text: /* crypto/asn1/a_verify.c */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * 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 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 acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS 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 AUTHOR OR 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.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  
  #include <stdio.h>
  #include <time.h>
  
  #include "cryptlib.h"
  #include "asn1_locl.h"
  
  #ifndef NO_SYS_TYPES_H
  # include <sys/types.h>
  #endif
  
  #include "bn.h"
  #include "x509.h"
  #include "objects.h"
  #include "buffer.h"
  #include "evp.h"
  
  #ifndef NO_ASN1_OLD
  
  int ASN1_verify(i2d_of_void *i2d, X509_ALGOR *a, ASN1_BIT_STRING *signature,
                  char *data, EVP_PKEY *pkey)
  {
      EVP_MD_CTX ctx;
      const EVP_MD *type;
      unsigned char *p, *buf_in = NULL;
      int ret = -1, i, inl;
  
      EVP_MD_CTX_init(&ctx);
      i = OBJ_obj2nid(a->algorithm);
      type = EVP_get_digestbyname(OBJ_nid2sn(i));
      if (type == NULL) {
          ASN1err(ASN1_F_ASN1_VERIFY, ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);
          goto err;
      }
  
      if (signature->type == V_ASN1_BIT_STRING && signature->flags & 0x7) {
          ASN1err(ASN1_F_ASN1_VERIFY, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);
          goto err;
      }
  
      inl = i2d(data, NULL);
      buf_in = OPENSSL_malloc((unsigned int)inl);
      if (buf_in == NULL) {
          ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_MALLOC_FAILURE);
          goto err;
      }
      p = buf_in;
  
      i2d(data, &p);
      if (!EVP_VerifyInit_ex(&ctx, type, NULL)
          || !EVP_VerifyUpdate(&ctx, (unsigned char *)buf_in, inl)) {
          ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_EVP_LIB);
          ret = 0;
          goto err;
      }
  
      OPENSSL_cleanse(buf_in, (unsigned int)inl);
      OPENSSL_free(buf_in);
  
      if (EVP_VerifyFinal(&ctx, (unsigned char *)signature->data,
                          (unsigned int)signature->length, pkey) <= 0) {
          ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_EVP_LIB);
          ret = 0;
          goto err;
      }
      /*
       * we don't need to zero the 'ctx' because we just checked public
       * information
       */
      /* memset(&ctx,0,sizeof(ctx)); */
      ret = 1;
   err:
      EVP_MD_CTX_cleanup(&ctx);
      return (ret);
  }
  
  #endif
  
  int ASN1_item_verify(const ASN1_ITEM *it, X509_ALGOR *a,
                       ASN1_BIT_STRING *signature, void *asn, EVP_PKEY *pkey)
  {
      EVP_MD_CTX ctx;
      unsigned char *buf_in = NULL;
      int ret = -1, inl;
  
      int mdnid, pknid;
  
      if (!pkey) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_PASSED_NULL_PARAMETER);
          return -1;
      }
  
      if (signature->type == V_ASN1_BIT_STRING && signature->flags & 0x7) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);
          return -1;
      }
  
      EVP_MD_CTX_init(&ctx);
  
      /* Convert signature OID into digest and public key OIDs */
      if (!OBJ_find_sigid_algs(OBJ_obj2nid(a->algorithm), &mdnid, &pknid)) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);
          goto err;
      }
      if (mdnid == NID_undef) {
          if (!pkey->ameth || !pkey->ameth->item_verify) {
              ASN1err(ASN1_F_ASN1_ITEM_VERIFY,
                      ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);
              goto err;
          }
          ret = pkey->ameth->item_verify(&ctx, it, asn, a, signature, pkey);
          /*
           * Return value of 2 means carry on, anything else means we exit
           * straight away: either a fatal error of the underlying verification
           * routine handles all verification.
           */
          if (ret != 2)
              goto err;
          ret = -1;
      } else {
          const EVP_MD *type;
          type = EVP_get_digestbynid(mdnid);
          if (type == NULL) {
              ASN1err(ASN1_F_ASN1_ITEM_VERIFY,
                      ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);
              goto err;
          }
  
          /* Check public key OID matches public key type */
          if (EVP_PKEY_type(pknid) != pkey->ameth->pkey_id) {
              ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_WRONG_PUBLIC_KEY_TYPE);
              goto err;
          }
  
          if (!EVP_DigestVerifyInit(&ctx, NULL, type, NULL, pkey)) {
              ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_EVP_LIB);
              ret = 0;
              goto err;
          }
  
      }
  
      inl = ASN1_item_i2d(asn, &buf_in, it);
  
      if (buf_in == NULL) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_MALLOC_FAILURE);
          goto err;
      }
  
      if (!EVP_DigestVerifyUpdate(&ctx, buf_in, inl)) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_EVP_LIB);
          ret = 0;
          goto err;
      }
  
      OPENSSL_cleanse(buf_in, (unsigned int)inl);
      OPENSSL_free(buf_in);
  
      if (EVP_DigestVerifyFinal(&ctx, signature->data,
                                (size_t)signature->length) <= 0) {
          ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_EVP_LIB);
          ret = 0;
          goto err;
      }
      /*
       * we don't need to zero the 'ctx' because we just checked public
       * information
       */
      /* memset(&ctx,0,sizeof(ctx)); */
      ret = 1;
   err:
      EVP_MD_CTX_cleanup(&ctx);
      return (ret);
  }
  