crypto/ct/ct_sct.c - third_party/openssl - Git at Google

 /*
  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  */

 #ifdef OPENSSL_NO_CT
 # error "CT disabled"
 #endif

 #include <openssl/ct.h>
 #include <openssl/err.h>
 #include <openssl/evp.h>
 #include <openssl/tls1.h>
 #include <openssl/x509.h>

 #include "ct_local.h"

 SCT *SCT_new(void)
 {
     SCT *sct = OPENSSL_zalloc(sizeof(*sct));

     if (sct == NULL) {
         CTerr(CT_F_SCT_NEW, ERR_R_MALLOC_FAILURE);
         return NULL;
     }

     sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;
     sct->version = SCT_VERSION_NOT_SET;
     return sct;
 }

 void SCT_free(SCT *sct)
 {
     if (sct == NULL)
         return;

     OPENSSL_free(sct->log_id);
     OPENSSL_free(sct->ext);
     OPENSSL_free(sct->sig);
     OPENSSL_free(sct->sct);
     OPENSSL_free(sct);
 }

 void SCT_LIST_free(STACK_OF(SCT) *a)
 {
     sk_SCT_pop_free(a, SCT_free);
 }

 int SCT_set_version(SCT *sct, sct_version_t version)
 {
     if (version != SCT_VERSION_V1) {
         CTerr(CT_F_SCT_SET_VERSION, CT_R_UNSUPPORTED_VERSION);
         return 0;
     }
     sct->version = version;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
     return 1;
 }

 int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
 {
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

     switch (entry_type) {
     case CT_LOG_ENTRY_TYPE_X509:
     case CT_LOG_ENTRY_TYPE_PRECERT:
         sct->entry_type = entry_type;
         return 1;
     case CT_LOG_ENTRY_TYPE_NOT_SET:
         break;
     }
     CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
     return 0;
 }

 int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)
 {
     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
         CTerr(CT_F_SCT_SET0_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
         return 0;
     }

     OPENSSL_free(sct->log_id);
     sct->log_id = log_id;
     sct->log_id_len = log_id_len;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
     return 1;
 }

 int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)
 {
     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
         CTerr(CT_F_SCT_SET1_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
         return 0;
     }

     OPENSSL_free(sct->log_id);
     sct->log_id = NULL;
     sct->log_id_len = 0;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

     if (log_id != NULL && log_id_len > 0) {
         sct->log_id = OPENSSL_memdup(log_id, log_id_len);
         if (sct->log_id == NULL) {
             CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
             return 0;
         }
         sct->log_id_len = log_id_len;
     }
     return 1;
 }


 void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
 {
     sct->timestamp = timestamp;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 }

 int SCT_set_signature_nid(SCT *sct, int nid)
 {
     switch (nid) {
     case NID_sha256WithRSAEncryption:
         sct->hash_alg = TLSEXT_hash_sha256;
         sct->sig_alg = TLSEXT_signature_rsa;
         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
         return 1;
     case NID_ecdsa_with_SHA256:
         sct->hash_alg = TLSEXT_hash_sha256;
         sct->sig_alg = TLSEXT_signature_ecdsa;
         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
         return 1;
     default:
         CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
         return 0;
     }
 }

 void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)
 {
     OPENSSL_free(sct->ext);
     sct->ext = ext;
     sct->ext_len = ext_len;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 }

 int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)
 {
     OPENSSL_free(sct->ext);
     sct->ext = NULL;
     sct->ext_len = 0;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

     if (ext != NULL && ext_len > 0) {
         sct->ext = OPENSSL_memdup(ext, ext_len);
         if (sct->ext == NULL) {
             CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
             return 0;
         }
         sct->ext_len = ext_len;
     }
     return 1;
 }

 void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len)
 {
     OPENSSL_free(sct->sig);
     sct->sig = sig;
     sct->sig_len = sig_len;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 }

 int SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len)
 {
     OPENSSL_free(sct->sig);
     sct->sig = NULL;
     sct->sig_len = 0;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

     if (sig != NULL && sig_len > 0) {
         sct->sig = OPENSSL_memdup(sig, sig_len);
         if (sct->sig == NULL) {
             CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
             return 0;
         }
         sct->sig_len = sig_len;
     }
     return 1;
 }

 sct_version_t SCT_get_version(const SCT *sct)
 {
     return sct->version;
 }

 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
 {
     return sct->entry_type;
 }

 size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)
 {
     *log_id = sct->log_id;
     return sct->log_id_len;
 }

 uint64_t SCT_get_timestamp(const SCT *sct)
 {
     return sct->timestamp;
 }

 int SCT_get_signature_nid(const SCT *sct)
 {
     if (sct->version == SCT_VERSION_V1) {
         if (sct->hash_alg == TLSEXT_hash_sha256) {
             switch (sct->sig_alg) {
             case TLSEXT_signature_ecdsa:
                 return NID_ecdsa_with_SHA256;
             case TLSEXT_signature_rsa:
                 return NID_sha256WithRSAEncryption;
             default:
                 return NID_undef;
             }
         }
     }
     return NID_undef;
 }

 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
 {
     *ext = sct->ext;
     return sct->ext_len;
 }

 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
 {
     *sig = sct->sig;
     return sct->sig_len;
 }

 int SCT_is_complete(const SCT *sct)
 {
     switch (sct->version) {
     case SCT_VERSION_NOT_SET:
         return 0;
     case SCT_VERSION_V1:
         return sct->log_id != NULL && SCT_signature_is_complete(sct);
     default:
         return sct->sct != NULL; /* Just need cached encoding */
     }
 }

 int SCT_signature_is_complete(const SCT *sct)
 {
     return SCT_get_signature_nid(sct) != NID_undef &&
         sct->sig != NULL && sct->sig_len > 0;
 }

 sct_source_t SCT_get_source(const SCT *sct)
 {
     return sct->source;
 }

 int SCT_set_source(SCT *sct, sct_source_t source)
 {
     sct->source = source;
     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
     switch (source) {
     case SCT_SOURCE_TLS_EXTENSION:
     case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
     case SCT_SOURCE_X509V3_EXTENSION:
         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
     case SCT_SOURCE_UNKNOWN:
         break;
     }
     /* if we aren't sure, leave the log entry type alone */
     return 1;
 }

 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
 {
     return sct->validation_status;
 }

 int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)
 {
     int is_sct_valid = -1;
     SCT_CTX *sctx = NULL;
     X509_PUBKEY *pub = NULL, *log_pkey = NULL;
     const CTLOG *log;

     /*
      * With an unrecognized SCT version we don't know what such an SCT means,
      * let alone validate one.  So we return validation failure (0).
      */
     if (sct->version != SCT_VERSION_V1) {
         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
         return 0;
     }

     log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
                                      sct->log_id, sct->log_id_len);

     /* Similarly, an SCT from an unknown log also cannot be validated. */
     if (log == NULL) {
         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
         return 0;
     }

     sctx = SCT_CTX_new();
     if (sctx == NULL)
         goto err;

     if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
         goto err;
     if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
         goto err;

     if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
         EVP_PKEY *issuer_pkey;

         if (ctx->issuer == NULL) {
             sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
             goto end;
         }

         issuer_pkey = X509_get0_pubkey(ctx->issuer);

         if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
             goto err;
         if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
             goto err;
     }

     SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms);

     /*
      * XXX: Potential for optimization.  This repeats some idempotent heavy
      * lifting on the certificate for each candidate SCT, and appears to not
      * use any information in the SCT itself, only the certificate is
      * processed.  So it may make more sense to to do this just once, perhaps
      * associated with the shared (by all SCTs) policy eval ctx.
      *
      * XXX: Failure here is global (SCT independent) and represents either an
      * issue with the certificate (e.g. duplicate extensions) or an out of
      * memory condition.  When the certificate is incompatible with CT, we just
      * mark the SCTs invalid, rather than report a failure to determine the
      * validation status.  That way, callbacks that want to do "soft" SCT
      * processing will not abort handshakes with false positive internal
      * errors.  Since the function does not distinguish between certificate
      * issues (peer's fault) and internal problems (out fault) the safe thing
      * to do is to report a validation failure and let the callback or
      * application decide what to do.
      */
     if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
         sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
     else
         sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ?
             SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;

 end:
     is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
 err:
     X509_PUBKEY_free(pub);
     X509_PUBKEY_free(log_pkey);
     SCT_CTX_free(sctx);

     return is_sct_valid;
 }

 int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)
 {
     int are_scts_valid = 1;
     int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
     int i;

     for (i = 0; i < sct_count; ++i) {
         int is_sct_valid = -1;
         SCT *sct = sk_SCT_value(scts, i);

         if (sct == NULL)
             continue;

         is_sct_valid = SCT_validate(sct, ctx);
         if (is_sct_valid < 0)
             return is_sct_valid;
         are_scts_valid &= is_sct_valid;
     }

     return are_scts_valid;
 }
	/*
	* Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
	*
	* Licensed under the Apache License 2.0 (the "License"). You may not use
	* this file except in compliance with the License. You can obtain a copy
	* in the file LICENSE in the source distribution or at
	* https://www.openssl.org/source/license.html
	*/

	#ifdef OPENSSL_NO_CT
	# error "CT disabled"
	#endif

	#include <openssl/ct.h>
	#include <openssl/err.h>
	#include <openssl/evp.h>
	#include <openssl/tls1.h>
	#include <openssl/x509.h>

	#include "ct_local.h"

	SCT *SCT_new(void)
	{
	SCT sct = OPENSSL_zalloc(sizeof(sct));

	if (sct == NULL) {
	CTerr(CT_F_SCT_NEW, ERR_R_MALLOC_FAILURE);
	return NULL;
	}

	sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;
	sct->version = SCT_VERSION_NOT_SET;
	return sct;
	}

	void SCT_free(SCT *sct)
	{
	if (sct == NULL)
	return;

	OPENSSL_free(sct->log_id);
	OPENSSL_free(sct->ext);
	OPENSSL_free(sct->sig);
	OPENSSL_free(sct->sct);
	OPENSSL_free(sct);
	}

	void SCT_LIST_free(STACK_OF(SCT) *a)
	{
	sk_SCT_pop_free(a, SCT_free);
	}

	int SCT_set_version(SCT *sct, sct_version_t version)
	{
	if (version != SCT_VERSION_V1) {
	CTerr(CT_F_SCT_SET_VERSION, CT_R_UNSUPPORTED_VERSION);
	return 0;
	}
	sct->version = version;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	return 1;
	}

	int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
	{
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

	switch (entry_type) {
	case CT_LOG_ENTRY_TYPE_X509:
	case CT_LOG_ENTRY_TYPE_PRECERT:
	sct->entry_type = entry_type;
	return 1;
	case CT_LOG_ENTRY_TYPE_NOT_SET:
	break;
	}
	CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
	return 0;
	}

	int SCT_set0_log_id(SCT sct, unsigned char log_id, size_t log_id_len)
	{
	if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
	CTerr(CT_F_SCT_SET0_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
	return 0;
	}

	OPENSSL_free(sct->log_id);
	sct->log_id = log_id;
	sct->log_id_len = log_id_len;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	return 1;
	}

	int SCT_set1_log_id(SCT sct, const unsigned char log_id, size_t log_id_len)
	{
	if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
	CTerr(CT_F_SCT_SET1_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
	return 0;
	}

	OPENSSL_free(sct->log_id);
	sct->log_id = NULL;
	sct->log_id_len = 0;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

	if (log_id != NULL && log_id_len > 0) {
	sct->log_id = OPENSSL_memdup(log_id, log_id_len);
	if (sct->log_id == NULL) {
	CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
	return 0;
	}
	sct->log_id_len = log_id_len;
	}
	return 1;
	}


	void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
	{
	sct->timestamp = timestamp;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	}

	int SCT_set_signature_nid(SCT *sct, int nid)
	{
	switch (nid) {
	case NID_sha256WithRSAEncryption:
	sct->hash_alg = TLSEXT_hash_sha256;
	sct->sig_alg = TLSEXT_signature_rsa;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	return 1;
	case NID_ecdsa_with_SHA256:
	sct->hash_alg = TLSEXT_hash_sha256;
	sct->sig_alg = TLSEXT_signature_ecdsa;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	return 1;
	default:
	CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
	return 0;
	}
	}

	void SCT_set0_extensions(SCT sct, unsigned char ext, size_t ext_len)
	{
	OPENSSL_free(sct->ext);
	sct->ext = ext;
	sct->ext_len = ext_len;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	}

	int SCT_set1_extensions(SCT sct, const unsigned char ext, size_t ext_len)
	{
	OPENSSL_free(sct->ext);
	sct->ext = NULL;
	sct->ext_len = 0;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

	if (ext != NULL && ext_len > 0) {
	sct->ext = OPENSSL_memdup(ext, ext_len);
	if (sct->ext == NULL) {
	CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
	return 0;
	}
	sct->ext_len = ext_len;
	}
	return 1;
	}

	void SCT_set0_signature(SCT sct, unsigned char sig, size_t sig_len)
	{
	OPENSSL_free(sct->sig);
	sct->sig = sig;
	sct->sig_len = sig_len;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	}

	int SCT_set1_signature(SCT sct, const unsigned char sig, size_t sig_len)
	{
	OPENSSL_free(sct->sig);
	sct->sig = NULL;
	sct->sig_len = 0;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

	if (sig != NULL && sig_len > 0) {
	sct->sig = OPENSSL_memdup(sig, sig_len);
	if (sct->sig == NULL) {
	CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
	return 0;
	}
	sct->sig_len = sig_len;
	}
	return 1;
	}

	sct_version_t SCT_get_version(const SCT *sct)
	{
	return sct->version;
	}

	ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
	{
	return sct->entry_type;
	}

	size_t SCT_get0_log_id(const SCT sct, unsigned char *log_id)
	{
	*log_id = sct->log_id;
	return sct->log_id_len;
	}

	uint64_t SCT_get_timestamp(const SCT *sct)
	{
	return sct->timestamp;
	}

	int SCT_get_signature_nid(const SCT *sct)
	{
	if (sct->version == SCT_VERSION_V1) {
	if (sct->hash_alg == TLSEXT_hash_sha256) {
	switch (sct->sig_alg) {
	case TLSEXT_signature_ecdsa:
	return NID_ecdsa_with_SHA256;
	case TLSEXT_signature_rsa:
	return NID_sha256WithRSAEncryption;
	default:
	return NID_undef;
	}
	}
	}
	return NID_undef;
	}

	size_t SCT_get0_extensions(const SCT sct, unsigned char *ext)
	{
	*ext = sct->ext;
	return sct->ext_len;
	}

	size_t SCT_get0_signature(const SCT sct, unsigned char *sig)
	{
	*sig = sct->sig;
	return sct->sig_len;
	}

	int SCT_is_complete(const SCT *sct)
	{
	switch (sct->version) {
	case SCT_VERSION_NOT_SET:
	return 0;
	case SCT_VERSION_V1:
	return sct->log_id != NULL && SCT_signature_is_complete(sct);
	default:
	return sct->sct != NULL; /* Just need cached encoding */
	}
	}

	int SCT_signature_is_complete(const SCT *sct)
	{
	return SCT_get_signature_nid(sct) != NID_undef &&
	sct->sig != NULL && sct->sig_len > 0;
	}

	sct_source_t SCT_get_source(const SCT *sct)
	{
	return sct->source;
	}

	int SCT_set_source(SCT *sct, sct_source_t source)
	{
	sct->source = source;
	sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
	switch (source) {
	case SCT_SOURCE_TLS_EXTENSION:
	case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
	return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
	case SCT_SOURCE_X509V3_EXTENSION:
	return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
	case SCT_SOURCE_UNKNOWN:
	break;
	}
	/* if we aren't sure, leave the log entry type alone */
	return 1;
	}

	sct_validation_status_t SCT_get_validation_status(const SCT *sct)
	{
	return sct->validation_status;
	}

	int SCT_validate(SCT sct, const CT_POLICY_EVAL_CTX ctx)
	{
	int is_sct_valid = -1;
	SCT_CTX *sctx = NULL;
	X509_PUBKEY pub = NULL, log_pkey = NULL;
	const CTLOG *log;

	/*
	* With an unrecognized SCT version we don't know what such an SCT means,
	* let alone validate one. So we return validation failure (0).
	*/
	if (sct->version != SCT_VERSION_V1) {
	sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
	return 0;
	}

	log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
	sct->log_id, sct->log_id_len);

	/* Similarly, an SCT from an unknown log also cannot be validated. */
	if (log == NULL) {
	sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
	return 0;
	}

	sctx = SCT_CTX_new();
	if (sctx == NULL)
	goto err;

	if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
	goto err;
	if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
	goto err;

	if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
	EVP_PKEY *issuer_pkey;

	if (ctx->issuer == NULL) {
	sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
	goto end;
	}

	issuer_pkey = X509_get0_pubkey(ctx->issuer);

	if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
	goto err;
	if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
	goto err;
	}

	SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms);

	/*
	* XXX: Potential for optimization. This repeats some idempotent heavy
	* lifting on the certificate for each candidate SCT, and appears to not
	* use any information in the SCT itself, only the certificate is
	* processed. So it may make more sense to to do this just once, perhaps
	* associated with the shared (by all SCTs) policy eval ctx.
	*
	* XXX: Failure here is global (SCT independent) and represents either an
	* issue with the certificate (e.g. duplicate extensions) or an out of
	* memory condition. When the certificate is incompatible with CT, we just
	* mark the SCTs invalid, rather than report a failure to determine the
	* validation status. That way, callbacks that want to do "soft" SCT
	* processing will not abort handshakes with false positive internal
	* errors. Since the function does not distinguish between certificate
	* issues (peer's fault) and internal problems (out fault) the safe thing
	* to do is to report a validation failure and let the callback or
	* application decide what to do.
	*/
	if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
	sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
	else
	sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ?
	SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;

	end:
	is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
	err:
	X509_PUBKEY_free(pub);
	X509_PUBKEY_free(log_pkey);
	SCT_CTX_free(sctx);

	return is_sct_valid;
	}

	int SCT_LIST_validate(const STACK_OF(SCT) scts, CT_POLICY_EVAL_CTX ctx)
	{
	int are_scts_valid = 1;
	int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
	int i;

	for (i = 0; i < sct_count; ++i) {
	int is_sct_valid = -1;
	SCT *sct = sk_SCT_value(scts, i);

	if (sct == NULL)
	continue;

	is_sct_valid = SCT_validate(sct, ctx);
	if (is_sct_valid < 0)
	return is_sct_valid;
	are_scts_valid &= is_sct_valid;
	}

	return are_scts_valid;
	}