1 /* 2 * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (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 */ 57 struct 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 */ 86 struct 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 }; 104 105 /* Context when evaluating whether a Certificate Transparency policy is met */ 106 struct ct_policy_eval_ctx_st { 107 X509 *cert; 108 X509 *issuer; 109 CTLOG_STORE *log_store; 110 /* milliseconds since epoch (to check that SCTs aren't from the future) */ 111 uint64_t epoch_time_in_ms; 112 }; 113 114 /* 115 * Creates a new context for verifying an SCT. 116 */ 117 SCT_CTX *SCT_CTX_new(void); 118 /* 119 * Deletes an SCT verification context. 120 */ 121 void SCT_CTX_free(SCT_CTX *sctx); 122 123 /* 124 * Sets the certificate that the SCT was created for. 125 * If *cert does not have a poison extension, presigner must be NULL. 126 * If *cert does not have a poison extension, it may have a single SCT 127 * (NID_ct_precert_scts) extension. 128 * If either *cert or *presigner have an AKID (NID_authority_key_identifier) 129 * extension, both must have one. 130 * Returns 1 on success, 0 on failure. 131 */ 132 __owur int SCT_CTX_set1_cert(SCT_CTX *sctx, X509 *cert, X509 *presigner); 133 134 /* 135 * Sets the issuer of the certificate that the SCT was created for. 136 * This is just a convenience method to save extracting the public key and 137 * calling SCT_CTX_set1_issuer_pubkey(). 138 * Issuer must not be NULL. 139 * Returns 1 on success, 0 on failure. 140 */ 141 __owur int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer); 142 143 /* 144 * Sets the public key of the issuer of the certificate that the SCT was created 145 * for. 146 * The public key must not be NULL. 147 * Returns 1 on success, 0 on failure. 148 */ 149 __owur int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey); 150 151 /* 152 * Sets the public key of the CT log that the SCT is from. 153 * Returns 1 on success, 0 on failure. 154 */ 155 __owur int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey); 156 157 /* 158 * Sets the time to evaluate the SCT against, in milliseconds since the Unix 159 * epoch. If the SCT's timestamp is after this time, it will be interpreted as 160 * having been issued in the future. RFC6962 states that "TLS clients MUST 161 * reject SCTs whose timestamp is in the future", so an SCT will not validate 162 * in this case. 163 */ 164 void SCT_CTX_set_time(SCT_CTX *sctx, uint64_t time_in_ms); 165 166 /* 167 * Verifies an SCT with the given context. 168 * Returns 1 if the SCT verifies successfully; any other value indicates 169 * failure. See EVP_DigestVerifyFinal() for the meaning of those values. 170 */ 171 __owur int SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct); 172 173 /* 174 * Does this SCT have the minimum fields populated to be usable? 175 * Returns 1 if so, 0 otherwise. 176 */ 177 __owur int SCT_is_complete(const SCT *sct); 178 179 /* 180 * Does this SCT have the signature-related fields populated? 181 * Returns 1 if so, 0 otherwise. 182 * This checks that the signature and hash algorithms are set to supported 183 * values and that the signature field is set. 184 */ 185 __owur int SCT_signature_is_complete(const SCT *sct); 186 187 /* 188 * TODO(RJPercival): Create an SCT_signature struct and make i2o_SCT_signature 189 * and o2i_SCT_signature conform to the i2d/d2i conventions. 190 */ 191 192 /* 193 * Serialize (to TLS format) an |sct| signature and write it to |out|. 194 * If |out| is null, no signature will be output but the length will be returned. 195 * If |out| points to a null pointer, a string will be allocated to hold the 196 * TLS-format signature. It is the responsibility of the caller to free it. 197 * If |out| points to an allocated string, the signature will be written to it. 198 * The length of the signature in TLS format will be returned. 199 */ 200 __owur int i2o_SCT_signature(const SCT *sct, unsigned char **out); 201 202 /* 203 * Parses an SCT signature in TLS format and populates the |sct| with it. 204 * |in| should be a pointer to a string containing the TLS-format signature. 205 * |in| will be advanced to the end of the signature if parsing succeeds. 206 * |len| should be the length of the signature in |in|. 207 * Returns the number of bytes parsed, or a negative integer if an error occurs. 208 * If an error occurs, the SCT's signature NID may be updated whilst the 209 * signature field itself remains unset. 210 */ 211 __owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len); 212 213 /* 214 * Handlers for Certificate Transparency X509v3/OCSP extensions 215 */ 216 extern const X509V3_EXT_METHOD v3_ct_scts[3]; 217