crypto/ct/ct_sct.c

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