src/shared/creds-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sys/file.h>
   4
   5 #if HAVE_OPENSSL
   6 #include <openssl/err.h>
   7 #endif
   8
   9 #include "sd-id128.h"
  10
  11 #include "blockdev-util.h"
  12 #include "chattr-util.h"
  13 #include "creds-util.h"
  14 #include "efi-api.h"
  15 #include "env-util.h"
  16 #include "fd-util.h"
  17 #include "fileio.h"
  18 #include "fs-util.h"
  19 #include "io-util.h"
  20 #include "memory-util.h"
  21 #include "mkdir.h"
  22 #include "openssl-util.h"
  23 #include "path-util.h"
  24 #include "random-util.h"
  25 #include "sparse-endian.h"
  26 #include "stat-util.h"
  27 #include "tpm2-util.h"
  28 #include "virt.h"
  29
  30 bool credential_name_valid(const char *s) {
  31         /* We want that credential names are both valid in filenames (since that's our primary way to pass
  32          * them around) and as fdnames (which is how we might want to pass them around eventually) */
  33         return filename_is_valid(s) && fdname_is_valid(s);
  34 }
  35
  36 static int get_credentials_dir_internal(const char *envvar, const char **ret) {
  37         const char *e;
  38
  39         assert(ret);
  40
  41         e = secure_getenv(envvar);
  42         if (!e)
  43                 return -ENXIO;
  44
  45         if (!path_is_absolute(e) || !path_is_normalized(e))
  46                 return -EINVAL;
  47
  48         *ret = e;
  49         return 0;
  50 }
  51
  52 int get_credentials_dir(const char **ret) {
  53         return get_credentials_dir_internal("CREDENTIALS_DIRECTORY", ret);
  54 }
  55
  56 int get_encrypted_credentials_dir(const char **ret) {
  57         return get_credentials_dir_internal("ENCRYPTED_CREDENTIALS_DIRECTORY", ret);
  58 }
  59
  60 int read_credential(const char *name, void **ret, size_t *ret_size) {
  61         _cleanup_free_ char *fn = NULL;
  62         const char *d;
  63         int r;
  64
  65         assert(ret);
  66
  67         if (!credential_name_valid(name))
  68                 return -EINVAL;
  69
  70         r = get_credentials_dir(&d);
  71         if (r < 0)
  72                 return r;
  73
  74         fn = path_join(d, name);
  75         if (!fn)
  76                 return -ENOMEM;
  77
  78         return read_full_file_full(
  79                         AT_FDCWD, fn,
  80                         UINT64_MAX, SIZE_MAX,
  81                         READ_FULL_FILE_SECURE,
  82                         NULL,
  83                         (char**) ret, ret_size);
  84 }
  85
  86 #if HAVE_OPENSSL
  87
  88 #define CREDENTIAL_HOST_SECRET_SIZE 4096
  89
  90 static const sd_id128_t credential_app_id =
  91         SD_ID128_MAKE(d3,ac,ec,ba,0d,ad,4c,df,b8,c9,38,15,28,93,6c,58);
  92
  93 struct credential_host_secret_format {
  94         /* The hashed machine ID of the machine this belongs to. Why? We want to ensure that each machine
  95          * gets its own secret, even if people forget to flush out this secret file. Hence we bind it to the
  96          * machine ID, for which there's hopefully a better chance it will be flushed out. We use a hashed
  97          * machine ID instead of the literal one, because it's trivial to, and it might be a good idea not
  98          * being able to directly associate a secret key file with a host. */
  99         sd_id128_t machine_id;
 100
 101         /* The actual secret key */
 102         uint8_t data[CREDENTIAL_HOST_SECRET_SIZE];
 103 } _packed_;
 104
 105 static void warn_not_encrypted(int fd, CredentialSecretFlags flags, const char *dirname, const char *filename) {
 106         int r;
 107
 108         assert(fd >= 0);
 109         assert(dirname);
 110         assert(filename);
 111
 112         if (!FLAGS_SET(flags, CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED))
 113                 return;
 114
 115         r = fd_is_encrypted(fd);
 116         if (r < 0)
 117                 log_debug_errno(r, "Failed to determine if credential secret file '%s/%s' is encrypted.",
 118                                 dirname, filename);
 119         else if (r == 0)
 120                 log_warning("Credential secret file '%s/%s' is not located on encrypted media, using anyway.",
 121                             dirname, filename);
 122 }
 123
 124 static int make_credential_host_secret(
 125                 int dfd,
 126                 const sd_id128_t machine_id,
 127                 CredentialSecretFlags flags,
 128                 const char *dirname,
 129                 const char *fn,
 130                 void **ret_data,
 131                 size_t *ret_size) {
 132
 133         struct credential_host_secret_format buf;
 134         _cleanup_free_ char *t = NULL;
 135         _cleanup_close_ int fd = -1;
 136         int r;
 137
 138         assert(dfd >= 0);
 139         assert(fn);
 140
 141         fd = openat(dfd, ".", O_CLOEXEC|O_WRONLY|O_TMPFILE, 0400);
 142         if (fd < 0) {
 143                 log_debug_errno(errno, "Failed to create temporary credential file with O_TMPFILE, proceeding without: %m");
 144
 145                 if (asprintf(&t, "credential.secret.%016" PRIx64, random_u64()) < 0)
 146                         return -ENOMEM;
 147
 148                 fd = openat(dfd, t, O_CLOEXEC|O_WRONLY|O_CREAT|O_EXCL|O_NOFOLLOW, 0400);
 149                 if (fd < 0)
 150                         return -errno;
 151         }
 152
 153         r = chattr_secret(fd, 0);
 154         if (r < 0)
 155                 log_debug_errno(r, "Failed to set file attributes for secrets file, ignoring: %m");
 156
 157         buf = (struct credential_host_secret_format) {
 158                 .machine_id = machine_id,
 159         };
 160
 161         r = crypto_random_bytes(buf.data, sizeof(buf.data));
 162         if (r < 0)
 163                 goto finish;
 164
 165         r = loop_write(fd, &buf, sizeof(buf), false);
 166         if (r < 0)
 167                 goto finish;
 168
 169         if (fsync(fd) < 0) {
 170                 r = -errno;
 171                 goto finish;
 172         }
 173
 174         warn_not_encrypted(fd, flags, dirname, fn);
 175
 176         if (t) {
 177                 r = rename_noreplace(dfd, t, dfd, fn);
 178                 if (r < 0)
 179                         goto finish;
 180
 181                 t = mfree(t);
 182         } else if (linkat(fd, "", dfd, fn, AT_EMPTY_PATH) < 0) {
 183                 r = -errno;
 184                 goto finish;
 185         }
 186
 187         if (fsync(dfd) < 0) {
 188                 r = -errno;
 189                 goto finish;
 190         }
 191
 192         if (ret_data) {
 193                 void *copy;
 194
 195                 copy = memdup(buf.data, sizeof(buf.data));
 196                 if (!copy) {
 197                         r = -ENOMEM;
 198                         goto finish;
 199                 }
 200
 201                 *ret_data = copy;
 202         }
 203
 204         if (ret_size)
 205                 *ret_size = sizeof(buf.data);
 206
 207         r = 0;
 208
 209 finish:
 210         if (t && unlinkat(dfd, t, 0) < 0)
 211                 log_debug_errno(errno, "Failed to remove temporary credential key: %m");
 212
 213         explicit_bzero_safe(&buf, sizeof(buf));
 214         return r;
 215 }
 216
 217 int get_credential_host_secret(CredentialSecretFlags flags, void **ret, size_t *ret_size) {
 218         _cleanup_free_ char *_dirname = NULL, *_filename = NULL;
 219         _cleanup_close_ int dfd = -1;
 220         sd_id128_t machine_id;
 221         const char *dirname, *filename;
 222         int r;
 223
 224         r = sd_id128_get_machine_app_specific(credential_app_id, &machine_id);
 225         if (r < 0)
 226                 return r;
 227
 228         const char *e = secure_getenv("SYSTEMD_CREDENTIAL_SECRET");
 229         if (e) {
 230                 if (!path_is_normalized(e))
 231                         return -EINVAL;
 232                 if (!path_is_absolute(e))
 233                         return -EINVAL;
 234
 235                 r = path_extract_directory(e, &_dirname);
 236                 if (r < 0)
 237                         return r;
 238
 239                 r = path_extract_filename(e, &_filename);
 240                 if (r < 0)
 241                         return r;
 242
 243                 dirname = _dirname;
 244                 filename = _filename;
 245         } else {
 246                 dirname = "/var/lib/systemd";
 247                 filename = "credential.secret";
 248         }
 249
 250         mkdir_parents(dirname, 0755);
 251         dfd = open_mkdir_at(AT_FDCWD, dirname, O_CLOEXEC, 0755);
 252         if (dfd < 0)
 253                 return log_debug_errno(dfd, "Failed to create or open directory '%s': %m", dirname);
 254
 255         if (FLAGS_SET(flags, CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS)) {
 256                 r = fd_is_temporary_fs(dfd);
 257                 if (r < 0)
 258                         return log_debug_errno(r, "Failed to check directory '%s': %m", dirname);
 259                 if (r > 0)
 260                         return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
 261                                                "Directory '%s' is on a temporary file system, refusing.", dirname);
 262         }
 263
 264         for (unsigned attempt = 0;; attempt++) {
 265                 _cleanup_(erase_and_freep) struct credential_host_secret_format *f = NULL;
 266                 _cleanup_close_ int fd = -1;
 267                 size_t l = 0;
 268                 ssize_t n = 0;
 269                 struct stat st;
 270
 271                 if (attempt >= 3) /* Somebody is playing games with us */
 272                         return log_debug_errno(SYNTHETIC_ERRNO(EIO),
 273                                                "All attempts to create secret store in %s failed.", dirname);
 274
 275                 fd = openat(dfd, filename, O_CLOEXEC|O_RDONLY|O_NOCTTY|O_NOFOLLOW);
 276                 if (fd < 0) {
 277                         if (errno != ENOENT || !FLAGS_SET(flags, CREDENTIAL_SECRET_GENERATE))
 278                                 return log_debug_errno(errno,
 279                                                        "Failed to open %s/%s: %m", dirname, filename);
 280
 281
 282                         r = make_credential_host_secret(dfd, machine_id, flags, dirname, filename, ret, ret_size);
 283                         if (r == -EEXIST) {
 284                                 log_debug_errno(r, "Credential secret %s/%s appeared while we were creating it, rereading.",
 285                                                 dirname, filename);
 286                                 continue;
 287                         }
 288                         if (r < 0)
 289                                 return log_debug_errno(r, "Failed to create credential secret %s/%s: %m",
 290                                                        dirname, filename);
 291                         return 0;
 292                 }
 293
 294                 if (fstat(fd, &st) < 0)
 295                         return log_debug_errno(errno, "Failed to stat %s/%s: %m", dirname, filename);
 296
 297                 r = stat_verify_regular(&st);
 298                 if (r < 0)
 299                         return log_debug_errno(r, "%s/%s is not a regular file: %m", dirname, filename);
 300                 if (st.st_nlink == 0) /* Deleted by now, try again */
 301                         continue;
 302                 if (st.st_nlink > 1)
 303                         /* Our deletion check won't work if hardlinked somewhere else */
 304                         return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
 305                                                "%s/%s has too many links, refusing.",
 306                                                dirname, filename);
 307                 if ((st.st_mode & 07777) != 0400)
 308                         /* Don't use file if not 0400 access mode */
 309                         return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
 310                                                "%s/%s has permissive access mode, refusing.",
 311                                                dirname, filename);
 312                 l = st.st_size;
 313                 if (l < offsetof(struct credential_host_secret_format, data) + 1)
 314                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
 315                                                "%s/%s is too small, refusing.", dirname, filename);
 316                 if (l > 16*1024*1024)
 317                         return log_debug_errno(SYNTHETIC_ERRNO(E2BIG),
 318                                                "%s/%s is too big, refusing.", dirname, filename);
 319
 320                 f = malloc(l+1);
 321                 if (!f)
 322                         return log_oom_debug();
 323
 324                 n = read(fd, f, l+1);
 325                 if (n < 0)
 326                         return log_debug_errno(errno,
 327                                                "Failed to read %s/%s: %m", dirname, filename);
 328                 if ((size_t) n != l) /* What? The size changed? */
 329                         return log_debug_errno(SYNTHETIC_ERRNO(EIO),
 330                                                "Failed to read %s/%s: %m", dirname, filename);
 331
 332                 if (sd_id128_equal(machine_id, f->machine_id)) {
 333                         size_t sz;
 334
 335                         warn_not_encrypted(fd, flags, dirname, filename);
 336
 337                         sz = l - offsetof(struct credential_host_secret_format, data);
 338                         assert(sz > 0);
 339
 340                         if (ret) {
 341                                 void *copy;
 342
 343                                 assert(sz <= sizeof(f->data)); /* Ensure we don't read past f->data bounds */
 344
 345                                 copy = memdup(f->data, sz);
 346                                 if (!copy)
 347                                         return log_oom_debug();
 348
 349                                 *ret = copy;
 350                         }
 351
 352                         if (ret_size)
 353                                 *ret_size = sz;
 354
 355                         return 0;
 356                 }
 357
 358                 /* Hmm, this secret is from somewhere else. Let's delete the file. Let's first acquire a lock
 359                  * to ensure we are the only ones accessing the file while we delete it. */
 360
 361                 if (flock(fd, LOCK_EX) < 0)
 362                         return log_debug_errno(errno,
 363                                                "Failed to flock %s/%s: %m", dirname, filename);
 364
 365                 /* Before we delete it check that the file is still linked into the file system */
 366                 if (fstat(fd, &st) < 0)
 367                         return log_debug_errno(errno, "Failed to stat %s/%s: %m", dirname, filename);
 368                 if (st.st_nlink == 0) /* Already deleted by now? */
 369                         continue;
 370                 if (st.st_nlink != 1) /* Safety check, someone is playing games with us */
 371                         return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
 372                                                "%s/%s unexpectedly has too many links.",
 373                                                dirname, filename);
 374                 if (unlinkat(dfd, filename, 0) < 0)
 375                         return log_debug_errno(errno, "Failed to unlink %s/%s: %m", dirname, filename);
 376
 377                 /* And now try again */
 378         }
 379 }
 380
 381 /* Construction is like this:
 382  *
 383  * A symmetric encryption key is derived from:
 384  *
 385  *      1. Either the "host" key (a key stored in /var/lib/credential.secret)
 386  *
 387  *      2. A key generated by letting the TPM2 calculate an HMAC hash of some nonce we pass to it, keyed
 388  *         by a key derived from its internal seed key.
 389  *
 390  *      3. The concatenation of the above.
 391  *
 392  *      4. Or a fixed "empty" key. This will not provide confidentiality or authenticity, of course, but is
 393  *         useful to encode credentials for the initrd on TPM-less systems, where we simply have no better
 394  *         concept to bind things to. Note that decryption of a key set up like this will be refused on
 395  *         systems that have a TPM and have SecureBoot enabled.
 396  *
 397  * The above is hashed with SHA256 which is then used as encryption key for AES256-GCM. The encrypted
 398  * credential is a short (unencrypted) header describing which of the three keys to use, the IV to use for
 399  * AES256-GCM and some more meta information (sizes of certain objects) that is strictly speaking redundant,
 400  * but kinda nice to have since we can have a more generic parser. If the TPM2 key is used this is followed
 401  * by another (unencrypted) header, with information about the TPM2 policy used (specifically: the PCR mask
 402  * to bind against, and a hash of the resulting policy — the latter being redundant, but speeding up things a
 403  * bit, since we can more quickly refuse PCR state), followed by a sealed/exported TPM2 HMAC key. This is
 404  * then followed by the encrypted data, which begins with a metadata header (which contains validity
 405  * timestamps as well as the credential name), followed by the actual credential payload. The file ends in
 406  * the AES256-GCM tag. To make things simple, the AES256-GCM AAD covers the main and the TPM2 header in
 407  * full. This means the whole file is either protected by AAD, or is ciphertext, or is the tag. No
 408  * unprotected data is included.
 409  */
 410
 411 struct _packed_ encrypted_credential_header {
 412         sd_id128_t id;
 413         le32_t key_size;
 414         le32_t block_size;
 415         le32_t iv_size;
 416         le32_t tag_size;
 417         uint8_t iv[];
 418         /* Followed by NUL bytes until next 8 byte boundary */
 419 };
 420
 421 struct _packed_ tpm2_credential_header {
 422         le64_t pcr_mask;    /* Note that the spec for PC Clients only mandates 24 PCRs, and that's what systems
 423                              * generally have. But keep the door open for more. */
 424         le16_t pcr_bank;    /* For now, either TPM2_ALG_SHA256 or TPM2_ALG_SHA1 */
 425         le16_t primary_alg; /* Primary key algorithm (either TPM2_ALG_RSA or TPM2_ALG_ECC for now) */
 426         le32_t blob_size;
 427         le32_t policy_hash_size;
 428         uint8_t policy_hash_and_blob[];
 429         /* Followed by NUL bytes until next 8 byte boundary */
 430 };
 431
 432 struct _packed_ metadata_credential_header {
 433         le64_t timestamp;
 434         le64_t not_after;
 435         le32_t name_size;
 436         char name[];
 437         /* Followed by NUL bytes until next 8 byte boundary */
 438 };
 439
 440 /* Some generic limit for parts of the encrypted credential for which we don't know the right size ahead of
 441  * time, but where we are really sure it won't be larger than this. Should be larger than any possible IV,
 442  * padding, tag size and so on. This is purely used for early filtering out of invalid sizes. */
 443 #define CREDENTIAL_FIELD_SIZE_MAX (16U*1024U)
 444
 445 static int sha256_hash_host_and_tpm2_key(
 446                 const void *host_key,
 447                 size_t host_key_size,
 448                 const void *tpm2_key,
 449                 size_t tpm2_key_size,
 450                 uint8_t ret[static SHA256_DIGEST_LENGTH]) {
 451
 452         _cleanup_(EVP_MD_CTX_freep) EVP_MD_CTX *md = NULL;
 453         unsigned l;
 454
 455         assert(host_key_size == 0 || host_key);
 456         assert(tpm2_key_size == 0 || tpm2_key);
 457         assert(ret);
 458
 459         /* Combines the host key and the TPM2 HMAC hash into a SHA256 hash value we'll use as symmetric encryption key. */
 460
 461         md = EVP_MD_CTX_new();
 462         if (!md)
 463                 return log_oom();
 464
 465         if (EVP_DigestInit_ex(md, EVP_sha256(), NULL) != 1)
 466                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initial SHA256 context.");
 467
 468         if (host_key && EVP_DigestUpdate(md, host_key, host_key_size) != 1)
 469                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to hash host key.");
 470
 471         if (tpm2_key && EVP_DigestUpdate(md, tpm2_key, tpm2_key_size) != 1)
 472                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to hash TPM2 key.");
 473
 474         assert(EVP_MD_CTX_size(md) == SHA256_DIGEST_LENGTH);
 475
 476         if (EVP_DigestFinal_ex(md, ret, &l) != 1)
 477                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finalize SHA256 hash.");
 478
 479         assert(l == SHA256_DIGEST_LENGTH);
 480         return 0;
 481 }
 482
 483 int encrypt_credential_and_warn(
 484                 sd_id128_t with_key,
 485                 const char *name,
 486                 usec_t timestamp,
 487                 usec_t not_after,
 488                 const char *tpm2_device,
 489                 uint32_t tpm2_pcr_mask,
 490                 const void *input,
 491                 size_t input_size,
 492                 void **ret,
 493                 size_t *ret_size) {
 494
 495         _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
 496         _cleanup_(erase_and_freep) void *host_key = NULL, *tpm2_key = NULL;
 497         size_t host_key_size = 0, tpm2_key_size = 0, tpm2_blob_size = 0, tpm2_policy_hash_size = 0, output_size, p, ml;
 498         _cleanup_free_ void *tpm2_blob = NULL, *tpm2_policy_hash = NULL, *iv = NULL, *output = NULL;
 499         _cleanup_free_ struct metadata_credential_header *m = NULL;
 500         uint16_t tpm2_pcr_bank = 0, tpm2_primary_alg = 0;
 501         struct encrypted_credential_header *h;
 502         int ksz, bsz, ivsz, tsz, added, r;
 503         uint8_t md[SHA256_DIGEST_LENGTH];
 504         const EVP_CIPHER *cc;
 505         sd_id128_t id;
 506
 507         assert(input || input_size == 0);
 508         assert(ret);
 509         assert(ret_size);
 510
 511         if (!sd_id128_in_set(with_key,
 512                              _CRED_AUTO,
 513                              _CRED_AUTO_INITRD,
 514                              CRED_AES256_GCM_BY_HOST,
 515                              CRED_AES256_GCM_BY_TPM2_HMAC,
 516                              CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC,
 517                              CRED_AES256_GCM_BY_TPM2_ABSENT))
 518                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid key type: " SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(with_key));
 519
 520         if (name && !credential_name_valid(name))
 521                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid credential name: %s", name);
 522
 523         if (not_after != USEC_INFINITY && timestamp != USEC_INFINITY && not_after < timestamp)
 524                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Credential is invalidated before it is valid (" USEC_FMT " < " USEC_FMT ").", not_after, timestamp);
 525
 526         if (DEBUG_LOGGING) {
 527                 char buf[FORMAT_TIMESTAMP_MAX];
 528
 529                 if (name)
 530                         log_debug("Including credential name '%s' in encrypted credential.", name);
 531                 if (timestamp != USEC_INFINITY)
 532                         log_debug("Including timestamp '%s' in encrypted credential.", format_timestamp(buf, sizeof(buf), timestamp));
 533                 if (not_after != USEC_INFINITY)
 534                         log_debug("Including not-after timestamp '%s' in encrypted credential.", format_timestamp(buf, sizeof(buf), not_after));
 535         }
 536
 537         if (sd_id128_in_set(with_key,
 538                             _CRED_AUTO,
 539                             CRED_AES256_GCM_BY_HOST,
 540                             CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC)) {
 541
 542                 r = get_credential_host_secret(
 543                                 CREDENTIAL_SECRET_GENERATE|
 544                                 CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED|
 545                                 (sd_id128_equal(with_key, _CRED_AUTO) ? CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS : 0),
 546                                 &host_key,
 547                                 &host_key_size);
 548                 if (r == -ENOMEDIUM && sd_id128_equal(with_key, _CRED_AUTO))
 549                         log_debug_errno(r, "Credential host secret location on temporary file system, not using.");
 550                 else if (r < 0)
 551                         return log_error_errno(r, "Failed to determine local credential host secret: %m");
 552         }
 553
 554 #if HAVE_TPM2
 555         bool try_tpm2;
 556         if (sd_id128_equal(with_key, _CRED_AUTO)) {
 557                 /* If automatic mode is selected and we are running in a container, let's not try TPM2. OTOH
 558                  * if user picks TPM2 explicitly, let's always honour the request and try. */
 559
 560                 r = detect_container();
 561                 if (r < 0)
 562                         log_debug_errno(r, "Failed to determine whether we are running in a container, ignoring: %m");
 563                 else if (r > 0)
 564                         log_debug("Running in container, not attempting to use TPM2.");
 565
 566                 try_tpm2 = r <= 0;
 567         } else if (sd_id128_equal(with_key, _CRED_AUTO_INITRD)) {
 568                 /* If automatic mode for initrds is selected, we'll use the TPM2 key if the firmware does it,
 569                  * otherwise we'll use a fixed key */
 570
 571                 try_tpm2 = efi_has_tpm2();
 572                 if (!try_tpm2)
 573                         log_debug("Firmware lacks TPM2 support, not attempting to use TPM2.");
 574         } else
 575                 try_tpm2 = sd_id128_in_set(with_key, CRED_AES256_GCM_BY_TPM2_HMAC, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC);
 576
 577         if (try_tpm2) {
 578                 r = tpm2_seal(tpm2_device,
 579                               tpm2_pcr_mask,
 580                               NULL,
 581                               &tpm2_key,
 582                               &tpm2_key_size,
 583                               &tpm2_blob,
 584                               &tpm2_blob_size,
 585                               &tpm2_policy_hash,
 586                               &tpm2_policy_hash_size,
 587                               &tpm2_pcr_bank,
 588                               &tpm2_primary_alg);
 589                 if (r < 0) {
 590                         if (sd_id128_equal(with_key, _CRED_AUTO_INITRD))
 591                                 log_warning("Firmware reported a TPM2 being present and used, but we didn't manage to talk to it. Credential will be refused if SecureBoot is enabled.");
 592                         else if (!sd_id128_equal(with_key, _CRED_AUTO))
 593                                 return r;
 594
 595                         log_notice_errno(r, "TPM2 sealing didn't work, continuing without TPM2: %m");
 596                 }
 597
 598                 assert(tpm2_blob_size <= CREDENTIAL_FIELD_SIZE_MAX);
 599                 assert(tpm2_policy_hash_size <= CREDENTIAL_FIELD_SIZE_MAX);
 600         }
 601 #endif
 602
 603         if (sd_id128_in_set(with_key, _CRED_AUTO, _CRED_AUTO_INITRD)) {
 604                 /* Let's settle the key type in auto mode now. */
 605
 606                 if (host_key && tpm2_key)
 607                         id = CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC;
 608                 else if (tpm2_key)
 609                         id = CRED_AES256_GCM_BY_TPM2_HMAC;
 610                 else if (host_key)
 611                         id = CRED_AES256_GCM_BY_HOST;
 612                 else if (sd_id128_equal(with_key, _CRED_AUTO_INITRD))
 613                         id = CRED_AES256_GCM_BY_TPM2_ABSENT;
 614                 else
 615                         return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
 616                                                "TPM2 not available and host key located on temporary file system, no encryption key available.");
 617         } else
 618                 id = with_key;
 619
 620         if (sd_id128_equal(id, CRED_AES256_GCM_BY_TPM2_ABSENT))
 621                 log_warning("Using a null key for encryption and signing. Confidentiality or authenticity will not be provided.");
 622
 623         /* Let's now take the host key and the TPM2 key and hash it together, to use as encryption key for the data */
 624         r = sha256_hash_host_and_tpm2_key(host_key, host_key_size, tpm2_key, tpm2_key_size, md);
 625         if (r < 0)
 626                 return r;
 627
 628         assert_se(cc = EVP_aes_256_gcm());
 629
 630         ksz = EVP_CIPHER_key_length(cc);
 631         assert(ksz == sizeof(md));
 632
 633         bsz = EVP_CIPHER_block_size(cc);
 634         assert(bsz > 0);
 635         assert((size_t) bsz <= CREDENTIAL_FIELD_SIZE_MAX);
 636
 637         ivsz = EVP_CIPHER_iv_length(cc);
 638         if (ivsz > 0) {
 639                 assert((size_t) ivsz <= CREDENTIAL_FIELD_SIZE_MAX);
 640
 641                 iv = malloc(ivsz);
 642                 if (!iv)
 643                         return log_oom();
 644
 645                 r = crypto_random_bytes(iv, ivsz);
 646                 if (r < 0)
 647                         return log_error_errno(r, "Failed to acquired randomized IV: %m");
 648         }
 649
 650         tsz = 16; /* FIXME: On OpenSSL 3 there is EVP_CIPHER_CTX_get_tag_length(), until then let's hardcode this */
 651
 652         context = EVP_CIPHER_CTX_new();
 653         if (!context)
 654                 return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to allocate encryption object: %s",
 655                                        ERR_error_string(ERR_get_error(), NULL));
 656
 657         if (EVP_EncryptInit_ex(context, cc, NULL, md, iv) != 1)
 658                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize encryption context: %s",
 659                                        ERR_error_string(ERR_get_error(), NULL));
 660
 661         /* Just an upper estimate */
 662         output_size =
 663                 ALIGN8(offsetof(struct encrypted_credential_header, iv) + ivsz) +
 664                 ALIGN8(tpm2_key ? offsetof(struct tpm2_credential_header, policy_hash_and_blob) + tpm2_blob_size + tpm2_policy_hash_size : 0) +
 665                 ALIGN8(offsetof(struct metadata_credential_header, name) + strlen_ptr(name)) +
 666                 input_size + 2U * (size_t) bsz +
 667                 tsz;
 668
 669         output = malloc0(output_size);
 670         if (!output)
 671                 return log_oom();
 672
 673         h = (struct encrypted_credential_header*) output;
 674         h->id = id;
 675         h->block_size = htole32(bsz);
 676         h->key_size = htole32(ksz);
 677         h->tag_size = htole32(tsz);
 678         h->iv_size = htole32(ivsz);
 679         memcpy(h->iv, iv, ivsz);
 680
 681         p = ALIGN8(offsetof(struct encrypted_credential_header, iv) + ivsz);
 682
 683         if (tpm2_key) {
 684                 struct tpm2_credential_header *t;
 685
 686                 t = (struct tpm2_credential_header*) ((uint8_t*) output + p);
 687                 t->pcr_mask = htole64(tpm2_pcr_mask);
 688                 t->pcr_bank = htole16(tpm2_pcr_bank);
 689                 t->primary_alg = htole16(tpm2_primary_alg);
 690                 t->blob_size = htole32(tpm2_blob_size);
 691                 t->policy_hash_size = htole32(tpm2_policy_hash_size);
 692                 memcpy(t->policy_hash_and_blob, tpm2_blob, tpm2_blob_size);
 693                 memcpy(t->policy_hash_and_blob + tpm2_blob_size, tpm2_policy_hash, tpm2_policy_hash_size);
 694
 695                 p += ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) + tpm2_blob_size + tpm2_policy_hash_size);
 696         }
 697
 698         /* Pass the encrypted + TPM2 header as AAD */
 699         if (EVP_EncryptUpdate(context, NULL, &added, output, p) != 1)
 700                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to write AAD data: %s",
 701                                        ERR_error_string(ERR_get_error(), NULL));
 702
 703         /* Now construct the metadata header */
 704         ml = strlen_ptr(name);
 705         m = malloc0(ALIGN8(offsetof(struct metadata_credential_header, name) + ml));
 706         if (!m)
 707                 return log_oom();
 708
 709         m->timestamp = htole64(timestamp);
 710         m->not_after = htole64(not_after);
 711         m->name_size = htole32(ml);
 712         memcpy_safe(m->name, name, ml);
 713
 714         /* And encrypt the metadata header */
 715         if (EVP_EncryptUpdate(context, (uint8_t*) output + p, &added, (const unsigned char*) m, ALIGN8(offsetof(struct metadata_credential_header, name) + ml)) != 1)
 716                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt metadata header: %s",
 717                                        ERR_error_string(ERR_get_error(), NULL));
 718
 719         assert(added >= 0);
 720         assert((size_t) added <= output_size - p);
 721         p += added;
 722
 723         /* Then encrypt the plaintext */
 724         if (EVP_EncryptUpdate(context, (uint8_t*) output + p, &added, input, input_size) != 1)
 725                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt data: %s",
 726                                        ERR_error_string(ERR_get_error(), NULL));
 727
 728         assert(added >= 0);
 729         assert((size_t) added <= output_size - p);
 730         p += added;
 731
 732         /* Finalize */
 733         if (EVP_EncryptFinal_ex(context, (uint8_t*) output + p, &added) != 1)
 734                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finalize data encryption: %s",
 735                                        ERR_error_string(ERR_get_error(), NULL));
 736
 737         assert(added >= 0);
 738         assert((size_t) added <= output_size - p);
 739         p += added;
 740
 741         assert(p <= output_size - tsz);
 742
 743         /* Append tag */
 744         if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_GET_TAG, tsz, (uint8_t*) output + p) != 1)
 745                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to get tag: %s",
 746                                        ERR_error_string(ERR_get_error(), NULL));
 747
 748         p += tsz;
 749         assert(p <= output_size);
 750
 751         if (DEBUG_LOGGING && input_size > 0) {
 752                 size_t base64_size;
 753
 754                 base64_size = DIV_ROUND_UP(p * 4, 3); /* Include base64 size increase in debug output */
 755                 assert(base64_size >= input_size);
 756                 log_debug("Input of %zu bytes grew to output of %zu bytes (+%2zu%%).", input_size, base64_size, base64_size * 100 / input_size - 100);
 757         }
 758
 759         *ret = TAKE_PTR(output);
 760         *ret_size = p;
 761
 762         return 0;
 763 }
 764
 765 int decrypt_credential_and_warn(
 766                 const char *validate_name,
 767                 usec_t validate_timestamp,
 768                 const char *tpm2_device,
 769                 const void *input,
 770                 size_t input_size,
 771                 void **ret,
 772                 size_t *ret_size) {
 773
 774         _cleanup_(erase_and_freep) void *host_key = NULL, *tpm2_key = NULL, *plaintext = NULL;
 775         _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
 776         size_t host_key_size = 0, tpm2_key_size = 0, plaintext_size, p, hs;
 777         struct encrypted_credential_header *h;
 778         struct metadata_credential_header *m;
 779         uint8_t md[SHA256_DIGEST_LENGTH];
 780         bool with_tpm2, with_host_key, is_tpm2_absent;
 781         const EVP_CIPHER *cc;
 782         int r, added;
 783
 784         assert(input || input_size == 0);
 785         assert(ret);
 786         assert(ret_size);
 787
 788         h = (struct encrypted_credential_header*) input;
 789
 790         /* The ID must fit in, for the current and all future formats */
 791         if (input_size < sizeof(h->id))
 792                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
 793
 794         with_host_key = sd_id128_in_set(h->id, CRED_AES256_GCM_BY_HOST, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC);
 795         with_tpm2 = sd_id128_in_set(h->id, CRED_AES256_GCM_BY_TPM2_HMAC, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC);
 796         is_tpm2_absent = sd_id128_equal(h->id, CRED_AES256_GCM_BY_TPM2_ABSENT);
 797
 798         if (!with_host_key && !with_tpm2 && !is_tpm2_absent)
 799                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Unknown encryption format, or corrupted data: %m");
 800
 801         if (is_tpm2_absent) {
 802                 /* So this is a credential encrypted with a zero length key. We support this to cover for the
 803                  * case where neither a host key not a TPM2 are available (specifically: initrd environments
 804                  * where the host key is not yet accessible and no TPM2 chip exists at all), to minimize
 805                  * different codeflow for TPM2 and non-TPM2 codepaths. Of course, credentials encoded this
 806                  * way offer no confidentiality nor authenticity. Because of that it's important we refuse to
 807                  * use them on systems that actually *do* have a TPM2 chip – if we are in SecureBoot
 808                  * mode. Otherwise an attacker could hand us credentials like this and we'd use them thinking
 809                  * they are trusted, even though they are not. */
 810
 811                 if (efi_has_tpm2()) {
 812                         if (is_efi_secure_boot())
 813                                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
 814                                                        "Credential uses fixed key for fallback use when TPM2 is absent — but TPM2 is present, and SecureBoot is enabled, refusing.");
 815
 816                         log_warning("Credential uses fixed key for use when TPM2 is absent, but TPM2 is present! Accepting anyway, since SecureBoot is disabled.");
 817                 } else
 818                         log_debug("Credential uses fixed key for use when TPM2 is absent, and TPM2 indeed is absent. Accepting.");
 819         }
 820
 821         /* Now we know the minimum header size */
 822         if (input_size < offsetof(struct encrypted_credential_header, iv))
 823                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
 824
 825         /* Verify some basic header values */
 826         if (le32toh(h->key_size) != sizeof(md))
 827                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected key size in header.");
 828         if (le32toh(h->block_size) <= 0 || le32toh(h->block_size) > CREDENTIAL_FIELD_SIZE_MAX)
 829                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected block size in header.");
 830         if (le32toh(h->iv_size) > CREDENTIAL_FIELD_SIZE_MAX)
 831                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "IV size too large.");
 832         if (le32toh(h->tag_size) != 16) /* FIXME: On OpenSSL 3, let's verify via EVP_CIPHER_CTX_get_tag_length() */
 833                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected tag size in header.");
 834
 835         /* Ensure we have space for the full header now (we don't know the size of the name hence this is a
 836          * lower limit only) */
 837         if (input_size <
 838             ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size)) +
 839             ALIGN8((with_tpm2 ? offsetof(struct tpm2_credential_header, policy_hash_and_blob) : 0)) +
 840             ALIGN8(offsetof(struct metadata_credential_header, name)) +
 841             le32toh(h->tag_size))
 842                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
 843
 844         p = ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size));
 845
 846         if (with_tpm2) {
 847 #if HAVE_TPM2
 848                 struct tpm2_credential_header* t = (struct tpm2_credential_header*) ((uint8_t*) input + p);
 849
 850                 if (le64toh(t->pcr_mask) >= (UINT64_C(1) << TPM2_PCRS_MAX))
 851                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 PCR mask out of range.");
 852                 if (!tpm2_pcr_bank_to_string(le16toh(t->pcr_bank)))
 853                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 PCR bank invalid or not supported");
 854                 if (!tpm2_primary_alg_to_string(le16toh(t->primary_alg)))
 855                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 primary key algorithm invalid or not supported.");
 856                 if (le32toh(t->blob_size) > CREDENTIAL_FIELD_SIZE_MAX)
 857                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected TPM2 blob size.");
 858                 if (le32toh(t->policy_hash_size) > CREDENTIAL_FIELD_SIZE_MAX)
 859                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected TPM2 policy hash size.");
 860
 861                 /* Ensure we have space for the full TPM2 header now (still don't know the name, and its size
 862                  * though, hence still just a lower limit test only) */
 863                 if (input_size <
 864                     ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size)) +
 865                     ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) + le32toh(t->blob_size) + le32toh(t->policy_hash_size)) +
 866                     ALIGN8(offsetof(struct metadata_credential_header, name)) +
 867                     le32toh(h->tag_size))
 868                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
 869
 870                 r = tpm2_unseal(tpm2_device,
 871                                 le64toh(t->pcr_mask),
 872                                 le16toh(t->pcr_bank),
 873                                 le16toh(t->primary_alg),
 874                                 t->policy_hash_and_blob,
 875                                 le32toh(t->blob_size),
 876                                 t->policy_hash_and_blob + le32toh(t->blob_size),
 877                                 le32toh(t->policy_hash_size),
 878                                 NULL,
 879                                 &tpm2_key,
 880                                 &tpm2_key_size);
 881                 if (r < 0)
 882                         return r;
 883
 884                 p += ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) +
 885                             le32toh(t->blob_size) +
 886                             le32toh(t->policy_hash_size));
 887 #else
 888                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Credential requires TPM2 support, but TPM2 support not available.");
 889 #endif
 890         }
 891
 892         if (with_host_key) {
 893                 r = get_credential_host_secret(
 894                                 0,
 895                                 &host_key,
 896                                 &host_key_size);
 897                 if (r < 0)
 898                         return log_error_errno(r, "Failed to determine local credential key: %m");
 899         }
 900
 901         if (is_tpm2_absent)
 902                 log_warning("Warning: using a null key for decryption and authentication. Confidentiality or authenticity are not provided.");
 903
 904         sha256_hash_host_and_tpm2_key(host_key, host_key_size, tpm2_key, tpm2_key_size, md);
 905
 906         assert_se(cc = EVP_aes_256_gcm());
 907
 908         /* Make sure cipher expectations match the header */
 909         if (EVP_CIPHER_key_length(cc) != (int) le32toh(h->key_size))
 910                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected key size in header.");
 911         if (EVP_CIPHER_block_size(cc) != (int) le32toh(h->block_size))
 912                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected block size in header.");
 913
 914         context = EVP_CIPHER_CTX_new();
 915         if (!context)
 916                 return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to allocate decryption object: %s",
 917                                        ERR_error_string(ERR_get_error(), NULL));
 918
 919         if (EVP_DecryptInit_ex(context, cc, NULL, NULL, NULL) != 1)
 920                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize decryption context: %s",
 921                                        ERR_error_string(ERR_get_error(), NULL));
 922
 923         if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_SET_IVLEN, le32toh(h->iv_size), NULL) != 1)
 924                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set IV size on decryption context: %s",
 925                                        ERR_error_string(ERR_get_error(), NULL));
 926
 927         if (EVP_DecryptInit_ex(context, NULL, NULL, md, h->iv) != 1)
 928                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set IV and key: %s",
 929                                        ERR_error_string(ERR_get_error(), NULL));
 930
 931         if (EVP_DecryptUpdate(context, NULL, &added, input, p) != 1)
 932                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to write AAD data: %s",
 933                                        ERR_error_string(ERR_get_error(), NULL));
 934
 935         plaintext = malloc(input_size - p - le32toh(h->tag_size));
 936         if (!plaintext)
 937                 return -ENOMEM;
 938
 939         if (EVP_DecryptUpdate(
 940                             context,
 941                             plaintext,
 942                             &added,
 943                             (uint8_t*) input + p,
 944                             input_size - p - le32toh(h->tag_size)) != 1)
 945                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to decrypt data: %s",
 946                                        ERR_error_string(ERR_get_error(), NULL));
 947
 948         assert(added >= 0);
 949         assert((size_t) added <= input_size - p - le32toh(h->tag_size));
 950         plaintext_size = added;
 951
 952         if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_SET_TAG, le32toh(h->tag_size), (uint8_t*) input + input_size - le32toh(h->tag_size)) != 1)
 953                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set tag: %s",
 954                                        ERR_error_string(ERR_get_error(), NULL));
 955
 956         if (EVP_DecryptFinal_ex(context, (uint8_t*) plaintext + plaintext_size, &added) != 1)
 957                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Decryption failed (incorrect key?): %s",
 958                                        ERR_error_string(ERR_get_error(), NULL));
 959
 960         plaintext_size += added;
 961
 962         if (plaintext_size < ALIGN8(offsetof(struct metadata_credential_header, name)))
 963                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Metadata header incomplete.");
 964
 965         m = plaintext;
 966
 967         if (le64toh(m->timestamp) != USEC_INFINITY &&
 968             le64toh(m->not_after) != USEC_INFINITY &&
 969             le64toh(m->timestamp) >= le64toh(m->not_after))
 970                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Timestamps of credential are not in order, refusing.");
 971
 972         if (le32toh(m->name_size) > CREDENTIAL_NAME_MAX)
 973                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name too long, refusing.");
 974
 975         hs = ALIGN8(offsetof(struct metadata_credential_header, name) + le32toh(m->name_size));
 976         if (plaintext_size < hs)
 977                 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Metadata header incomplete.");
 978
 979         if (le32toh(m->name_size) > 0) {
 980                 _cleanup_free_ char *embedded_name = NULL;
 981
 982                 if (memchr(m->name, 0, le32toh(m->name_size)))
 983                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name contains NUL byte, refusing.");
 984
 985                 embedded_name = memdup_suffix0(m->name, le32toh(m->name_size));
 986                 if (!embedded_name)
 987                         return log_oom();
 988
 989                 if (!credential_name_valid(embedded_name))
 990                         return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name is not valid, refusing.");
 991
 992                 if (validate_name && !streq(embedded_name, validate_name)) {
 993
 994                         r = getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NAME");
 995                         if (r < 0 && r != -ENXIO)
 996                                 log_debug_errno(r, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NAME: %m");
 997                         if (r != 0)
 998                                 return log_error_errno(SYNTHETIC_ERRNO(EREMOTE), "Embedded credential name '%s' does not match filename '%s', refusing.", embedded_name, validate_name);
 999
1000                         log_debug("Embedded credential name '%s' does not match expected name '%s', but configured to use credential anyway.", embedded_name, validate_name);
1001                 }
1002         }
1003
1004         if (validate_timestamp != USEC_INFINITY) {
1005                 if (le64toh(m->timestamp) != USEC_INFINITY && le64toh(m->timestamp) > validate_timestamp)
1006                         log_debug("Credential timestamp is from the future, assuming clock skew.");
1007
1008                 if (le64toh(m->not_after) != USEC_INFINITY && le64toh(m->not_after) < validate_timestamp) {
1009
1010                         r = getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER");
1011                         if (r < 0 && r != -ENXIO)
1012                                 log_debug_errno(r, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER: %m");
1013                         if (r != 0)
1014                                 return log_error_errno(SYNTHETIC_ERRNO(ESTALE), "Credential's time passed, refusing to use.");
1015
1016                         log_debug("Credential not-after timestamp has passed, but configured to use credential anyway.");
1017                 }
1018         }
1019
1020         if (ret) {
1021                 char *without_metadata;
1022
1023                 without_metadata = memdup((uint8_t*) plaintext + hs, plaintext_size - hs);
1024                 if (!without_metadata)
1025                         return log_oom();
1026
1027                 *ret = without_metadata;
1028         }
1029
1030         if (ret_size)
1031                 *ret_size = plaintext_size - hs;
1032
1033         return 0;
1034 }
1035
1036 #else
1037
1038 int get_credential_host_secret(CredentialSecretFlags flags, void **ret, size_t *ret_size) {
1039         return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
1040 }
1041
1042 int encrypt_credential_and_warn(sd_id128_t with_key, const char *name, usec_t timestamp, usec_t not_after, const char *tpm2_device, uint32_t tpm2_pcr_mask, const void *input, size_t input_size, void **ret, size_t *ret_size) {
1043         return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
1044 }
1045
1046 int decrypt_credential_and_warn(const char *validate_name, usec_t validate_timestamp, const char *tpm2_device, const void *input, size_t input_size, void **ret, size_t *ret_size) {
1047         return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
1048 }
1049
1050 #endif