aboutsummaryrefslogtreecommitdiff
path: root/crypto/ct/ct_locl.h
blob: 9f983c91beae422eac6994d1608e536c5b894f9e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
/*
 * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stddef.h>
#include <openssl/ct.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/safestack.h>

/*
 * From RFC6962: opaque SerializedSCT<1..2^16-1>; struct { SerializedSCT
 * sct_list <1..2^16-1>; } SignedCertificateTimestampList;
 */
# define MAX_SCT_SIZE            65535
# define MAX_SCT_LIST_SIZE       MAX_SCT_SIZE

/*
 * Macros to read and write integers in network-byte order.
 */

#define n2s(c,s)        ((s=(((unsigned int)((c)[0]))<< 8)| \
                            (((unsigned int)((c)[1]))    )),c+=2)

#define s2n(s,c)        ((c[0]=(unsigned char)(((s)>> 8)&0xff), \
                          c[1]=(unsigned char)(((s)    )&0xff)),c+=2)

#define l2n3(l,c)       ((c[0]=(unsigned char)(((l)>>16)&0xff), \
                          c[1]=(unsigned char)(((l)>> 8)&0xff), \
                          c[2]=(unsigned char)(((l)    )&0xff)),c+=3)

#define n2l8(c,l)       (l =((uint64_t)(*((c)++)))<<56, \
                         l|=((uint64_t)(*((c)++)))<<48, \
                         l|=((uint64_t)(*((c)++)))<<40, \
                         l|=((uint64_t)(*((c)++)))<<32, \
                         l|=((uint64_t)(*((c)++)))<<24, \
                         l|=((uint64_t)(*((c)++)))<<16, \
                         l|=((uint64_t)(*((c)++)))<< 8, \
                         l|=((uint64_t)(*((c)++))))

#define l2n8(l,c)       (*((c)++)=(unsigned char)(((l)>>56)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>48)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>40)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>32)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>24)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>16)&0xff), \
                         *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
                         *((c)++)=(unsigned char)(((l)    )&0xff))

/* Signed Certificate Timestamp */
struct sct_st {
    sct_version_t version;
    /* If version is not SCT_VERSION_V1, this contains the encoded SCT */
    unsigned char *sct;
    size_t sct_len;
    /* If version is SCT_VERSION_V1, fields below contain components of the SCT */
    unsigned char *log_id;
    size_t log_id_len;
    /*
    * Note, we cannot distinguish between an unset timestamp, and one
    * that is set to 0.  However since CT didn't exist in 1970, no real
    * SCT should ever be set as such.
    */
    uint64_t timestamp;
    unsigned char *ext;
    size_t ext_len;
    unsigned char hash_alg;
    unsigned char sig_alg;
    unsigned char *sig;
    size_t sig_len;
    /* Log entry type */
    ct_log_entry_type_t entry_type;
    /* Where this SCT was found, e.g. certificate, OCSP response, etc. */
    sct_source_t source;
    /* The result of the last attempt to validate this SCT. */
    sct_validation_status_t validation_status;
};

/* Miscellaneous data that is useful when verifying an SCT  */
struct sct_ctx_st {
    /* Public key */
    EVP_PKEY *pkey;
    /* Hash of public key */
    unsigned char *pkeyhash;
    size_t pkeyhashlen;
    /* For pre-certificate: issuer public key hash */
    unsigned char *ihash;
    size_t ihashlen;
    /* certificate encoding */
    unsigned char *certder;
    size_t certderlen;
    /* pre-certificate encoding */
    unsigned char *preder;
    size_t prederlen;
    /* milliseconds since epoch (to check that the SCT isn't from the future) */
    uint64_t epoch_time_in_ms;
};

/* Context when evaluating whether a Certificate Transparency policy is met */
struct ct_policy_eval_ctx_st {
    X509 *cert;
    X509 *issuer;
    CTLOG_STORE *log_store;
    /* milliseconds since epoch (to check that SCTs aren't from the future) */
    uint64_t epoch_time_in_ms;
};

/*
 * Creates a new context for verifying an SCT.
 */
SCT_CTX *SCT_CTX_new(void);
/*
 * Deletes an SCT verification context.
 */
void SCT_CTX_free(SCT_CTX *sctx);

/*
 * Sets the certificate that the SCT was created for.
 * If *cert does not have a poison extension, presigner must be NULL.
 * If *cert does not have a poison extension, it may have a single SCT
 * (NID_ct_precert_scts) extension.
 * If either *cert or *presigner have an AKID (NID_authority_key_identifier)
 * extension, both must have one.
 * Returns 1 on success, 0 on failure.
 */
__owur int SCT_CTX_set1_cert(SCT_CTX *sctx, X509 *cert, X509 *presigner);

/*
 * Sets the issuer of the certificate that the SCT was created for.
 * This is just a convenience method to save extracting the public key and
 * calling SCT_CTX_set1_issuer_pubkey().
 * Issuer must not be NULL.
 * Returns 1 on success, 0 on failure.
 */
__owur int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer);

/*
 * Sets the public key of the issuer of the certificate that the SCT was created
 * for.
 * The public key must not be NULL.
 * Returns 1 on success, 0 on failure.
 */
__owur int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);

/*
 * Sets the public key of the CT log that the SCT is from.
 * Returns 1 on success, 0 on failure.
 */
__owur int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey);

/*
 * Sets the time to evaluate the SCT against, in milliseconds since the Unix
 * epoch. If the SCT's timestamp is after this time, it will be interpreted as
 * having been issued in the future. RFC6962 states that "TLS clients MUST
 * reject SCTs whose timestamp is in the future", so an SCT will not validate
 * in this case.
 */
void SCT_CTX_set_time(SCT_CTX *sctx, uint64_t time_in_ms);

/*
 * Verifies an SCT with the given context.
 * Returns 1 if the SCT verifies successfully; any other value indicates
 * failure. See EVP_DigestVerifyFinal() for the meaning of those values.
 */
__owur int SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct);

/*
 * Does this SCT have the minimum fields populated to be usable?
 * Returns 1 if so, 0 otherwise.
 */
__owur int SCT_is_complete(const SCT *sct);

/*
 * Does this SCT have the signature-related fields populated?
 * Returns 1 if so, 0 otherwise.
 * This checks that the signature and hash algorithms are set to supported
 * values and that the signature field is set.
 */
__owur int SCT_signature_is_complete(const SCT *sct);

/*
 * TODO(RJPercival): Create an SCT_signature struct and make i2o_SCT_signature
 * and o2i_SCT_signature conform to the i2d/d2i conventions.
 */

/*
* Serialize (to TLS format) an |sct| signature and write it to |out|.
* If |out| is null, no signature will be output but the length will be returned.
* If |out| points to a null pointer, a string will be allocated to hold the
* TLS-format signature. It is the responsibility of the caller to free it.
* If |out| points to an allocated string, the signature will be written to it.
* The length of the signature in TLS format will be returned.
*/
__owur int i2o_SCT_signature(const SCT *sct, unsigned char **out);

/*
* Parses an SCT signature in TLS format and populates the |sct| with it.
* |in| should be a pointer to a string containing the TLS-format signature.
* |in| will be advanced to the end of the signature if parsing succeeds.
* |len| should be the length of the signature in |in|.
* Returns the number of bytes parsed, or a negative integer if an error occurs.
* If an error occurs, the SCT's signature NID may be updated whilst the
* signature field itself remains unset.
*/
__owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len);

/*
 * Handlers for Certificate Transparency X509v3/OCSP extensions
 */
extern const X509V3_EXT_METHOD v3_ct_scts[3];