text: /*
   * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   * 2000.
   */
  /* ====================================================================
   * Copyright (c) 2000-2004 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  
  #include <openssl/ocsp.h>
  #include "ocsp_lcl.h"
  #include <openssl/err.h>
  #include <string.h>
  
  static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
                              STACK_OF(X509) *certs, unsigned long flags);
  static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
  static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain);
  static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp,
                            OCSP_CERTID **ret);
  static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
                                 STACK_OF(OCSP_SINGLERESP) *sresp);
  static int ocsp_check_delegated(X509 *x);
  static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
                                  X509_NAME *nm, STACK_OF(X509) *certs,
                                  unsigned long flags);
  
  /* Verify a basic response message */
  
  int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                        X509_STORE *st, unsigned long flags)
  {
      X509 *signer, *x;
      STACK_OF(X509) *chain = NULL;
      STACK_OF(X509) *untrusted = NULL;
      X509_STORE_CTX ctx;
      int i, ret = ocsp_find_signer(&signer, bs, certs, flags);
  
      if (!ret) {
          OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
                  OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
          goto end;
      }
      if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
          flags |= OCSP_NOVERIFY;
      if (!(flags & OCSP_NOSIGS)) {
          EVP_PKEY *skey;
          skey = X509_get0_pubkey(signer);
          if (skey)
              ret = OCSP_BASICRESP_verify(bs, skey, 0);
          if (!skey || ret <= 0) {
              OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
              goto end;
          }
      }
      if (!(flags & OCSP_NOVERIFY)) {
          int init_res;
          if (flags & OCSP_NOCHAIN) {
              untrusted = NULL;
          } else if (bs->certs && certs) {
              untrusted = sk_X509_dup(bs->certs);
              for (i = 0; i < sk_X509_num(certs); i++) {
                  if (!sk_X509_push(untrusted, sk_X509_value(certs, i))) {
                      OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
                      goto end;
                  }
              }
          } else {
              untrusted = bs->certs;
          }
          init_res = X509_STORE_CTX_init(&ctx, st, signer, untrusted);
          if (!init_res) {
              ret = -1;
              OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_X509_LIB);
              goto end;
          }
  
          X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
          ret = X509_verify_cert(&ctx);
          chain = X509_STORE_CTX_get1_chain(&ctx);
          X509_STORE_CTX_cleanup(&ctx);
          if (ret <= 0) {
              i = X509_STORE_CTX_get_error(&ctx);
              OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,
                      OCSP_R_CERTIFICATE_VERIFY_ERROR);
              ERR_add_error_data(2, "Verify error:",
                                 X509_verify_cert_error_string(i));
              goto end;
          }
          if (flags & OCSP_NOCHECKS) {
              ret = 1;
              goto end;
          }
          /*
           * At this point we have a valid certificate chain need to verify it
           * against the OCSP issuer criteria.
           */
          ret = ocsp_check_issuer(bs, chain);
  
          /* If fatal error or valid match then finish */
          if (ret != 0)
              goto end;
  
          /*
           * Easy case: explicitly trusted. Get root CA and check for explicit
           * trust
           */
          if (flags & OCSP_NOEXPLICIT)
              goto end;
  
          x = sk_X509_value(chain, sk_X509_num(chain) - 1);
          if (X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) {
              OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_ROOT_CA_NOT_TRUSTED);
              goto end;
          }
          ret = 1;
      }
  
   end:
      sk_X509_pop_free(chain, X509_free);
      if (bs->certs && certs)
          sk_X509_free(untrusted);
      return ret;
  }
  
  static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
                              STACK_OF(X509) *certs, unsigned long flags)
  {
      X509 *signer;
      OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
      if ((signer = ocsp_find_signer_sk(certs, rid))) {
          *psigner = signer;
          return 2;
      }
      if (!(flags & OCSP_NOINTERN) &&
          (signer = ocsp_find_signer_sk(bs->certs, rid))) {
          *psigner = signer;
          return 1;
      }
      /* Maybe lookup from store if by subject name */
  
      *psigner = NULL;
      return 0;
  }
  
  static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
  {
      int i;
      unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
      X509 *x;
  
      /* Easy if lookup by name */
      if (id->type == V_OCSP_RESPID_NAME)
          return X509_find_by_subject(certs, id->value.byName);
  
      /* Lookup by key hash */
  
      /* If key hash isn't SHA1 length then forget it */
      if (id->value.byKey->length != SHA_DIGEST_LENGTH)
          return NULL;
      keyhash = id->value.byKey->data;
      /* Calculate hash of each key and compare */
      for (i = 0; i < sk_X509_num(certs); i++) {
          x = sk_X509_value(certs, i);
          X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
          if (!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
              return x;
      }
      return NULL;
  }
  
  static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain)
  {
      STACK_OF(OCSP_SINGLERESP) *sresp;
      X509 *signer, *sca;
      OCSP_CERTID *caid = NULL;
      int i;
      sresp = bs->tbsResponseData.responses;
  
      if (sk_X509_num(chain) <= 0) {
          OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
          return -1;
      }
  
      /* See if the issuer IDs match. */
      i = ocsp_check_ids(sresp, &caid);
  
      /* If ID mismatch or other error then return */
      if (i <= 0)
          return i;
  
      signer = sk_X509_value(chain, 0);
      /* Check to see if OCSP responder CA matches request CA */
      if (sk_X509_num(chain) > 1) {
          sca = sk_X509_value(chain, 1);
          i = ocsp_match_issuerid(sca, caid, sresp);
          if (i < 0)
              return i;
          if (i) {
              /* We have a match, if extensions OK then success */
              if (ocsp_check_delegated(signer))
                  return 1;
              return 0;
          }
      }
  
      /* Otherwise check if OCSP request signed directly by request CA */
      return ocsp_match_issuerid(signer, caid, sresp);
  }
  
  /*
   * Check the issuer certificate IDs for equality. If there is a mismatch with
   * the same algorithm then there's no point trying to match any certificates
   * against the issuer. If the issuer IDs all match then we just need to check
   * equality against one of them.
   */
  
  static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
  {
      OCSP_CERTID *tmpid, *cid;
      int i, idcount;
  
      idcount = sk_OCSP_SINGLERESP_num(sresp);
      if (idcount <= 0) {
          OCSPerr(OCSP_F_OCSP_CHECK_IDS,
                  OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
          return -1;
      }
  
      cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
  
      *ret = NULL;
  
      for (i = 1; i < idcount; i++) {
          tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
          /* Check to see if IDs match */
          if (OCSP_id_issuer_cmp(cid, tmpid)) {
              /* If algorithm mismatch let caller deal with it */
              if (OBJ_cmp(tmpid->hashAlgorithm.algorithm,
                          cid->hashAlgorithm.algorithm))
                  return 2;
              /* Else mismatch */
              return 0;
          }
      }
  
      /* All IDs match: only need to check one ID */
      *ret = cid;
      return 1;
  }
  
  static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
                                 STACK_OF(OCSP_SINGLERESP) *sresp)
  {
      /* If only one ID to match then do it */
      if (cid) {
          const EVP_MD *dgst;
          X509_NAME *iname;
          int mdlen;
          unsigned char md[EVP_MAX_MD_SIZE];
          if ((dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm))
                  == NULL) {
              OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID,
                      OCSP_R_UNKNOWN_MESSAGE_DIGEST);
              return -1;
          }
  
          mdlen = EVP_MD_size(dgst);
          if (mdlen < 0)
              return -1;
          if ((cid->issuerNameHash.length != mdlen) ||
              (cid->issuerKeyHash.length != mdlen))
              return 0;
          iname = X509_get_subject_name(cert);
          if (!X509_NAME_digest(iname, dgst, md, NULL))
              return -1;
          if (memcmp(md, cid->issuerNameHash.data, mdlen))
              return 0;
          X509_pubkey_digest(cert, dgst, md, NULL);
          if (memcmp(md, cid->issuerKeyHash.data, mdlen))
              return 0;
  
          return 1;
  
      } else {
          /* We have to match the whole lot */
          int i, ret;
          OCSP_CERTID *tmpid;
          for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) {
              tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
              ret = ocsp_match_issuerid(cert, tmpid, NULL);
              if (ret <= 0)
                  return ret;
          }
          return 1;
      }
  
  }
  
  static int ocsp_check_delegated(X509 *x)
  {
      if ((X509_get_extension_flags(x) & EXFLAG_XKUSAGE)
          && (X509_get_extended_key_usage(x) & XKU_OCSP_SIGN))
          return 1;
      OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
      return 0;
  }
  
  /*
   * Verify an OCSP request. This is fortunately much easier than OCSP response
   * verify. Just find the signers certificate and verify it against a given
   * trust value.
   */
  
  int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
                          X509_STORE *store, unsigned long flags)
  {
      X509 *signer;
      X509_NAME *nm;
      GENERAL_NAME *gen;
      int ret;
      X509_STORE_CTX ctx;
      if (!req->optionalSignature) {
          OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
          return 0;
      }
      gen = req->tbsRequest.requestorName;
      if (!gen || gen->type != GEN_DIRNAME) {
          OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
                  OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
          return 0;
      }
      nm = gen->d.directoryName;
      ret = ocsp_req_find_signer(&signer, req, nm, certs, flags);
      if (ret <= 0) {
          OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
                  OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
          return 0;
      }
      if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
          flags |= OCSP_NOVERIFY;
      if (!(flags & OCSP_NOSIGS)) {
          EVP_PKEY *skey;
          skey = X509_get0_pubkey(signer);
          ret = OCSP_REQUEST_verify(req, skey);
          if (ret <= 0) {
              OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
              return 0;
          }
      }
      if (!(flags & OCSP_NOVERIFY)) {
          int init_res;
          if (flags & OCSP_NOCHAIN)
              init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
          else
              init_res = X509_STORE_CTX_init(&ctx, store, signer,
                                             req->optionalSignature->certs);
          if (!init_res) {
              OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, ERR_R_X509_LIB);
              return 0;
          }
  
          X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
          X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
          ret = X509_verify_cert(&ctx);
          X509_STORE_CTX_cleanup(&ctx);
          if (ret <= 0) {
              ret = X509_STORE_CTX_get_error(&ctx);
              OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,
                      OCSP_R_CERTIFICATE_VERIFY_ERROR);
              ERR_add_error_data(2, "Verify error:",
                                 X509_verify_cert_error_string(ret));
              return 0;
          }
      }
      return 1;
  }
  
  static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
                                  X509_NAME *nm, STACK_OF(X509) *certs,
                                  unsigned long flags)
  {
      X509 *signer;
      if (!(flags & OCSP_NOINTERN)) {
          signer = X509_find_by_subject(req->optionalSignature->certs, nm);
          if (signer) {
              *psigner = signer;
              return 1;
          }
      }
  
      signer = X509_find_by_subject(certs, nm);
      if (signer) {
          *psigner = signer;
          return 2;
      }
      return 0;
  }
  