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 "rm-rf.h"
  18 #include "signal-util.h"
  19 #include "siphash24.h"
  20 #include "string-util.h"
  21 #include "strv.h"
  22 #include "util.h"
  23 #include "web-util.h"
  24
  25 #define FILENAME_ESCAPE "/.#\"\'"
  26 #define HASH_URL_THRESHOLD_LENGTH (_POSIX_PATH_MAX - 16)
  27
  28 int pull_find_old_etags(
  29                 const char *url,
  30                 const char *image_root,
  31                 int dt,
  32                 const char *prefix,
  33                 const char *suffix,
  34                 char ***etags) {
  35
  36         _cleanup_free_ char *escaped_url = NULL;
  37         _cleanup_closedir_ DIR *d = NULL;
  38         _cleanup_strv_free_ char **l = NULL;
  39         struct dirent *de;
  40         int r;
  41
  42         assert(url);
  43         assert(etags);
  44
  45         if (!image_root)
  46                 image_root = "/var/lib/machines";
  47
  48         escaped_url = xescape(url, FILENAME_ESCAPE);
  49         if (!escaped_url)
  50                 return -ENOMEM;
  51
  52         d = opendir(image_root);
  53         if (!d) {
  54                 if (errno == ENOENT) {
  55                         *etags = NULL;
  56                         return 0;
  57                 }
  58
  59                 return -errno;
  60         }
  61
  62         FOREACH_DIRENT_ALL(de, d, return -errno) {
  63                 const char *a, *b;
  64                 char *u;
  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                 r = cunescape_length(a, b - a, 0, &u);
  96                 if (r < 0)
  97                         return r;
  98
  99                 if (!http_etag_is_valid(u)) {
 100                         free(u);
 101                         continue;
 102                 }
 103
 104                 r = strv_consume(&l, u);
 105                 if (r < 0)
 106                         return r;
 107         }
 108
 109         *etags = TAKE_PTR(l);
 110
 111         return 0;
 112 }
 113
 114 int pull_make_local_copy(const char *final, const char *image_root, const char *local, bool force_local) {
 115         const char *p;
 116         int r;
 117
 118         assert(final);
 119         assert(local);
 120
 121         if (!image_root)
 122                 image_root = "/var/lib/machines";
 123
 124         p = strjoina(image_root, "/", local);
 125
 126         if (force_local)
 127                 (void) rm_rf(p, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);
 128
 129         r = btrfs_subvol_snapshot(final, p,
 130                                   BTRFS_SNAPSHOT_QUOTA|
 131                                   BTRFS_SNAPSHOT_FALLBACK_COPY|
 132                                   BTRFS_SNAPSHOT_FALLBACK_DIRECTORY|
 133                                   BTRFS_SNAPSHOT_RECURSIVE);
 134         if (r < 0)
 135                 return log_error_errno(r, "Failed to create local image: %m");
 136
 137         log_info("Created new local image '%s'.", local);
 138
 139         return 0;
 140 }
 141
 142 static int hash_url(const char *url, char **ret) {
 143         uint64_t h;
 144         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);
 145
 146         assert(url);
 147
 148         h = siphash24(url, strlen(url), k.bytes);
 149         if (asprintf(ret, "%"PRIx64, h) < 0)
 150                 return -ENOMEM;
 151
 152         return 0;
 153 }
 154
 155 int pull_make_path(const char *url, const char *etag, const char *image_root, const char *prefix, const char *suffix, char **ret) {
 156         _cleanup_free_ char *escaped_url = NULL, *escaped_etag = NULL;
 157         char *path;
 158
 159         assert(url);
 160         assert(ret);
 161
 162         if (!image_root)
 163                 image_root = "/var/lib/machines";
 164
 165         escaped_url = xescape(url, FILENAME_ESCAPE);
 166         if (!escaped_url)
 167                 return -ENOMEM;
 168
 169         if (etag) {
 170                 escaped_etag = xescape(etag, FILENAME_ESCAPE);
 171                 if (!escaped_etag)
 172                         return -ENOMEM;
 173         }
 174
 175         path = strjoin(image_root, "/", strempty(prefix), escaped_url, escaped_etag ? "." : "",
 176                        strempty(escaped_etag), strempty(suffix));
 177         if (!path)
 178                 return -ENOMEM;
 179
 180         /* URLs might make the path longer than the maximum allowed length for a file name.
 181          * When that happens, a URL hash is used instead. Paths returned by this function
 182          * can be later used with tempfn_random() which adds 16 bytes to the resulting name. */
 183         if (strlen(path) >= HASH_URL_THRESHOLD_LENGTH) {
 184                 _cleanup_free_ char *hash = NULL;
 185                 int r;
 186
 187                 free(path);
 188
 189                 r = hash_url(url, &hash);
 190                 if (r < 0)
 191                         return r;
 192
 193                 path = strjoin(image_root, "/", strempty(prefix), hash, escaped_etag ? "." : "",
 194                                strempty(escaped_etag), strempty(suffix));
 195                 if (!path)
 196                         return -ENOMEM;
 197         }
 198
 199         *ret = path;
 200         return 0;
 201 }
 202
 203 int pull_make_auxiliary_job(
 204                 PullJob **ret,
 205                 const char *url,
 206                 int (*strip_suffixes)(const char *name, char **ret),
 207                 const char *suffix,
 208                 CurlGlue *glue,
 209                 PullJobFinished on_finished,
 210                 void *userdata) {
 211
 212         _cleanup_free_ char *last_component = NULL, *ll = NULL, *auxiliary_url = NULL;
 213         _cleanup_(pull_job_unrefp) PullJob *job = NULL;
 214         const char *q;
 215         int r;
 216
 217         assert(ret);
 218         assert(url);
 219         assert(strip_suffixes);
 220         assert(glue);
 221
 222         r = import_url_last_component(url, &last_component);
 223         if (r < 0)
 224                 return r;
 225
 226         r = strip_suffixes(last_component, &ll);
 227         if (r < 0)
 228                 return r;
 229
 230         q = strjoina(ll, suffix);
 231
 232         r = import_url_change_last_component(url, q, &auxiliary_url);
 233         if (r < 0)
 234                 return r;
 235
 236         r = pull_job_new(&job, auxiliary_url, glue, userdata);
 237         if (r < 0)
 238                 return r;
 239
 240         job->on_finished = on_finished;
 241         job->compressed_max = job->uncompressed_max = 1ULL * 1024ULL * 1024ULL;
 242
 243         *ret = TAKE_PTR(job);
 244
 245         return 0;
 246 }
 247
 248 int pull_make_verification_jobs(
 249                 PullJob **ret_checksum_job,
 250                 PullJob **ret_signature_job,
 251                 ImportVerify verify,
 252                 const char *url,
 253                 CurlGlue *glue,
 254                 PullJobFinished on_finished,
 255                 void *userdata) {
 256
 257         _cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;
 258         int r;
 259         const char *chksums = NULL;
 260
 261         assert(ret_checksum_job);
 262         assert(ret_signature_job);
 263         assert(verify >= 0);
 264         assert(verify < _IMPORT_VERIFY_MAX);
 265         assert(url);
 266         assert(glue);
 267
 268         if (verify != IMPORT_VERIFY_NO) {
 269                 _cleanup_free_ char *checksum_url = NULL, *fn = NULL;
 270
 271                 /* Queue jobs for the checksum file for the image. */
 272                 r = import_url_last_component(url, &fn);
 273                 if (r < 0)
 274                         return r;
 275
 276                 chksums = strjoina(fn, ".sha256");
 277
 278                 r = import_url_change_last_component(url, chksums, &checksum_url);
 279                 if (r < 0)
 280                         return r;
 281
 282                 r = pull_job_new(&checksum_job, checksum_url, glue, userdata);
 283                 if (r < 0)
 284                         return r;
 285
 286                 checksum_job->on_finished = on_finished;
 287                 checksum_job->uncompressed_max = checksum_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 288         }
 289
 290         if (verify == IMPORT_VERIFY_SIGNATURE) {
 291                 _cleanup_free_ char *signature_url = NULL;
 292
 293                 /* Queue job for the SHA256SUMS.gpg file for the image. */
 294                 r = import_url_change_last_component(url, "SHA256SUMS.gpg", &signature_url);
 295                 if (r < 0)
 296                         return r;
 297
 298                 r = pull_job_new(&signature_job, signature_url, glue, userdata);
 299                 if (r < 0)
 300                         return r;
 301
 302                 signature_job->on_finished = on_finished;
 303                 signature_job->uncompressed_max = signature_job->compressed_max = 1ULL * 1024ULL * 1024ULL;
 304         }
 305
 306         *ret_checksum_job = checksum_job;
 307         *ret_signature_job = signature_job;
 308
 309         checksum_job = signature_job = NULL;
 310
 311         return 0;
 312 }
 313
 314 static int verify_one(PullJob *checksum_job, PullJob *job) {
 315         _cleanup_free_ char *fn = NULL;
 316         const char *line, *p;
 317         int r;
 318
 319         assert(checksum_job);
 320
 321         if (!job)
 322                 return 0;
 323
 324         assert(IN_SET(job->state, PULL_JOB_DONE, PULL_JOB_FAILED));
 325
 326         /* Don't verify the checksum if we didn't actually successfully download something new */
 327         if (job->state != PULL_JOB_DONE)
 328                 return 0;
 329         if (job->error != 0)
 330                 return 0;
 331         if (job->etag_exists)
 332                 return 0;
 333
 334         assert(job->calc_checksum);
 335         assert(job->checksum);
 336
 337         r = import_url_last_component(job->url, &fn);
 338         if (r < 0)
 339                 return log_oom();
 340
 341         if (!filename_is_valid(fn)) {
 342                 log_error("Cannot verify checksum, could not determine server-side file name.");
 343                 return -EBADMSG;
 344         }
 345
 346         line = strjoina(job->checksum, " *", fn, "\n");
 347
 348         p = memmem(checksum_job->payload,
 349                    checksum_job->payload_size,
 350                    line,
 351                    strlen(line));
 352
 353         if (!p) {
 354                 line = strjoina(job->checksum, "  ", fn, "\n");
 355
 356                 p = memmem(checksum_job->payload,
 357                         checksum_job->payload_size,
 358                         line,
 359                         strlen(line));
 360         }
 361
 362         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n')) {
 363                 log_error("DOWNLOAD INVALID: Checksum of %s file did not checkout, file has been tampered with.", fn);
 364                 return -EBADMSG;
 365         }
 366
 367         log_info("SHA256 checksum of %s is valid.", job->url);
 368         return 1;
 369 }
 370
 371 int pull_verify(PullJob *main_job,
 372                 PullJob *roothash_job,
 373                 PullJob *settings_job,
 374                 PullJob *checksum_job,
 375                 PullJob *signature_job) {
 376
 377         _cleanup_close_pair_ int gpg_pipe[2] = { -1, -1 };
 378         _cleanup_close_ int sig_file = -1;
 379         char sig_file_path[] = "/tmp/sigXXXXXX", gpg_home[] = "/tmp/gpghomeXXXXXX";
 380         _cleanup_(sigkill_waitp) pid_t pid = 0;
 381         bool gpg_home_created = false;
 382         int r;
 383
 384         assert(main_job);
 385         assert(main_job->state == PULL_JOB_DONE);
 386
 387         if (!checksum_job)
 388                 return 0;
 389
 390         assert(main_job->calc_checksum);
 391         assert(main_job->checksum);
 392
 393         assert(checksum_job->state == PULL_JOB_DONE);
 394
 395         if (!checksum_job->payload || checksum_job->payload_size <= 0) {
 396                 log_error("Checksum is empty, cannot verify.");
 397                 return -EBADMSG;
 398         }
 399
 400         r = verify_one(checksum_job, main_job);
 401         if (r < 0)
 402                 return r;
 403
 404         r = verify_one(checksum_job, roothash_job);
 405         if (r < 0)
 406                 return r;
 407
 408         r = verify_one(checksum_job, settings_job);
 409         if (r < 0)
 410                 return r;
 411
 412         if (!signature_job)
 413                 return 0;
 414
 415         if (checksum_job->style == VERIFICATION_PER_FILE)
 416                 signature_job = checksum_job;
 417
 418         assert(signature_job->state == PULL_JOB_DONE);
 419
 420         if (!signature_job->payload || signature_job->payload_size <= 0) {
 421                 log_error("Signature is empty, cannot verify.");
 422                 return -EBADMSG;
 423         }
 424
 425         r = pipe2(gpg_pipe, O_CLOEXEC);
 426         if (r < 0)
 427                 return log_error_errno(errno, "Failed to create pipe for gpg: %m");
 428
 429         sig_file = mkostemp(sig_file_path, O_RDWR);
 430         if (sig_file < 0)
 431                 return log_error_errno(errno, "Failed to create temporary file: %m");
 432
 433         r = loop_write(sig_file, signature_job->payload, signature_job->payload_size, false);
 434         if (r < 0) {
 435                 log_error_errno(r, "Failed to write to temporary file: %m");
 436                 goto finish;
 437         }
 438
 439         if (!mkdtemp(gpg_home)) {
 440                 r = log_error_errno(errno, "Failed to create tempory home for gpg: %m");
 441                 goto finish;
 442         }
 443
 444         gpg_home_created = true;
 445
 446         r = safe_fork("(gpg)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
 447         if (r < 0)
 448                 return r;
 449         if (r == 0) {
 450                 const char *cmd[] = {
 451                         "gpg",
 452                         "--no-options",
 453                         "--no-default-keyring",
 454                         "--no-auto-key-locate",
 455                         "--no-auto-check-trustdb",
 456                         "--batch",
 457                         "--trust-model=always",
 458                         NULL, /* --homedir=  */
 459                         NULL, /* --keyring= */
 460                         NULL, /* --verify */
 461                         NULL, /* signature file */
 462                         NULL, /* dash */
 463                         NULL  /* trailing NULL */
 464                 };
 465                 unsigned k = ELEMENTSOF(cmd) - 6;
 466
 467                 /* Child */
 468
 469                 gpg_pipe[1] = safe_close(gpg_pipe[1]);
 470
 471                 r = rearrange_stdio(gpg_pipe[0], -1, STDERR_FILENO);
 472                 if (r < 0) {
 473                         log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
 474                         _exit(EXIT_FAILURE);
 475                 }
 476
 477                 cmd[k++] = strjoina("--homedir=", gpg_home);
 478
 479                 /* We add the user keyring only to the command line
 480                  * arguments, if it's around since gpg fails
 481                  * otherwise. */
 482                 if (access(USER_KEYRING_PATH, F_OK) >= 0)
 483                         cmd[k++] = "--keyring=" USER_KEYRING_PATH;
 484                 else
 485                         cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;
 486
 487                 cmd[k++] = "--verify";
 488                 if (checksum_job->style == VERIFICATION_PER_DIRECTORY) {
 489                         cmd[k++] = sig_file_path;
 490                         cmd[k++] = "-";
 491                         cmd[k++] = NULL;
 492                 }
 493
 494                 execvp("gpg2", (char * const *) cmd);
 495                 execvp("gpg", (char * const *) cmd);
 496                 log_error_errno(errno, "Failed to execute gpg: %m");
 497                 _exit(EXIT_FAILURE);
 498         }
 499
 500         gpg_pipe[0] = safe_close(gpg_pipe[0]);
 501
 502         r = loop_write(gpg_pipe[1], checksum_job->payload, checksum_job->payload_size, false);
 503         if (r < 0) {
 504                 log_error_errno(r, "Failed to write to pipe: %m");
 505                 goto finish;
 506         }
 507
 508         gpg_pipe[1] = safe_close(gpg_pipe[1]);
 509
 510         r = wait_for_terminate_and_check("gpg", pid, WAIT_LOG_ABNORMAL);
 511         pid = 0;
 512         if (r < 0)
 513                 goto finish;
 514         if (r != EXIT_SUCCESS) {
 515                 log_error("DOWNLOAD INVALID: Signature verification failed.");
 516                 r = -EBADMSG;
 517         } else {
 518                 log_info("Signature verification succeeded.");
 519                 r = 0;
 520         }
 521
 522 finish:
 523         (void) unlink(sig_file_path);
 524
 525         if (gpg_home_created)
 526                 (void) rm_rf(gpg_home, REMOVE_ROOT|REMOVE_PHYSICAL);
 527
 528         return r;
 529 }