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 DEFINE_STACK_OF(SCT)
  23
  24 SCT *SCT_new(void)
  25 {
  26     SCT *sct = OPENSSL_zalloc(sizeof(*sct));
  27
  28     if (sct == NULL) {
  29         CTerr(CT_F_SCT_NEW, ERR_R_MALLOC_FAILURE);
  30         return NULL;
  31     }
  32
  33     sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;
  34     sct->version = SCT_VERSION_NOT_SET;
  35     return sct;
  36 }
  37
  38 void SCT_free(SCT *sct)
  39 {
  40     if (sct == NULL)
  41         return;
  42
  43     OPENSSL_free(sct->log_id);
  44     OPENSSL_free(sct->ext);
  45     OPENSSL_free(sct->sig);
  46     OPENSSL_free(sct->sct);
  47     OPENSSL_free(sct);
  48 }
  49
  50 void SCT_LIST_free(STACK_OF(SCT) *a)
  51 {
  52     sk_SCT_pop_free(a, SCT_free);
  53 }
  54
  55 int SCT_set_version(SCT *sct, sct_version_t version)
  56 {
  57     if (version != SCT_VERSION_V1) {
  58         CTerr(CT_F_SCT_SET_VERSION, CT_R_UNSUPPORTED_VERSION);
  59         return 0;
  60     }
  61     sct->version = version;
  62     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  63     return 1;
  64 }
  65
  66 int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
  67 {
  68     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  69
  70     switch (entry_type) {
  71     case CT_LOG_ENTRY_TYPE_X509:
  72     case CT_LOG_ENTRY_TYPE_PRECERT:
  73         sct->entry_type = entry_type;
  74         return 1;
  75     case CT_LOG_ENTRY_TYPE_NOT_SET:
  76         break;
  77     }
  78     CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
  79     return 0;
  80 }
  81
  82 int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)
  83 {
  84     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
  85         CTerr(CT_F_SCT_SET0_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
  86         return 0;
  87     }
  88
  89     OPENSSL_free(sct->log_id);
  90     sct->log_id = log_id;
  91     sct->log_id_len = log_id_len;
  92     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  93     return 1;
  94 }
  95
  96 int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)
  97 {
  98     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
  99         CTerr(CT_F_SCT_SET1_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
 100         return 0;
 101     }
 102
 103     OPENSSL_free(sct->log_id);
 104     sct->log_id = NULL;
 105     sct->log_id_len = 0;
 106     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 107
 108     if (log_id != NULL && log_id_len > 0) {
 109         sct->log_id = OPENSSL_memdup(log_id, log_id_len);
 110         if (sct->log_id == NULL) {
 111             CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
 112             return 0;
 113         }
 114         sct->log_id_len = log_id_len;
 115     }
 116     return 1;
 117 }
 118
 119
 120 void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
 121 {
 122     sct->timestamp = timestamp;
 123     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 124 }
 125
 126 int SCT_set_signature_nid(SCT *sct, int nid)
 127 {
 128     switch (nid) {
 129     case NID_sha256WithRSAEncryption:
 130         sct->hash_alg = TLSEXT_hash_sha256;
 131         sct->sig_alg = TLSEXT_signature_rsa;
 132         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 133         return 1;
 134     case NID_ecdsa_with_SHA256:
 135         sct->hash_alg = TLSEXT_hash_sha256;
 136         sct->sig_alg = TLSEXT_signature_ecdsa;
 137         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 138         return 1;
 139     default:
 140         CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
 141         return 0;
 142     }
 143 }
 144
 145 void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)
 146 {
 147     OPENSSL_free(sct->ext);
 148     sct->ext = ext;
 149     sct->ext_len = ext_len;
 150     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 151 }
 152
 153 int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)
 154 {
 155     OPENSSL_free(sct->ext);
 156     sct->ext = NULL;
 157     sct->ext_len = 0;
 158     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 159
 160     if (ext != NULL && ext_len > 0) {
 161         sct->ext = OPENSSL_memdup(ext, ext_len);
 162         if (sct->ext == NULL) {
 163             CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
 164             return 0;
 165         }
 166         sct->ext_len = ext_len;
 167     }
 168     return 1;
 169 }
 170
 171 void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len)
 172 {
 173     OPENSSL_free(sct->sig);
 174     sct->sig = sig;
 175     sct->sig_len = sig_len;
 176     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 177 }
 178
 179 int SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len)
 180 {
 181     OPENSSL_free(sct->sig);
 182     sct->sig = NULL;
 183     sct->sig_len = 0;
 184     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 185
 186     if (sig != NULL && sig_len > 0) {
 187         sct->sig = OPENSSL_memdup(sig, sig_len);
 188         if (sct->sig == NULL) {
 189             CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
 190             return 0;
 191         }
 192         sct->sig_len = sig_len;
 193     }
 194     return 1;
 195 }
 196
 197 sct_version_t SCT_get_version(const SCT *sct)
 198 {
 199     return sct->version;
 200 }
 201
 202 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
 203 {
 204     return sct->entry_type;
 205 }
 206
 207 size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)
 208 {
 209     *log_id = sct->log_id;
 210     return sct->log_id_len;
 211 }
 212
 213 uint64_t SCT_get_timestamp(const SCT *sct)
 214 {
 215     return sct->timestamp;
 216 }
 217
 218 int SCT_get_signature_nid(const SCT *sct)
 219 {
 220     if (sct->version == SCT_VERSION_V1) {
 221         if (sct->hash_alg == TLSEXT_hash_sha256) {
 222             switch (sct->sig_alg) {
 223             case TLSEXT_signature_ecdsa:
 224                 return NID_ecdsa_with_SHA256;
 225             case TLSEXT_signature_rsa:
 226                 return NID_sha256WithRSAEncryption;
 227             default:
 228                 return NID_undef;
 229             }
 230         }
 231     }
 232     return NID_undef;
 233 }
 234
 235 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
 236 {
 237     *ext = sct->ext;
 238     return sct->ext_len;
 239 }
 240
 241 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
 242 {
 243     *sig = sct->sig;
 244     return sct->sig_len;
 245 }
 246
 247 int SCT_is_complete(const SCT *sct)
 248 {
 249     switch (sct->version) {
 250     case SCT_VERSION_NOT_SET:
 251         return 0;
 252     case SCT_VERSION_V1:
 253         return sct->log_id != NULL && SCT_signature_is_complete(sct);
 254     default:
 255         return sct->sct != NULL; /* Just need cached encoding */
 256     }
 257 }
 258
 259 int SCT_signature_is_complete(const SCT *sct)
 260 {
 261     return SCT_get_signature_nid(sct) != NID_undef &&
 262         sct->sig != NULL && sct->sig_len > 0;
 263 }
 264
 265 sct_source_t SCT_get_source(const SCT *sct)
 266 {
 267     return sct->source;
 268 }
 269
 270 int SCT_set_source(SCT *sct, sct_source_t source)
 271 {
 272     sct->source = source;
 273     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 274     switch (source) {
 275     case SCT_SOURCE_TLS_EXTENSION:
 276     case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
 277         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
 278     case SCT_SOURCE_X509V3_EXTENSION:
 279         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
 280     case SCT_SOURCE_UNKNOWN:
 281         break;
 282     }
 283     /* if we aren't sure, leave the log entry type alone */
 284     return 1;
 285 }
 286
 287 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
 288 {
 289     return sct->validation_status;
 290 }
 291
 292 int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)
 293 {
 294     int is_sct_valid = -1;
 295     SCT_CTX *sctx = NULL;
 296     X509_PUBKEY *pub = NULL, *log_pkey = NULL;
 297     const CTLOG *log;
 298
 299     /*
 300      * With an unrecognized SCT version we don't know what such an SCT means,
 301      * let alone validate one.  So we return validation failure (0).
 302      */
 303     if (sct->version != SCT_VERSION_V1) {
 304         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
 305         return 0;
 306     }
 307
 308     log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
 309                                      sct->log_id, sct->log_id_len);
 310
 311     /* Similarly, an SCT from an unknown log also cannot be validated. */
 312     if (log == NULL) {
 313         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
 314         return 0;
 315     }
 316
 317     sctx = SCT_CTX_new(ctx->libctx, ctx->propq);
 318     if (sctx == NULL)
 319         goto err;
 320
 321     if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
 322         goto err;
 323     if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
 324         goto err;
 325
 326     if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
 327         EVP_PKEY *issuer_pkey;
 328
 329         if (ctx->issuer == NULL) {
 330             sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 331             goto end;
 332         }
 333
 334         issuer_pkey = X509_get0_pubkey(ctx->issuer);
 335
 336         if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
 337             goto err;
 338         if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
 339             goto err;
 340     }
 341
 342     SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms);
 343
 344     /*
 345      * XXX: Potential for optimization.  This repeats some idempotent heavy
 346      * lifting on the certificate for each candidate SCT, and appears to not
 347      * use any information in the SCT itself, only the certificate is
 348      * processed.  So it may make more sense to to do this just once, perhaps
 349      * associated with the shared (by all SCTs) policy eval ctx.
 350      *
 351      * XXX: Failure here is global (SCT independent) and represents either an
 352      * issue with the certificate (e.g. duplicate extensions) or an out of
 353      * memory condition.  When the certificate is incompatible with CT, we just
 354      * mark the SCTs invalid, rather than report a failure to determine the
 355      * validation status.  That way, callbacks that want to do "soft" SCT
 356      * processing will not abort handshakes with false positive internal
 357      * errors.  Since the function does not distinguish between certificate
 358      * issues (peer's fault) and internal problems (out fault) the safe thing
 359      * to do is to report a validation failure and let the callback or
 360      * application decide what to do.
 361      */
 362     if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
 363         sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 364     else
 365         sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ?
 366             SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;
 367
 368 end:
 369     is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
 370 err:
 371     X509_PUBKEY_free(pub);
 372     X509_PUBKEY_free(log_pkey);
 373     SCT_CTX_free(sctx);
 374
 375     return is_sct_valid;
 376 }
 377
 378 int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)
 379 {
 380     int are_scts_valid = 1;
 381     int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
 382     int i;
 383
 384     for (i = 0; i < sct_count; ++i) {
 385         int is_sct_valid = -1;
 386         SCT *sct = sk_SCT_value(scts, i);
 387
 388         if (sct == NULL)
 389             continue;
 390
 391         is_sct_valid = SCT_validate(sct, ctx);
 392         if (is_sct_valid < 0)
 393             return is_sct_valid;
 394         are_scts_valid &= is_sct_valid;
 395     }
 396
 397     return are_scts_valid;
 398 }