crypto/ct/ct_sct.c

   1 /*
   2  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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_locl.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 int SCT_set_version(SCT *sct, sct_version_t version)
  49 {
  50     if (version != SCT_VERSION_V1) {
  51         CTerr(CT_F_SCT_SET_VERSION, CT_R_UNSUPPORTED_VERSION);
  52         return 0;
  53     }
  54     sct->version = version;
  55     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  56     return 1;
  57 }
  58
  59 int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)
  60 {
  61     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  62
  63     switch (entry_type) {
  64     case CT_LOG_ENTRY_TYPE_X509:
  65     case CT_LOG_ENTRY_TYPE_PRECERT:
  66         sct->entry_type = entry_type;
  67         return 1;
  68     default:
  69         CTerr(CT_F_SCT_SET_LOG_ENTRY_TYPE, CT_R_UNSUPPORTED_ENTRY_TYPE);
  70         return 0;
  71     }
  72 }
  73
  74 int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)
  75 {
  76     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
  77         CTerr(CT_F_SCT_SET0_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
  78         return 0;
  79     }
  80
  81     OPENSSL_free(sct->log_id);
  82     sct->log_id = log_id;
  83     sct->log_id_len = log_id_len;
  84     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  85     return 1;
  86 }
  87
  88 int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)
  89 {
  90     if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {
  91         CTerr(CT_F_SCT_SET1_LOG_ID, CT_R_INVALID_LOG_ID_LENGTH);
  92         return 0;
  93     }
  94
  95     OPENSSL_free(sct->log_id);
  96     sct->log_id = NULL;
  97     sct->log_id_len = 0;
  98     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
  99
 100     if (log_id != NULL && log_id_len > 0) {
 101         sct->log_id = OPENSSL_memdup(log_id, log_id_len);
 102         if (sct->log_id == NULL) {
 103             CTerr(CT_F_SCT_SET1_LOG_ID, ERR_R_MALLOC_FAILURE);
 104             return 0;
 105         }
 106         sct->log_id_len = log_id_len;
 107     }
 108     return 1;
 109 }
 110
 111
 112 void SCT_set_timestamp(SCT *sct, uint64_t timestamp)
 113 {
 114     sct->timestamp = timestamp;
 115     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 116 }
 117
 118 int SCT_set_signature_nid(SCT *sct, int nid)
 119 {
 120     switch (nid) {
 121     case NID_sha256WithRSAEncryption:
 122         sct->hash_alg = TLSEXT_hash_sha256;
 123         sct->sig_alg = TLSEXT_signature_rsa;
 124         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 125         return 1;
 126     case NID_ecdsa_with_SHA256:
 127         sct->hash_alg = TLSEXT_hash_sha256;
 128         sct->sig_alg = TLSEXT_signature_ecdsa;
 129         sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 130         return 1;
 131     default:
 132         CTerr(CT_F_SCT_SET_SIGNATURE_NID, CT_R_UNRECOGNIZED_SIGNATURE_NID);
 133         return 0;
 134     }
 135 }
 136
 137 void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)
 138 {
 139     OPENSSL_free(sct->ext);
 140     sct->ext = ext;
 141     sct->ext_len = ext_len;
 142     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 143 }
 144
 145 int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)
 146 {
 147     OPENSSL_free(sct->ext);
 148     sct->ext = NULL;
 149     sct->ext_len = 0;
 150     sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;
 151
 152     if (ext != NULL && ext_len > 0) {
 153         sct->ext = OPENSSL_memdup(ext, ext_len);
 154         if (sct->ext == NULL) {
 155             CTerr(CT_F_SCT_SET1_EXTENSIONS, ERR_R_MALLOC_FAILURE);
 156             return 0;
 157         }
 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             CTerr(CT_F_SCT_SET1_SIGNATURE, ERR_R_MALLOC_FAILURE);
 182             return 0;
 183         }
 184         sct->sig_len = sig_len;
 185     }
 186     return 1;
 187 }
 188
 189 sct_version_t SCT_get_version(const SCT *sct)
 190 {
 191     return sct->version;
 192 }
 193
 194 ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)
 195 {
 196     return sct->entry_type;
 197 }
 198
 199 size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)
 200 {
 201     *log_id = sct->log_id;
 202     return sct->log_id_len;
 203 }
 204
 205 uint64_t SCT_get_timestamp(const SCT *sct)
 206 {
 207     return sct->timestamp;
 208 }
 209
 210 int SCT_get_signature_nid(const SCT *sct)
 211 {
 212     if (sct->version == SCT_VERSION_V1) {
 213         if (sct->hash_alg == TLSEXT_hash_sha256) {
 214             switch (sct->sig_alg) {
 215             case TLSEXT_signature_ecdsa:
 216                 return NID_ecdsa_with_SHA256;
 217             case TLSEXT_signature_rsa:
 218                 return NID_sha256WithRSAEncryption;
 219             default:
 220                 return NID_undef;
 221             }
 222         }
 223     }
 224     return NID_undef;
 225 }
 226
 227 size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)
 228 {
 229     *ext = sct->ext;
 230     return sct->ext_len;
 231 }
 232
 233 size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)
 234 {
 235     *sig = sct->sig;
 236     return sct->sig_len;
 237 }
 238
 239 int SCT_is_complete(const SCT *sct)
 240 {
 241     switch (sct->version) {
 242     case SCT_VERSION_NOT_SET:
 243         return 0;
 244     case SCT_VERSION_V1:
 245         return sct->log_id != NULL && SCT_signature_is_complete(sct);
 246     default:
 247         return sct->sct != NULL; /* Just need cached encoding */
 248     }
 249 }
 250
 251 int SCT_signature_is_complete(const SCT *sct)
 252 {
 253     return SCT_get_signature_nid(sct) != NID_undef &&
 254         sct->sig != NULL && sct->sig_len > 0;
 255 }
 256
 257 sct_source_t SCT_get_source(const SCT *sct)
 258 {
 259     return sct->source;
 260 }
 261
 262 int SCT_set_source(SCT *sct, sct_source_t source)
 263 {
 264     sct->source = source;
 265     switch (source) {
 266     case SCT_SOURCE_TLS_EXTENSION:
 267     case SCT_SOURCE_OCSP_STAPLED_RESPONSE:
 268         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);
 269     case SCT_SOURCE_X509V3_EXTENSION:
 270         return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);
 271     default: /* if we aren't sure, leave the log entry type alone */
 272         return 1;
 273     }
 274 }
 275
 276 sct_validation_status_t SCT_get_validation_status(const SCT *sct)
 277 {
 278     return sct->validation_status;
 279 }
 280
 281 int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)
 282 {
 283     int is_sct_valid = -1;
 284     SCT_CTX *sctx = NULL;
 285     X509_PUBKEY *pub = NULL, *log_pkey = NULL;
 286     const CTLOG *log;
 287
 288     /*
 289      * With an unrecognized SCT version we don't know what such an SCT means,
 290      * let alone validate one.  So we return validation failure (0).
 291      */
 292     if (sct->version != SCT_VERSION_V1) {
 293         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;
 294         return 0;
 295     }
 296
 297     log = CTLOG_STORE_get0_log_by_id(ctx->log_store,
 298                                      sct->log_id, sct->log_id_len);
 299
 300     /* Similarly, an SCT from an unknown log also cannot be validated. */
 301     if (log == NULL) {
 302         sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;
 303         return 0;
 304     }
 305
 306     sctx = SCT_CTX_new();
 307     if (sctx == NULL)
 308         goto err;
 309
 310     if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)
 311         goto err;
 312     if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)
 313         goto err;
 314
 315     if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {
 316         EVP_PKEY *issuer_pkey;
 317
 318         if (ctx->issuer == NULL) {
 319             sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 320             goto end;
 321         }
 322
 323         issuer_pkey = X509_get0_pubkey(ctx->issuer);
 324
 325         if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)
 326             goto err;
 327         if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)
 328             goto err;
 329     }
 330
 331     /*
 332      * XXX: Potential for optimization.  This repeats some idempotent heavy
 333      * lifting on the certificate for each candidate SCT, and appears to not
 334      * use any information in the SCT itself, only the certificate is
 335      * processed.  So it may make more sense to to do this just once, perhaps
 336      * associated with the shared (by all SCTs) policy eval ctx.
 337      *
 338      * XXX: Failure here is global (SCT independent) and represents either an
 339      * issue with the certificate (e.g. duplicate extensions) or an out of
 340      * memory condition.  When the certificate is incompatible with CT, we just
 341      * mark the SCTs invalid, rather than report a failure to determine the
 342      * validation status.  That way, callbacks that want to do "soft" SCT
 343      * processing will not abort handshakes with false positive internal
 344      * errors.  Since the function does not distinguish between certificate
 345      * issues (peer's fault) and internal problems (out fault) the safe thing
 346      * to do is to report a validation failure and let the callback or
 347      * application decide what to do.
 348      */
 349     if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)
 350         sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;
 351     else
 352         sct->validation_status = SCT_verify(sctx, sct) == 1 ?
 353             SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;
 354
 355 end:
 356     is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;
 357 err:
 358     X509_PUBKEY_free(pub);
 359     X509_PUBKEY_free(log_pkey);
 360     SCT_CTX_free(sctx);
 361
 362     return is_sct_valid;
 363 }
 364
 365 int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)
 366 {
 367     int are_scts_valid = 1;
 368     int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;
 369     int i;
 370
 371     for (i = 0; i < sct_count; ++i) {
 372         int is_sct_valid = -1;
 373         SCT *sct = sk_SCT_value(scts, i);
 374
 375         if (sct == NULL)
 376             continue;
 377
 378         is_sct_valid = SCT_validate(sct, ctx);
 379         if (is_sct_valid < 0)
 380             return is_sct_valid;
 381         are_scts_valid &= is_sct_valid;
 382     }
 383
 384     return are_scts_valid;
 385 }