1/* 2 * Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10#include <stddef.h> 11#include <openssl/ct.h> 12#include <openssl/evp.h> 13#include <openssl/x509.h> 14#include <openssl/x509v3.h> 15#include <openssl/safestack.h> 16 17/* 18 * From RFC6962: opaque SerializedSCT<1..2^16-1>; struct { SerializedSCT 19 * sct_list <1..2^16-1>; } SignedCertificateTimestampList; 20 */ 21# define MAX_SCT_SIZE 65535 22# define MAX_SCT_LIST_SIZE MAX_SCT_SIZE 23 24/* 25 * Macros to read and write integers in network-byte order. 26 */ 27 28#define n2s(c,s) ((s=(((unsigned int)((c)[0]))<< 8)| \ 29 (((unsigned int)((c)[1])) )),c+=2) 30 31#define s2n(s,c) ((c[0]=(unsigned char)(((s)>> 8)&0xff), \ 32 c[1]=(unsigned char)(((s) )&0xff)),c+=2) 33 34#define l2n3(l,c) ((c[0]=(unsigned char)(((l)>>16)&0xff), \ 35 c[1]=(unsigned char)(((l)>> 8)&0xff), \ 36 c[2]=(unsigned char)(((l) )&0xff)),c+=3) 37 38#define n2l8(c,l) (l =((uint64_t)(*((c)++)))<<56, \ 39 l|=((uint64_t)(*((c)++)))<<48, \ 40 l|=((uint64_t)(*((c)++)))<<40, \ 41 l|=((uint64_t)(*((c)++)))<<32, \ 42 l|=((uint64_t)(*((c)++)))<<24, \ 43 l|=((uint64_t)(*((c)++)))<<16, \ 44 l|=((uint64_t)(*((c)++)))<< 8, \ 45 l|=((uint64_t)(*((c)++)))) 46 47#define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \ 48 *((c)++)=(unsigned char)(((l)>>48)&0xff), \ 49 *((c)++)=(unsigned char)(((l)>>40)&0xff), \ 50 *((c)++)=(unsigned char)(((l)>>32)&0xff), \ 51 *((c)++)=(unsigned char)(((l)>>24)&0xff), \ 52 *((c)++)=(unsigned char)(((l)>>16)&0xff), \ 53 *((c)++)=(unsigned char)(((l)>> 8)&0xff), \ 54 *((c)++)=(unsigned char)(((l) )&0xff)) 55 56/* Signed Certificate Timestamp */ 57struct sct_st { 58 sct_version_t version; 59 /* If version is not SCT_VERSION_V1, this contains the encoded SCT */ 60 unsigned char *sct; 61 size_t sct_len; 62 /* If version is SCT_VERSION_V1, fields below contain components of the SCT */ 63 unsigned char *log_id; 64 size_t log_id_len; 65 /* 66 * Note, we cannot distinguish between an unset timestamp, and one 67 * that is set to 0. However since CT didn't exist in 1970, no real 68 * SCT should ever be set as such. 69 */ 70 uint64_t timestamp; 71 unsigned char *ext; 72 size_t ext_len; 73 unsigned char hash_alg; 74 unsigned char sig_alg; 75 unsigned char *sig; 76 size_t sig_len; 77 /* Log entry type */ 78 ct_log_entry_type_t entry_type; 79 /* Where this SCT was found, e.g. certificate, OCSP response, etc. */ 80 sct_source_t source; 81 /* The result of the last attempt to validate this SCT. */ 82 sct_validation_status_t validation_status; 83}; 84 85/* Miscellaneous data that is useful when verifying an SCT */ 86struct sct_ctx_st { 87 /* Public key */ 88 EVP_PKEY *pkey; 89 /* Hash of public key */ 90 unsigned char *pkeyhash; 91 size_t pkeyhashlen; 92 /* For pre-certificate: issuer public key hash */ 93 unsigned char *ihash; 94 size_t ihashlen; 95 /* certificate encoding */ 96 unsigned char *certder; 97 size_t certderlen; 98 /* pre-certificate encoding */ 99 unsigned char *preder; 100 size_t prederlen; 101 /* milliseconds since epoch (to check that the SCT isn't from the future) */ 102 uint64_t epoch_time_in_ms; 103 104 OSSL_LIB_CTX *libctx; 105 char *propq; 106}; 107 108/* Context when evaluating whether a Certificate Transparency policy is met */ 109struct ct_policy_eval_ctx_st { 110 X509 *cert; 111 X509 *issuer; 112 CTLOG_STORE *log_store; 113 /* milliseconds since epoch (to check that SCTs aren't from the future) */ 114 uint64_t epoch_time_in_ms; 115 116 OSSL_LIB_CTX *libctx; 117 char *propq; 118}; 119 120/* 121 * Creates a new context for verifying an SCT. 122 */ 123SCT_CTX *SCT_CTX_new(OSSL_LIB_CTX *ctx, const char *propq); 124/* 125 * Deletes an SCT verification context. 126 */ 127void SCT_CTX_free(SCT_CTX *sctx); 128 129/* 130 * Sets the certificate that the SCT was created for. 131 * If *cert does not have a poison extension, presigner must be NULL. 132 * If *cert does not have a poison extension, it may have a single SCT 133 * (NID_ct_precert_scts) extension. 134 * If either *cert or *presigner have an AKID (NID_authority_key_identifier) 135 * extension, both must have one. 136 * Returns 1 on success, 0 on failure. 137 */ 138__owur int SCT_CTX_set1_cert(SCT_CTX *sctx, X509 *cert, X509 *presigner); 139 140/* 141 * Sets the issuer of the certificate that the SCT was created for. 142 * This is just a convenience method to save extracting the public key and 143 * calling SCT_CTX_set1_issuer_pubkey(). 144 * Issuer must not be NULL. 145 * Returns 1 on success, 0 on failure. 146 */ 147__owur int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer); 148 149/* 150 * Sets the public key of the issuer of the certificate that the SCT was created 151 * for. 152 * The public key must not be NULL. 153 * Returns 1 on success, 0 on failure. 154 */ 155__owur int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey); 156 157/* 158 * Sets the public key of the CT log that the SCT is from. 159 * Returns 1 on success, 0 on failure. 160 */ 161__owur int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey); 162 163/* 164 * Sets the time to evaluate the SCT against, in milliseconds since the Unix 165 * epoch. If the SCT's timestamp is after this time, it will be interpreted as 166 * having been issued in the future. RFC6962 states that "TLS clients MUST 167 * reject SCTs whose timestamp is in the future", so an SCT will not validate 168 * in this case. 169 */ 170void SCT_CTX_set_time(SCT_CTX *sctx, uint64_t time_in_ms); 171 172/* 173 * Verifies an SCT with the given context. 174 * Returns 1 if the SCT verifies successfully; any other value indicates 175 * failure. See EVP_DigestVerifyFinal() for the meaning of those values. 176 */ 177__owur int SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct); 178 179/* 180 * Does this SCT have the minimum fields populated to be usable? 181 * Returns 1 if so, 0 otherwise. 182 */ 183__owur int SCT_is_complete(const SCT *sct); 184 185/* 186 * Does this SCT have the signature-related fields populated? 187 * Returns 1 if so, 0 otherwise. 188 * This checks that the signature and hash algorithms are set to supported 189 * values and that the signature field is set. 190 */ 191__owur int SCT_signature_is_complete(const SCT *sct); 192 193/* 194* Serialize (to TLS format) an |sct| signature and write it to |out|. 195* If |out| is null, no signature will be output but the length will be returned. 196* If |out| points to a null pointer, a string will be allocated to hold the 197* TLS-format signature. It is the responsibility of the caller to free it. 198* If |out| points to an allocated string, the signature will be written to it. 199* The length of the signature in TLS format will be returned. 200*/ 201__owur int i2o_SCT_signature(const SCT *sct, unsigned char **out); 202 203/* 204* Parses an SCT signature in TLS format and populates the |sct| with it. 205* |in| should be a pointer to a string containing the TLS-format signature. 206* |in| will be advanced to the end of the signature if parsing succeeds. 207* |len| should be the length of the signature in |in|. 208* Returns the number of bytes parsed, or a negative integer if an error occurs. 209* If an error occurs, the SCT's signature NID may be updated whilst the 210* signature field itself remains unset. 211*/ 212__owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len); 213 214/* 215 * Handlers for Certificate Transparency X509v3/OCSP extensions 216 */ 217extern const X509V3_EXT_METHOD ossl_v3_ct_scts[3]; 218