crypto/ct/ct_sct.c

   1 /*
   2  * Written by Rob Stradling (rob@comodo.com), Stephen Henson (steve@openssl.org)
   3  * and Adam Eijdenberg (adam.eijdenberg@gmail.com) for the OpenSSL project 2016.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2014 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59 #ifdef OPENSSL_NO_CT
  60 # error "CT disabled"
  61 #endif
  62
  63 #include <openssl/ct.h>
  64 #include <openssl/err.h>
  65 #include <openssl/evp.h>
  66 #include <openssl/tls1.h>
  67 #include <openssl/x509.h>
  68
  69 #include "ct_locl.h"
  70
  71 SCT *SCT_new(void)
  72 {
  73     SCT *sct = OPENSSL_zalloc(sizeof(*sct));
  74
  75     if (sct == NULL) {
  76         CTerr(CT_F_SCT_NEW, ERR_R_MALLOC_FAILURE);
  77         return NULL;
  78     }
  79
  80     sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;
  81     sct->version = SCT_VERSION_NOT_SET;
  82     return sct;
  83 }
  84
  85 void SCT_free(SCT *sct)
  86 {
  87     if (sct == NULL)
  88         return;
  89
  90     OPENSSL_free(sct->log_id);
  91     OPENSSL_free(sct->ext);
  92     OPENSSL_free(sct->sig);
  93     OPENSSL_free(sct->sct);
  94     OPENSSL_free(sct);
  95 }
  96
  97 int SCT_set_version(SCT *sct, sct_version_t version)
  98 {
  99     if (version != SCT_VERSION_V1) {
 100         CTerr(CT_F_SCT_SET_VERSION, CT_R_UNSUPPORTED_VERSION);
 101         return 0;
 102     }
 103     sct->version = version;
 104     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 105     return 1;
 106 }
 107
 108 int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
 109 {
 110     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 111
 112     switch (entry_type) {
 113     case CT_LOG_ENTRY_TYPE_X509:
 114     case CT_LOG_ENTRY_TYPE_PRECERT:
 115         sct->entry_type = entry_type;
 116         return 1;
 117     default:
 118         CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
 119         return 0;
 120     }
 121 }
 122
 123 int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)
 124 {
 125     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
 126         CTerr(CT_F_SCT_SET0_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
 127         return 0;
 128     }
 129
 130     OPENSSL_free(sct->log_id);
 131     sct->log_id = log_id;
 132     sct->log_id_len = log_id_len;
 133     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 134     return 1;
 135 }
 136
 137 int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)
 138 {
 139     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
 140         CTerr(CT_F_SCT_SET1_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
 141         return 0;
 142     }
 143
 144     OPENSSL_free(sct->log_id);
 145     sct->log_id = NULL;
 146     sct->log_id_len = 0;
 147     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 148
 149     if (log_id != NULL && log_id_len > 0) {
 150         sct->log_id = OPENSSL_memdup(log_id, log_id_len);
 151         if (sct->log_id == NULL) {
 152             CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
 153             return 0;
 154         }
 155         sct->log_id_len = log_id_len;
 156     }
 157     return 1;
 158 }
 159
 160
 161 void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
 162 {
 163     sct->timestamp = timestamp;
 164     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 165 }
 166
 167 int SCT_set_signature_nid(SCT *sct, int nid)
 168 {
 169   switch (nid) {
 170     case NID_sha256WithRSAEncryption:
 171         sct->hash_alg = TLSEXT_hash_sha256;
 172         sct->sig_alg = TLSEXT_signature_rsa;
 173         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 174         return 1;
 175     case NID_ecdsa_with_SHA256:
 176         sct->hash_alg = TLSEXT_hash_sha256;
 177         sct->sig_alg = TLSEXT_signature_ecdsa;
 178         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 179         return 1;
 180     default:
 181         CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
 182         return 0;
 183     }
 184 }
 185
 186 void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)
 187 {
 188     OPENSSL_free(sct->ext);
 189     sct->ext = ext;
 190     sct->ext_len = ext_len;
 191     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 192 }
 193
 194 int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)
 195 {
 196     OPENSSL_free(sct->ext);
 197     sct->ext = NULL;
 198     sct->ext_len = 0;
 199     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 200
 201     if (ext != NULL && ext_len > 0) {
 202         sct->ext = OPENSSL_memdup(ext, ext_len);
 203         if (sct->ext == NULL) {
 204             CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
 205             return 0;
 206         }
 207         sct->ext_len = ext_len;
 208     }
 209     return 1;
 210 }
 211
 212 void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len)
 213 {
 214     OPENSSL_free(sct->sig);
 215     sct->sig = sig;
 216     sct->sig_len = sig_len;
 217     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 218 }
 219
 220 int SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len)
 221 {
 222     OPENSSL_free(sct->sig);
 223     sct->sig = NULL;
 224     sct->sig_len = 0;
 225     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 226
 227     if (sig != NULL && sig_len > 0) {
 228         sct->sig = OPENSSL_memdup(sig, sig_len);
 229         if (sct->sig == NULL) {
 230             CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
 231             return 0;
 232         }
 233         sct->sig_len = sig_len;
 234     }
 235     return 1;
 236 }
 237
 238 sct_version_t SCT_get_version(const SCT *sct)
 239 {
 240     return sct->version;
 241 }
 242
 243 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
 244 {
 245     return sct->entry_type;
 246 }
 247
 248 size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)
 249 {
 250     *log_id = sct->log_id;
 251     return sct->log_id_len;
 252 }
 253
 254 uint64_t SCT_get_timestamp(const SCT *sct)
 255 {
 256     return sct->timestamp;
 257 }
 258
 259 int SCT_get_signature_nid(const SCT *sct)
 260 {
 261     if (sct->version == SCT_VERSION_V1) {
 262         if (sct->hash_alg == TLSEXT_hash_sha256) {
 263             switch (sct->sig_alg) {
 264             case TLSEXT_signature_ecdsa:
 265                 return NID_ecdsa_with_SHA256;
 266             case TLSEXT_signature_rsa:
 267                 return NID_sha256WithRSAEncryption;
 268             default:
 269                 return NID_undef;
 270             }
 271         }
 272     }
 273     return NID_undef;
 274 }
 275
 276 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
 277 {
 278     *ext = sct->ext;
 279     return sct->ext_len;
 280 }
 281
 282 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
 283 {
 284     *sig = sct->sig;
 285     return sct->sig_len;
 286 }
 287
 288 int SCT_is_complete(const SCT *sct)
 289 {
 290     switch (sct->version) {
 291     case SCT_VERSION_NOT_SET:
 292         return 0;
 293     case SCT_VERSION_V1:
 294         return sct->log_id != NULL && SCT_signature_is_complete(sct);
 295     default:
 296         return sct->sct != NULL; /* Just need cached encoding */
 297     }
 298 }
 299
 300 int SCT_signature_is_complete(const SCT *sct)
 301 {
 302     return SCT_get_signature_nid(sct) != NID_undef &&
 303         sct->sig != NULL && sct->sig_len > 0;
 304 }
 305
 306 sct_source_t SCT_get_source(const SCT *sct)
 307 {
 308     return sct->source;
 309 }
 310
 311 int SCT_set_source(SCT *sct, sct_source_t source)
 312 {
 313     sct->source = source;
 314     switch (source) {
 315     case SCT_SOURCE_TLS_EXTENSION:
 316     case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
 317         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
 318     case SCT_SOURCE_X509V3_EXTENSION:
 319         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
 320     default: /* if we aren't sure, leave the log entry type alone */
 321         return 1;
 322     }
 323 }
 324
 325 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
 326 {
 327     return sct->validation_status;
 328 }
 329
 330 int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)
 331 {
 332     int is_sct_valid = -1;
 333     SCT_CTX *sctx = NULL;
 334     X509_PUBKEY *pub = NULL, *log_pkey = NULL;
 335     const CTLOG *log;
 336
 337     /*
 338      * With an unrecognized SCT version we don't know what such an SCT means,
 339      * let alone validate one.  So we return validation failure (0).
 340      */
 341     if (sct->version != SCT_VERSION_V1) {
 342         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
 343         return 0;
 344     }
 345
 346     log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
 347                                      sct->log_id, sct->log_id_len);
 348
 349     /* Similarly, an SCT from an unknown log also cannot be validated. */
 350     if (log == NULL) {
 351         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
 352         return 0;
 353     }
 354
 355     sctx = SCT_CTX_new();
 356     if (sctx == NULL)
 357         goto err;
 358
 359     if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
 360         goto err;
 361     if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
 362         goto err;
 363
 364     if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
 365         EVP_PKEY *issuer_pkey;
 366
 367         if (ctx->issuer == NULL) {
 368             sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 369             goto end;
 370         }
 371
 372         issuer_pkey = X509_get0_pubkey(ctx->issuer);
 373
 374         if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
 375             goto err;
 376         if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
 377             goto err;
 378     }
 379
 380     /*
 381      * XXX: Potential for optimization.  This repeats some idempotent heavy
 382      * lifting on the certificate for each candidate SCT, and appears to not
 383      * use any information in the SCT itself, only the certificate is
 384      * processed.  So it may make more sense to to do this just once, perhaps
 385      * associated with the shared (by all SCTs) policy eval ctx.
 386      *
 387      * XXX: Failure here is global (SCT independent) and represents either an
 388      * issue with the certificate (e.g. duplicate extensions) or an out of
 389      * memory condition.  When the certificate is incompatible with CT, we just
 390      * mark the SCTs invalid, rather than report a failure to determine the
 391      * validation status.  That way, callbacks that want to do "soft" SCT
 392      * processing will not abort handshakes with false positive internal
 393      * errors.  Since the function does not distinguish between certificate
 394      * issues (peer's fault) and internal problems (out fault) the safe thing
 395      * to do is to report a validation failure and let the callback or
 396      * application decide what to do.
 397      */
 398     if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
 399         sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 400     else
 401         sct->validation_status = SCT_verify(sctx, sct) == 1 ?
 402             SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;
 403
 404 end:
 405     is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
 406 err:
 407     X509_PUBKEY_free(pub);
 408     X509_PUBKEY_free(log_pkey);
 409     SCT_CTX_free(sctx);
 410
 411     return is_sct_valid;
 412 }
 413
 414 int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)
 415 {
 416     int are_scts_valid = 1;
 417     int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
 418     int i;
 419
 420     for (i = 0; i < sct_count; ++i) {
 421         int is_sct_valid = -1;
 422         SCT *sct = sk_SCT_value(scts, i);
 423
 424         if (sct == NULL)
 425             continue;
 426
 427         is_sct_valid = SCT_validate(sct, ctx);
 428         if (is_sct_valid < 0)
 429             return is_sct_valid;
 430         are_scts_valid &= is_sct_valid;
 431     }
 432
 433     return are_scts_valid;
 434 }