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