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