[331] | 1 | /*
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| 2 | * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <stddef.h>
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| 11 | #include <openssl/ct.h>
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| 12 | #include <openssl/evp.h>
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| 13 | #include <openssl/x509.h>
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| 14 | #include <openssl/x509v3.h>
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| 15 | #include <openssl/safestack.h>
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| 16 |
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| 17 | /*
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| 18 | * From RFC6962: opaque SerializedSCT<1..2^16-1>; struct { SerializedSCT
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| 19 | * sct_list <1..2^16-1>; } SignedCertificateTimestampList;
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| 20 | */
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| 21 | # define MAX_SCT_SIZE 65535
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| 22 | # define MAX_SCT_LIST_SIZE MAX_SCT_SIZE
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| 23 |
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| 24 | /*
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| 25 | * Macros to read and write integers in network-byte order.
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| 26 | */
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| 27 |
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| 28 | #define n2s(c,s) ((s=(((unsigned int)((c)[0]))<< 8)| \
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| 29 | (((unsigned int)((c)[1])) )),c+=2)
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| 30 |
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| 31 | #define s2n(s,c) ((c[0]=(unsigned char)(((s)>> 8)&0xff), \
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| 32 | c[1]=(unsigned char)(((s) )&0xff)),c+=2)
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| 33 |
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| 34 | #define l2n3(l,c) ((c[0]=(unsigned char)(((l)>>16)&0xff), \
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| 35 | c[1]=(unsigned char)(((l)>> 8)&0xff), \
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| 36 | c[2]=(unsigned char)(((l) )&0xff)),c+=3)
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| 37 |
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| 38 | #define n2l8(c,l) (l =((uint64_t)(*((c)++)))<<56, \
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| 39 | l|=((uint64_t)(*((c)++)))<<48, \
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| 40 | l|=((uint64_t)(*((c)++)))<<40, \
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| 41 | l|=((uint64_t)(*((c)++)))<<32, \
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| 42 | l|=((uint64_t)(*((c)++)))<<24, \
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| 43 | l|=((uint64_t)(*((c)++)))<<16, \
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| 44 | l|=((uint64_t)(*((c)++)))<< 8, \
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| 45 | l|=((uint64_t)(*((c)++))))
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| 46 |
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| 47 | #define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \
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| 48 | *((c)++)=(unsigned char)(((l)>>48)&0xff), \
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| 49 | *((c)++)=(unsigned char)(((l)>>40)&0xff), \
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| 50 | *((c)++)=(unsigned char)(((l)>>32)&0xff), \
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| 51 | *((c)++)=(unsigned char)(((l)>>24)&0xff), \
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| 52 | *((c)++)=(unsigned char)(((l)>>16)&0xff), \
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| 53 | *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
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| 54 | *((c)++)=(unsigned char)(((l) )&0xff))
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| 55 |
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| 56 | /* Signed Certificate Timestamp */
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| 57 | struct sct_st {
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| 58 | sct_version_t version;
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| 59 | /* If version is not SCT_VERSION_V1, this contains the encoded SCT */
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| 60 | unsigned char *sct;
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| 61 | size_t sct_len;
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| 62 | /* If version is SCT_VERSION_V1, fields below contain components of the SCT */
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| 63 | unsigned char *log_id;
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| 64 | size_t log_id_len;
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| 65 | /*
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| 66 | * Note, we cannot distinguish between an unset timestamp, and one
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| 67 | * that is set to 0. However since CT didn't exist in 1970, no real
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| 68 | * SCT should ever be set as such.
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| 69 | */
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| 70 | uint64_t timestamp;
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| 71 | unsigned char *ext;
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| 72 | size_t ext_len;
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| 73 | unsigned char hash_alg;
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| 74 | unsigned char sig_alg;
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| 75 | unsigned char *sig;
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| 76 | size_t sig_len;
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| 77 | /* Log entry type */
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| 78 | ct_log_entry_type_t entry_type;
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| 79 | /* Where this SCT was found, e.g. certificate, OCSP response, etc. */
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| 80 | sct_source_t source;
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| 81 | /* The result of the last attempt to validate this SCT. */
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| 82 | sct_validation_status_t validation_status;
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| 83 | };
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| 84 |
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| 85 | /* Miscellaneous data that is useful when verifying an SCT */
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| 86 | struct sct_ctx_st {
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| 87 | /* Public key */
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| 88 | EVP_PKEY *pkey;
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| 89 | /* Hash of public key */
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| 90 | unsigned char *pkeyhash;
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| 91 | size_t pkeyhashlen;
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| 92 | /* For pre-certificate: issuer public key hash */
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| 93 | unsigned char *ihash;
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| 94 | size_t ihashlen;
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| 95 | /* certificate encoding */
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| 96 | unsigned char *certder;
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| 97 | size_t certderlen;
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| 98 | /* pre-certificate encoding */
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| 99 | unsigned char *preder;
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| 100 | size_t prederlen;
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| 101 | /* milliseconds since epoch (to check that the SCT isn't from the future) */
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| 102 | uint64_t epoch_time_in_ms;
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| 103 | };
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| 104 |
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| 105 | /* Context when evaluating whether a Certificate Transparency policy is met */
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| 106 | struct ct_policy_eval_ctx_st {
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| 107 | X509 *cert;
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| 108 | X509 *issuer;
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| 109 | CTLOG_STORE *log_store;
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| 110 | /* milliseconds since epoch (to check that SCTs aren't from the future) */
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| 111 | uint64_t epoch_time_in_ms;
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| 112 | };
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| 113 |
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| 114 | /*
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| 115 | * Creates a new context for verifying an SCT.
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| 116 | */
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| 117 | SCT_CTX *SCT_CTX_new(void);
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| 118 | /*
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| 119 | * Deletes an SCT verification context.
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| 120 | */
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| 121 | void SCT_CTX_free(SCT_CTX *sctx);
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| 122 |
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| 123 | /*
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| 124 | * Sets the certificate that the SCT was created for.
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| 125 | * If *cert does not have a poison extension, presigner must be NULL.
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| 126 | * If *cert does not have a poison extension, it may have a single SCT
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| 127 | * (NID_ct_precert_scts) extension.
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| 128 | * If either *cert or *presigner have an AKID (NID_authority_key_identifier)
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| 129 | * extension, both must have one.
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| 130 | * Returns 1 on success, 0 on failure.
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| 131 | */
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| 132 | __owur int SCT_CTX_set1_cert(SCT_CTX *sctx, X509 *cert, X509 *presigner);
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| 133 |
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| 134 | /*
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| 135 | * Sets the issuer of the certificate that the SCT was created for.
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| 136 | * This is just a convenience method to save extracting the public key and
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| 137 | * calling SCT_CTX_set1_issuer_pubkey().
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| 138 | * Issuer must not be NULL.
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| 139 | * Returns 1 on success, 0 on failure.
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| 140 | */
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| 141 | __owur int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer);
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| 142 |
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| 143 | /*
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| 144 | * Sets the public key of the issuer of the certificate that the SCT was created
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| 145 | * for.
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| 146 | * The public key must not be NULL.
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| 147 | * Returns 1 on success, 0 on failure.
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| 148 | */
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| 149 | __owur int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);
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| 150 |
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| 151 | /*
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| 152 | * Sets the public key of the CT log that the SCT is from.
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| 153 | * Returns 1 on success, 0 on failure.
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| 154 | */
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| 155 | __owur int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);
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| 156 |
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| 157 | /*
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| 158 | * Sets the time to evaluate the SCT against, in milliseconds since the Unix
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| 159 | * epoch. If the SCT's timestamp is after this time, it will be interpreted as
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| 160 | * having been issued in the future. RFC6962 states that "TLS clients MUST
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| 161 | * reject SCTs whose timestamp is in the future", so an SCT will not validate
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| 162 | * in this case.
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| 163 | */
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| 164 | void SCT_CTX_set_time(SCT_CTX *sctx, uint64_t time_in_ms);
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| 165 |
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| 166 | /*
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| 167 | * Verifies an SCT with the given context.
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| 168 | * Returns 1 if the SCT verifies successfully; any other value indicates
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| 169 | * failure. See EVP_DigestVerifyFinal() for the meaning of those values.
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| 170 | */
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| 171 | __owur int SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct);
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| 172 |
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| 173 | /*
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| 174 | * Does this SCT have the minimum fields populated to be usable?
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| 175 | * Returns 1 if so, 0 otherwise.
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| 176 | */
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| 177 | __owur int SCT_is_complete(const SCT *sct);
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| 178 |
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| 179 | /*
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| 180 | * Does this SCT have the signature-related fields populated?
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| 181 | * Returns 1 if so, 0 otherwise.
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| 182 | * This checks that the signature and hash algorithms are set to supported
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| 183 | * values and that the signature field is set.
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| 184 | */
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| 185 | __owur int SCT_signature_is_complete(const SCT *sct);
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| 186 |
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| 187 | /*
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| 188 | * TODO(RJPercival): Create an SCT_signature struct and make i2o_SCT_signature
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| 189 | * and o2i_SCT_signature conform to the i2d/d2i conventions.
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| 190 | */
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| 191 |
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| 192 | /*
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| 193 | * Serialize (to TLS format) an |sct| signature and write it to |out|.
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| 194 | * If |out| is null, no signature will be output but the length will be returned.
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| 195 | * If |out| points to a null pointer, a string will be allocated to hold the
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| 196 | * TLS-format signature. It is the responsibility of the caller to free it.
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| 197 | * If |out| points to an allocated string, the signature will be written to it.
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| 198 | * The length of the signature in TLS format will be returned.
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| 199 | */
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| 200 | __owur int i2o_SCT_signature(const SCT *sct, unsigned char **out);
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| 201 |
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| 202 | /*
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| 203 | * Parses an SCT signature in TLS format and populates the |sct| with it.
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| 204 | * |in| should be a pointer to a string containing the TLS-format signature.
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| 205 | * |in| will be advanced to the end of the signature if parsing succeeds.
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| 206 | * |len| should be the length of the signature in |in|.
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| 207 | * Returns the number of bytes parsed, or a negative integer if an error occurs.
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| 208 | * If an error occurs, the SCT's signature NID may be updated whilst the
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| 209 | * signature field itself remains unset.
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| 210 | */
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| 211 | __owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len);
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| 212 |
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| 213 | /*
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| 214 | * Handlers for Certificate Transparency X509v3/OCSP extensions
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| 215 | */
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| 216 | extern const X509V3_EXT_METHOD v3_ct_scts[3];
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