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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 
SCT_new(void)22 SCT *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 
SCT_free(SCT * sct)36 void 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 
SCT_LIST_free(STACK_OF (SCT)* a)48 void SCT_LIST_free(STACK_OF(SCT) *a)
49 {
50     sk_SCT_pop_free(a, SCT_free);
51 }
52 
SCT_set_version(SCT * sct,sct_version_t version)53 int 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 
SCT_set_log_entry_type(SCT * sct,ct_log_entry_type_t entry_type)64 int 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 
SCT_set0_log_id(SCT * sct,unsigned char * log_id,size_t log_id_len)80 int 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 
SCT_set1_log_id(SCT * sct,const unsigned char * log_id,size_t log_id_len)94 int 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 
SCT_set_timestamp(SCT * sct,uint64_t timestamp)118 void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
119 {
120     sct->timestamp = timestamp;
121     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
122 }
123 
SCT_set_signature_nid(SCT * sct,int nid)124 int 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 
SCT_set0_extensions(SCT * sct,unsigned char * ext,size_t ext_len)143 void 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 
SCT_set1_extensions(SCT * sct,const unsigned char * ext,size_t ext_len)151 int 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 
SCT_set0_signature(SCT * sct,unsigned char * sig,size_t sig_len)169 void 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 
SCT_set1_signature(SCT * sct,const unsigned char * sig,size_t sig_len)177 int 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 
SCT_get_version(const SCT * sct)195 sct_version_t SCT_get_version(const SCT *sct)
196 {
197     return sct->version;
198 }
199 
SCT_get_log_entry_type(const SCT * sct)200 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
201 {
202     return sct->entry_type;
203 }
204 
SCT_get0_log_id(const SCT * sct,unsigned char ** log_id)205 size_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 
SCT_get_timestamp(const SCT * sct)211 uint64_t SCT_get_timestamp(const SCT *sct)
212 {
213     return sct->timestamp;
214 }
215 
SCT_get_signature_nid(const SCT * sct)216 int 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 
SCT_get0_extensions(const SCT * sct,unsigned char ** ext)233 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
234 {
235     *ext = sct->ext;
236     return sct->ext_len;
237 }
238 
SCT_get0_signature(const SCT * sct,unsigned char ** sig)239 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
240 {
241     *sig = sct->sig;
242     return sct->sig_len;
243 }
244 
SCT_is_complete(const SCT * sct)245 int 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 
SCT_signature_is_complete(const SCT * sct)257 int 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 
SCT_get_source(const SCT * sct)263 sct_source_t SCT_get_source(const SCT *sct)
264 {
265     return sct->source;
266 }
267 
SCT_set_source(SCT * sct,sct_source_t source)268 int 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 
SCT_get_validation_status(const SCT * sct)285 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
286 {
287     return sct->validation_status;
288 }
289 
SCT_validate(SCT * sct,const CT_POLICY_EVAL_CTX * ctx)290 int 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 
366 end:
367     is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
368 err:
369     X509_PUBKEY_free(pub);
370     X509_PUBKEY_free(log_pkey);
371     SCT_CTX_free(sctx);
372 
373     return is_sct_valid;
374 }
375 
SCT_LIST_validate(const STACK_OF (SCT)* scts,CT_POLICY_EVAL_CTX * ctx)376 int 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