2 * Public API for Certificate Transparency (CT).
3 * Written by Rob Percival (robpercival@google.com) for the OpenSSL project.
5 /* ====================================================================
6 * Copyright (c) 2016 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
55 # error "CT is disabled"
61 # include <openssl/ossl_typ.h>
62 # include <openssl/safestack.h>
63 # include <openssl/x509.h>
69 /* Minimum RSA key size, from RFC6962 */
70 # define SCT_MIN_RSA_BITS 2048
72 /* All hashes are SHA256 in v1 of Certificate Transparency */
73 # define CT_V1_HASHLEN SHA256_DIGEST_LENGTH
76 CT_LOG_ENTRY_TYPE_NOT_SET = -1,
77 CT_LOG_ENTRY_TYPE_X509 = 0,
78 CT_LOG_ENTRY_TYPE_PRECERT = 1
79 } ct_log_entry_type_t;
82 SCT_VERSION_NOT_SET = -1,
88 SCT_SOURCE_TLS_EXTENSION,
89 SCT_SOURCE_X509V3_EXTENSION,
90 SCT_SOURCE_OCSP_STAPLED_RESPONSE
94 SCT_VALIDATION_STATUS_NOT_SET,
95 SCT_VALIDATION_STATUS_UNKNOWN_LOG,
96 SCT_VALIDATION_STATUS_VALID,
97 SCT_VALIDATION_STATUS_INVALID,
98 SCT_VALIDATION_STATUS_UNVERIFIED,
99 SCT_VALIDATION_STATUS_UNKNOWN_VERSION
100 } sct_validation_status_t;
103 DEFINE_STACK_OF(CTLOG)
105 /******************************************
106 * CT policy evaluation context functions *
107 ******************************************/
109 /* Creates a new, empty policy evaluation context */
110 CT_POLICY_EVAL_CTX *CT_POLICY_EVAL_CTX_new(void);
112 /* Deletes a policy evaluation context */
113 void CT_POLICY_EVAL_CTX_free(CT_POLICY_EVAL_CTX *ctx);
115 /* Gets the peer certificate that the SCTs are for */
116 X509* CT_POLICY_EVAL_CTX_get0_cert(CT_POLICY_EVAL_CTX *ctx);
118 /* Sets the certificate associated with the received SCTs */
119 void CT_POLICY_EVAL_CTX_set0_cert(CT_POLICY_EVAL_CTX *ctx, X509 *cert);
121 /* Gets the issuer of the aforementioned certificate */
122 X509* CT_POLICY_EVAL_CTX_get0_issuer(CT_POLICY_EVAL_CTX *ctx);
124 /* Sets the issuer of the certificate associated with the received SCTs */
125 void CT_POLICY_EVAL_CTX_set0_issuer(CT_POLICY_EVAL_CTX *ctx, X509 *issuer);
127 /* Gets the CT logs that are trusted sources of SCTs */
128 CTLOG_STORE *CT_POLICY_EVAL_CTX_get0_log_store(CT_POLICY_EVAL_CTX *ctx);
130 /* Sets the log store that is in use */
131 void CT_POLICY_EVAL_CTX_set0_log_store(CT_POLICY_EVAL_CTX *ctx,
132 CTLOG_STORE *log_store);
135 * A callback for verifying that the received SCTs are sufficient.
136 * Expected to return 1 if they are sufficient, otherwise 0.
137 * May return a negative integer if an error occurs.
138 * A connection should be aborted if the SCTs are deemed insufficient.
140 typedef int(*ct_validation_cb)(const CT_POLICY_EVAL_CTX *ctx,
141 const STACK_OF(SCT) *scts, void *arg);
142 /* Returns 0 if there are invalid SCTs */
143 int CT_verify_no_bad_scts(const CT_POLICY_EVAL_CTX *ctx,
144 const STACK_OF(SCT) *scts, void *arg);
145 /* Returns 0 if there are invalid SCTS or fewer than one valid SCT */
146 int CT_verify_at_least_one_good_sct(const CT_POLICY_EVAL_CTX *ctx,
147 const STACK_OF(SCT) *scts, void *arg);
154 * Creates a new, blank SCT.
155 * The caller is responsible for calling SCT_free when finished with the SCT.
160 * Creates a new SCT from some base64-encoded strings.
161 * The caller is responsible for calling SCT_free when finished with the SCT.
163 SCT *SCT_new_from_base64(unsigned char version,
164 const char *logid_base64,
165 ct_log_entry_type_t entry_type,
167 const char *extensions_base64,
168 const char *signature_base64);
171 * Frees the SCT and the underlying data structures.
173 void SCT_free(SCT *sct);
176 * Free a stack of SCTs, and the underlying SCTs themselves.
177 * Intended to be compatible with X509V3_EXT_FREE.
179 void SCT_LIST_free(STACK_OF(SCT) *a);
182 * Returns the version of the SCT.
184 sct_version_t SCT_get_version(const SCT *sct);
187 * Set the version of an SCT.
188 * Returns 1 on success, 0 if the version is unrecognized.
190 __owur int SCT_set_version(SCT *sct, sct_version_t version);
193 * Returns the log entry type of the SCT.
195 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct);
198 * Set the log entry type of an SCT.
199 * Returns 1 on success, 0 otherwise.
201 __owur int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type);
204 * Gets the ID of the log that an SCT came from.
205 * Ownership of the log ID remains with the SCT.
206 * Returns the length of the log ID.
208 size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id);
211 * Set the log ID of an SCT to point directly to the *log_id specified.
212 * The SCT takes ownership of the specified pointer.
213 * Returns 1 on success, 0 otherwise.
215 __owur int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len);
218 * Set the log ID of an SCT.
219 * This makes a copy of the log_id.
220 * Returns 1 on success, 0 otherwise.
222 __owur int SCT_set1_log_id(SCT *sct, const unsigned char *log_id,
226 * Gets the name of the log that an SCT came from.
227 * Ownership of the log name remains with the SCT.
228 * Returns the log name, or NULL if it is not known.
230 const char *SCT_get0_log_name(const SCT *sct);
233 * Returns the timestamp for the SCT (epoch time in milliseconds).
235 uint64_t SCT_get_timestamp(const SCT *sct);
238 * Set the timestamp of an SCT (epoch time in milliseconds).
240 void SCT_set_timestamp(SCT *sct, uint64_t timestamp);
243 * Return the NID for the signature used by the SCT.
244 * For CT v1, this will be either NID_sha256WithRSAEncryption or
245 * NID_ecdsa_with_SHA256 (or NID_undef if incorrect/unset).
247 int SCT_get_signature_nid(const SCT *sct);
250 * Set the signature type of an SCT
251 * For CT v1, this should be either NID_sha256WithRSAEncryption or
252 * NID_ecdsa_with_SHA256.
253 * Returns 1 on success, 0 otherwise.
255 __owur int SCT_set_signature_nid(SCT *sct, int nid);
258 * Set *ext to point to the extension data for the SCT. ext must not be NULL.
259 * The SCT retains ownership of this pointer.
260 * Returns length of the data pointed to.
262 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext);
265 * Set the extensions of an SCT to point directly to the *ext specified.
266 * The SCT takes ownership of the specified pointer.
268 void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len);
271 * Set the extensions of an SCT.
272 * This takes a copy of the ext.
273 * Returns 1 on success, 0 otherwise.
275 __owur int SCT_set1_extensions(SCT *sct, const unsigned char *ext,
279 * Set *sig to point to the signature for the SCT. sig must not be NULL.
280 * The SCT retains ownership of this pointer.
281 * Returns length of the data pointed to.
283 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig);
286 * Set the signature of an SCT to point directly to the *sig specified.
287 * The SCT takes ownership of the specified pointer.
289 void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len);
292 * Set the signature of an SCT to be a copy of the *sig specified.
293 * Returns 1 on success, 0 otherwise.
295 __owur int SCT_set1_signature(SCT *sct, const unsigned char *sig,
299 * The origin of this SCT, e.g. TLS extension, OCSP response, etc.
301 sct_source_t SCT_get_source(const SCT *sct);
304 * Set the origin of this SCT, e.g. TLS extension, OCSP response, etc.
305 * Returns 1 on success, 0 otherwise.
307 __owur int SCT_set_source(SCT *sct, sct_source_t source);
310 * Gets information about the log the SCT came from, if set.
312 const CTLOG *SCT_get0_log(const SCT *sct);
315 * Looks up information about the log the SCT came from using a CT log store.
316 * The CTLOG_STORE must outlive the SCT, as ownership of the CTLOG remains with
318 * Returns 1 if information about the log is found, 0 otherwise.
319 * The information can be accessed via SCT_get0_log.
321 int SCT_set0_log(SCT *sct, const CTLOG_STORE* ct_logs);
324 * Pretty-prints an |sct| to |out|.
325 * It will be indented by the number of spaces specified by |indent|.
327 void SCT_print(const SCT *sct, BIO *out, int indent);
330 * Pretty-prints an |sct_list| to |out|.
331 * It will be indented by the number of spaces specified by |indent|.
332 * SCTs will be delimited by |separator|.
334 void SCT_LIST_print(const STACK_OF(SCT) *sct_list, BIO *out, int indent,
335 const char *separator);
338 * Verifies an SCT with the given context.
339 * Returns 1 if the SCT verifies successfully, 0 otherwise.
341 __owur int SCT_verify(const SCT_CTX *sctx, const SCT *sct);
344 * Verifies an SCT against the provided data.
345 * Returns 1 if the SCT verifies successfully, 0 otherwise.
347 __owur int SCT_verify_v1(SCT *sct, X509 *cert, X509 *preissuer,
348 X509_PUBKEY *log_pubkey, X509 *issuer_cert);
351 * Gets the last result of validating this SCT.
352 * If it has not been validated yet, returns SCT_VALIDATION_STATUS_NOT_SET.
354 sct_validation_status_t SCT_get_validation_status(const SCT *sct);
357 * Validates the given SCT with the provided context.
358 * Sets the "validation_status" field of the SCT.
359 * Returns 1 if the SCT is valid and the signature verifies.
360 * Returns 0 if the SCT is invalid or could not be verified.
361 * Returns -1 if an error occurs.
363 __owur int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx);
366 * Validates the given list of SCTs with the provided context.
367 * Populates the "good_scts" and "bad_scts" of the evaluation context.
368 * Returns 1 if there are no invalid SCTs and all signatures verify.
369 * Returns 0 if at least one SCT is invalid or could not be verified.
370 * Returns a negative integer if an error occurs.
372 __owur int SCT_LIST_validate(const STACK_OF(SCT) *scts,
373 CT_POLICY_EVAL_CTX *ctx);
376 /*********************************
377 * SCT parsing and serialisation *
378 *********************************/
381 * Serialize (to TLS format) a stack of SCTs and return the length.
382 * "a" must not be NULL.
383 * If "pp" is NULL, just return the length of what would have been serialized.
384 * If "pp" is not NULL and "*pp" is null, function will allocate a new pointer
385 * for data that caller is responsible for freeing (only if function returns
387 * If "pp" is NULL and "*pp" is not NULL, caller is responsible for ensuring
388 * that "*pp" is large enough to accept all of the serializied data.
389 * Returns < 0 on error, >= 0 indicating bytes written (or would have been)
392 __owur int i2o_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **pp);
395 * Convert TLS format SCT list to a stack of SCTs.
396 * If "a" or "*a" is NULL, a new stack will be created that the caller is
397 * responsible for freeing (by calling SCT_LIST_free).
398 * "**pp" and "*pp" must not be NULL.
399 * Upon success, "*pp" will point to after the last bytes read, and a stack
401 * Upon failure, a NULL pointer will be returned, and the position of "*pp" is
404 STACK_OF(SCT) *o2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,
408 * Serialize (to DER format) a stack of SCTs and return the length.
409 * "a" must not be NULL.
410 * If "pp" is NULL, just returns the length of what would have been serialized.
411 * If "pp" is not NULL and "*pp" is null, function will allocate a new pointer
412 * for data that caller is responsible for freeing (only if function returns
414 * If "pp" is NULL and "*pp" is not NULL, caller is responsible for ensuring
415 * that "*pp" is large enough to accept all of the serializied data.
416 * Returns < 0 on error, >= 0 indicating bytes written (or would have been)
419 __owur int i2d_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **pp);
422 * Parses an SCT list in DER format and returns it.
423 * If "a" or "*a" is NULL, a new stack will be created that the caller is
424 * responsible for freeing (by calling SCT_LIST_free).
425 * "**pp" and "*pp" must not be NULL.
426 * Upon success, "*pp" will point to after the last bytes read, and a stack
428 * Upon failure, a NULL pointer will be returned, and the position of "*pp" is
431 STACK_OF(SCT) *d2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,
435 * Serialize (to TLS format) an |sct| and write it to |out|.
436 * If |out| is null, no SCT will be output but the length will still be returned.
437 * If |out| points to a null pointer, a string will be allocated to hold the
438 * TLS-format SCT. It is the responsibility of the caller to free it.
439 * If |out| points to an allocated string, the TLS-format SCT will be written
441 * The length of the SCT in TLS format will be returned.
443 __owur int i2o_SCT(const SCT *sct, unsigned char **out);
446 * Parses an SCT in TLS format and returns it.
447 * If |psct| is not null, it will end up pointing to the parsed SCT. If it
448 * already points to a non-null pointer, the pointer will be free'd.
449 * |in| should be a pointer to a string contianing the TLS-format SCT.
450 * |in| will be advanced to the end of the SCT if parsing succeeds.
451 * |len| should be the length of the SCT in |in|.
452 * Returns NULL if an error occurs.
453 * If the SCT is an unsupported version, only the SCT's 'sct' and 'sct_len'
454 * fields will be populated (with |in| and |len| respectively).
456 SCT *o2i_SCT(SCT **psct, const unsigned char **in, size_t len);
459 * Serialize (to TLS format) an |sct| signature and write it to |out|.
460 * If |out| is null, no signature will be output but the length will be returned.
461 * If |out| points to a null pointer, a string will be allocated to hold the
462 * TLS-format signature. It is the responsibility of the caller to free it.
463 * If |out| points to an allocated string, the signature will be written to it.
464 * The length of the signature in TLS format will be returned.
466 __owur int i2o_SCT_signature(const SCT *sct, unsigned char **out);
469 * Parses an SCT signature in TLS format and populates the |sct| with it.
470 * |in| should be a pointer to a string contianing the TLS-format signature.
471 * |in| will be advanced to the end of the signature if parsing succeeds.
472 * |len| should be the length of the signature in |in|.
473 * Returns the number of bytes parsed, or a negative integer if an error occurs.
475 __owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len);
477 /********************
479 ********************/
482 * Creates a new CT log instance with the given |public_key| and |name|.
483 * Should be deleted by the caller using CTLOG_free when no longer needed.
485 CTLOG *CTLOG_new(EVP_PKEY *public_key, const char *name);
488 * Creates a new, blank CT log instance.
489 * Should be deleted by the caller using CTLOG_free when no longer needed.
491 CTLOG *CTLOG_new_null(void);
494 * Creates a new CT log instance with the given base64 public_key and |name|.
495 * Should be deleted by the caller using CTLOG_free when no longer needed.
497 CTLOG *CTLOG_new_from_base64(const char *pkey_base64, const char *name);
500 * Deletes a CT log instance and its fields.
502 void CTLOG_free(CTLOG *log);
504 /* Gets the name of the CT log */
505 const char *CTLOG_get0_name(const CTLOG *log);
506 /* Gets the ID of the CT log */
507 void CTLOG_get0_log_id(const CTLOG *log, const uint8_t **log_id,
509 /* Gets the public key of the CT log */
510 EVP_PKEY *CTLOG_get0_public_key(const CTLOG *log);
512 /**************************
513 * CT log store functions *
514 **************************/
517 * Creates a new CT log store.
518 * Should be deleted by the caller using CTLOG_STORE_free when no longer needed.
520 CTLOG_STORE *CTLOG_STORE_new(void);
523 * Deletes a CT log store and all of the CT log instances held within.
525 void CTLOG_STORE_free(CTLOG_STORE *store);
528 * Finds a CT log in the store based on its log ID.
529 * Returns the CT log, or NULL if no match is found.
531 const CTLOG *CTLOG_STORE_get0_log_by_id(const CTLOG_STORE *store,
532 const uint8_t *log_id,
536 * Loads a CT log list into a |store| from a |file|.
537 * Returns 1 if loading is successful, or 0 otherwise.
539 __owur int CTLOG_STORE_load_file(CTLOG_STORE *store, const char *file);
542 * Loads the default CT log list into a |store|.
543 * See internal/cryptlib.h for the environment variable and file path that are
544 * consulted to find the default file.
545 * Returns 1 if loading is successful, or 0 otherwise.
547 __owur int CTLOG_STORE_load_default_file(CTLOG_STORE *store);
549 /* BEGIN ERROR CODES */
551 * The following lines are auto generated by the script mkerr.pl. Any changes
552 * made after this point may be overwritten when the script is next run.
554 void ERR_load_CT_strings(void);
556 /* Error codes for the CT functions. */
558 /* Function codes. */
559 # define CT_F_CTLOG_NEW 117
560 # define CT_F_CTLOG_NEW_FROM_BASE64 118
561 # define CT_F_CTLOG_NEW_FROM_CONF 119
562 # define CT_F_CTLOG_NEW_NULL 120
563 # define CT_F_CTLOG_STORE_GET0_LOG_BY_ID 121
564 # define CT_F_CTLOG_STORE_LOAD_CTX_NEW 122
565 # define CT_F_CTLOG_STORE_LOAD_FILE 123
566 # define CT_F_CT_BASE64_DECODE 124
567 # define CT_F_CT_POLICY_EVAL_CTX_GET0_CERT 130
568 # define CT_F_CT_POLICY_EVAL_CTX_GET0_ISSUER 131
569 # define CT_F_CT_POLICY_EVAL_CTX_GET0_LOG_STORE 132
570 # define CT_F_CT_POLICY_EVAL_CTX_NEW 133
571 # define CT_F_CT_POLICY_EVAL_CTX_SET0_CERT 134
572 # define CT_F_CT_POLICY_EVAL_CTX_SET0_ISSUER 135
573 # define CT_F_CT_POLICY_EVAL_CTX_SET0_LOG_STORE 136
574 # define CT_F_CT_V1_LOG_ID_FROM_PKEY 125
575 # define CT_F_CT_VERIFY_AT_LEAST_ONE_GOOD_SCT 137
576 # define CT_F_CT_VERIFY_NO_BAD_SCTS 138
577 # define CT_F_D2I_SCT_LIST 105
578 # define CT_F_I2D_SCT_LIST 106
579 # define CT_F_I2O_SCT 107
580 # define CT_F_I2O_SCT_LIST 108
581 # define CT_F_I2O_SCT_SIGNATURE 109
582 # define CT_F_O2I_SCT 110
583 # define CT_F_O2I_SCT_LIST 111
584 # define CT_F_O2I_SCT_SIGNATURE 112
585 # define CT_F_SCT_CTX_NEW 126
586 # define CT_F_SCT_LIST_VALIDATE 139
587 # define CT_F_SCT_NEW 100
588 # define CT_F_SCT_NEW_FROM_BASE64 127
589 # define CT_F_SCT_SET0_LOG_ID 101
590 # define CT_F_SCT_SET1_EXTENSIONS 114
591 # define CT_F_SCT_SET1_LOG_ID 115
592 # define CT_F_SCT_SET1_SIGNATURE 116
593 # define CT_F_SCT_SET_LOG_ENTRY_TYPE 102
594 # define CT_F_SCT_SET_SIGNATURE_NID 103
595 # define CT_F_SCT_SET_VERSION 104
596 # define CT_F_SCT_SIGNATURE_IS_VALID 113
597 # define CT_F_SCT_VALIDATE 140
598 # define CT_F_SCT_VERIFY 128
599 # define CT_F_SCT_VERIFY_V1 129
602 # define CT_R_BASE64_DECODE_ERROR 108
603 # define CT_R_INVALID_LOG_ID_LENGTH 100
604 # define CT_R_LOG_CONF_INVALID 109
605 # define CT_R_LOG_CONF_INVALID_KEY 110
606 # define CT_R_LOG_CONF_MISSING_DESCRIPTION 111
607 # define CT_R_LOG_CONF_MISSING_KEY 112
608 # define CT_R_LOG_KEY_INVALID 113
609 # define CT_R_NOT_ENOUGH_SCTS 116
610 # define CT_R_SCT_INVALID 104
611 # define CT_R_SCT_INVALID_SIGNATURE 107
612 # define CT_R_SCT_LIST_INVALID 105
613 # define CT_R_SCT_LOG_ID_MISMATCH 114
614 # define CT_R_SCT_NOT_SET 106
615 # define CT_R_SCT_UNSUPPORTED_VERSION 115
616 # define CT_R_SCT_VALIDATION_STATUS_NOT_SET 117
617 # define CT_R_UNRECOGNIZED_SIGNATURE_NID 101
618 # define CT_R_UNSUPPORTED_ENTRY_TYPE 102
619 # define CT_R_UNSUPPORTED_VERSION 103