crypto/ct/ct_sct.c

   1 /*
   2  * Copyright 2016-2020 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
  22 SCT *SCT_new(void)
  23 {
  24     SCT *sct = OPENSSL_zalloc(sizeof(*sct));
  25
  26     if (sct == NULL) {
  27         CTerr(CT_F_SCT_NEW, 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
  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
  48 void SCT_LIST_free(STACK_OF(SCT) *a)
  49 {
  50     sk_SCT_pop_free(a, SCT_free);
  51 }
  52
  53 int SCT_set_version(SCT *sct, sct_version_t version)
  54 {
  55     if (version != SCT_VERSION_V1) {
  56         CTerr(CT_F_SCT_SET_VERSION, 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
  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     CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
  77     return 0;
  78 }
  79
  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         CTerr(CT_F_SCT_SET0_LOG_ID, 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
  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         CTerr(CT_F_SCT_SET1_LOG_ID, 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             CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
 110             return 0;
 111         }
 112         sct->log_id_len = log_id_len;
 113     }
 114     return 1;
 115 }
 116
 117
 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
 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         CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
 139         return 0;
 140     }
 141 }
 142
 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
 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             CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
 162             return 0;
 163         }
 164         sct->ext_len = ext_len;
 165     }
 166     return 1;
 167 }
 168
 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
 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             CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
 188             return 0;
 189         }
 190         sct->sig_len = sig_len;
 191     }
 192     return 1;
 193 }
 194
 195 sct_version_t SCT_get_version(const SCT *sct)
 196 {
 197     return sct->version;
 198 }
 199
 200 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
 201 {
 202     return sct->entry_type;
 203 }
 204
 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
 211 uint64_t SCT_get_timestamp(const SCT *sct)
 212 {
 213     return sct->timestamp;
 214 }
 215
 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
 233 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
 234 {
 235     *ext = sct->ext;
 236     return sct->ext_len;
 237 }
 238
 239 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
 240 {
 241     *sig = sct->sig;
 242     return sct->sig_len;
 243 }
 244
 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
 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
 263 sct_source_t SCT_get_source(const SCT *sct)
 264 {
 265     return sct->source;
 266 }
 267
 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
 285 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
 286 {
 287     return sct->validation_status;
 288 }
 289
 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 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
 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 }