crypto/ct/ct_locl.h

   1 /*
   2  * Copyright 2015-2016 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 */
  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];