1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
6 #include <openssl/err.h>
11 #include "blockdev-util.h"
12 #include "capability-util.h"
13 #include "chattr-util.h"
14 #include "constants.h"
15 #include "creds-util.h"
22 #include "memory-util.h"
24 #include "openssl-util.h"
25 #include "parse-util.h"
26 #include "path-util.h"
27 #include "random-util.h"
28 #include "sparse-endian.h"
29 #include "stat-util.h"
30 #include "tpm2-util.h"
33 #define PUBLIC_KEY_MAX (UINT32_C(1024) * UINT32_C(1024))
35 bool credential_name_valid(const char *s
) {
36 /* We want that credential names are both valid in filenames (since that's our primary way to pass
37 * them around) and as fdnames (which is how we might want to pass them around eventually) */
38 return filename_is_valid(s
) && fdname_is_valid(s
);
41 bool credential_glob_valid(const char *s
) {
45 /* Checks if a credential glob expression is valid. Note that this is more restrictive than
46 * fnmatch()! We only allow trailing asterisk matches for now (simply because we want some freedom
47 * with automatically extending the pattern in a systematic way to cover for unit instances getting
48 * per-instance credentials or similar. Moreover, credential globbing expressions are also more
49 * restrictive then credential names: we don't allow *, ?, [, ] in them (except for the asterisk
50 * match at the end of the string), simply to not allow ambiguity. After all, we want the flexibility
51 * to one day add full globbing should the need arise. */
56 /* Find first glob (or NUL byte) */
57 n
= strcspn(s
, "*?[]");
60 /* For now, only allow asterisk wildcards, and only at the end of the string. If it's anything else, refuse. */
62 return credential_name_valid(s
);
64 if (!streq(e
, "*")) /* only allow trailing "*", no other globs */
67 if (n
== 0) /* Explicitly allow the complete wildcard. */
70 if (n
> NAME_MAX
+ strlen(e
)) /* before we make a copy on the stack, let's check this is not overly large */
73 /* Make a copy of the string without the '*' suffix */
74 a
= strndupa_safe(s
, n
);
76 return credential_name_valid(a
);
79 static int get_credentials_dir_internal(const char *envvar
, const char **ret
) {
84 e
= secure_getenv(envvar
);
88 if (!path_is_absolute(e
) || !path_is_normalized(e
))
95 int get_credentials_dir(const char **ret
) {
96 return get_credentials_dir_internal("CREDENTIALS_DIRECTORY", ret
);
99 int get_encrypted_credentials_dir(const char **ret
) {
100 return get_credentials_dir_internal("ENCRYPTED_CREDENTIALS_DIRECTORY", ret
);
103 int read_credential(const char *name
, void **ret
, size_t *ret_size
) {
104 _cleanup_free_
char *fn
= NULL
;
110 if (!credential_name_valid(name
))
113 r
= get_credentials_dir(&d
);
117 fn
= path_join(d
, name
);
121 return read_full_file_full(
123 UINT64_MAX
, SIZE_MAX
,
124 READ_FULL_FILE_SECURE
,
126 (char**) ret
, ret_size
);
129 int read_credential_with_decryption(const char *name
, void **ret
, size_t *ret_size
) {
130 _cleanup_(erase_and_freep
) void *data
= NULL
;
131 _cleanup_free_
char *fn
= NULL
;
138 /* Just like read_credential() but will also look for encrypted credentials. Note that services only
139 * receive decrypted credentials, hence use read_credential() for those. This helper here is for
140 * generators, i.e. code that runs outside of service context, and thus has no decrypted credentials
143 * Note that read_credential_harder_and_warn() logs on its own, while read_credential() does not!
144 * (It's a lot more complex and error prone given its TPM2 connectivity, and is generally called from
145 * generators only where logging is OK).
147 * Error handling is also a bit different: if we can't find a credential we'll return 0 and NULL
148 * pointers/zero size, rather than -ENXIO/-ENOENT. */
150 if (!credential_name_valid(name
))
151 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Invalid credential name: %s", name
);
153 r
= read_credential(name
, ret
, ret_size
);
155 return 1; /* found */
156 if (!IN_SET(r
, -ENXIO
, -ENOENT
))
157 return log_error_errno(r
, "Failed read unencrypted credential '%s': %m", name
);
159 r
= get_encrypted_credentials_dir(&d
);
163 return log_error_errno(r
, "Failed to determine encrypted credentials directory: %m");
165 fn
= path_join(d
, name
);
169 r
= read_full_file_full(
171 UINT64_MAX
, SIZE_MAX
,
172 READ_FULL_FILE_SECURE
,
174 (char**) &data
, &sz
);
178 return log_error_errno(r
, "Failed to read encrypted credential data: %m");
180 r
= decrypt_credential_and_warn(
183 /* tpm2_device = */ NULL
,
184 /* tpm2_signature_path = */ NULL
,
192 return 1; /* found */
200 return 0; /* not found */
203 int read_credential_strings_many_internal(
204 const char *first_name
, char **first_value
,
207 _cleanup_free_
void *b
= NULL
;
210 /* Reads a bunch of credentials into the specified buffers. If the specified buffers are already
211 * non-NULL frees them if a credential is found. Only supports string-based credentials
212 * (i.e. refuses embedded NUL bytes).
214 * 0 is returned when some or all credentials are missing.
220 r
= read_credential(first_name
, &b
, NULL
);
221 if (r
== -ENXIO
) /* No creds passed at all? Bail immediately. */
227 free_and_replace(*first_value
, b
);
230 va_start(ap
, first_value
);
233 _cleanup_free_
void *bb
= NULL
;
237 name
= va_arg(ap
, const char *);
241 value
= va_arg(ap
, char **);
245 r
= read_credential(name
, &bb
, NULL
);
247 if (ret
>= 0 && r
!= -ENOENT
)
250 free_and_replace(*value
, bb
);
257 int read_credential_bool(const char *name
) {
258 _cleanup_free_
void *data
= NULL
;
261 r
= read_credential(name
, &data
, NULL
);
263 return IN_SET(r
, -ENXIO
, -ENOENT
) ? 0 : r
;
265 return parse_boolean(data
);
268 int get_credential_user_password(const char *username
, char **ret_password
, bool *ret_is_hashed
) {
269 _cleanup_(erase_and_freep
) char *creds_password
= NULL
;
270 _cleanup_free_
char *cn
= NULL
;
273 /* Try to pick up the password for this account via the credentials logic */
274 cn
= strjoin("passwd.hashed-password.", username
);
278 r
= read_credential(cn
, (void**) &creds_password
, NULL
);
281 cn
= strjoin("passwd.plaintext-password.", username
);
285 r
= read_credential(cn
, (void**) &creds_password
, NULL
);
287 log_debug_errno(r
, "Couldn't read credential '%s', ignoring: %m", cn
);
289 *ret_is_hashed
= false;
291 log_debug_errno(r
, "Couldn't read credential '%s', ignoring: %m", cn
);
293 *ret_is_hashed
= true;
295 *ret_password
= TAKE_PTR(creds_password
);
302 #define CREDENTIAL_HOST_SECRET_SIZE 4096
304 static const sd_id128_t credential_app_id
=
305 SD_ID128_MAKE(d3
,ac
,ec
,ba
,0d
,ad
,4c
,df
,b8
,c9
,38,15,28,93,6c
,58);
307 struct credential_host_secret_format
{
308 /* The hashed machine ID of the machine this belongs to. Why? We want to ensure that each machine
309 * gets its own secret, even if people forget to flush out this secret file. Hence we bind it to the
310 * machine ID, for which there's hopefully a better chance it will be flushed out. We use a hashed
311 * machine ID instead of the literal one, because it's trivial to, and it might be a good idea not
312 * being able to directly associate a secret key file with a host. */
313 sd_id128_t machine_id
;
315 /* The actual secret key */
316 uint8_t data
[CREDENTIAL_HOST_SECRET_SIZE
];
319 static void warn_not_encrypted(int fd
, CredentialSecretFlags flags
, const char *dirname
, const char *filename
) {
326 if (!FLAGS_SET(flags
, CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED
))
329 r
= fd_is_encrypted(fd
);
331 log_debug_errno(r
, "Failed to determine if credential secret file '%s/%s' is encrypted.",
334 log_warning("Credential secret file '%s/%s' is not located on encrypted media, using anyway.",
338 static int make_credential_host_secret(
340 const sd_id128_t machine_id
,
341 CredentialSecretFlags flags
,
347 _cleanup_free_
char *t
= NULL
;
348 _cleanup_close_
int fd
= -EBADF
;
354 /* For non-root users creating a temporary file using the openat(2) over "." will fail later, in the
355 * linkat(2) step at the end. The reason is that linkat(2) requires the CAP_DAC_READ_SEARCH
356 * capability when it uses the AT_EMPTY_PATH flag. */
357 if (have_effective_cap(CAP_DAC_READ_SEARCH
) > 0) {
358 fd
= openat(dfd
, ".", O_CLOEXEC
|O_WRONLY
|O_TMPFILE
, 0400);
360 log_debug_errno(errno
, "Failed to create temporary credential file with O_TMPFILE, proceeding without: %m");
363 if (asprintf(&t
, "credential.secret.%016" PRIx64
, random_u64()) < 0)
366 fd
= openat(dfd
, t
, O_CLOEXEC
|O_WRONLY
|O_CREAT
|O_EXCL
|O_NOFOLLOW
, 0400);
371 r
= chattr_secret(fd
, 0);
373 log_debug_errno(r
, "Failed to set file attributes for secrets file, ignoring: %m");
375 struct credential_host_secret_format buf
= {
376 .machine_id
= machine_id
,
381 r
= crypto_random_bytes(buf
.data
, sizeof(buf
.data
));
385 r
= loop_write(fd
, &buf
, sizeof(buf
));
394 warn_not_encrypted(fd
, flags
, dirname
, fn
);
397 r
= rename_noreplace(dfd
, t
, dfd
, fn
);
402 } else if (linkat(fd
, "", dfd
, fn
, AT_EMPTY_PATH
) < 0) {
407 if (fsync(dfd
) < 0) {
415 copy
= memdup(buf
.data
, sizeof(buf
.data
));
425 *ret_size
= sizeof(buf
.data
);
430 if (t
&& unlinkat(dfd
, t
, 0) < 0)
431 log_debug_errno(errno
, "Failed to remove temporary credential key: %m");
436 int get_credential_host_secret(CredentialSecretFlags flags
, void **ret
, size_t *ret_size
) {
437 _cleanup_free_
char *_dirname
= NULL
, *_filename
= NULL
;
438 _cleanup_close_
int dfd
= -EBADF
;
439 sd_id128_t machine_id
;
440 const char *dirname
, *filename
;
443 r
= sd_id128_get_machine_app_specific(credential_app_id
, &machine_id
);
447 const char *e
= secure_getenv("SYSTEMD_CREDENTIAL_SECRET");
449 if (!path_is_normalized(e
))
451 if (!path_is_absolute(e
))
454 r
= path_extract_directory(e
, &_dirname
);
458 r
= path_extract_filename(e
, &_filename
);
463 filename
= _filename
;
465 dirname
= "/var/lib/systemd";
466 filename
= "credential.secret";
472 mkdir_parents(dirname
, 0755);
473 dfd
= open_mkdir_at(AT_FDCWD
, dirname
, O_CLOEXEC
, 0755);
475 return log_debug_errno(dfd
, "Failed to create or open directory '%s': %m", dirname
);
477 if (FLAGS_SET(flags
, CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS
)) {
478 r
= fd_is_temporary_fs(dfd
);
480 return log_debug_errno(r
, "Failed to check directory '%s': %m", dirname
);
482 return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM
),
483 "Directory '%s' is on a temporary file system, refusing.", dirname
);
486 for (unsigned attempt
= 0;; attempt
++) {
487 _cleanup_(erase_and_freep
) struct credential_host_secret_format
*f
= NULL
;
488 _cleanup_close_
int fd
= -EBADF
;
493 if (attempt
>= 3) /* Somebody is playing games with us */
494 return log_debug_errno(SYNTHETIC_ERRNO(EIO
),
495 "All attempts to create secret store in %s failed.", dirname
);
497 fd
= openat(dfd
, filename
, O_CLOEXEC
|O_RDONLY
|O_NOCTTY
|O_NOFOLLOW
);
499 if (errno
!= ENOENT
|| !FLAGS_SET(flags
, CREDENTIAL_SECRET_GENERATE
))
500 return log_debug_errno(errno
,
501 "Failed to open %s/%s: %m", dirname
, filename
);
504 r
= make_credential_host_secret(dfd
, machine_id
, flags
, dirname
, filename
, ret
, ret_size
);
506 log_debug_errno(r
, "Credential secret %s/%s appeared while we were creating it, rereading.",
511 return log_debug_errno(r
, "Failed to create credential secret %s/%s: %m",
516 if (fstat(fd
, &st
) < 0)
517 return log_debug_errno(errno
, "Failed to stat %s/%s: %m", dirname
, filename
);
519 r
= stat_verify_regular(&st
);
521 return log_debug_errno(r
, "%s/%s is not a regular file: %m", dirname
, filename
);
522 if (st
.st_nlink
== 0) /* Deleted by now, try again */
525 /* Our deletion check won't work if hardlinked somewhere else */
526 return log_debug_errno(SYNTHETIC_ERRNO(EPERM
),
527 "%s/%s has too many links, refusing.",
529 if ((st
.st_mode
& 07777) != 0400)
530 /* Don't use file if not 0400 access mode */
531 return log_debug_errno(SYNTHETIC_ERRNO(EPERM
),
532 "%s/%s has permissive access mode, refusing.",
535 if (l
< offsetof(struct credential_host_secret_format
, data
) + 1)
536 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL
),
537 "%s/%s is too small, refusing.", dirname
, filename
);
538 if (l
> 16*1024*1024)
539 return log_debug_errno(SYNTHETIC_ERRNO(E2BIG
),
540 "%s/%s is too big, refusing.", dirname
, filename
);
544 return log_oom_debug();
546 n
= read(fd
, f
, l
+1);
548 return log_debug_errno(errno
,
549 "Failed to read %s/%s: %m", dirname
, filename
);
550 if ((size_t) n
!= l
) /* What? The size changed? */
551 return log_debug_errno(SYNTHETIC_ERRNO(EIO
),
552 "Failed to read %s/%s: %m", dirname
, filename
);
554 if (sd_id128_equal(machine_id
, f
->machine_id
)) {
557 warn_not_encrypted(fd
, flags
, dirname
, filename
);
559 sz
= l
- offsetof(struct credential_host_secret_format
, data
);
565 assert(sz
<= sizeof(f
->data
)); /* Ensure we don't read past f->data bounds */
567 copy
= memdup(f
->data
, sz
);
569 return log_oom_debug();
580 /* Hmm, this secret is from somewhere else. Let's delete the file. Let's first acquire a lock
581 * to ensure we are the only ones accessing the file while we delete it. */
583 if (flock(fd
, LOCK_EX
) < 0)
584 return log_debug_errno(errno
,
585 "Failed to flock %s/%s: %m", dirname
, filename
);
587 /* Before we delete it check that the file is still linked into the file system */
588 if (fstat(fd
, &st
) < 0)
589 return log_debug_errno(errno
, "Failed to stat %s/%s: %m", dirname
, filename
);
590 if (st
.st_nlink
== 0) /* Already deleted by now? */
592 if (st
.st_nlink
!= 1) /* Safety check, someone is playing games with us */
593 return log_debug_errno(SYNTHETIC_ERRNO(EPERM
),
594 "%s/%s unexpectedly has too many links.",
596 if (unlinkat(dfd
, filename
, 0) < 0)
597 return log_debug_errno(errno
, "Failed to unlink %s/%s: %m", dirname
, filename
);
599 /* And now try again */
603 /* Construction is like this:
605 * A symmetric encryption key is derived from:
607 * 1. Either the "host" key (a key stored in /var/lib/credential.secret)
609 * 2. A key generated by letting the TPM2 calculate an HMAC hash of some nonce we pass to it, keyed
610 * by a key derived from its internal seed key.
612 * 3. The concatenation of the above.
614 * 4. Or a fixed "empty" key. This will not provide confidentiality or authenticity, of course, but is
615 * useful to encode credentials for the initrd on TPM-less systems, where we simply have no better
616 * concept to bind things to. Note that decryption of a key set up like this will be refused on
617 * systems that have a TPM and have SecureBoot enabled.
619 * The above is hashed with SHA256 which is then used as encryption key for AES256-GCM. The encrypted
620 * credential is a short (unencrypted) header describing which of the three keys to use, the IV to use for
621 * AES256-GCM and some more meta information (sizes of certain objects) that is strictly speaking redundant,
622 * but kinda nice to have since we can have a more generic parser. If the TPM2 key is used this is followed
623 * by another (unencrypted) header, with information about the TPM2 policy used (specifically: the PCR mask
624 * to bind against, and a hash of the resulting policy — the latter being redundant, but speeding up things a
625 * bit, since we can more quickly refuse PCR state), followed by a sealed/exported TPM2 HMAC key. This is
626 * then followed by the encrypted data, which begins with a metadata header (which contains validity
627 * timestamps as well as the credential name), followed by the actual credential payload. The file ends in
628 * the AES256-GCM tag. To make things simple, the AES256-GCM AAD covers the main and the TPM2 header in
629 * full. This means the whole file is either protected by AAD, or is ciphertext, or is the tag. No
630 * unprotected data is included.
633 struct _packed_ encrypted_credential_header
{
640 /* Followed by NUL bytes until next 8 byte boundary */
643 struct _packed_ tpm2_credential_header
{
644 le64_t pcr_mask
; /* Note that the spec for PC Clients only mandates 24 PCRs, and that's what systems
645 * generally have. But keep the door open for more. */
646 le16_t pcr_bank
; /* For now, either TPM2_ALG_SHA256 or TPM2_ALG_SHA1 */
647 le16_t primary_alg
; /* Primary key algorithm (either TPM2_ALG_RSA or TPM2_ALG_ECC for now) */
649 le32_t policy_hash_size
;
650 uint8_t policy_hash_and_blob
[];
651 /* Followed by NUL bytes until next 8 byte boundary */
654 struct _packed_ tpm2_public_key_credential_header
{
655 le64_t pcr_mask
; /* PCRs used for the public key PCR policy (usually just PCR 11, i.e. the unified kernel) */
656 le32_t size
; /* Size of DER public key */
657 uint8_t data
[]; /* DER public key */
658 /* Followed by NUL bytes until next 8 byte boundary */
661 struct _packed_ metadata_credential_header
{
666 /* Followed by NUL bytes until next 8 byte boundary */
669 /* Some generic limit for parts of the encrypted credential for which we don't know the right size ahead of
670 * time, but where we are really sure it won't be larger than this. Should be larger than any possible IV,
671 * padding, tag size and so on. This is purely used for early filtering out of invalid sizes. */
672 #define CREDENTIAL_FIELD_SIZE_MAX (16U*1024U)
674 static int sha256_hash_host_and_tpm2_key(
675 const void *host_key
,
676 size_t host_key_size
,
677 const void *tpm2_key
,
678 size_t tpm2_key_size
,
679 uint8_t ret
[static SHA256_DIGEST_LENGTH
]) {
681 _cleanup_(EVP_MD_CTX_freep
) EVP_MD_CTX
*md
= NULL
;
684 assert(host_key_size
== 0 || host_key
);
685 assert(tpm2_key_size
== 0 || tpm2_key
);
688 /* Combines the host key and the TPM2 HMAC hash into a SHA256 hash value we'll use as symmetric encryption key. */
690 md
= EVP_MD_CTX_new();
694 if (EVP_DigestInit_ex(md
, EVP_sha256(), NULL
) != 1)
695 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to initial SHA256 context.");
697 if (host_key
&& EVP_DigestUpdate(md
, host_key
, host_key_size
) != 1)
698 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to hash host key.");
700 if (tpm2_key
&& EVP_DigestUpdate(md
, tpm2_key
, tpm2_key_size
) != 1)
701 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to hash TPM2 key.");
703 assert(EVP_MD_CTX_size(md
) == SHA256_DIGEST_LENGTH
);
705 if (EVP_DigestFinal_ex(md
, ret
, &l
) != 1)
706 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to finalize SHA256 hash.");
708 assert(l
== SHA256_DIGEST_LENGTH
);
712 int encrypt_credential_and_warn(
717 const char *tpm2_device
,
718 uint32_t tpm2_hash_pcr_mask
,
719 const char *tpm2_pubkey_path
,
720 uint32_t tpm2_pubkey_pcr_mask
,
726 _cleanup_(EVP_CIPHER_CTX_freep
) EVP_CIPHER_CTX
*context
= NULL
;
727 _cleanup_(erase_and_freep
) void *host_key
= NULL
, *tpm2_key
= NULL
;
728 size_t host_key_size
= 0, tpm2_key_size
= 0, tpm2_blob_size
= 0, tpm2_policy_hash_size
= 0, output_size
, p
, ml
;
729 _cleanup_free_
void *tpm2_blob
= NULL
, *tpm2_policy_hash
= NULL
, *iv
= NULL
, *output
= NULL
;
730 _cleanup_free_
struct metadata_credential_header
*m
= NULL
;
731 uint16_t tpm2_pcr_bank
= 0, tpm2_primary_alg
= 0;
732 struct encrypted_credential_header
*h
;
733 int ksz
, bsz
, ivsz
, tsz
, added
, r
;
734 _cleanup_free_
void *pubkey
= NULL
;
735 size_t pubkey_size
= 0;
736 uint8_t md
[SHA256_DIGEST_LENGTH
];
737 const EVP_CIPHER
*cc
;
740 assert(input
|| input_size
== 0);
744 if (!sd_id128_in_set(with_key
,
747 CRED_AES256_GCM_BY_HOST
,
748 CRED_AES256_GCM_BY_TPM2_HMAC
,
749 CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK
,
750 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
,
751 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
,
752 CRED_AES256_GCM_BY_TPM2_ABSENT
))
753 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Invalid key type: " SD_ID128_FORMAT_STR
, SD_ID128_FORMAT_VAL(with_key
));
755 if (name
&& !credential_name_valid(name
))
756 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Invalid credential name: %s", name
);
758 if (not_after
!= USEC_INFINITY
&& timestamp
!= USEC_INFINITY
&& not_after
< timestamp
)
759 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Credential is invalidated before it is valid (" USEC_FMT
" < " USEC_FMT
").", not_after
, timestamp
);
762 char buf
[FORMAT_TIMESTAMP_MAX
];
765 log_debug("Including credential name '%s' in encrypted credential.", name
);
766 if (timestamp
!= USEC_INFINITY
)
767 log_debug("Including timestamp '%s' in encrypted credential.", format_timestamp(buf
, sizeof(buf
), timestamp
));
768 if (not_after
!= USEC_INFINITY
)
769 log_debug("Including not-after timestamp '%s' in encrypted credential.", format_timestamp(buf
, sizeof(buf
), not_after
));
772 if (sd_id128_in_set(with_key
,
774 CRED_AES256_GCM_BY_HOST
,
775 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
,
776 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
)) {
778 r
= get_credential_host_secret(
779 CREDENTIAL_SECRET_GENERATE
|
780 CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED
|
781 (sd_id128_equal(with_key
, _CRED_AUTO
) ? CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS
: 0),
784 if (r
== -ENOMEDIUM
&& sd_id128_equal(with_key
, _CRED_AUTO
))
785 log_debug_errno(r
, "Credential host secret location on temporary file system, not using.");
787 return log_error_errno(r
, "Failed to determine local credential host secret: %m");
792 if (sd_id128_in_set(with_key
, _CRED_AUTO
, _CRED_AUTO_INITRD
)) {
793 /* If automatic mode is selected lets see if a TPM2 it is present. If we are running in a
794 * container tpm2_support will detect this, and will return a different flag combination of
795 * TPM2_SUPPORT_FULL, effectively skipping the use of TPM2 when inside one. */
797 try_tpm2
= tpm2_support() == TPM2_SUPPORT_FULL
;
799 log_debug("System lacks TPM2 support or running in a container, not attempting to use TPM2.");
801 try_tpm2
= sd_id128_in_set(with_key
,
802 CRED_AES256_GCM_BY_TPM2_HMAC
,
803 CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK
,
804 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
,
805 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
);
808 if (sd_id128_in_set(with_key
,
811 CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK
,
812 CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
)) {
814 /* Load public key for PCR policies, if one is specified, or explicitly requested */
816 r
= tpm2_load_pcr_public_key(tpm2_pubkey_path
, &pubkey
, &pubkey_size
);
818 if (tpm2_pubkey_path
|| r
!= -ENOENT
|| !sd_id128_in_set(with_key
, _CRED_AUTO
, _CRED_AUTO_INITRD
))
819 return log_error_errno(r
, "Failed read TPM PCR public key: %m");
821 log_debug_errno(r
, "Failed to read TPM2 PCR public key, proceeding without: %m");
826 tpm2_pubkey_pcr_mask
= 0;
828 _cleanup_(tpm2_context_unrefp
) Tpm2Context
*tpm2_context
= NULL
;
829 r
= tpm2_context_new(tpm2_device
, &tpm2_context
);
831 return log_error_errno(r
, "Failed to create TPM2 context: %m");
833 r
= tpm2_get_best_pcr_bank(tpm2_context
, tpm2_hash_pcr_mask
| tpm2_pubkey_pcr_mask
, &tpm2_pcr_bank
);
835 return log_error_errno(r
, "Could not find best pcr bank: %m");
837 TPML_PCR_SELECTION tpm2_hash_pcr_selection
;
838 tpm2_tpml_pcr_selection_from_mask(tpm2_hash_pcr_mask
, tpm2_pcr_bank
, &tpm2_hash_pcr_selection
);
840 _cleanup_free_ Tpm2PCRValue
*tpm2_hash_pcr_values
= NULL
;
841 size_t tpm2_n_hash_pcr_values
;
842 r
= tpm2_pcr_read(tpm2_context
, &tpm2_hash_pcr_selection
, &tpm2_hash_pcr_values
, &tpm2_n_hash_pcr_values
);
844 return log_error_errno(r
, "Could not read PCR values: %m");
848 r
= tpm2_tpm2b_public_from_pem(pubkey
, pubkey_size
, &public);
850 return log_error_errno(r
, "Could not convert public key to TPM2B_PUBLIC: %m");
853 TPM2B_DIGEST tpm2_policy
= TPM2B_DIGEST_MAKE(NULL
, TPM2_SHA256_DIGEST_SIZE
);
854 r
= tpm2_calculate_sealing_policy(
855 tpm2_hash_pcr_values
,
856 tpm2_n_hash_pcr_values
,
857 pubkey
? &public : NULL
,
858 /* use_pin= */ false,
859 /* pcrlock_policy= */ NULL
,
862 return log_error_errno(r
, "Could not calculate sealing policy digest: %m");
864 r
= tpm2_seal(tpm2_context
,
865 /* seal_key_handle= */ 0,
868 &tpm2_key
, &tpm2_key_size
,
869 &tpm2_blob
, &tpm2_blob_size
,
871 /* ret_srk_buf= */ NULL
,
872 /* ret_srk_buf_size= */ NULL
);
874 if (sd_id128_equal(with_key
, _CRED_AUTO_INITRD
))
875 log_warning("TPM2 present and used, but we didn't manage to talk to it. Credential will be refused if SecureBoot is enabled.");
876 else if (!sd_id128_equal(with_key
, _CRED_AUTO
))
877 return log_error_errno(r
, "Failed to seal to TPM2: %m");
879 log_notice_errno(r
, "TPM2 sealing didn't work, continuing without TPM2: %m");
882 tpm2_policy_hash_size
= tpm2_policy
.size
;
883 tpm2_policy_hash
= malloc(tpm2_policy_hash_size
);
884 if (!tpm2_policy_hash
)
886 memcpy(tpm2_policy_hash
, tpm2_policy
.buffer
, tpm2_policy_hash_size
);
888 assert(tpm2_blob_size
<= CREDENTIAL_FIELD_SIZE_MAX
);
889 assert(tpm2_policy_hash_size
<= CREDENTIAL_FIELD_SIZE_MAX
);
893 if (sd_id128_in_set(with_key
, _CRED_AUTO
, _CRED_AUTO_INITRD
)) {
894 /* Let's settle the key type in auto mode now. */
896 if (host_key
&& tpm2_key
)
897 id
= pubkey
? CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
: CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
;
899 id
= pubkey
? CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK
: CRED_AES256_GCM_BY_TPM2_HMAC
;
901 id
= CRED_AES256_GCM_BY_HOST
;
902 else if (sd_id128_equal(with_key
, _CRED_AUTO_INITRD
))
903 id
= CRED_AES256_GCM_BY_TPM2_ABSENT
;
905 return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE
),
906 "TPM2 not available and host key located on temporary file system, no encryption key available.");
910 if (sd_id128_equal(id
, CRED_AES256_GCM_BY_TPM2_ABSENT
))
911 log_warning("Using a null key for encryption and signing. Confidentiality or authenticity will not be provided.");
913 /* Let's now take the host key and the TPM2 key and hash it together, to use as encryption key for the data */
914 r
= sha256_hash_host_and_tpm2_key(host_key
, host_key_size
, tpm2_key
, tpm2_key_size
, md
);
918 assert_se(cc
= EVP_aes_256_gcm());
920 ksz
= EVP_CIPHER_key_length(cc
);
921 assert(ksz
== sizeof(md
));
923 bsz
= EVP_CIPHER_block_size(cc
);
925 assert((size_t) bsz
<= CREDENTIAL_FIELD_SIZE_MAX
);
927 ivsz
= EVP_CIPHER_iv_length(cc
);
929 assert((size_t) ivsz
<= CREDENTIAL_FIELD_SIZE_MAX
);
935 r
= crypto_random_bytes(iv
, ivsz
);
937 return log_error_errno(r
, "Failed to acquired randomized IV: %m");
940 tsz
= 16; /* FIXME: On OpenSSL 3 there is EVP_CIPHER_CTX_get_tag_length(), until then let's hardcode this */
942 context
= EVP_CIPHER_CTX_new();
944 return log_error_errno(SYNTHETIC_ERRNO(ENOMEM
), "Failed to allocate encryption object: %s",
945 ERR_error_string(ERR_get_error(), NULL
));
947 if (EVP_EncryptInit_ex(context
, cc
, NULL
, md
, iv
) != 1)
948 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to initialize encryption context: %s",
949 ERR_error_string(ERR_get_error(), NULL
));
951 /* Just an upper estimate */
953 ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + ivsz
) +
954 ALIGN8(tpm2_key
? offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) + tpm2_blob_size
+ tpm2_policy_hash_size
: 0) +
955 ALIGN8(pubkey
? offsetof(struct tpm2_public_key_credential_header
, data
) + pubkey_size
: 0) +
956 ALIGN8(offsetof(struct metadata_credential_header
, name
) + strlen_ptr(name
)) +
957 input_size
+ 2U * (size_t) bsz
+
960 output
= malloc0(output_size
);
964 h
= (struct encrypted_credential_header
*) output
;
966 h
->block_size
= htole32(bsz
);
967 h
->key_size
= htole32(ksz
);
968 h
->tag_size
= htole32(tsz
);
969 h
->iv_size
= htole32(ivsz
);
970 memcpy(h
->iv
, iv
, ivsz
);
972 p
= ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + ivsz
);
975 struct tpm2_credential_header
*t
;
977 t
= (struct tpm2_credential_header
*) ((uint8_t*) output
+ p
);
978 t
->pcr_mask
= htole64(tpm2_hash_pcr_mask
);
979 t
->pcr_bank
= htole16(tpm2_pcr_bank
);
980 t
->primary_alg
= htole16(tpm2_primary_alg
);
981 t
->blob_size
= htole32(tpm2_blob_size
);
982 t
->policy_hash_size
= htole32(tpm2_policy_hash_size
);
983 memcpy(t
->policy_hash_and_blob
, tpm2_blob
, tpm2_blob_size
);
984 memcpy(t
->policy_hash_and_blob
+ tpm2_blob_size
, tpm2_policy_hash
, tpm2_policy_hash_size
);
986 p
+= ALIGN8(offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) + tpm2_blob_size
+ tpm2_policy_hash_size
);
990 struct tpm2_public_key_credential_header
*z
;
992 z
= (struct tpm2_public_key_credential_header
*) ((uint8_t*) output
+ p
);
993 z
->pcr_mask
= htole64(tpm2_pubkey_pcr_mask
);
994 z
->size
= htole32(pubkey_size
);
995 memcpy(z
->data
, pubkey
, pubkey_size
);
997 p
+= ALIGN8(offsetof(struct tpm2_public_key_credential_header
, data
) + pubkey_size
);
1000 /* Pass the encrypted + TPM2 header as AAD */
1001 if (EVP_EncryptUpdate(context
, NULL
, &added
, output
, p
) != 1)
1002 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to write AAD data: %s",
1003 ERR_error_string(ERR_get_error(), NULL
));
1005 /* Now construct the metadata header */
1006 ml
= strlen_ptr(name
);
1007 m
= malloc0(ALIGN8(offsetof(struct metadata_credential_header
, name
) + ml
));
1011 m
->timestamp
= htole64(timestamp
);
1012 m
->not_after
= htole64(not_after
);
1013 m
->name_size
= htole32(ml
);
1014 memcpy_safe(m
->name
, name
, ml
);
1016 /* And encrypt the metadata header */
1017 if (EVP_EncryptUpdate(context
, (uint8_t*) output
+ p
, &added
, (const unsigned char*) m
, ALIGN8(offsetof(struct metadata_credential_header
, name
) + ml
)) != 1)
1018 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to encrypt metadata header: %s",
1019 ERR_error_string(ERR_get_error(), NULL
));
1022 assert((size_t) added
<= output_size
- p
);
1025 /* Then encrypt the plaintext */
1026 if (EVP_EncryptUpdate(context
, (uint8_t*) output
+ p
, &added
, input
, input_size
) != 1)
1027 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to encrypt data: %s",
1028 ERR_error_string(ERR_get_error(), NULL
));
1031 assert((size_t) added
<= output_size
- p
);
1035 if (EVP_EncryptFinal_ex(context
, (uint8_t*) output
+ p
, &added
) != 1)
1036 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to finalize data encryption: %s",
1037 ERR_error_string(ERR_get_error(), NULL
));
1040 assert((size_t) added
<= output_size
- p
);
1043 assert(p
<= output_size
- tsz
);
1046 if (EVP_CIPHER_CTX_ctrl(context
, EVP_CTRL_GCM_GET_TAG
, tsz
, (uint8_t*) output
+ p
) != 1)
1047 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to get tag: %s",
1048 ERR_error_string(ERR_get_error(), NULL
));
1051 assert(p
<= output_size
);
1053 if (DEBUG_LOGGING
&& input_size
> 0) {
1056 base64_size
= DIV_ROUND_UP(p
* 4, 3); /* Include base64 size increase in debug output */
1057 assert(base64_size
>= input_size
);
1058 log_debug("Input of %zu bytes grew to output of %zu bytes (+%2zu%%).", input_size
, base64_size
, base64_size
* 100 / input_size
- 100);
1061 *ret
= TAKE_PTR(output
);
1067 int decrypt_credential_and_warn(
1068 const char *validate_name
,
1069 usec_t validate_timestamp
,
1070 const char *tpm2_device
,
1071 const char *tpm2_signature_path
,
1077 _cleanup_(erase_and_freep
) void *host_key
= NULL
, *tpm2_key
= NULL
, *plaintext
= NULL
;
1078 _cleanup_(json_variant_unrefp
) JsonVariant
*signature_json
= NULL
;
1079 _cleanup_(EVP_CIPHER_CTX_freep
) EVP_CIPHER_CTX
*context
= NULL
;
1080 size_t host_key_size
= 0, tpm2_key_size
= 0, plaintext_size
, p
, hs
;
1081 struct encrypted_credential_header
*h
;
1082 struct metadata_credential_header
*m
;
1083 uint8_t md
[SHA256_DIGEST_LENGTH
];
1084 bool with_tpm2
, with_host_key
, is_tpm2_absent
, with_tpm2_pk
;
1085 const EVP_CIPHER
*cc
;
1088 assert(input
|| input_size
== 0);
1092 h
= (struct encrypted_credential_header
*) input
;
1094 /* The ID must fit in, for the current and all future formats */
1095 if (input_size
< sizeof(h
->id
))
1096 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Encrypted file too short.");
1098 with_host_key
= sd_id128_in_set(h
->id
, CRED_AES256_GCM_BY_HOST
, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
);
1099 with_tpm2_pk
= sd_id128_in_set(h
->id
, CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK
, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK
);
1100 with_tpm2
= sd_id128_in_set(h
->id
, CRED_AES256_GCM_BY_TPM2_HMAC
, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC
) || with_tpm2_pk
;
1101 is_tpm2_absent
= sd_id128_equal(h
->id
, CRED_AES256_GCM_BY_TPM2_ABSENT
);
1103 if (!with_host_key
&& !with_tpm2
&& !is_tpm2_absent
)
1104 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
), "Unknown encryption format, or corrupted data: %m");
1107 r
= tpm2_load_pcr_signature(tpm2_signature_path
, &signature_json
);
1109 return log_error_errno(r
, "Failed to load pcr signature: %m");
1112 if (is_tpm2_absent
) {
1113 /* So this is a credential encrypted with a zero length key. We support this to cover for the
1114 * case where neither a host key not a TPM2 are available (specifically: initrd environments
1115 * where the host key is not yet accessible and no TPM2 chip exists at all), to minimize
1116 * different codeflow for TPM2 and non-TPM2 codepaths. Of course, credentials encoded this
1117 * way offer no confidentiality nor authenticity. Because of that it's important we refuse to
1118 * use them on systems that actually *do* have a TPM2 chip – if we are in SecureBoot
1119 * mode. Otherwise an attacker could hand us credentials like this and we'd use them thinking
1120 * they are trusted, even though they are not. */
1122 if (efi_has_tpm2()) {
1123 if (is_efi_secure_boot())
1124 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
),
1125 "Credential uses fixed key for fallback use when TPM2 is absent — but TPM2 is present, and SecureBoot is enabled, refusing.");
1127 log_warning("Credential uses fixed key for use when TPM2 is absent, but TPM2 is present! Accepting anyway, since SecureBoot is disabled.");
1129 log_debug("Credential uses fixed key for use when TPM2 is absent, and TPM2 indeed is absent. Accepting.");
1132 /* Now we know the minimum header size */
1133 if (input_size
< offsetof(struct encrypted_credential_header
, iv
))
1134 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Encrypted file too short.");
1136 /* Verify some basic header values */
1137 if (le32toh(h
->key_size
) != sizeof(md
))
1138 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected key size in header.");
1139 if (le32toh(h
->block_size
) <= 0 || le32toh(h
->block_size
) > CREDENTIAL_FIELD_SIZE_MAX
)
1140 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected block size in header.");
1141 if (le32toh(h
->iv_size
) > CREDENTIAL_FIELD_SIZE_MAX
)
1142 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "IV size too large.");
1143 if (le32toh(h
->tag_size
) != 16) /* FIXME: On OpenSSL 3, let's verify via EVP_CIPHER_CTX_get_tag_length() */
1144 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected tag size in header.");
1146 /* Ensure we have space for the full header now (we don't know the size of the name hence this is a
1147 * lower limit only) */
1149 ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + le32toh(h
->iv_size
)) +
1150 ALIGN8(with_tpm2
? offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) : 0) +
1151 ALIGN8(with_tpm2_pk
? offsetof(struct tpm2_public_key_credential_header
, data
) : 0) +
1152 ALIGN8(offsetof(struct metadata_credential_header
, name
)) +
1153 le32toh(h
->tag_size
))
1154 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Encrypted file too short.");
1156 p
= ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + le32toh(h
->iv_size
));
1160 struct tpm2_credential_header
* t
= (struct tpm2_credential_header
*) ((uint8_t*) input
+ p
);
1161 struct tpm2_public_key_credential_header
*z
= NULL
;
1163 if (!TPM2_PCR_MASK_VALID(t
->pcr_mask
))
1164 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "TPM2 PCR mask out of range.");
1165 if (!tpm2_hash_alg_to_string(le16toh(t
->pcr_bank
)))
1166 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "TPM2 PCR bank invalid or not supported");
1167 if (!tpm2_asym_alg_to_string(le16toh(t
->primary_alg
)))
1168 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "TPM2 primary key algorithm invalid or not supported.");
1169 if (le32toh(t
->blob_size
) > CREDENTIAL_FIELD_SIZE_MAX
)
1170 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected TPM2 blob size.");
1171 if (le32toh(t
->policy_hash_size
) > CREDENTIAL_FIELD_SIZE_MAX
)
1172 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected TPM2 policy hash size.");
1174 /* Ensure we have space for the full TPM2 header now (still don't know the name, and its size
1175 * though, hence still just a lower limit test only) */
1177 ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + le32toh(h
->iv_size
)) +
1178 ALIGN8(offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) + le32toh(t
->blob_size
) + le32toh(t
->policy_hash_size
)) +
1179 ALIGN8(with_tpm2_pk
? offsetof(struct tpm2_public_key_credential_header
, data
) : 0) +
1180 ALIGN8(offsetof(struct metadata_credential_header
, name
)) +
1181 le32toh(h
->tag_size
))
1182 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Encrypted file too short.");
1184 p
+= ALIGN8(offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) +
1185 le32toh(t
->blob_size
) +
1186 le32toh(t
->policy_hash_size
));
1189 z
= (struct tpm2_public_key_credential_header
*) ((uint8_t*) input
+ p
);
1191 if (!TPM2_PCR_MASK_VALID(le64toh(z
->pcr_mask
)) || le64toh(z
->pcr_mask
) == 0)
1192 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "TPM2 PCR mask out of range.");
1193 if (le32toh(z
->size
) > PUBLIC_KEY_MAX
)
1194 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected public key size.");
1197 ALIGN8(offsetof(struct encrypted_credential_header
, iv
) + le32toh(h
->iv_size
)) +
1198 ALIGN8(offsetof(struct tpm2_credential_header
, policy_hash_and_blob
) + le32toh(t
->blob_size
) + le32toh(t
->policy_hash_size
)) +
1199 ALIGN8(offsetof(struct tpm2_public_key_credential_header
, data
) + le32toh(z
->size
)) +
1200 ALIGN8(offsetof(struct metadata_credential_header
, name
)) +
1201 le32toh(h
->tag_size
))
1202 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Encrypted file too short.");
1204 p
+= ALIGN8(offsetof(struct tpm2_public_key_credential_header
, data
) +
1208 _cleanup_(tpm2_context_unrefp
) Tpm2Context
*tpm2_context
= NULL
;
1209 r
= tpm2_context_new(tpm2_device
, &tpm2_context
);
1213 // TODO: Add the SRK data to the credential structure so it can be plumbed
1214 // through and used to verify the TPM session.
1215 r
= tpm2_unseal(tpm2_context
,
1216 le64toh(t
->pcr_mask
),
1217 le16toh(t
->pcr_bank
),
1219 z
? le32toh(z
->size
) : 0,
1220 z
? le64toh(z
->pcr_mask
) : 0,
1223 /* pcrlock_policy= */ NULL
,
1224 le16toh(t
->primary_alg
),
1225 t
->policy_hash_and_blob
,
1226 le32toh(t
->blob_size
),
1227 t
->policy_hash_and_blob
+ le32toh(t
->blob_size
),
1228 le32toh(t
->policy_hash_size
),
1229 /* srk_buf= */ NULL
,
1230 /* srk_buf_size= */ 0,
1234 return log_error_errno(r
, "Failed to unseal secret using TPM2: %m");
1236 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
), "Credential requires TPM2 support, but TPM2 support not available.");
1240 if (with_host_key
) {
1241 r
= get_credential_host_secret(
1246 return log_error_errno(r
, "Failed to determine local credential key: %m");
1250 log_warning("Warning: using a null key for decryption and authentication. Confidentiality or authenticity are not provided.");
1252 sha256_hash_host_and_tpm2_key(host_key
, host_key_size
, tpm2_key
, tpm2_key_size
, md
);
1254 assert_se(cc
= EVP_aes_256_gcm());
1256 /* Make sure cipher expectations match the header */
1257 if (EVP_CIPHER_key_length(cc
) != (int) le32toh(h
->key_size
))
1258 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected key size in header.");
1259 if (EVP_CIPHER_block_size(cc
) != (int) le32toh(h
->block_size
))
1260 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Unexpected block size in header.");
1262 context
= EVP_CIPHER_CTX_new();
1264 return log_error_errno(SYNTHETIC_ERRNO(ENOMEM
), "Failed to allocate decryption object: %s",
1265 ERR_error_string(ERR_get_error(), NULL
));
1267 if (EVP_DecryptInit_ex(context
, cc
, NULL
, NULL
, NULL
) != 1)
1268 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to initialize decryption context: %s",
1269 ERR_error_string(ERR_get_error(), NULL
));
1271 if (EVP_CIPHER_CTX_ctrl(context
, EVP_CTRL_GCM_SET_IVLEN
, le32toh(h
->iv_size
), NULL
) != 1)
1272 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to set IV size on decryption context: %s",
1273 ERR_error_string(ERR_get_error(), NULL
));
1275 if (EVP_DecryptInit_ex(context
, NULL
, NULL
, md
, h
->iv
) != 1)
1276 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to set IV and key: %s",
1277 ERR_error_string(ERR_get_error(), NULL
));
1279 if (EVP_DecryptUpdate(context
, NULL
, &added
, input
, p
) != 1)
1280 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to write AAD data: %s",
1281 ERR_error_string(ERR_get_error(), NULL
));
1283 plaintext
= malloc(input_size
- p
- le32toh(h
->tag_size
));
1287 if (EVP_DecryptUpdate(
1291 (uint8_t*) input
+ p
,
1292 input_size
- p
- le32toh(h
->tag_size
)) != 1)
1293 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to decrypt data: %s",
1294 ERR_error_string(ERR_get_error(), NULL
));
1297 assert((size_t) added
<= input_size
- p
- le32toh(h
->tag_size
));
1298 plaintext_size
= added
;
1300 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)
1301 return log_error_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to set tag: %s",
1302 ERR_error_string(ERR_get_error(), NULL
));
1304 if (EVP_DecryptFinal_ex(context
, (uint8_t*) plaintext
+ plaintext_size
, &added
) != 1)
1305 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Decryption failed (incorrect key?): %s",
1306 ERR_error_string(ERR_get_error(), NULL
));
1308 plaintext_size
+= added
;
1310 if (plaintext_size
< ALIGN8(offsetof(struct metadata_credential_header
, name
)))
1311 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Metadata header incomplete.");
1315 if (le64toh(m
->timestamp
) != USEC_INFINITY
&&
1316 le64toh(m
->not_after
) != USEC_INFINITY
&&
1317 le64toh(m
->timestamp
) >= le64toh(m
->not_after
))
1318 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Timestamps of credential are not in order, refusing.");
1320 if (le32toh(m
->name_size
) > CREDENTIAL_NAME_MAX
)
1321 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Embedded credential name too long, refusing.");
1323 hs
= ALIGN8(offsetof(struct metadata_credential_header
, name
) + le32toh(m
->name_size
));
1324 if (plaintext_size
< hs
)
1325 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Metadata header incomplete.");
1327 if (le32toh(m
->name_size
) > 0) {
1328 _cleanup_free_
char *embedded_name
= NULL
;
1330 r
= make_cstring(m
->name
, le32toh(m
->name_size
), MAKE_CSTRING_REFUSE_TRAILING_NUL
, &embedded_name
);
1332 return log_error_errno(r
, "Unable to convert embedded credential name to C string: %m");
1334 if (!credential_name_valid(embedded_name
))
1335 return log_error_errno(SYNTHETIC_ERRNO(EBADMSG
), "Embedded credential name is not valid, refusing.");
1337 if (validate_name
&& !streq(embedded_name
, validate_name
)) {
1339 r
= getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NAME");
1340 if (r
< 0 && r
!= -ENXIO
)
1341 log_debug_errno(r
, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NAME: %m");
1343 return log_error_errno(SYNTHETIC_ERRNO(EREMOTE
), "Embedded credential name '%s' does not match filename '%s', refusing.", embedded_name
, validate_name
);
1345 log_debug("Embedded credential name '%s' does not match expected name '%s', but configured to use credential anyway.", embedded_name
, validate_name
);
1349 if (validate_timestamp
!= USEC_INFINITY
) {
1350 if (le64toh(m
->timestamp
) != USEC_INFINITY
&& le64toh(m
->timestamp
) > validate_timestamp
)
1351 log_debug("Credential timestamp is from the future, assuming clock skew.");
1353 if (le64toh(m
->not_after
) != USEC_INFINITY
&& le64toh(m
->not_after
) < validate_timestamp
) {
1355 r
= getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER");
1356 if (r
< 0 && r
!= -ENXIO
)
1357 log_debug_errno(r
, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER: %m");
1359 return log_error_errno(SYNTHETIC_ERRNO(ESTALE
), "Credential's time passed, refusing to use.");
1361 log_debug("Credential not-after timestamp has passed, but configured to use credential anyway.");
1366 char *without_metadata
;
1368 without_metadata
= memdup((uint8_t*) plaintext
+ hs
, plaintext_size
- hs
);
1369 if (!without_metadata
)
1372 *ret
= without_metadata
;
1376 *ret_size
= plaintext_size
- hs
;
1383 int get_credential_host_secret(CredentialSecretFlags flags
, void **ret
, size_t *ret_size
) {
1384 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
), "Support for encrypted credentials not available.");
1387 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_hash_pcr_mask
, const char *tpm2_pubkey_path
, uint32_t tpm2_pubkey_pcr_mask
, const void *input
, size_t input_size
, void **ret
, size_t *ret_size
) {
1388 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
), "Support for encrypted credentials not available.");
1391 int decrypt_credential_and_warn(const char *validate_name
, usec_t validate_timestamp
, const char *tpm2_device
, const char *tpm2_signature_path
, const void *input
, size_t input_size
, void **ret
, size_t *ret_size
) {
1392 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
), "Support for encrypted credentials not available.");