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 */
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
105/* Context when evaluating whether a Certificate Transparency policy is met */
106struct 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 */
117SCT_CTX *SCT_CTX_new(void);
118/*
119 * Deletes an SCT verification context.
120 */
121void 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 */
164void 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 */
216extern const X509V3_EXT_METHOD v3_ct_scts[3];
217