1/*
2 * Copyright 2016-2021 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#ifdef OPENSSL_NO_CT
11# error "CT disabled"
12#endif
13
14#include <openssl/ct.h>
15#include <openssl/err.h>
16#include <openssl/evp.h>
17#include <openssl/tls1.h>
18#include <openssl/x509.h>
19
20#include "ct_local.h"
21
22SCT *SCT_new(void)
23{
24    SCT *sct = OPENSSL_zalloc(sizeof(*sct));
25
26    if (sct == NULL) {
27        ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);
28        return NULL;
29    }
30
31    sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;
32    sct->version = SCT_VERSION_NOT_SET;
33    return sct;
34}
35
36void SCT_free(SCT *sct)
37{
38    if (sct == NULL)
39        return;
40
41    OPENSSL_free(sct->log_id);
42    OPENSSL_free(sct->ext);
43    OPENSSL_free(sct->sig);
44    OPENSSL_free(sct->sct);
45    OPENSSL_free(sct);
46}
47
48void SCT_LIST_free(STACK_OF(SCT) *a)
49{
50    sk_SCT_pop_free(a, SCT_free);
51}
52
53int SCT_set_version(SCT *sct, sct_version_t version)
54{
55    if (version != SCT_VERSION_V1) {
56        ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_VERSION);
57        return 0;
58    }
59    sct->version = version;
60    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
61    return 1;
62}
63
64int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
65{
66    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
67
68    switch (entry_type) {
69    case CT_LOG_ENTRY_TYPE_X509:
70    case CT_LOG_ENTRY_TYPE_PRECERT:
71        sct->entry_type = entry_type;
72        return 1;
73    case CT_LOG_ENTRY_TYPE_NOT_SET:
74        break;
75    }
76    ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_ENTRY_TYPE);
77    return 0;
78}
79
80int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)
81{
82    if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
83        ERR_raise(ERR_LIB_CT, CT_R_INVALID_LOG_ID_LENGTH);
84        return 0;
85    }
86
87    OPENSSL_free(sct->log_id);
88    sct->log_id = log_id;
89    sct->log_id_len = log_id_len;
90    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
91    return 1;
92}
93
94int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)
95{
96    if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
97        ERR_raise(ERR_LIB_CT, CT_R_INVALID_LOG_ID_LENGTH);
98        return 0;
99    }
100
101    OPENSSL_free(sct->log_id);
102    sct->log_id = NULL;
103    sct->log_id_len = 0;
104    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
105
106    if (log_id != NULL && log_id_len > 0) {
107        sct->log_id = OPENSSL_memdup(log_id, log_id_len);
108        if (sct->log_id == NULL) {
109            ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);
110            return 0;
111        }
112        sct->log_id_len = log_id_len;
113    }
114    return 1;
115}
116
117
118void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
119{
120    sct->timestamp = timestamp;
121    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
122}
123
124int SCT_set_signature_nid(SCT *sct, int nid)
125{
126    switch (nid) {
127    case NID_sha256WithRSAEncryption:
128        sct->hash_alg = TLSEXT_hash_sha256;
129        sct->sig_alg = TLSEXT_signature_rsa;
130        sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
131        return 1;
132    case NID_ecdsa_with_SHA256:
133        sct->hash_alg = TLSEXT_hash_sha256;
134        sct->sig_alg = TLSEXT_signature_ecdsa;
135        sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
136        return 1;
137    default:
138        ERR_raise(ERR_LIB_CT, CT_R_UNRECOGNIZED_SIGNATURE_NID);
139        return 0;
140    }
141}
142
143void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)
144{
145    OPENSSL_free(sct->ext);
146    sct->ext = ext;
147    sct->ext_len = ext_len;
148    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
149}
150
151int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)
152{
153    OPENSSL_free(sct->ext);
154    sct->ext = NULL;
155    sct->ext_len = 0;
156    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
157
158    if (ext != NULL && ext_len > 0) {
159        sct->ext = OPENSSL_memdup(ext, ext_len);
160        if (sct->ext == NULL) {
161            ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);
162            return 0;
163        }
164        sct->ext_len = ext_len;
165    }
166    return 1;
167}
168
169void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len)
170{
171    OPENSSL_free(sct->sig);
172    sct->sig = sig;
173    sct->sig_len = sig_len;
174    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
175}
176
177int SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len)
178{
179    OPENSSL_free(sct->sig);
180    sct->sig = NULL;
181    sct->sig_len = 0;
182    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
183
184    if (sig != NULL && sig_len > 0) {
185        sct->sig = OPENSSL_memdup(sig, sig_len);
186        if (sct->sig == NULL) {
187            ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);
188            return 0;
189        }
190        sct->sig_len = sig_len;
191    }
192    return 1;
193}
194
195sct_version_t SCT_get_version(const SCT *sct)
196{
197    return sct->version;
198}
199
200ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
201{
202    return sct->entry_type;
203}
204
205size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)
206{
207    *log_id = sct->log_id;
208    return sct->log_id_len;
209}
210
211uint64_t SCT_get_timestamp(const SCT *sct)
212{
213    return sct->timestamp;
214}
215
216int SCT_get_signature_nid(const SCT *sct)
217{
218    if (sct->version == SCT_VERSION_V1) {
219        if (sct->hash_alg == TLSEXT_hash_sha256) {
220            switch (sct->sig_alg) {
221            case TLSEXT_signature_ecdsa:
222                return NID_ecdsa_with_SHA256;
223            case TLSEXT_signature_rsa:
224                return NID_sha256WithRSAEncryption;
225            default:
226                return NID_undef;
227            }
228        }
229    }
230    return NID_undef;
231}
232
233size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
234{
235    *ext = sct->ext;
236    return sct->ext_len;
237}
238
239size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
240{
241    *sig = sct->sig;
242    return sct->sig_len;
243}
244
245int SCT_is_complete(const SCT *sct)
246{
247    switch (sct->version) {
248    case SCT_VERSION_NOT_SET:
249        return 0;
250    case SCT_VERSION_V1:
251        return sct->log_id != NULL && SCT_signature_is_complete(sct);
252    default:
253        return sct->sct != NULL; /* Just need cached encoding */
254    }
255}
256
257int SCT_signature_is_complete(const SCT *sct)
258{
259    return SCT_get_signature_nid(sct) != NID_undef &&
260        sct->sig != NULL && sct->sig_len > 0;
261}
262
263sct_source_t SCT_get_source(const SCT *sct)
264{
265    return sct->source;
266}
267
268int SCT_set_source(SCT *sct, sct_source_t source)
269{
270    sct->source = source;
271    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
272    switch (source) {
273    case SCT_SOURCE_TLS_EXTENSION:
274    case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
275        return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
276    case SCT_SOURCE_X509V3_EXTENSION:
277        return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
278    case SCT_SOURCE_UNKNOWN:
279        break;
280    }
281    /* if we aren't sure, leave the log entry type alone */
282    return 1;
283}
284
285sct_validation_status_t SCT_get_validation_status(const SCT *sct)
286{
287    return sct->validation_status;
288}
289
290int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)
291{
292    int is_sct_valid = -1;
293    SCT_CTX *sctx = NULL;
294    X509_PUBKEY *pub = NULL, *log_pkey = NULL;
295    const CTLOG *log;
296
297    /*
298     * With an unrecognized SCT version we don't know what such an SCT means,
299     * let alone validate one.  So we return validation failure (0).
300     */
301    if (sct->version != SCT_VERSION_V1) {
302        sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
303        return 0;
304    }
305
306    log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
307                                     sct->log_id, sct->log_id_len);
308
309    /* Similarly, an SCT from an unknown log also cannot be validated. */
310    if (log == NULL) {
311        sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
312        return 0;
313    }
314
315    sctx = SCT_CTX_new(ctx->libctx, ctx->propq);
316    if (sctx == NULL)
317        goto err;
318
319    if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
320        goto err;
321    if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
322        goto err;
323
324    if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
325        EVP_PKEY *issuer_pkey;
326
327        if (ctx->issuer == NULL) {
328            sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
329            goto end;
330        }
331
332        issuer_pkey = X509_get0_pubkey(ctx->issuer);
333
334        if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
335            goto err;
336        if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
337            goto err;
338    }
339
340    SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms);
341
342    /*
343     * XXX: Potential for optimization.  This repeats some idempotent heavy
344     * lifting on the certificate for each candidate SCT, and appears to not
345     * use any information in the SCT itself, only the certificate is
346     * processed.  So it may make more sense to do this just once, perhaps
347     * associated with the shared (by all SCTs) policy eval ctx.
348     *
349     * XXX: Failure here is global (SCT independent) and represents either an
350     * issue with the certificate (e.g. duplicate extensions) or an out of
351     * memory condition.  When the certificate is incompatible with CT, we just
352     * mark the SCTs invalid, rather than report a failure to determine the
353     * validation status.  That way, callbacks that want to do "soft" SCT
354     * processing will not abort handshakes with false positive internal
355     * errors.  Since the function does not distinguish between certificate
356     * issues (peer's fault) and internal problems (out fault) the safe thing
357     * to do is to report a validation failure and let the callback or
358     * application decide what to do.
359     */
360    if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
361        sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
362    else
363        sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ?
364            SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;
365
366end:
367    is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
368err:
369    X509_PUBKEY_free(pub);
370    X509_PUBKEY_free(log_pkey);
371    SCT_CTX_free(sctx);
372
373    return is_sct_valid;
374}
375
376int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)
377{
378    int are_scts_valid = 1;
379    int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
380    int i;
381
382    for (i = 0; i < sct_count; ++i) {
383        int is_sct_valid = -1;
384        SCT *sct = sk_SCT_value(scts, i);
385
386        if (sct == NULL)
387            continue;
388
389        is_sct_valid = SCT_validate(sct, ctx);
390        if (is_sct_valid < 0)
391            return is_sct_valid;
392        are_scts_valid &= is_sct_valid;
393    }
394
395    return are_scts_valid;
396}
397