src/gpt-auto-generator/gpt-auto-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <blkid.h>
   4 #include <stdlib.h>
   5 #include <sys/statfs.h>
   6 #include <unistd.h>
   7
   8 #include "sd-device.h"
   9 #include "sd-id128.h"
  10
  11 #include "alloc-util.h"
  12 #include "blkid-util.h"
  13 #include "blockdev-util.h"
  14 #include "btrfs-util.h"
  15 #include "dirent-util.h"
  16 #include "dissect-image.h"
  17 #include "efivars.h"
  18 #include "fd-util.h"
  19 #include "fileio.h"
  20 #include "fstab-util.h"
  21 #include "generator.h"
  22 #include "gpt.h"
  23 #include "missing.h"
  24 #include "mkdir.h"
  25 #include "mount-util.h"
  26 #include "parse-util.h"
  27 #include "path-util.h"
  28 #include "proc-cmdline.h"
  29 #include "special.h"
  30 #include "specifier.h"
  31 #include "stat-util.h"
  32 #include "string-util.h"
  33 #include "strv.h"
  34 #include "unit-name.h"
  35 #include "util.h"
  36 #include "virt.h"
  37
  38 static const char *arg_dest = "/tmp";
  39 static bool arg_enabled = true;
  40 static bool arg_root_enabled = true;
  41 static bool arg_root_rw = false;
  42
  43 static int add_cryptsetup(const char *id, const char *what, bool rw, bool require, char **device) {
  44         _cleanup_free_ char *e = NULL, *n = NULL, *d = NULL, *id_escaped = NULL, *what_escaped = NULL;
  45         _cleanup_fclose_ FILE *f = NULL;
  46         const char *p;
  47         int r;
  48
  49         assert(id);
  50         assert(what);
  51
  52         r = unit_name_from_path(what, ".device", &d);
  53         if (r < 0)
  54                 return log_error_errno(r, "Failed to generate unit name: %m");
  55
  56         e = unit_name_escape(id);
  57         if (!e)
  58                 return log_oom();
  59
  60         r = unit_name_build("systemd-cryptsetup", e, ".service", &n);
  61         if (r < 0)
  62                 return log_error_errno(r, "Failed to generate unit name: %m");
  63
  64         id_escaped = specifier_escape(id);
  65         if (!id_escaped)
  66                 return log_oom();
  67
  68         what_escaped = specifier_escape(what);
  69         if (!what_escaped)
  70                 return log_oom();
  71
  72         p = strjoina(arg_dest, "/", n);
  73         f = fopen(p, "wxe");
  74         if (!f)
  75                 return log_error_errno(errno, "Failed to create unit file %s: %m", p);
  76
  77         fprintf(f,
  78                 "# Automatically generated by systemd-gpt-auto-generator\n\n"
  79                 "[Unit]\n"
  80                 "Description=Cryptography Setup for %%I\n"
  81                 "Documentation=man:systemd-gpt-auto-generator(8) man:systemd-cryptsetup@.service(8)\n"
  82                 "DefaultDependencies=no\n"
  83                 "Conflicts=umount.target\n"
  84                 "BindsTo=dev-mapper-%%i.device %s\n"
  85                 "Before=umount.target cryptsetup.target\n"
  86                 "After=%s\n"
  87                 "IgnoreOnIsolate=true\n"
  88                 "[Service]\n"
  89                 "Type=oneshot\n"
  90                 "RemainAfterExit=yes\n"
  91                 "TimeoutSec=0\n" /* the binary handles timeouts anyway */
  92                 "KeyringMode=shared\n" /* make sure we can share cached keys among instances */
  93                 "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '' '%s'\n"
  94                 "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
  95                 d, d,
  96                 id_escaped, what_escaped, rw ? "" : "read-only",
  97                 id_escaped);
  98
  99         r = fflush_and_check(f);
 100         if (r < 0)
 101                 return log_error_errno(r, "Failed to write file %s: %m", p);
 102
 103         r = generator_add_symlink(arg_dest, d, "wants", n);
 104         if (r < 0)
 105                 return r;
 106
 107         if (require) {
 108                 const char *dmname;
 109
 110                 r = generator_add_symlink(arg_dest, "cryptsetup.target", "requires", n);
 111                 if (r < 0)
 112                         return r;
 113
 114                 dmname = strjoina("dev-mapper-", e, ".device");
 115                 r = generator_add_symlink(arg_dest, dmname, "requires", n);
 116                 if (r < 0)
 117                         return r;
 118         }
 119
 120         p = strjoina(arg_dest, "/dev-mapper-", e, ".device.d/50-job-timeout-sec-0.conf");
 121         mkdir_parents_label(p, 0755);
 122         r = write_string_file(p,
 123                         "# Automatically generated by systemd-gpt-auto-generator\n\n"
 124                         "[Unit]\n"
 125                         "JobTimeoutSec=0\n",
 126                         WRITE_STRING_FILE_CREATE); /* the binary handles timeouts anyway */
 127         if (r < 0)
 128                 return log_error_errno(r, "Failed to write device drop-in: %m");
 129
 130         if (device) {
 131                 char *ret;
 132
 133                 ret = strappend("/dev/mapper/", id);
 134                 if (!ret)
 135                         return log_oom();
 136
 137                 *device = ret;
 138         }
 139
 140         return 0;
 141 }
 142
 143 static int add_mount(
 144                 const char *id,
 145                 const char *what,
 146                 const char *where,
 147                 const char *fstype,
 148                 bool rw,
 149                 const char *options,
 150                 const char *description,
 151                 const char *post) {
 152
 153         _cleanup_free_ char *unit = NULL, *crypto_what = NULL, *p = NULL;
 154         _cleanup_fclose_ FILE *f = NULL;
 155         int r;
 156
 157         /* Note that we don't apply specifier escaping on the input strings here, since we know they are not configured
 158          * externally, but all originate from our own sources here, and hence we know they contain no % characters that
 159          * could potentially be understood as specifiers. */
 160
 161         assert(id);
 162         assert(what);
 163         assert(where);
 164         assert(description);
 165
 166         log_debug("Adding %s: %s %s", where, what, strna(fstype));
 167
 168         if (streq_ptr(fstype, "crypto_LUKS")) {
 169
 170                 r = add_cryptsetup(id, what, rw, true, &crypto_what);
 171                 if (r < 0)
 172                         return r;
 173
 174                 what = crypto_what;
 175                 fstype = NULL;
 176         }
 177
 178         r = unit_name_from_path(where, ".mount", &unit);
 179         if (r < 0)
 180                 return log_error_errno(r, "Failed to generate unit name: %m");
 181
 182         p = strjoin(arg_dest, "/", unit);
 183         if (!p)
 184                 return log_oom();
 185
 186         f = fopen(p, "wxe");
 187         if (!f)
 188                 return log_error_errno(errno, "Failed to create unit file %s: %m", unit);
 189
 190         fprintf(f,
 191                 "# Automatically generated by systemd-gpt-auto-generator\n\n"
 192                 "[Unit]\n"
 193                 "Description=%s\n"
 194                 "Documentation=man:systemd-gpt-auto-generator(8)\n",
 195                 description);
 196
 197         if (post)
 198                 fprintf(f, "Before=%s\n", post);
 199
 200         r = generator_write_fsck_deps(f, arg_dest, what, where, fstype);
 201         if (r < 0)
 202                 return r;
 203
 204         fprintf(f,
 205                 "\n"
 206                 "[Mount]\n"
 207                 "What=%s\n"
 208                 "Where=%s\n",
 209                 what, where);
 210
 211         if (fstype)
 212                 fprintf(f, "Type=%s\n", fstype);
 213
 214         if (options)
 215                 fprintf(f, "Options=%s,%s\n", options, rw ? "rw" : "ro");
 216         else
 217                 fprintf(f, "Options=%s\n", rw ? "rw" : "ro");
 218
 219         r = fflush_and_check(f);
 220         if (r < 0)
 221                 return log_error_errno(r, "Failed to write unit file %s: %m", p);
 222
 223         if (post)
 224                 return generator_add_symlink(arg_dest, post, "requires", unit);
 225         return 0;
 226 }
 227
 228 static int path_is_busy(const char *where) {
 229         int r;
 230
 231         /* already a mountpoint; generators run during reload */
 232         r = path_is_mount_point(where, NULL, AT_SYMLINK_FOLLOW);
 233         if (r > 0)
 234                 return false;
 235
 236         /* the directory might not exist on a stateless system */
 237         if (r == -ENOENT)
 238                 return false;
 239
 240         if (r < 0)
 241                 return log_warning_errno(r, "Cannot check if \"%s\" is a mount point: %m", where);
 242
 243         /* not a mountpoint but it contains files */
 244         r = dir_is_empty(where);
 245         if (r < 0)
 246                 return log_warning_errno(r, "Cannot check if \"%s\" is empty: %m", where);
 247         if (r > 0)
 248                 return false;
 249
 250         log_debug("\"%s\" already populated, ignoring.", where);
 251         return true;
 252 }
 253
 254 static int add_partition_mount(
 255                 DissectedPartition *p,
 256                 const char *id,
 257                 const char *where,
 258                 const char *description) {
 259
 260         int r;
 261         assert(p);
 262
 263         r = path_is_busy(where);
 264         if (r != 0)
 265                 return r < 0 ? r : 0;
 266
 267         return add_mount(
 268                         id,
 269                         p->node,
 270                         where,
 271                         p->fstype,
 272                         p->rw,
 273                         NULL,
 274                         description,
 275                         SPECIAL_LOCAL_FS_TARGET);
 276 }
 277
 278 static int add_swap(const char *path) {
 279         _cleanup_free_ char *name = NULL, *unit = NULL;
 280         _cleanup_fclose_ FILE *f = NULL;
 281         int r;
 282
 283         assert(path);
 284
 285         /* Disable the swap auto logic if at least one swap is defined in /etc/fstab, see #6192. */
 286         r = fstab_has_fstype("swap");
 287         if (r < 0)
 288                 return log_error_errno(r, "Failed to parse fstab: %m");
 289         if (r > 0) {
 290                 log_debug("swap specified in fstab, ignoring.");
 291                 return 0;
 292         }
 293
 294         log_debug("Adding swap: %s", path);
 295
 296         r = unit_name_from_path(path, ".swap", &name);
 297         if (r < 0)
 298                 return log_error_errno(r, "Failed to generate unit name: %m");
 299
 300         unit = strjoin(arg_dest, "/", name);
 301         if (!unit)
 302                 return log_oom();
 303
 304         f = fopen(unit, "wxe");
 305         if (!f)
 306                 return log_error_errno(errno, "Failed to create unit file %s: %m", unit);
 307
 308         fprintf(f,
 309                 "# Automatically generated by systemd-gpt-auto-generator\n\n"
 310                 "[Unit]\n"
 311                 "Description=Swap Partition\n"
 312                 "Documentation=man:systemd-gpt-auto-generator(8)\n\n"
 313                 "[Swap]\n"
 314                 "What=%s\n",
 315                 path);
 316
 317         r = fflush_and_check(f);
 318         if (r < 0)
 319                 return log_error_errno(r, "Failed to write unit file %s: %m", unit);
 320
 321         return generator_add_symlink(arg_dest, SPECIAL_SWAP_TARGET, "wants", name);
 322 }
 323
 324 #if ENABLE_EFI
 325 static int add_automount(
 326                 const char *id,
 327                 const char *what,
 328                 const char *where,
 329                 const char *fstype,
 330                 bool rw,
 331                 const char *options,
 332                 const char *description,
 333                 usec_t timeout) {
 334
 335         _cleanup_free_ char *unit = NULL;
 336         _cleanup_fclose_ FILE *f = NULL;
 337         const char *opt = "noauto", *p;
 338         int r;
 339
 340         assert(id);
 341         assert(where);
 342         assert(description);
 343
 344         if (options)
 345                 opt = strjoina(options, ",", opt);
 346
 347         r = add_mount(id,
 348                       what,
 349                       where,
 350                       fstype,
 351                       rw,
 352                       opt,
 353                       description,
 354                       NULL);
 355         if (r < 0)
 356                 return r;
 357
 358         r = unit_name_from_path(where, ".automount", &unit);
 359         if (r < 0)
 360                 return log_error_errno(r, "Failed to generate unit name: %m");
 361
 362         p = strjoina(arg_dest, "/", unit);
 363         f = fopen(p, "wxe");
 364         if (!f)
 365                 return log_error_errno(errno, "Failed to create unit file %s: %m", unit);
 366
 367         fprintf(f,
 368                 "# Automatically generated by systemd-gpt-auto-generator\n\n"
 369                 "[Unit]\n"
 370                 "Description=%s\n"
 371                 "Documentation=man:systemd-gpt-auto-generator(8)\n"
 372                 "[Automount]\n"
 373                 "Where=%s\n"
 374                 "TimeoutIdleSec="USEC_FMT"\n",
 375                 description,
 376                 where,
 377                 timeout / USEC_PER_SEC);
 378
 379         r = fflush_and_check(f);
 380         if (r < 0)
 381                 return log_error_errno(r, "Failed to write unit file %s: %m", p);
 382
 383         return generator_add_symlink(arg_dest, SPECIAL_LOCAL_FS_TARGET, "wants", unit);
 384 }
 385
 386 static int add_esp(DissectedPartition *p) {
 387         const char *esp;
 388         int r;
 389
 390         assert(p);
 391
 392         if (in_initrd()) {
 393                 log_debug("In initrd, ignoring the ESP.");
 394                 return 0;
 395         }
 396
 397         /* If /efi exists we'll use that. Otherwise we'll use /boot, as that's usually the better choice */
 398         esp = access("/efi/", F_OK) >= 0 ? "/efi" : "/boot";
 399
 400         /* We create an .automount which is not overridden by the .mount from the fstab generator. */
 401         r = fstab_is_mount_point(esp);
 402         if (r < 0)
 403                 return log_error_errno(r, "Failed to parse fstab: %m");
 404         if (r > 0) {
 405                 log_debug("%s specified in fstab, ignoring.", esp);
 406                 return 0;
 407         }
 408
 409         r = path_is_busy(esp);
 410         if (r != 0)
 411                 return r < 0 ? r : 0;
 412
 413         if (is_efi_boot()) {
 414                 sd_id128_t loader_uuid;
 415
 416                 /* If this is an EFI boot, be extra careful, and only mount the ESP if it was the ESP used for booting. */
 417
 418                 r = efi_loader_get_device_part_uuid(&loader_uuid);
 419                 if (r == -ENOENT) {
 420                         log_debug("EFI loader partition unknown.");
 421                         return 0;
 422                 }
 423                 if (r < 0)
 424                         return log_error_errno(r, "Failed to read ESP partition UUID: %m");
 425
 426                 if (!sd_id128_equal(p->uuid, loader_uuid)) {
 427                         log_debug("Partition for %s does not appear to be the partition we are booted from.", esp);
 428                         return 0;
 429                 }
 430         } else
 431                 log_debug("Not an EFI boot, skipping ESP check.");
 432
 433         return add_automount("boot",
 434                              p->node,
 435                              esp,
 436                              p->fstype,
 437                              true,
 438                              "umask=0077",
 439                              "EFI System Partition Automount",
 440                              120 * USEC_PER_SEC);
 441 }
 442 #else
 443 static int add_esp(DissectedPartition *p) {
 444         return 0;
 445 }
 446 #endif
 447
 448 static int open_parent(dev_t devnum, int *ret) {
 449         _cleanup_(sd_device_unrefp) sd_device *d = NULL;
 450         const char *name, *devtype, *node;
 451         sd_device *parent;
 452         dev_t pn;
 453         int fd, r;
 454
 455         assert(ret);
 456
 457         r = sd_device_new_from_devnum(&d, 'b', devnum);
 458         if (r < 0)
 459                 return log_debug_errno(r, "Failed to open device: %m");
 460
 461         if (sd_device_get_devname(d, &name) < 0) {
 462                 r = sd_device_get_syspath(d, &name);
 463                 if (r < 0) {
 464                         log_debug_errno(r, "Device %u:%u does not have a name, ignoring: %m", major(devnum), minor(devnum));
 465                         return 0;
 466                 }
 467         }
 468
 469         r = sd_device_get_parent(d, &parent);
 470         if (r < 0) {
 471                 log_debug_errno(r, "%s: not a partitioned device, ignoring: %m", name);
 472                 return 0;
 473         }
 474
 475         /* Does it have a devtype? */
 476         r = sd_device_get_devtype(parent, &devtype);
 477         if (r < 0) {
 478                 log_debug_errno(r, "%s: parent doesn't have a device type, ignoring: %m", name);
 479                 return 0;
 480         }
 481
 482         /* Is this a disk or a partition? We only care for disks... */
 483         if (!streq(devtype, "disk")) {
 484                 log_debug("%s: parent isn't a raw disk, ignoring.", name);
 485                 return 0;
 486         }
 487
 488         /* Does it have a device node? */
 489         r = sd_device_get_devname(parent, &node);
 490         if (r < 0) {
 491                 log_debug_errno(r, "%s: parent device does not have device node, ignoring: %m", name);
 492                 return 0;
 493         }
 494
 495         log_debug("%s: root device %s.", name, node);
 496
 497         r = sd_device_get_devnum(parent, &pn);
 498         if (r < 0) {
 499                 log_debug_errno(r, "%s: parent device is not a proper block device, ignoring: %m", name);
 500                 return 0;
 501         }
 502
 503         fd = open(node, O_RDONLY|O_CLOEXEC|O_NOCTTY);
 504         if (fd < 0)
 505                 return log_error_errno(errno, "Failed to open %s: %m", node);
 506
 507         *ret = fd;
 508         return 1;
 509 }
 510
 511 static int enumerate_partitions(dev_t devnum) {
 512         _cleanup_close_ int fd = -1;
 513         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 514         int r, k;
 515
 516         r = open_parent(devnum, &fd);
 517         if (r <= 0)
 518                 return r;
 519
 520         r = dissect_image(fd, NULL, 0, DISSECT_IMAGE_GPT_ONLY, &m);
 521         if (r == -ENOPKG) {
 522                 log_debug_errno(r, "No suitable partition table found, ignoring.");
 523                 return 0;
 524         }
 525         if (r < 0)
 526                 return log_error_errno(r, "Failed to dissect: %m");
 527
 528         if (m->partitions[PARTITION_SWAP].found) {
 529                 k = add_swap(m->partitions[PARTITION_SWAP].node);
 530                 if (k < 0)
 531                         r = k;
 532         }
 533
 534         if (m->partitions[PARTITION_ESP].found) {
 535                 k = add_esp(m->partitions + PARTITION_ESP);
 536                 if (k < 0)
 537                         r = k;
 538         }
 539
 540         if (m->partitions[PARTITION_HOME].found) {
 541                 k = add_partition_mount(m->partitions + PARTITION_HOME, "home", "/home", "Home Partition");
 542                 if (k < 0)
 543                         r = k;
 544         }
 545
 546         if (m->partitions[PARTITION_SRV].found) {
 547                 k = add_partition_mount(m->partitions + PARTITION_SRV, "srv", "/srv", "Server Data Partition");
 548                 if (k < 0)
 549                         r = k;
 550         }
 551
 552         return r;
 553 }
 554
 555 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 556         int r;
 557
 558         assert(key);
 559
 560         if (STR_IN_SET(key, "systemd.gpt_auto", "rd.systemd.gpt_auto")) {
 561
 562                 r = value ? parse_boolean(value) : 1;
 563                 if (r < 0)
 564                         log_warning("Failed to parse gpt-auto switch \"%s\". Ignoring.", value);
 565                 else
 566                         arg_enabled = r;
 567
 568         } else if (streq(key, "root")) {
 569
 570                 if (proc_cmdline_value_missing(key, value))
 571                         return 0;
 572
 573                 /* Disable root disk logic if there's a root= value
 574                  * specified (unless it happens to be "gpt-auto") */
 575
 576                 arg_root_enabled = streq(value, "gpt-auto");
 577
 578         } else if (streq(key, "roothash")) {
 579
 580                 if (proc_cmdline_value_missing(key, value))
 581                         return 0;
 582
 583                 /* Disable root disk logic if there's roothash= defined (i.e. verity enabled) */
 584
 585                 arg_root_enabled = false;
 586
 587         } else if (streq(key, "rw") && !value)
 588                 arg_root_rw = true;
 589         else if (streq(key, "ro") && !value)
 590                 arg_root_rw = false;
 591
 592         return 0;
 593 }
 594
 595 #if ENABLE_EFI
 596 static int add_root_cryptsetup(void) {
 597
 598         /* If a device /dev/gpt-auto-root-luks appears, then make it pull in systemd-cryptsetup-root.service, which
 599          * sets it up, and causes /dev/gpt-auto-root to appear which is all we are looking for. */
 600
 601         return add_cryptsetup("root", "/dev/gpt-auto-root-luks", true, false, NULL);
 602 }
 603 #endif
 604
 605 static int add_root_mount(void) {
 606
 607 #if ENABLE_EFI
 608         int r;
 609
 610         if (!is_efi_boot()) {
 611                 log_debug("Not a EFI boot, not creating root mount.");
 612                 return 0;
 613         }
 614
 615         r = efi_loader_get_device_part_uuid(NULL);
 616         if (r == -ENOENT) {
 617                 log_debug("EFI loader partition unknown, exiting.");
 618                 return 0;
 619         } else if (r < 0)
 620                 return log_error_errno(r, "Failed to read ESP partition UUID: %m");
 621
 622         /* OK, we have an ESP partition, this is fantastic, so let's
 623          * wait for a root device to show up. A udev rule will create
 624          * the link for us under the right name. */
 625
 626         if (in_initrd()) {
 627                 r = generator_write_initrd_root_device_deps(arg_dest, "/dev/gpt-auto-root");
 628                 if (r < 0)
 629                         return 0;
 630
 631                 r = add_root_cryptsetup();
 632                 if (r < 0)
 633                         return r;
 634         }
 635
 636         return add_mount(
 637                         "root",
 638                         "/dev/gpt-auto-root",
 639                         in_initrd() ? "/sysroot" : "/",
 640                         NULL,
 641                         arg_root_rw,
 642                         NULL,
 643                         "Root Partition",
 644                         in_initrd() ? SPECIAL_INITRD_ROOT_FS_TARGET : SPECIAL_LOCAL_FS_TARGET);
 645 #else
 646         return 0;
 647 #endif
 648 }
 649
 650 static int add_mounts(void) {
 651         dev_t devno;
 652         int r;
 653
 654         r = get_block_device_harder("/", &devno);
 655         if (r < 0)
 656                 return log_error_errno(r, "Failed to determine block device of root file system: %m");
 657         if (r == 0) {
 658                 r = get_block_device_harder("/usr", &devno);
 659                 if (r < 0)
 660                         return log_error_errno(r, "Failed to determine block device of /usr file system: %m");
 661                 if (r == 0) {
 662                         log_debug("Neither root nor /usr file system are on a (single) block device.");
 663                         return 0;
 664                 }
 665         }
 666
 667         return enumerate_partitions(devno);
 668 }
 669
 670 int main(int argc, char *argv[]) {
 671         int r, k;
 672
 673         if (argc > 1 && argc != 4) {
 674                 log_error("This program takes three or no arguments.");
 675                 return EXIT_FAILURE;
 676         }
 677
 678         if (argc > 1)
 679                 arg_dest = argv[3];
 680
 681         log_set_prohibit_ipc(true);
 682         log_set_target(LOG_TARGET_AUTO);
 683         log_parse_environment();
 684         log_open();
 685
 686         umask(0022);
 687
 688         if (detect_container() > 0) {
 689                 log_debug("In a container, exiting.");
 690                 return EXIT_SUCCESS;
 691         }
 692
 693         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
 694         if (r < 0)
 695                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 696
 697         if (!arg_enabled) {
 698                 log_debug("Disabled, exiting.");
 699                 return EXIT_SUCCESS;
 700         }
 701
 702         if (arg_root_enabled)
 703                 r = add_root_mount();
 704         else
 705                 r = 0;
 706
 707         if (!in_initrd()) {
 708                 k = add_mounts();
 709                 if (k < 0)
 710                         r = k;
 711         }
 712
 713         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 714 }