m", p);
 188
 189         if (!noauto) {
 190                 r = generator_add_symlink(arg_dest, d, "wants", n);
 191                 if (r < 0)
 192                         return r;
 193
 194                 r = generator_add_symlink(arg_dest, "cryptsetup.target",
 195                                           nofail ? "wants" : "requires", n);
 196                 if (r < 0)
 197                         return r;
 198         }
 199
 200         dmname = strjoina("dev-mapper-", e, ".device");
 201         r = generator_add_symlink(arg_dest, dmname, "requires", n);
 202         if (r < 0)
 203                 return r;
 204
 205         if (!noauto && !nofail) {
 206                 r = write_drop_in(arg_dest, dmname, 90, "device-timeout",
 207                                   "# Automatically generated by systemd-cryptsetup-generator \n\n"
 208                                   "[Unit]\nJobTimeoutSec=0");
 209                 if (r < 0)
 210                         return log_error_errno(r, "Failed to write device drop-in: %m");
 211         }
 212
 213         return 0;
 214 }
 215
 216 static void free_arg_disks(void) {
 217         crypto_device *d;
 218
 219         while ((d = hashmap_steal_first(arg_disks))) {
 220                 free(d->uuid);
 221                 free(d->keyfile);
 222                 free(d->name);
 223                 free(d->options);
 224                 free(d);
 225         }
 226
 227         hashmap_free(arg_disks);
 228 }
 229
 230 static crypto_device *get_crypto_device(const char *uuid) {
 231         int r;
 232         crypto_device *d;
 233
 234         assert(uuid);
 235
 236         d = hashmap_get(arg_disks, uuid);
 237         if (!d) {
 238                 d = new0(struct crypto_device, 1);
 239                 if (!d)
 240                         return NULL;
 241
 242                 d->create = false;
 243                 d->keyfile = d->options = d->name = NULL;
 244
 245                 d->uuid = strdup(uuid);
 246                 if (!d->uuid)
 247                         return mfree(d);
 248
 249                 r = hashmap_put(arg_disks, d->uuid, d);
 250                 if (r < 0) {
 251                         free(d->uuid);
 252                         return mfree(d);
 253                 }
 254         }
 255
 256         return d;
 257 }
 258
 259 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 260         _cleanup_free_ char *uuid = NULL, *uuid_value = NULL;
 261         crypto_device *d;
 262         int r;
 263
 264         if (streq(key, "luks")) {
 265
 266                 r = value ? parse_boolean(value) : 1;
 267                 if (r < 0)
 268                         log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value);
 269                 else
 270                         arg_enabled = r;
 271
 272         } else if (streq(key, "luks.crypttab")) {
 273
 274                 r = value ? parse_boolean(value) : 1;
 275                 if (r < 0)
 276                         log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value);
 277                 else
 278                         arg_read_crypttab = r;
 279
 280         } else if (streq(key, "luks.uuid")) {
 281
 282                 if (proc_cmdline_value_missing(key, value))
 283                         return 0;
 284
 285                 d = get_crypto_device(startswith(value, "luks-") ? value+5 : value);
 286                 if (!d)
 287                         return log_oom();
 288
 289                 d->create = arg_whitelist = true;
 290
 291         } else if (streq(key, "luks.options")) {
 292
 293                 if (proc_cmdline_value_missing(key, value))
 294                         return 0;
 295
 296                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 297                 if (r == 2) {
 298                         d = get_crypto_device(uuid);
 299                         if (!d)
 300                                 return log_oom();
 301
 302                         free_and_replace(d->options, uuid_value);
 303                 } else if (free_and_strdup(&arg_default_options, value) < 0)
 304                         return log_oom();
 305
 306         } else if (streq(key, "luks.key")) {
 307
 308                 if (proc_cmdline_value_missing(key, value))
 309                         return 0;
 310
 311                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 312                 if (r == 2) {
 313                         d = get_crypto_device(uuid);
 314                         if (!d)
 315                                 return log_oom();
 316
 317                         free_and_replace(d->keyfile, uuid_value);
 318                 } else if (free_and_strdup(&arg_default_keyfile, value) < 0)
 319                         return log_oom();
 320
 321         } else if (streq(key, "luks.name")) {
 322
 323                 if (proc_cmdline_value_missing(key, value))
 324                         return 0;
 325
 326                 r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value);
 327                 if (r == 2) {
 328                         d = get_crypto_device(uuid);
 329                         if (!d)
 330                                 return log_oom();
 331
 332                         d->create = arg_whitelist = true;
 333
 334                         free(d->name);
 335                         d->name = uuid_value;
 336                         uuid_value = NULL;
 337                 } else
 338                         log_warning("Failed to parse luks name switch %s. Ignoring.", value);
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int add_crypttab_devices(void) {
 345         struct stat st;
 346         unsigned crypttab_line = 0;
 347         _cleanup_fclose_ FILE *f = NULL;
 348
 349         if (!arg_read_crypttab)
 350                 return 0;
 351
 352         f = fopen("/etc/crypttab", "re");
 353         if (!f) {
 354                 if (errno != ENOENT)
 355                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
 356                 return 0;
 357         }
 358
 359         if (fstat(fileno(f), &st) < 0) {
 360                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
 361                 return 0;
 362         }
 363
 364         for (;;) {
 365                 int r, k;
 366                 char line[LINE_MAX], *l, *uuid;
 367                 crypto_device *d = NULL;
 368                 _cleanup_free_ char *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL;
 369
 370                 if (!fgets(line, sizeof(line), f))
 371                         break;
 372
 373                 crypttab_line++;
 374
 375                 l = strstrip(line);
 376                 if (*l == '#' || *l == 0)
 377                         continue;
 378
 379                 k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options);
 380                 if (k < 2 || k > 4) {
 381                         log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line);
 382                         continue;
 383                 }
 384
 385                 uuid = startswith(device, "UUID=");
 386                 if (!uuid)
 387                         uuid = path_startswith(device, "/dev/disk/by-uuid/");
 388                 if (!uuid)
 389                         uuid = startswith(name, "luks-");
 390                 if (uuid)
 391                         d = hashmap_get(arg_disks, uuid);
 392
 393                 if (arg_whitelist && !d) {
 394                         log_info("Not creating device '%s' because it was not specified on the kernel command line.", name);
 395                         continue;
 396                 }
 397
 398                 r = create_disk(name, device, keyfile, (d && d->options) ? d->options : options);
 399                 if (r < 0)
 400                         return r;
 401
 402                 if (d)
 403                         d->create = false;
 404         }
 405
 406         return 0;
 407 }
 408
 409 static int add_proc_cmdline_devices(void) {
 410         int r;
 411         Iterator i;
 412         crypto_device *d;
 413
 414         HASHMAP_FOREACH(d, arg_disks, i) {
 415                 const char *options;
 416                 _cleanup_free_ char *device = NULL;
 417
 418                 if (!d->create)
 419                         continue;
 420
 421                 if (!d->name) {
 422                         d->name = strappend("luks-", d->uuid);
 423                         if (!d->name)
 424                                 return log_oom();
 425                 }
 426
 427                 device = strappend("UUID=", d->uuid);
 428                 if (!device)
 429                         return log_oom();
 430
 431                 if (d->options)
 432                         options = d->options;
 433                 else if (arg_default_options)
 434                         options = arg_default_options;
 435                 else
 436                         options = "timeout=0";
 437
 438                 r = create_disk(d->name, device, d->keyfile ?: arg_default_keyfile, options);
 439                 if (r < 0)
 440                         return r;
 441         }
 442
 443         return 0;
 444 }
 445
 446 int main(int argc, char *argv[]) {
 447         int r;
 448
 449         if (argc > 1 && argc != 4) {
 450                 log_error("This program takes three or no arguments.");
 451                 return EXIT_FAILURE;
 452         }
 453
 454         if (argc > 1)
 455                 arg_dest = argv[1];
 456
 457         log_set_target(LOG_TARGET_SAFE);
 458         log_parse_environment();
 459         log_open();
 460
 461         umask(0022);
 462
 463         arg_disks = hashmap_new(&string_hash_ops);
 464         if (!arg_disks) {
 465                 r = log_oom();
 466                 goto finish;
 467         }
 468
 469         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
 470         if (r < 0) {
 471                 log_warning_errno(r, "Failed to parse kernel command line: %m");
 472                 goto finish;
 473         }
 474
 475         if (!arg_enabled) {
 476                 r = 0;
 477                 goto finish;
 478         }
 479
 480         r = add_crypttab_devices();
 481         if (r < 0)
 482                 goto finish;
 483
 484         r = add_proc_cmdline_devices();
 485         if (r < 0)
 486                 goto finish;
 487
 488         r = 0;
 489
 490 finish:
 491         free_arg_disks();
 492         free(arg_default_options);
 493         free(arg_default_keyfile);
 494
 495         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 496 }