src/import/pull-common.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "sd-id128.h"
   4
   5 #include "alloc-util.h"
   6 #include "dirent-util.h"
   7 #include "escape.h"
   8 #include "fd-util.h"
   9 #include "io-util.h"
  10 #include "log.h"
  11 #include "memory-util.h"
  12 #include "os-util.h"
  13 #include "path-util.h"
  14 #include "process-util.h"
  15 #include "pull-common.h"
  16 #include "pull-job.h"
  17 #include "rm-rf.h"
  18 #include "siphash24.h"
  19 #include "string-util.h"
  20 #include "strv.h"
  21 #include "tmpfile-util.h"
  22 #include "web-util.h"
  23
  24 #define FILENAME_ESCAPE "/.#\"\'"
  25 #define HASH_URL_THRESHOLD_LENGTH (_POSIX_PATH_MAX - 16)
  26
  27 int pull_find_old_etags(
  28                 const char *url,
  29                 const char *image_root,
  30                 int dt,
  31                 const char *prefix,
  32                 const char *suffix,
  33                 char ***etags) {
  34
  35         int r;
  36
  37         assert(url);
  38         assert(image_root);
  39         assert(etags);
  40
  41         _cleanup_free_ char *escaped_url = xescape(url, FILENAME_ESCAPE);
  42         if (!escaped_url)
  43                 return -ENOMEM;
  44
  45         _cleanup_closedir_ DIR *d = opendir(image_root);
  46         if (!d) {
  47                 if (errno == ENOENT) {
  48                         *etags = NULL;
  49                         return 0;
  50                 }
  51
  52                 return -errno;
  53         }
  54
  55         _cleanup_strv_free_ char **ans = NULL;
  56
  57         FOREACH_DIRENT_ALL(de, d, return -errno) {
  58                 _cleanup_free_ char *u = NULL;
  59                 const char *a, *b;
  60
  61                 if (de->d_type != DT_UNKNOWN &&
  62                     de->d_type != dt)
  63                         continue;
  64
  65                 if (prefix) {
  66                         a = startswith(de->d_name, prefix);
  67                         if (!a)
  68                                 continue;
  69                 } else
  70                         a = de->d_name;
  71
  72                 a = startswith(a, escaped_url);
  73                 if (!a)
  74                         continue;
  75
  76                 a = startswith(a, ".");
  77                 if (!a)
  78                         continue;
  79
  80                 if (suffix) {
  81                         b = endswith(de->d_name, suffix);
  82                         if (!b)
  83                                 continue;
  84                 } else
  85                         b = strchr(de->d_name, 0);
  86
  87                 if (a >= b)
  88                         continue;
  89
  90                 ssize_t l = cunescape_length(a, b - a, 0, &u);
  91                 if (l < 0) {
  92                         assert(l >= INT8_MIN);
  93                         return l;
  94                 }
  95
  96                 if (!http_etag_is_valid(u))
  97                         continue;
  98
  99                 r = strv_consume(&ans, TAKE_PTR(u));
 100                 if (r < 0)
 101                         return r;
 102         }
 103
 104         *etags = TAKE_PTR(ans);
 105
 106         return 0;
 107 }
 108
 109 static int hash_url(const char *url, char **ret) {
 110         uint64_t h;
 111         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);
 112
 113         assert(url);
 114
 115         h = siphash24(url, strlen(url), k.bytes);
 116         if (asprintf(ret, "%"PRIx64, h) < 0)
 117                 return -ENOMEM;
 118
 119         return 0;
 120 }
 121
 122 int pull_make_path(const char *url, const char *etag, const char *image_root, const char *prefix, const char *suffix, char **ret) {
 123         _cleanup_free_ char *escaped_url = NULL, *escaped_etag = NULL;
 124         char *path;
 125
 126         assert(url);
 127         assert(image_root);
 128         assert(ret);
 129
 130         escaped_url = xescape(url, FILENAME_ESCAPE);
 131         if (!escaped_url)
 132                 return -ENOMEM;
 133
 134         if (etag) {
 135                 escaped_etag = xescape(etag, FILENAME_ESCAPE);
 136                 if (!escaped_etag)
 137                         return -ENOMEM;
 138         }
 139
 140         path = strjoin(image_root, "/", strempty(prefix), escaped_url, escaped_etag ? "." : "",
 141                        strempty(escaped_etag), strempty(suffix));
 142         if (!path)
 143                 return -ENOMEM;
 144
 145         /* URLs might make the path longer than the maximum allowed length for a file name.
 146          * When that happens, a URL hash is used instead. Paths returned by this function
 147          * can be later used with tempfn_random() which adds 16 bytes to the resulting name. */
 148         if (strlen(path) >= HASH_URL_THRESHOLD_LENGTH) {
 149                 _cleanup_free_ char *hash = NULL;
 150                 int r;
 151
 152                 free(path);
 153
 154                 r = hash_url(url, &hash);
 155                 if (r < 0)
 156                         return r;
 157
 158                 path = strjoin(image_root, "/", strempty(prefix), hash, escaped_etag ? "." : "",
 159                                strempty(escaped_etag), strempty(suffix));
 160                 if (!path)
 161                         return -ENOMEM;
 162         }
 163
 164         *ret = path;
 165         return 0;
 166 }
 167
 168 int pull_make_auxiliary_job(
 169                 PullJob **ret,
 170                 const char *url,
 171                 int (*strip_suffixes)(const char *name, char **ret),
 172                 const char *suffix,
 173                 ImportVerify verify,
 174                 CurlGlue *glue,
 175                 PullJobOpenDisk on_open_disk,
 176                 PullJobFinished on_finished,
 177                 void *userdata) {
 178
 179         _cleanup_free_ char *last_component = NULL, *ll = NULL, *auxiliary_url = NULL;
 180         _cleanup_(pull_job_unrefp) PullJob *job = NULL;
 181         const char *q;
 182         int r;
 183
 184         assert(ret);
 185         assert(url);
 186         assert(strip_suffixes);
 187         assert(glue);
 188
 189         r = import_url_last_component(url, &last_component);
 190         if (r < 0)
 191                 return r;
 192
 193         r = strip_suffixes(last_component, &ll);
 194         if (r < 0)
 195                 return r;
 196
 197         q = strjoina(ll, suffix);
 198
 199         r = import_url_change_last_component(url, q, &auxiliary_url);
 200         if (r < 0)
 201                 return r;
 202
 203         r = pull_job_new(&job, auxiliary_url, glue, userdata);
 204         if (r < 0)
 205                 return r;
 206
 207         job->on_open_disk = on_open_disk;
 208         job->on_finished = on_finished;
 209         job->compressed_max = job->uncompressed_max = 1ULL * 1024ULL * 1024ULL;
 210         job->calc_checksum = IN_SET(verify, IMPORT_VERIFY_CHECKSUM, IMPORT_VERIFY_SIGNATURE);
 211
 212         *ret = TAKE_PTR(job);
 213         return 0;
 214 }
 215
 216 static bool is_checksum_file(const char *fn) {
 217         /* Returns true if the specified filename refers to a checksum file we grok */
 218
 219         if (!fn)
 220                 return false;
 221
 222         return streq(fn, "SHA256SUMS") || endswith(fn, ".sha256");
 223 }
 224
 225 static SignatureStyle signature_style_from_filename(const char *fn) {
 226         /* Returns true if the specified filename refers to a signature file we grok */
 227
 228         if (!fn)
 229                 return _SIGNATURE_STYLE_INVALID;
 230
 231         if (streq(fn, "SHA256SUMS.gpg"))
 232                 return SIGNATURE_GPG_PER_DIRECTORY;
 233
 234         if (streq(fn, "SHA256SUMS.asc"))
 235                 return SIGNATURE_ASC_PER_DIRECTORY;
 236
 237         if (endswith(fn, ".sha256.gpg"))
 238                 return SIGNATURE_GPG_PER_FILE;
 239
 240         if (endswith(fn, ".sha256.asc"))
 241                 return SIGNATURE_ASC_PER_FILE;
 242
 243         return _SIGNATURE_STYLE_INVALID;
 244 }
 245
 246 int pull_make_verification_jobs(
 247                 PullJob **ret_checksum_job,
 248                 PullJob **ret_signature_job,
 249                 ImportVerify verify,
 250                 const char *checksum, /* set if literal checksum verification is requested, in which case 'verify' is set to _IMPORT_VERIFY_INVALID */
 251                 const char *url,
 252                 CurlGlue *glue,
 253                 PullJobFinished on_finished,
 254                 void *userdata) {
 255
 256         _cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;
 257         _cleanup_free_ char *fn = NULL;
 258         int r;
 259
 260         assert(ret_checksum_job);
 261         assert(ret_signature_job);
 262         assert(verify == _IMPORT_VERIFY_INVALID || verify < _IMPORT_VERIFY_MAX);
 263         assert(verify == _IMPORT_VERIFY_INVALID || verify >= 0);
 264         assert((verify < 0) || !checksum);
 265         assert(url);
 266         assert(glue);
 267
 268         /* If verification is turned off, or if the checksum to validate is already specified we don't need
 269          * to download a checksum file or signature, hence shortcut things */
 270         if (verify == IMPORT_VERIFY_NO || checksum) {
 271                 *ret_checksum_job = *ret_signature_job = NULL;
 272                 return 0;
 273         }
 274
 275         r = import_url_last_component(url, &fn);
 276         if (r < 0 && r != -EADDRNOTAVAIL) /* EADDRNOTAVAIL means there was no last component, which is OK for
 277                                            * us, we'll just assume it's not a checksum/signature file */
 278                 return r;
 279
 280         /* Acquire the checksum file if verification or signature verification is requested and the main file
 281          * to acquire isn't a checksum or signature file anyway */
 282         if (verify != IMPORT_VERIFY_NO && !is_checksum_file(fn) && signature_style_from_filename(fn) < 0) {
 283                 _cleanup_free_ char *checksum_url = NULL;
 284                 const char *suffixed = NULL;
 285
 286                 /* Queue jobs for the checksum file for the image. */
 287
 288                 if (fn)
 289                         suffixed = strjoina(fn, ".sha256"); /* Start with the suse-style checksum (if there's a base filename) */
 290                 else
 291                         suffixed = "SHA256SUMS";
 292
 293                 r = import_url_change_last_component(url, suffixed, &checksum_url);
 294                 if (r < 0)
 295                         return r;
 296
 297                 r = pull_job_new(&checksum_job, checksum_url, glue, userdata);
 298                 if (r < 0)
 299                         return r;
 300
 301                 checksum_job->on_finished = on_finished;
 302                 checksum_job->uncompressed_max = checksum_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 303                 checksum_job->on_not_found = pull_job_restart_with_sha256sum; /* if this fails, look for ubuntu-style checksum */
 304         }
 305
 306         if (verify == IMPORT_VERIFY_SIGNATURE && signature_style_from_filename(fn) < 0) {
 307                 _cleanup_free_ char *signature_url = NULL;
 308                 const char *suffixed = NULL;
 309
 310                 if (fn)
 311                         suffixed = strjoina(fn, ".sha256.asc"); /* Start with the suse-style checksum (if there's a base filename) */
 312                 else
 313                         suffixed = "SHA256SUMS.gpg";
 314
 315                 /* Queue job for the signature file for the image. */
 316                 r = import_url_change_last_component(url, suffixed, &signature_url);
 317                 if (r < 0)
 318                         return r;
 319
 320                 r = pull_job_new(&signature_job, signature_url, glue, userdata);
 321                 if (r < 0)
 322                         return r;
 323
 324                 signature_job->on_finished = on_finished;
 325                 signature_job->uncompressed_max = signature_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 326                 signature_job->on_not_found = pull_job_restart_with_signature;
 327         }
 328
 329         *ret_checksum_job = TAKE_PTR(checksum_job);
 330         *ret_signature_job = TAKE_PTR(signature_job);
 331         return 0;
 332 }
 333
 334 static int verify_one(PullJob *checksum_job, PullJob *job) {
 335         _cleanup_free_ char *fn = NULL;
 336         const char *line, *p;
 337         int r;
 338
 339         assert(checksum_job);
 340
 341         if (!job)
 342                 return 0;
 343
 344         assert(IN_SET(job->state, PULL_JOB_DONE, PULL_JOB_FAILED));
 345
 346         /* Don't verify the checksum if we didn't actually successfully download something new */
 347         if (job->state != PULL_JOB_DONE)
 348                 return 0;
 349         if (job->error != 0)
 350                 return 0;
 351         if (job->etag_exists)
 352                 return 0;
 353
 354         assert(job->calc_checksum);
 355         assert(job->checksum);
 356
 357         r = import_url_last_component(job->url, &fn);
 358         if (r < 0)
 359                 return log_error_errno(r, "Failed to extract filename from URL '%s': %m", job->url);
 360
 361         if (!filename_is_valid(fn))
 362                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 363                                        "Cannot verify checksum, could not determine server-side file name.");
 364
 365         if (is_checksum_file(fn) || signature_style_from_filename(fn) >= 0) /* We cannot verify checksum files or signature files with a checksum file */
 366                 return log_error_errno(SYNTHETIC_ERRNO(ELOOP),
 367                                        "Cannot verify checksum/signature files via themselves.");
 368
 369         line = strjoina(job->checksum, " *", fn, "\n"); /* string for binary mode */
 370         p = memmem_safe(checksum_job->payload,
 371                         checksum_job->payload_size,
 372                         line,
 373                         strlen(line));
 374         if (!p) {
 375                 line = strjoina(job->checksum, "  ", fn, "\n"); /* string for text mode */
 376                 p = memmem_safe(checksum_job->payload,
 377                                 checksum_job->payload_size,
 378                                 line,
 379                                 strlen(line));
 380         }
 381
 382         /* Only counts if found at beginning of a line */
 383         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n'))
 384                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 385                                        "DOWNLOAD INVALID: Checksum of %s file did not check out, file has been tampered with.", fn);
 386
 387         log_info("SHA256 checksum of %s is valid.", job->url);
 388         return 1;
 389 }
 390
 391 static int verify_gpg(
 392                 const void *payload, size_t payload_size,
 393                 const void *signature, size_t signature_size) {
 394
 395         _cleanup_close_pair_ int gpg_pipe[2] = EBADF_PAIR;
 396         _cleanup_(rm_rf_physical_and_freep) char *gpg_home = NULL;
 397         char sig_file_path[] = "/tmp/sigXXXXXX";
 398         _cleanup_(sigkill_waitp) pid_t pid = 0;
 399         int r;
 400
 401         assert(payload || payload_size == 0);
 402         assert(signature || signature_size == 0);
 403
 404         r = pipe2(gpg_pipe, O_CLOEXEC);
 405         if (r < 0)
 406                 return log_error_errno(errno, "Failed to create pipe for gpg: %m");
 407
 408         if (signature_size > 0) {
 409                 _cleanup_close_ int sig_file = -EBADF;
 410
 411                 sig_file = mkostemp(sig_file_path, O_RDWR);
 412                 if (sig_file < 0)
 413                         return log_error_errno(errno, "Failed to create temporary file: %m");
 414
 415                 r = loop_write(sig_file, signature, signature_size);
 416                 if (r < 0) {
 417                         log_error_errno(r, "Failed to write to temporary file: %m");
 418                         goto finish;
 419                 }
 420         }
 421
 422         r = mkdtemp_malloc("/tmp/gpghomeXXXXXX", &gpg_home);
 423         if (r < 0) {
 424                 log_error_errno(r, "Failed to create temporary home for gpg: %m");
 425                 goto finish;
 426         }
 427
 428         r = safe_fork_full("(gpg)",
 429                            (int[]) { gpg_pipe[0], -EBADF, STDERR_FILENO },
 430                            NULL, 0,
 431                            FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG_SIGTERM|FORK_REARRANGE_STDIO|FORK_LOG|FORK_RLIMIT_NOFILE_SAFE,
 432                            &pid);
 433         if (r < 0)
 434                 return r;
 435         if (r == 0) {
 436                 const char *cmd[] = {
 437                         "gpg",
 438                         "--no-options",
 439                         "--no-default-keyring",
 440                         "--no-auto-key-locate",
 441                         "--no-auto-check-trustdb",
 442                         "--batch",
 443                         "--trust-model=always",
 444                         NULL, /* --homedir=  */
 445                         NULL, /* --keyring= */
 446                         NULL, /* --verify */
 447                         NULL, /* signature file */
 448                         NULL, /* dash */
 449                         NULL  /* trailing NULL */
 450                 };
 451                 size_t k = ELEMENTSOF(cmd) - 6;
 452
 453                 /* Child */
 454
 455                 cmd[k++] = strjoina("--homedir=", gpg_home);
 456
 457                 /* We add the user keyring only to the command line arguments, if it's around since gpg fails
 458                  * otherwise. */
 459                 if (access(USER_KEYRING_PATH, F_OK) >= 0)
 460                         cmd[k++] = "--keyring=" USER_KEYRING_PATH;
 461                 else if (access(USER_KEYRING_PATH_LEGACY, F_OK) >= 0)
 462                         cmd[k++] = "--keyring=" USER_KEYRING_PATH_LEGACY;
 463                 else
 464                         cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;
 465
 466                 cmd[k++] = "--verify";
 467                 if (signature) {
 468                         cmd[k++] = sig_file_path;
 469                         cmd[k++] = "-";
 470                         cmd[k++] = NULL;
 471                 }
 472
 473                 execvp("gpg2", (char * const *) cmd);
 474                 execvp("gpg", (char * const *) cmd);
 475                 log_error_errno(errno, "Failed to execute gpg: %m");
 476                 _exit(EXIT_FAILURE);
 477         }
 478
 479         gpg_pipe[0] = safe_close(gpg_pipe[0]);
 480
 481         r = loop_write(gpg_pipe[1], payload, payload_size);
 482         if (r < 0) {
 483                 log_error_errno(r, "Failed to write to pipe: %m");
 484                 goto finish;
 485         }
 486
 487         gpg_pipe[1] = safe_close(gpg_pipe[1]);
 488
 489         r = wait_for_terminate_and_check("gpg", TAKE_PID(pid), WAIT_LOG_ABNORMAL);
 490         if (r < 0)
 491                 goto finish;
 492         if (r != EXIT_SUCCESS)
 493                 r = log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 494                                     "DOWNLOAD INVALID: Signature verification failed.");
 495         else {
 496                 log_info("Signature verification succeeded.");
 497                 r = 0;
 498         }
 499
 500 finish:
 501         if (signature_size > 0)
 502                 (void) unlink(sig_file_path);
 503
 504         return r;
 505 }
 506
 507 int pull_verify(ImportVerify verify,
 508                 const char *checksum, /* Verify with literal checksum */
 509                 PullJob *main_job,
 510                 PullJob *checksum_job,
 511                 PullJob *signature_job,
 512                 PullJob *settings_job,
 513                 PullJob *roothash_job,
 514                 PullJob *roothash_signature_job,
 515                 PullJob *verity_job) {
 516
 517         _cleanup_free_ char *fn = NULL;
 518         VerificationStyle style;
 519         PullJob *verify_job;
 520         int r;
 521
 522         assert(verify == _IMPORT_VERIFY_INVALID || verify < _IMPORT_VERIFY_MAX);
 523         assert(verify == _IMPORT_VERIFY_INVALID || verify >= 0);
 524         assert((verify < 0) || !checksum);
 525         assert(main_job);
 526         assert(main_job->state == PULL_JOB_DONE);
 527
 528         if (verify == IMPORT_VERIFY_NO) /* verification turned off */
 529                 return 0;
 530
 531         if (checksum) {
 532                 /* Verification by literal checksum */
 533                 assert(!checksum_job);
 534                 assert(!signature_job);
 535                 assert(!settings_job);
 536                 assert(!roothash_job);
 537                 assert(!roothash_signature_job);
 538                 assert(!verity_job);
 539
 540                 assert(main_job->calc_checksum);
 541                 assert(main_job->checksum);
 542
 543                 if (!strcaseeq(checksum, main_job->checksum))
 544                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 545                                                "DOWNLOAD INVALID: Checksum of %s file did not check out, file has been tampered with.",
 546                                                main_job->url);
 547
 548                 return 0;
 549         }
 550
 551         r = import_url_last_component(main_job->url, &fn);
 552         if (r < 0)
 553                 return log_error_errno(r, "Failed to extract filename from URL '%s': %m", main_job->url);
 554
 555         if (signature_style_from_filename(fn) >= 0)
 556                 return log_error_errno(SYNTHETIC_ERRNO(ELOOP),
 557                                        "Main download is a signature file, can't verify it.");
 558
 559         if (is_checksum_file(fn)) {
 560                 log_debug("Main download is a checksum file, can't validate its checksum with itself, skipping.");
 561                 verify_job = main_job;
 562         } else {
 563                 assert(main_job->calc_checksum);
 564                 assert(main_job->checksum);
 565                 assert(checksum_job);
 566                 assert(checksum_job->state == PULL_JOB_DONE);
 567
 568                 if (!checksum_job->payload || checksum_job->payload_size <= 0)
 569                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 570                                                "Checksum is empty, cannot verify.");
 571
 572                 PullJob *j;
 573                 FOREACH_ARGUMENT(j, main_job, settings_job, roothash_job, roothash_signature_job, verity_job) {
 574                         r = verify_one(checksum_job, j);
 575                         if (r < 0)
 576                                 return r;
 577                 }
 578
 579                 verify_job = checksum_job;
 580         }
 581
 582         if (verify != IMPORT_VERIFY_SIGNATURE)
 583                 return 0;
 584
 585         assert(verify_job);
 586
 587         r = verification_style_from_url(verify_job->url, &style);
 588         if (r < 0)
 589                 return log_error_errno(r, "Failed to determine verification style from URL '%s': %m", verify_job->url);
 590
 591         assert(signature_job);
 592         assert(signature_job->state == PULL_JOB_DONE);
 593
 594         if (!signature_job->payload || signature_job->payload_size <= 0)
 595                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 596                                        "Signature is empty, cannot verify.");
 597
 598         return verify_gpg(verify_job->payload, verify_job->payload_size, signature_job->payload, signature_job->payload_size);
 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                 *ret = NULL;
 641                 return 0;
 642         }
 643
 644         assert(style == VERIFICATION_PER_FILE); /* This must have been .sha256 style URL before */
 645
 646         log_debug("Got 404 for '%s', now trying to get SHA256SUMS instead.", j->url);
 647
 648         r = import_url_change_last_component(j->url, "SHA256SUMS", ret);
 649         if (r < 0)
 650                 return log_error_errno(r, "Failed to replace SHA256SUMS suffix: %m");
 651
 652         return 1;
 653 }
 654
 655 int signature_style_from_url(const char *url, SignatureStyle *ret, char **ret_filename) {
 656         _cleanup_free_ char *last = NULL;
 657         SignatureStyle style;
 658         int r;
 659
 660         assert(url);
 661         assert(ret);
 662         assert(ret_filename);
 663
 664         /* Determines which kind of signature style is appropriate for this url */
 665
 666         r = import_url_last_component(url, &last);
 667         if (r < 0)
 668                 return r;
 669
 670         style = signature_style_from_filename(last);
 671         if (style < 0)
 672                 return style;
 673
 674         *ret_filename = TAKE_PTR(last);
 675         *ret = style;
 676         return 0;
 677 }
 678
 679 int pull_job_restart_with_signature(PullJob *j, char **ret) {
 680         _cleanup_free_ char *last = NULL;
 681         SignatureStyle style;
 682         int r;
 683
 684         assert(j);
 685
 686         /* Generic implementation of a PullJobNotFound handler, that restarts the job requesting a different
 687          * signature file. After the initial file, additional *.sha256.gpg, SHA256SUMS.gpg and SHA256SUMS.asc
 688          * are tried in this order. */
 689
 690         r = signature_style_from_url(j->url, &style, &last);
 691         if (r < 0)
 692                 return log_error_errno(r, "Failed to determine signature style of URL '%s': %m", j->url);
 693
 694         switch (style) {
 695
 696         case SIGNATURE_ASC_PER_DIRECTORY: /* Nothing to do anymore */
 697                 *ret = NULL;
 698                 return 0;
 699
 700         case SIGNATURE_ASC_PER_FILE: { /* Try .sha256.gpg next */
 701                 char *ext;
 702
 703                 log_debug("Got 404 for '%s', now trying to get .sha256.gpg instead.", j->url);
 704
 705                 ext = endswith(last, ".asc");
 706                 assert(ext);
 707                 strcpy(ext, ".gpg");
 708
 709                 r = import_url_change_last_component(j->url, last, ret);
 710                 if (r < 0)
 711                         return log_error_errno(r, "Failed to replace .sha256.asc suffix: %m");
 712                 break;
 713         }
 714
 715         case SIGNATURE_GPG_PER_FILE: /* Try SHA256SUMS.gpg next */
 716                 log_debug("Got 404 for '%s', now trying to get SHA256SUMS.gpg instead.", j->url);
 717                 r = import_url_change_last_component(j->url, "SHA256SUMS.gpg", ret);
 718                 if (r < 0)
 719                         return log_error_errno(r, "Failed to replace SHA256SUMS suffix: %m");
 720                 break;
 721
 722         case SIGNATURE_GPG_PER_DIRECTORY:
 723                 log_debug("Got 404 for '%s', now trying to get SHA256SUMS.asc instead.", j->url);
 724                 r = import_url_change_last_component(j->url, "SHA256SUMS.asc", ret);
 725                 if (r < 0)
 726                         return log_error_errno(r, "Failed to replace SHA256SUMS.gpg suffix: %m");
 727                 break;
 728
 729         default:
 730                 assert_not_reached();
 731         }
 732
 733         return 1;
 734 }
 735
 736 bool pull_validate_local(const char *name, ImportFlags flags) {
 737
 738         if (FLAGS_SET(flags, IMPORT_DIRECT))
 739                 return path_is_valid(name);
 740
 741         return image_name_is_valid(name);
 742 }
 743
 744 int pull_url_needs_checksum(const char *url) {
 745         _cleanup_free_ char *fn = NULL;
 746         int r;
 747
 748         /* Returns true if we need to validate this resource via a hash value. This returns true for all
 749          * files — except for gpg signature files and SHA256SUMS files and the like, which are validated with
 750          * a validation tool like gpg. */
 751
 752         r = import_url_last_component(url, &fn);
 753         if (r == -EADDRNOTAVAIL) /* no last component? then let's assume it's not a signature/checksum file */
 754                 return false;
 755         if (r < 0)
 756                 return r;
 757
 758         return !is_checksum_file(fn) && signature_style_from_filename(fn) < 0;
 759 }