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/*
* Copyright 2015-2016 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
*/
#include <stddef.h>
#include <openssl/ct.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/safestack.h>
/*
* From RFC6962: opaque SerializedSCT<1..2^16-1>; struct { SerializedSCT
* sct_list <1..2^16-1>; } SignedCertificateTimestampList;
*/
# define MAX_SCT_SIZE 65535
# define MAX_SCT_LIST_SIZE MAX_SCT_SIZE
/*
* Macros to read and write integers in network-byte order.
*/
#define n2s(c,s) ((s=(((unsigned int)((c)[0]))<< 8)| \
(((unsigned int)((c)[1])) )),c+=2)
#define s2n(s,c) ((c[0]=(unsigned char)(((s)>> 8)&0xff), \
c[1]=(unsigned char)(((s) )&0xff)),c+=2)
#define l2n3(l,c) ((c[0]=(unsigned char)(((l)>>16)&0xff), \
c[1]=(unsigned char)(((l)>> 8)&0xff), \
c[2]=(unsigned char)(((l) )&0xff)),c+=3)
#define n2l8(c,l) (l =((uint64_t)(*((c)++)))<<56, \
l|=((uint64_t)(*((c)++)))<<48, \
l|=((uint64_t)(*((c)++)))<<40, \
l|=((uint64_t)(*((c)++)))<<32, \
l|=((uint64_t)(*((c)++)))<<24, \
l|=((uint64_t)(*((c)++)))<<16, \
l|=((uint64_t)(*((c)++)))<< 8, \
l|=((uint64_t)(*((c)++))))
#define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \
*((c)++)=(unsigned char)(((l)>>48)&0xff), \
*((c)++)=(unsigned char)(((l)>>40)&0xff), \
*((c)++)=(unsigned char)(((l)>>32)&0xff), \
*((c)++)=(unsigned char)(((l)>>24)&0xff), \
*((c)++)=(unsigned char)(((l)>>16)&0xff), \
*((c)++)=(unsigned char)(((l)>> 8)&0xff), \
*((c)++)=(unsigned char)(((l) )&0xff))
/* Signed Certificate Timestamp */
struct sct_st {
sct_version_t version;
/* If version is not SCT_VERSION_V1, this contains the encoded SCT */
unsigned char *sct;
size_t sct_len;
/* If version is SCT_VERSION_V1, fields below contain components of the SCT */
unsigned char *log_id;
size_t log_id_len;
/*
* Note, we cannot distinguish between an unset timestamp, and one
* that is set to 0. However since CT didn't exist in 1970, no real
* SCT should ever be set as such.
*/
uint64_t timestamp;
unsigned char *ext;
size_t ext_len;
unsigned char hash_alg;
unsigned char sig_alg;
unsigned char *sig;
size_t sig_len;
/* Log entry type */
ct_log_entry_type_t entry_type;
/* Where this SCT was found, e.g. certificate, OCSP response, etc. */
sct_source_t source;
/* The result of the last attempt to validate this SCT. */
sct_validation_status_t validation_status;
};
/* Miscellaneous data that is useful when verifying an SCT */
struct sct_ctx_st {
/* Public key */
EVP_PKEY *pkey;
/* Hash of public key */
unsigned char *pkeyhash;
size_t pkeyhashlen;
/* For pre-certificate: issuer public key hash */
unsigned char *ihash;
size_t ihashlen;
/* certificate encoding */
unsigned char *certder;
size_t certderlen;
/* pre-certificate encoding */
unsigned char *preder;
size_t prederlen;
/* milliseconds since epoch (to check that the SCT isn't from the future) */
uint64_t epoch_time_in_ms;
};
/* Context when evaluating whether a Certificate Transparency policy is met */
struct ct_policy_eval_ctx_st {
X509 *cert;
X509 *issuer;
CTLOG_STORE *log_store;
/* milliseconds since epoch (to check that SCTs aren't from the future) */
uint64_t epoch_time_in_ms;
};
/*
* Creates a new context for verifying an SCT.
*/
SCT_CTX *SCT_CTX_new(void);
/*
* Deletes an SCT verification context.
*/
void SCT_CTX_free(SCT_CTX *sctx);
/*
* Sets the certificate that the SCT was created for.
* If *cert does not have a poison extension, presigner must be NULL.
* If *cert does not have a poison extension, it may have a single SCT
* (NID_ct_precert_scts) extension.
* If either *cert or *presigner have an AKID (NID_authority_key_identifier)
* extension, both must have one.
* Returns 1 on success, 0 on failure.
*/
__owur int SCT_CTX_set1_cert(SCT_CTX *sctx, X509 *cert, X509 *presigner);
/*
* Sets the issuer of the certificate that the SCT was created for.
* This is just a convenience method to save extracting the public key and
* calling SCT_CTX_set1_issuer_pubkey().
* Issuer must not be NULL.
* Returns 1 on success, 0 on failure.
*/
__owur int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer);
/*
* Sets the public key of the issuer of the certificate that the SCT was created
* for.
* The public key must not be NULL.
* Returns 1 on success, 0 on failure.
*/
__owur int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);
/*
* Sets the public key of the CT log that the SCT is from.
* Returns 1 on success, 0 on failure.
*/
__owur int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);
/*
* Sets the time to evaluate the SCT against, in milliseconds since the Unix
* epoch. If the SCT's timestamp is after this time, it will be interpreted as
* having been issued in the future. RFC6962 states that "TLS clients MUST
* reject SCTs whose timestamp is in the future", so an SCT will not validate
* in this case.
*/
void SCT_CTX_set_time(SCT_CTX *sctx, uint64_t time_in_ms);
/*
* Verifies an SCT with the given context.
* Returns 1 if the SCT verifies successfully; any other value indicates
* failure. See EVP_DigestVerifyFinal() for the meaning of those values.
*/
__owur int SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct);
/*
* Does this SCT have the minimum fields populated to be usable?
* Returns 1 if so, 0 otherwise.
*/
__owur int SCT_is_complete(const SCT *sct);
/*
* Does this SCT have the signature-related fields populated?
* Returns 1 if so, 0 otherwise.
* This checks that the signature and hash algorithms are set to supported
* values and that the signature field is set.
*/
__owur int SCT_signature_is_complete(const SCT *sct);
/*
* TODO(RJPercival): Create an SCT_signature struct and make i2o_SCT_signature
* and o2i_SCT_signature conform to the i2d/d2i conventions.
*/
/*
* Serialize (to TLS format) an |sct| signature and write it to |out|.
* If |out| is null, no signature will be output but the length will be returned.
* If |out| points to a null pointer, a string will be allocated to hold the
* TLS-format signature. It is the responsibility of the caller to free it.
* If |out| points to an allocated string, the signature will be written to it.
* The length of the signature in TLS format will be returned.
*/
__owur int i2o_SCT_signature(const SCT *sct, unsigned char **out);
/*
* Parses an SCT signature in TLS format and populates the |sct| with it.
* |in| should be a pointer to a string containing the TLS-format signature.
* |in| will be advanced to the end of the signature if parsing succeeds.
* |len| should be the length of the signature in |in|.
* Returns the number of bytes parsed, or a negative integer if an error occurs.
* If an error occurs, the SCT's signature NID may be updated whilst the
* signature field itself remains unset.
*/
__owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len);
/*
* Handlers for Certificate Transparency X509v3/OCSP extensions
*/
extern const X509V3_EXT_METHOD v3_ct_scts[3];
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