src/import/pull-common.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sys/prctl.h>
   4
   5 #include "alloc-util.h"
   6 #include "btrfs-util.h"
   7 #include "capability-util.h"
   8 #include "copy.h"
   9 #include "dirent-util.h"
  10 #include "escape.h"
  11 #include "fd-util.h"
  12 #include "hostname-util.h"
  13 #include "io-util.h"
  14 #include "memory-util.h"
  15 #include "path-util.h"
  16 #include "process-util.h"
  17 #include "pull-common.h"
  18 #include "pull-job.h"
  19 #include "rlimit-util.h"
  20 #include "rm-rf.h"
  21 #include "signal-util.h"
  22 #include "siphash24.h"
  23 #include "string-util.h"
  24 #include "strv.h"
  25 #include "web-util.h"
  26
  27 #define FILENAME_ESCAPE "/.#\"\'"
  28 #define HASH_URL_THRESHOLD_LENGTH (_POSIX_PATH_MAX - 16)
  29
  30 int pull_find_old_etags(
  31                 const char *url,
  32                 const char *image_root,
  33                 int dt,
  34                 const char *prefix,
  35                 const char *suffix,
  36                 char ***etags) {
  37
  38         int r;
  39
  40         assert(url);
  41         assert(etags);
  42
  43         if (!image_root)
  44                 image_root = "/var/lib/machines";
  45
  46         _cleanup_free_ char *escaped_url = xescape(url, FILENAME_ESCAPE);
  47         if (!escaped_url)
  48                 return -ENOMEM;
  49
  50         _cleanup_closedir_ DIR *d = opendir(image_root);
  51         if (!d) {
  52                 if (errno == ENOENT) {
  53                         *etags = NULL;
  54                         return 0;
  55                 }
  56
  57                 return -errno;
  58         }
  59
  60         _cleanup_strv_free_ char **ans = NULL;
  61
  62         FOREACH_DIRENT_ALL(de, d, return -errno) {
  63                 _cleanup_free_ char *u = NULL;
  64                 const char *a, *b;
  65
  66                 if (de->d_type != DT_UNKNOWN &&
  67                     de->d_type != dt)
  68                         continue;
  69
  70                 if (prefix) {
  71                         a = startswith(de->d_name, prefix);
  72                         if (!a)
  73                                 continue;
  74                 } else
  75                         a = de->d_name;
  76
  77                 a = startswith(a, escaped_url);
  78                 if (!a)
  79                         continue;
  80
  81                 a = startswith(a, ".");
  82                 if (!a)
  83                         continue;
  84
  85                 if (suffix) {
  86                         b = endswith(de->d_name, suffix);
  87                         if (!b)
  88                                 continue;
  89                 } else
  90                         b = strchr(de->d_name, 0);
  91
  92                 if (a >= b)
  93                         continue;
  94
  95                 ssize_t l = cunescape_length(a, b - a, 0, &u);
  96                 if (l < 0) {
  97                         assert(l >= INT8_MIN);
  98                         return l;
  99                 }
 100
 101                 if (!http_etag_is_valid(u))
 102                         continue;
 103
 104                 r = strv_consume(&ans, TAKE_PTR(u));
 105                 if (r < 0)
 106                         return r;
 107         }
 108
 109         *etags = TAKE_PTR(ans);
 110
 111         return 0;
 112 }
 113
 114 static int hash_url(const char *url, char **ret) {
 115         uint64_t h;
 116         static const sd_id128_t k = SD_ID128_ARRAY(df,89,16,87,01,cc,42,30,98,ab,4a,19,a6,a5,63,4f);
 117
 118         assert(url);
 119
 120         h = siphash24(url, strlen(url), k.bytes);
 121         if (asprintf(ret, "%"PRIx64, h) < 0)
 122                 return -ENOMEM;
 123
 124         return 0;
 125 }
 126
 127 int pull_make_path(const char *url, const char *etag, const char *image_root, const char *prefix, const char *suffix, char **ret) {
 128         _cleanup_free_ char *escaped_url = NULL, *escaped_etag = NULL;
 129         char *path;
 130
 131         assert(url);
 132         assert(ret);
 133
 134         if (!image_root)
 135                 image_root = "/var/lib/machines";
 136
 137         escaped_url = xescape(url, FILENAME_ESCAPE);
 138         if (!escaped_url)
 139                 return -ENOMEM;
 140
 141         if (etag) {
 142                 escaped_etag = xescape(etag, FILENAME_ESCAPE);
 143                 if (!escaped_etag)
 144                         return -ENOMEM;
 145         }
 146
 147         path = strjoin(image_root, "/", strempty(prefix), escaped_url, escaped_etag ? "." : "",
 148                        strempty(escaped_etag), strempty(suffix));
 149         if (!path)
 150                 return -ENOMEM;
 151
 152         /* URLs might make the path longer than the maximum allowed length for a file name.
 153          * When that happens, a URL hash is used instead. Paths returned by this function
 154          * can be later used with tempfn_random() which adds 16 bytes to the resulting name. */
 155         if (strlen(path) >= HASH_URL_THRESHOLD_LENGTH) {
 156                 _cleanup_free_ char *hash = NULL;
 157                 int r;
 158
 159                 free(path);
 160
 161                 r = hash_url(url, &hash);
 162                 if (r < 0)
 163                         return r;
 164
 165                 path = strjoin(image_root, "/", strempty(prefix), hash, escaped_etag ? "." : "",
 166                                strempty(escaped_etag), strempty(suffix));
 167                 if (!path)
 168                         return -ENOMEM;
 169         }
 170
 171         *ret = path;
 172         return 0;
 173 }
 174
 175 int pull_make_auxiliary_job(
 176                 PullJob **ret,
 177                 const char *url,
 178                 int (*strip_suffixes)(const char *name, char **ret),
 179                 const char *suffix,
 180                 ImportVerify verify,
 181                 CurlGlue *glue,
 182                 PullJobOpenDisk on_open_disk,
 183                 PullJobFinished on_finished,
 184                 void *userdata) {
 185
 186         _cleanup_free_ char *last_component = NULL, *ll = NULL, *auxiliary_url = NULL;
 187         _cleanup_(pull_job_unrefp) PullJob *job = NULL;
 188         const char *q;
 189         int r;
 190
 191         assert(ret);
 192         assert(url);
 193         assert(strip_suffixes);
 194         assert(glue);
 195
 196         r = import_url_last_component(url, &last_component);
 197         if (r < 0)
 198                 return r;
 199
 200         r = strip_suffixes(last_component, &ll);
 201         if (r < 0)
 202                 return r;
 203
 204         q = strjoina(ll, suffix);
 205
 206         r = import_url_change_last_component(url, q, &auxiliary_url);
 207         if (r < 0)
 208                 return r;
 209
 210         r = pull_job_new(&job, auxiliary_url, glue, userdata);
 211         if (r < 0)
 212                 return r;
 213
 214         job->on_open_disk = on_open_disk;
 215         job->on_finished = on_finished;
 216         job->compressed_max = job->uncompressed_max = 1ULL * 1024ULL * 1024ULL;
 217         job->calc_checksum = IN_SET(verify, IMPORT_VERIFY_CHECKSUM, IMPORT_VERIFY_SIGNATURE);
 218
 219         *ret = TAKE_PTR(job);
 220         return 0;
 221 }
 222
 223 static bool is_checksum_file(const char *fn) {
 224         /* Returns true if the specified filename refers to a checksum file we grok */
 225
 226         if (!fn)
 227                 return false;
 228
 229         return streq(fn, "SHA256SUMS") || endswith(fn, ".sha256");
 230 }
 231
 232 static bool is_signature_file(const char *fn) {
 233         /* Returns true if the specified filename refers to a signature file we grok (reminder:
 234          * suse-style .sha256 files are inline signed) */
 235
 236         if (!fn)
 237                 return false;
 238
 239         return streq(fn, "SHA256SUMS.gpg") || endswith(fn, ".sha256");
 240 }
 241
 242 int pull_make_verification_jobs(
 243                 PullJob **ret_checksum_job,
 244                 PullJob **ret_signature_job,
 245                 ImportVerify verify,
 246                 const char *checksum, /* set if literal checksum verification is requested, in which case 'verify' is set to _IMPORT_VERIFY_INVALID */
 247                 const char *url,
 248                 CurlGlue *glue,
 249                 PullJobFinished on_finished,
 250                 void *userdata) {
 251
 252         _cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;
 253         _cleanup_free_ char *fn = NULL;
 254         int r;
 255
 256         assert(ret_checksum_job);
 257         assert(ret_signature_job);
 258         assert(verify == _IMPORT_VERIFY_INVALID || verify < _IMPORT_VERIFY_MAX);
 259         assert(verify == _IMPORT_VERIFY_INVALID || verify >= 0);
 260         assert((verify < 0) || !checksum);
 261         assert(url);
 262         assert(glue);
 263
 264         /* If verification is turned off, or if the checksum to validate is already specified we don't need
 265          * to download a checksum file or signature, hence shortcut things */
 266         if (verify == IMPORT_VERIFY_NO || checksum) {
 267                 *ret_checksum_job = *ret_signature_job = NULL;
 268                 return 0;
 269         }
 270
 271         r = import_url_last_component(url, &fn);
 272         if (r < 0 && r != -EADDRNOTAVAIL) /* EADDRNOTAVAIL means there was no last component, which is OK for
 273                                            * us, we'll just assume it's not a checksum/signature file */
 274                 return r;
 275
 276         /* Acquire the checksum file if verification or signature verification is requested and the main file
 277          * to acquire isn't a checksum or signature file anyway */
 278         if (verify != IMPORT_VERIFY_NO && !is_checksum_file(fn) && !is_signature_file(fn)) {
 279                 _cleanup_free_ char *checksum_url = NULL;
 280                 const char *suffixed = NULL;
 281
 282                 /* Queue jobs for the checksum file for the image. */
 283
 284                 if (fn)
 285                         suffixed = strjoina(fn, ".sha256"); /* Start with the suse-style checksum (if there's a base filename) */
 286                 else
 287                         suffixed = "SHA256SUMS";
 288
 289                 r = import_url_change_last_component(url, suffixed, &checksum_url);
 290                 if (r < 0)
 291                         return r;
 292
 293                 r = pull_job_new(&checksum_job, checksum_url, glue, userdata);
 294                 if (r < 0)
 295                         return r;
 296
 297                 checksum_job->on_finished = on_finished;
 298                 checksum_job->uncompressed_max = checksum_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 299                 checksum_job->on_not_found = pull_job_restart_with_sha256sum; /* if this fails, look for ubuntu-style checksum */
 300         }
 301
 302         if (verify == IMPORT_VERIFY_SIGNATURE && !is_signature_file(fn)) {
 303                 _cleanup_free_ char *signature_url = NULL;
 304
 305                 /* Queue job for the SHA256SUMS.gpg file for the image. */
 306                 r = import_url_change_last_component(url, "SHA256SUMS.gpg", &signature_url);
 307                 if (r < 0)
 308                         return r;
 309
 310                 r = pull_job_new(&signature_job, signature_url, glue, userdata);
 311                 if (r < 0)
 312                         return r;
 313
 314                 signature_job->on_finished = on_finished;
 315                 signature_job->uncompressed_max = signature_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 316         }
 317
 318         *ret_checksum_job = TAKE_PTR(checksum_job);
 319         *ret_signature_job = TAKE_PTR(signature_job);
 320         return 0;
 321 }
 322
 323 static int verify_one(PullJob *checksum_job, PullJob *job) {
 324         _cleanup_free_ char *fn = NULL;
 325         const char *line, *p;
 326         int r;
 327
 328         assert(checksum_job);
 329
 330         if (!job)
 331                 return 0;
 332
 333         assert(IN_SET(job->state, PULL_JOB_DONE, PULL_JOB_FAILED));
 334
 335         /* Don't verify the checksum if we didn't actually successfully download something new */
 336         if (job->state != PULL_JOB_DONE)
 337                 return 0;
 338         if (job->error != 0)
 339                 return 0;
 340         if (job->etag_exists)
 341                 return 0;
 342
 343         assert(job->calc_checksum);
 344         assert(job->checksum);
 345
 346         r = import_url_last_component(job->url, &fn);
 347         if (r < 0)
 348                 return log_error_errno(r, "Failed to extract filename from URL '%s': %m", job->url);
 349
 350         if (!filename_is_valid(fn))
 351                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 352                                        "Cannot verify checksum, could not determine server-side file name.");
 353
 354         if (is_checksum_file(fn) || is_signature_file(fn)) /* We cannot verify checksum files or signature files with a checksum file */
 355                 return log_error_errno(SYNTHETIC_ERRNO(ELOOP),
 356                                        "Cannot verify checksum/signature files via themselves.");
 357
 358         line = strjoina(job->checksum, " *", fn, "\n"); /* string for binary mode */
 359         p = memmem_safe(checksum_job->payload,
 360                         checksum_job->payload_size,
 361                         line,
 362                         strlen(line));
 363         if (!p) {
 364                 line = strjoina(job->checksum, "  ", fn, "\n"); /* string for text mode */
 365                 p = memmem_safe(checksum_job->payload,
 366                                 checksum_job->payload_size,
 367                                 line,
 368                                 strlen(line));
 369         }
 370
 371         /* Only counts if found at beginning of a line */
 372         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n'))
 373                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 374                                        "DOWNLOAD INVALID: Checksum of %s file did not check out, file has been tampered with.", fn);
 375
 376         log_info("SHA256 checksum of %s is valid.", job->url);
 377         return 1;
 378 }
 379
 380 static int verify_gpg(
 381                 const void *payload, size_t payload_size,
 382                 const void *signature, size_t signature_size) {
 383
 384         _cleanup_close_pair_ int gpg_pipe[2] = { -EBADF, -EBADF };
 385         char sig_file_path[] = "/tmp/sigXXXXXX", gpg_home[] = "/tmp/gpghomeXXXXXX";
 386         _cleanup_(sigkill_waitp) pid_t pid = 0;
 387         bool gpg_home_created = false;
 388         int r;
 389
 390         assert(payload || payload_size == 0);
 391         assert(signature || signature_size == 0);
 392
 393         r = pipe2(gpg_pipe, O_CLOEXEC);
 394         if (r < 0)
 395                 return log_error_errno(errno, "Failed to create pipe for gpg: %m");
 396
 397         if (signature_size > 0) {
 398                 _cleanup_close_ int sig_file = -1;
 399
 400                 sig_file = mkostemp(sig_file_path, O_RDWR);
 401                 if (sig_file < 0)
 402                         return log_error_errno(errno, "Failed to create temporary file: %m");
 403
 404                 r = loop_write(sig_file, signature, signature_size, false);
 405                 if (r < 0) {
 406                         log_error_errno(r, "Failed to write to temporary file: %m");
 407                         goto finish;
 408                 }
 409         }
 410
 411         if (!mkdtemp(gpg_home)) {
 412                 r = log_error_errno(errno, "Failed to create temporary home for gpg: %m");
 413                 goto finish;
 414         }
 415
 416         gpg_home_created = true;
 417
 418         r = safe_fork("(gpg)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
 419         if (r < 0)
 420                 return r;
 421         if (r == 0) {
 422                 const char *cmd[] = {
 423                         "gpg",
 424                         "--no-options",
 425                         "--no-default-keyring",
 426                         "--no-auto-key-locate",
 427                         "--no-auto-check-trustdb",
 428                         "--batch",
 429                         "--trust-model=always",
 430                         NULL, /* --homedir=  */
 431                         NULL, /* --keyring= */
 432                         NULL, /* --verify */
 433                         NULL, /* signature file */
 434                         NULL, /* dash */
 435                         NULL  /* trailing NULL */
 436                 };
 437                 size_t k = ELEMENTSOF(cmd) - 6;
 438
 439                 /* Child */
 440
 441                 gpg_pipe[1] = safe_close(gpg_pipe[1]);
 442
 443                 r = rearrange_stdio(TAKE_FD(gpg_pipe[0]), -1, STDERR_FILENO);
 444                 if (r < 0) {
 445                         log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
 446                         _exit(EXIT_FAILURE);
 447                 }
 448
 449                 (void) rlimit_nofile_safe();
 450
 451                 cmd[k++] = strjoina("--homedir=", gpg_home);
 452
 453                 /* We add the user keyring only to the command line arguments, if it's around since gpg fails
 454                  * otherwise. */
 455                 if (access(USER_KEYRING_PATH, F_OK) >= 0)
 456                         cmd[k++] = "--keyring=" USER_KEYRING_PATH;
 457                 else
 458                         cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;
 459
 460                 cmd[k++] = "--verify";
 461                 if (signature) {
 462                         cmd[k++] = sig_file_path;
 463                         cmd[k++] = "-";
 464                         cmd[k++] = NULL;
 465                 }
 466
 467                 execvp("gpg2", (char * const *) cmd);
 468                 execvp("gpg", (char * const *) cmd);
 469                 log_error_errno(errno, "Failed to execute gpg: %m");
 470                 _exit(EXIT_FAILURE);
 471         }
 472
 473         gpg_pipe[0] = safe_close(gpg_pipe[0]);
 474
 475         r = loop_write(gpg_pipe[1], payload, payload_size, false);
 476         if (r < 0) {
 477                 log_error_errno(r, "Failed to write to pipe: %m");
 478                 goto finish;
 479         }
 480
 481         gpg_pipe[1] = safe_close(gpg_pipe[1]);
 482
 483         r = wait_for_terminate_and_check("gpg", TAKE_PID(pid), WAIT_LOG_ABNORMAL);
 484         if (r < 0)
 485                 goto finish;
 486         if (r != EXIT_SUCCESS)
 487                 r = log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 488                                     "DOWNLOAD INVALID: Signature verification failed.");
 489         else {
 490                 log_info("Signature verification succeeded.");
 491                 r = 0;
 492         }
 493
 494 finish:
 495         if (signature_size > 0)
 496                 (void) unlink(sig_file_path);
 497
 498         if (gpg_home_created)
 499                 (void) rm_rf(gpg_home, REMOVE_ROOT|REMOVE_PHYSICAL);
 500
 501         return r;
 502 }
 503
 504 int pull_verify(ImportVerify verify,
 505                 const char *checksum, /* Verify with literal checksum */
 506                 PullJob *main_job,
 507                 PullJob *checksum_job,
 508                 PullJob *signature_job,
 509                 PullJob *settings_job,
 510                 PullJob *roothash_job,
 511                 PullJob *roothash_signature_job,
 512                 PullJob *verity_job) {
 513
 514         _cleanup_free_ char *fn = NULL;
 515         VerificationStyle style;
 516         PullJob *verify_job;
 517         int r;
 518
 519         assert(verify == _IMPORT_VERIFY_INVALID || verify < _IMPORT_VERIFY_MAX);
 520         assert(verify == _IMPORT_VERIFY_INVALID || verify >= 0);
 521         assert((verify < 0) || !checksum);
 522         assert(main_job);
 523         assert(main_job->state == PULL_JOB_DONE);
 524
 525         if (verify == IMPORT_VERIFY_NO) /* verification turned off */
 526                 return 0;
 527
 528         if (checksum) {
 529                 /* Verification by literal checksum */
 530                 assert(!checksum_job);
 531                 assert(!signature_job);
 532                 assert(!settings_job);
 533                 assert(!roothash_job);
 534                 assert(!roothash_signature_job);
 535                 assert(!verity_job);
 536
 537                 assert(main_job->calc_checksum);
 538                 assert(main_job->checksum);
 539
 540                 if (!strcaseeq(checksum, main_job->checksum))
 541                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 542                                                "DOWNLOAD INVALID: Checksum of %s file did not check out, file has been tampered with.",
 543                                                main_job->url);
 544
 545                 return 0;
 546         }
 547
 548         r = import_url_last_component(main_job->url, &fn);
 549         if (r < 0)
 550                 return log_error_errno(r, "Failed to extract filename from URL '%s': %m", main_job->url);
 551
 552         if (is_signature_file(fn))
 553                 return log_error_errno(SYNTHETIC_ERRNO(ELOOP),
 554                                        "Main download is a signature file, can't verify it.");
 555
 556         if (is_checksum_file(fn)) {
 557                 log_debug("Main download is a checksum file, can't validate its checksum with itself, skipping.");
 558                 verify_job = main_job;
 559         } else {
 560                 PullJob *j;
 561                 assert(main_job->calc_checksum);
 562                 assert(main_job->checksum);
 563                 assert(checksum_job);
 564                 assert(checksum_job->state == PULL_JOB_DONE);
 565
 566                 if (!checksum_job->payload || checksum_job->payload_size <= 0)
 567                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 568                                                "Checksum is empty, cannot verify.");
 569
 570                 FOREACH_POINTER(j, main_job, settings_job, roothash_job, roothash_signature_job, verity_job) {
 571                         r = verify_one(checksum_job, j);
 572                         if (r < 0)
 573                                 return r;
 574                 }
 575
 576                 verify_job = checksum_job;
 577         }
 578
 579         if (verify != IMPORT_VERIFY_SIGNATURE)
 580                 return 0;
 581
 582         assert(verify_job);
 583
 584         r = verification_style_from_url(verify_job->url, &style);
 585         if (r < 0)
 586                 return log_error_errno(r, "Failed to determine verification style from URL '%s': %m", verify_job->url);
 587
 588         if (style == VERIFICATION_PER_DIRECTORY) {
 589                 assert(signature_job);
 590                 assert(signature_job->state == PULL_JOB_DONE);
 591
 592                 if (!signature_job->payload || signature_job->payload_size <= 0)
 593                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 594                                                "Signature is empty, cannot verify.");
 595
 596                 return verify_gpg(verify_job->payload, verify_job->payload_size, signature_job->payload, signature_job->payload_size);
 597         } else
 598                 return verify_gpg(verify_job->payload, verify_job->payload_size, NULL, 0);
 599 }
 600
 601 int verification_style_from_url(const char *url, VerificationStyle *ret) {
 602         _cleanup_free_ char *last = NULL;
 603         int r;
 604
 605         assert(url);
 606         assert(ret);
 607
 608         /* Determines which kind of verification style is appropriate for this url */
 609
 610         r = import_url_last_component(url, &last);
 611         if (r < 0)
 612                 return r;
 613
 614         if (streq(last, "SHA256SUMS")) {
 615                 *ret = VERIFICATION_PER_DIRECTORY;
 616                 return 0;
 617         }
 618
 619         if (endswith(last, ".sha256")) {
 620                 *ret = VERIFICATION_PER_FILE;
 621                 return 0;
 622         }
 623
 624         return -EINVAL;
 625 }
 626
 627 int pull_job_restart_with_sha256sum(PullJob *j, char **ret) {
 628         VerificationStyle style;
 629         int r;
 630
 631         assert(j);
 632
 633         /* Generic implementation of a PullJobNotFound handler, that restarts the job requesting SHA256SUMS */
 634
 635         r = verification_style_from_url(j->url, &style);
 636         if (r < 0)
 637                 return log_error_errno(r, "Failed to determine verification style of URL '%s': %m", j->url);
 638
 639         if (style == VERIFICATION_PER_DIRECTORY) /* Nothing to do anymore */
 640                 return 0;
 641
 642         assert(style == VERIFICATION_PER_FILE); /* This must have been .sha256 style URL before */
 643
 644         log_debug("Got 404 for %s, now trying to get SHA256SUMS instead.", j->url);
 645
 646         r = import_url_change_last_component(j->url, "SHA256SUMS", ret);
 647         if (r < 0)
 648                 return log_error_errno(r, "Failed to replace SHA256SUMS suffix: %m");
 649
 650         return 1;
 651 }
 652
 653 bool pull_validate_local(const char *name, PullFlags flags) {
 654
 655         if (FLAGS_SET(flags, PULL_DIRECT))
 656                 return path_is_valid(name);
 657
 658         return hostname_is_valid(name, 0);
 659 }
 660
 661 int pull_url_needs_checksum(const char *url) {
 662         _cleanup_free_ char *fn = NULL;
 663         int r;
 664
 665         /* Returns true if we need to validate this resource via a hash value. This returns true for all
 666          * files — except for gpg signature files and SHA256SUMS files and the like, which are validated with
 667          * a validation tool like gpg. */
 668
 669         r = import_url_last_component(url, &fn);
 670         if (r == -EADDRNOTAVAIL) /* no last component? then let's assume it's not a signature/checksum file */
 671                 return false;
 672         if (r < 0)
 673                 return r;
 674
 675         return !is_checksum_file(fn) && !is_signature_file(fn);
 676 }