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