src/import/pull-common.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 "io-util.h"
  13 #include "path-util.h"
  14 #include "process-util.h"
  15 #include "pull-common.h"
  16 #include "pull-job.h"
  17 #include "rlimit-util.h"
  18 #include "rm-rf.h"
  19 #include "signal-util.h"
  20 #include "siphash24.h"
  21 #include "string-util.h"
  22 #include "strv.h"
  23 #include "util.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         _cleanup_free_ char *escaped_url = NULL;
  38         _cleanup_closedir_ DIR *d = NULL;
  39         _cleanup_strv_free_ char **l = NULL;
  40         struct dirent *de;
  41         int r;
  42
  43         assert(url);
  44         assert(etags);
  45
  46         if (!image_root)
  47                 image_root = "/var/lib/machines";
  48
  49         escaped_url = xescape(url, FILENAME_ESCAPE);
  50         if (!escaped_url)
  51                 return -ENOMEM;
  52
  53         d = opendir(image_root);
  54         if (!d) {
  55                 if (errno == ENOENT) {
  56                         *etags = NULL;
  57                         return 0;
  58                 }
  59
  60                 return -errno;
  61         }
  62
  63         FOREACH_DIRENT_ALL(de, d, return -errno) {
  64                 _cleanup_free_ char *u = NULL;
  65                 const char *a, *b;
  66
  67                 if (de->d_type != DT_UNKNOWN &&
  68                     de->d_type != dt)
  69                         continue;
  70
  71                 if (prefix) {
  72                         a = startswith(de->d_name, prefix);
  73                         if (!a)
  74                                 continue;
  75                 } else
  76                         a = de->d_name;
  77
  78                 a = startswith(a, escaped_url);
  79                 if (!a)
  80                         continue;
  81
  82                 a = startswith(a, ".");
  83                 if (!a)
  84                         continue;
  85
  86                 if (suffix) {
  87                         b = endswith(de->d_name, suffix);
  88                         if (!b)
  89                                 continue;
  90                 } else
  91                         b = strchr(de->d_name, 0);
  92
  93                 if (a >= b)
  94                         continue;
  95
  96                 r = cunescape_length(a, b - a, 0, &u);
  97                 if (r < 0)
  98                         return r;
  99
 100                 if (!http_etag_is_valid(u))
 101                         continue;
 102
 103                 r = strv_consume(&l, TAKE_PTR(u));
 104                 if (r < 0)
 105                         return r;
 106         }
 107
 108         *etags = TAKE_PTR(l);
 109
 110         return 0;
 111 }
 112
 113 int pull_make_local_copy(const char *final, const char *image_root, const char *local, bool force_local) {
 114         const char *p;
 115         int r;
 116
 117         assert(final);
 118         assert(local);
 119
 120         if (!image_root)
 121                 image_root = "/var/lib/machines";
 122
 123         p = prefix_roota(image_root, local);
 124
 125         if (force_local)
 126                 (void) rm_rf(p, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);
 127
 128         r = btrfs_subvol_snapshot(final, p,
 129                                   BTRFS_SNAPSHOT_QUOTA|
 130                                   BTRFS_SNAPSHOT_FALLBACK_COPY|
 131                                   BTRFS_SNAPSHOT_FALLBACK_DIRECTORY|
 132                                   BTRFS_SNAPSHOT_RECURSIVE);
 133         if (r < 0)
 134                 return log_error_errno(r, "Failed to create local image: %m");
 135
 136         log_info("Created new local image '%s'.", local);
 137
 138         return 0;
 139 }
 140
 141 static int hash_url(const char *url, char **ret) {
 142         uint64_t h;
 143         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);
 144
 145         assert(url);
 146
 147         h = siphash24(url, strlen(url), k.bytes);
 148         if (asprintf(ret, "%"PRIx64, h) < 0)
 149                 return -ENOMEM;
 150
 151         return 0;
 152 }
 153
 154 int pull_make_path(const char *url, const char *etag, const char *image_root, const char *prefix, const char *suffix, char **ret) {
 155         _cleanup_free_ char *escaped_url = NULL, *escaped_etag = NULL;
 156         char *path;
 157
 158         assert(url);
 159         assert(ret);
 160
 161         if (!image_root)
 162                 image_root = "/var/lib/machines";
 163
 164         escaped_url = xescape(url, FILENAME_ESCAPE);
 165         if (!escaped_url)
 166                 return -ENOMEM;
 167
 168         if (etag) {
 169                 escaped_etag = xescape(etag, FILENAME_ESCAPE);
 170                 if (!escaped_etag)
 171                         return -ENOMEM;
 172         }
 173
 174         path = strjoin(image_root, "/", strempty(prefix), escaped_url, escaped_etag ? "." : "",
 175                        strempty(escaped_etag), strempty(suffix));
 176         if (!path)
 177                 return -ENOMEM;
 178
 179         /* URLs might make the path longer than the maximum allowed length for a file name.
 180          * When that happens, a URL hash is used instead. Paths returned by this function
 181          * can be later used with tempfn_random() which adds 16 bytes to the resulting name. */
 182         if (strlen(path) >= HASH_URL_THRESHOLD_LENGTH) {
 183                 _cleanup_free_ char *hash = NULL;
 184                 int r;
 185
 186                 free(path);
 187
 188                 r = hash_url(url, &hash);
 189                 if (r < 0)
 190                         return r;
 191
 192                 path = strjoin(image_root, "/", strempty(prefix), hash, escaped_etag ? "." : "",
 193                                strempty(escaped_etag), strempty(suffix));
 194                 if (!path)
 195                         return -ENOMEM;
 196         }
 197
 198         *ret = path;
 199         return 0;
 200 }
 201
 202 int pull_make_auxiliary_job(
 203                 PullJob **ret,
 204                 const char *url,
 205                 int (*strip_suffixes)(const char *name, char **ret),
 206                 const char *suffix,
 207                 CurlGlue *glue,
 208                 PullJobFinished on_finished,
 209                 void *userdata) {
 210
 211         _cleanup_free_ char *last_component = NULL, *ll = NULL, *auxiliary_url = NULL;
 212         _cleanup_(pull_job_unrefp) PullJob *job = NULL;
 213         const char *q;
 214         int r;
 215
 216         assert(ret);
 217         assert(url);
 218         assert(strip_suffixes);
 219         assert(glue);
 220
 221         r = import_url_last_component(url, &last_component);
 222         if (r < 0)
 223                 return r;
 224
 225         r = strip_suffixes(last_component, &ll);
 226         if (r < 0)
 227                 return r;
 228
 229         q = strjoina(ll, suffix);
 230
 231         r = import_url_change_last_component(url, q, &auxiliary_url);
 232         if (r < 0)
 233                 return r;
 234
 235         r = pull_job_new(&job, auxiliary_url, glue, userdata);
 236         if (r < 0)
 237                 return r;
 238
 239         job->on_finished = on_finished;
 240         job->compressed_max = job->uncompressed_max = 1ULL * 1024ULL * 1024ULL;
 241
 242         *ret = TAKE_PTR(job);
 243
 244         return 0;
 245 }
 246
 247 int pull_make_verification_jobs(
 248                 PullJob **ret_checksum_job,
 249                 PullJob **ret_signature_job,
 250                 ImportVerify verify,
 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         int r;
 258         const char *chksums = NULL;
 259
 260         assert(ret_checksum_job);
 261         assert(ret_signature_job);
 262         assert(verify >= 0);
 263         assert(verify < _IMPORT_VERIFY_MAX);
 264         assert(url);
 265         assert(glue);
 266
 267         if (verify != IMPORT_VERIFY_NO) {
 268                 _cleanup_free_ char *checksum_url = NULL, *fn = NULL;
 269
 270                 /* Queue jobs for the checksum file for the image. */
 271                 r = import_url_last_component(url, &fn);
 272                 if (r < 0)
 273                         return r;
 274
 275                 chksums = strjoina(fn, ".sha256");
 276
 277                 r = import_url_change_last_component(url, chksums, &checksum_url);
 278                 if (r < 0)
 279                         return r;
 280
 281                 r = pull_job_new(&checksum_job, checksum_url, glue, userdata);
 282                 if (r < 0)
 283                         return r;
 284
 285                 checksum_job->on_finished = on_finished;
 286                 checksum_job->uncompressed_max = checksum_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 287         }
 288
 289         if (verify == IMPORT_VERIFY_SIGNATURE) {
 290                 _cleanup_free_ char *signature_url = NULL;
 291
 292                 /* Queue job for the SHA256SUMS.gpg file for the image. */
 293                 r = import_url_change_last_component(url, "SHA256SUMS.gpg", &signature_url);
 294                 if (r < 0)
 295                         return r;
 296
 297                 r = pull_job_new(&signature_job, signature_url, glue, userdata);
 298                 if (r < 0)
 299                         return r;
 300
 301                 signature_job->on_finished = on_finished;
 302                 signature_job->uncompressed_max = signature_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 303         }
 304
 305         *ret_checksum_job = checksum_job;
 306         *ret_signature_job = signature_job;
 307
 308         checksum_job = signature_job = NULL;
 309
 310         return 0;
 311 }
 312
 313 static int verify_one(PullJob *checksum_job, PullJob *job) {
 314         _cleanup_free_ char *fn = NULL;
 315         const char *line, *p;
 316         int r;
 317
 318         assert(checksum_job);
 319
 320         if (!job)
 321                 return 0;
 322
 323         assert(IN_SET(job->state, PULL_JOB_DONE, PULL_JOB_FAILED));
 324
 325         /* Don't verify the checksum if we didn't actually successfully download something new */
 326         if (job->state != PULL_JOB_DONE)
 327                 return 0;
 328         if (job->error != 0)
 329                 return 0;
 330         if (job->etag_exists)
 331                 return 0;
 332
 333         assert(job->calc_checksum);
 334         assert(job->checksum);
 335
 336         r = import_url_last_component(job->url, &fn);
 337         if (r < 0)
 338                 return log_oom();
 339
 340         if (!filename_is_valid(fn))
 341                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 342                                        "Cannot verify checksum, could not determine server-side file name.");
 343
 344         line = strjoina(job->checksum, " *", fn, "\n");
 345
 346         p = memmem(checksum_job->payload,
 347                    checksum_job->payload_size,
 348                    line,
 349                    strlen(line));
 350
 351         if (!p) {
 352                 line = strjoina(job->checksum, "  ", fn, "\n");
 353
 354                 p = memmem(checksum_job->payload,
 355                         checksum_job->payload_size,
 356                         line,
 357                         strlen(line));
 358         }
 359
 360         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n'))
 361                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 362                                        "DOWNLOAD INVALID: Checksum of %s file did not checkout, file has been tampered with.", fn);
 363
 364         log_info("SHA256 checksum of %s is valid.", job->url);
 365         return 1;
 366 }
 367
 368 int pull_verify(PullJob *main_job,
 369                 PullJob *roothash_job,
 370                 PullJob *settings_job,
 371                 PullJob *checksum_job,
 372                 PullJob *signature_job) {
 373
 374         _cleanup_close_pair_ int gpg_pipe[2] = { -1, -1 };
 375         _cleanup_close_ int sig_file = -1;
 376         char sig_file_path[] = "/tmp/sigXXXXXX", gpg_home[] = "/tmp/gpghomeXXXXXX";
 377         _cleanup_(sigkill_waitp) pid_t pid = 0;
 378         bool gpg_home_created = false;
 379         int r;
 380
 381         assert(main_job);
 382         assert(main_job->state == PULL_JOB_DONE);
 383
 384         if (!checksum_job)
 385                 return 0;
 386
 387         assert(main_job->calc_checksum);
 388         assert(main_job->checksum);
 389
 390         assert(checksum_job->state == PULL_JOB_DONE);
 391
 392         if (!checksum_job->payload || checksum_job->payload_size <= 0)
 393                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 394                                        "Checksum is empty, cannot verify.");
 395
 396         r = verify_one(checksum_job, main_job);
 397         if (r < 0)
 398                 return r;
 399
 400         r = verify_one(checksum_job, roothash_job);
 401         if (r < 0)
 402                 return r;
 403
 404         r = verify_one(checksum_job, settings_job);
 405         if (r < 0)
 406                 return r;
 407
 408         if (!signature_job)
 409                 return 0;
 410
 411         if (checksum_job->style == VERIFICATION_PER_FILE)
 412                 signature_job = checksum_job;
 413
 414         assert(signature_job->state == PULL_JOB_DONE);
 415
 416         if (!signature_job->payload || signature_job->payload_size <= 0)
 417                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 418                                        "Signature is empty, cannot verify.");
 419
 420         r = pipe2(gpg_pipe, O_CLOEXEC);
 421         if (r < 0)
 422                 return log_error_errno(errno, "Failed to create pipe for gpg: %m");
 423
 424         sig_file = mkostemp(sig_file_path, O_RDWR);
 425         if (sig_file < 0)
 426                 return log_error_errno(errno, "Failed to create temporary file: %m");
 427
 428         r = loop_write(sig_file, signature_job->payload, signature_job->payload_size, false);
 429         if (r < 0) {
 430                 log_error_errno(r, "Failed to write to temporary file: %m");
 431                 goto finish;
 432         }
 433
 434         if (!mkdtemp(gpg_home)) {
 435                 r = log_error_errno(errno, "Failed to create temporary home for gpg: %m");
 436                 goto finish;
 437         }
 438
 439         gpg_home_created = true;
 440
 441         r = safe_fork("(gpg)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
 442         if (r < 0)
 443                 return r;
 444         if (r == 0) {
 445                 const char *cmd[] = {
 446                         "gpg",
 447                         "--no-options",
 448                         "--no-default-keyring",
 449                         "--no-auto-key-locate",
 450                         "--no-auto-check-trustdb",
 451                         "--batch",
 452                         "--trust-model=always",
 453                         NULL, /* --homedir=  */
 454                         NULL, /* --keyring= */
 455                         NULL, /* --verify */
 456                         NULL, /* signature file */
 457                         NULL, /* dash */
 458                         NULL  /* trailing NULL */
 459                 };
 460                 unsigned k = ELEMENTSOF(cmd) - 6;
 461
 462                 /* Child */
 463
 464                 gpg_pipe[1] = safe_close(gpg_pipe[1]);
 465
 466                 r = rearrange_stdio(gpg_pipe[0], -1, STDERR_FILENO);
 467                 if (r < 0) {
 468                         log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
 469                         _exit(EXIT_FAILURE);
 470                 }
 471
 472                 (void) rlimit_nofile_safe();
 473
 474                 cmd[k++] = strjoina("--homedir=", gpg_home);
 475
 476                 /* We add the user keyring only to the command line
 477                  * arguments, if it's around since gpg fails
 478                  * otherwise. */
 479                 if (access(USER_KEYRING_PATH, F_OK) >= 0)
 480                         cmd[k++] = "--keyring=" USER_KEYRING_PATH;
 481                 else
 482                         cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;
 483
 484                 cmd[k++] = "--verify";
 485                 if (checksum_job->style == VERIFICATION_PER_DIRECTORY) {
 486                         cmd[k++] = sig_file_path;
 487                         cmd[k++] = "-";
 488                         cmd[k++] = NULL;
 489                 }
 490
 491                 execvp("gpg2", (char * const *) cmd);
 492                 execvp("gpg", (char * const *) cmd);
 493                 log_error_errno(errno, "Failed to execute gpg: %m");
 494                 _exit(EXIT_FAILURE);
 495         }
 496
 497         gpg_pipe[0] = safe_close(gpg_pipe[0]);
 498
 499         r = loop_write(gpg_pipe[1], checksum_job->payload, checksum_job->payload_size, false);
 500         if (r < 0) {
 501                 log_error_errno(r, "Failed to write to pipe: %m");
 502                 goto finish;
 503         }
 504
 505         gpg_pipe[1] = safe_close(gpg_pipe[1]);
 506
 507         r = wait_for_terminate_and_check("gpg", pid, WAIT_LOG_ABNORMAL);
 508         pid = 0;
 509         if (r < 0)
 510                 goto finish;
 511         if (r != EXIT_SUCCESS) {
 512                 log_error("DOWNLOAD INVALID: Signature verification failed.");
 513                 r = -EBADMSG;
 514         } else {
 515                 log_info("Signature verification succeeded.");
 516                 r = 0;
 517         }
 518
 519 finish:
 520         (void) unlink(sig_file_path);
 521
 522         if (gpg_home_created)
 523                 (void) rm_rf(gpg_home, REMOVE_ROOT|REMOVE_PHYSICAL);
 524
 525         return r;
 526 }