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