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rsa_pk1.c
/* crypto/rsa/rsa_pk1.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 "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>

int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
           const unsigned char *from, int flen)
      {
      int j;
      unsigned char *p;

      if (flen > (tlen-RSA_PKCS1_PADDING_SIZE))
            {
            RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_1,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
            return(0);
            }
      
      p=(unsigned char *)to;

      *(p++)=0;
      *(p++)=1; /* Private Key BT (Block Type) */

      /* pad out with 0xff data */
      j=tlen-3-flen;
      memset(p,0xff,j);
      p+=j;
      *(p++)='\0';
      memcpy(p,from,(unsigned int)flen);
      return(1);
      }

int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
           const unsigned char *from, int flen, int num)
      {
      int i,j;
      const unsigned char *p;

      p=from;
      if ((num != (flen+1)) || (*(p++) != 01))
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BLOCK_TYPE_IS_NOT_01);
            return(-1);
            }

      /* scan over padding data */
      j=flen-1; /* one for type. */
      for (i=0; i<j; i++)
            {
            if (*p != 0xff) /* should decrypt to 0xff */
                  {
                  if (*p == 0)
                        { p++; break; }
                  else  {
                        RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_FIXED_HEADER_DECRYPT);
                        return(-1);
                        }
                  }
            p++;
            }

      if (i == j)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_NULL_BEFORE_BLOCK_MISSING);
            return(-1);
            }

      if (i < 8)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_PAD_BYTE_COUNT);
            return(-1);
            }
      i++; /* Skip over the '\0' */
      j-=i;
      if (j > tlen)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_DATA_TOO_LARGE);
            return(-1);
            }
      memcpy(to,p,(unsigned int)j);

      return(j);
      }

int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
           const unsigned char *from, int flen)
      {
      int i,j;
      unsigned char *p;
      
      if (flen > (tlen-11))
            {
            RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_2,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
            return(0);
            }
      
      p=(unsigned char *)to;

      *(p++)=0;
      *(p++)=2; /* Public Key BT (Block Type) */

      /* pad out with non-zero random data */
      j=tlen-3-flen;

      if (RAND_bytes(p,j) <= 0)
            return(0);
      for (i=0; i<j; i++)
            {
            if (*p == '\0')
                  do    {
                        if (RAND_bytes(p,1) <= 0)
                              return(0);
                        } while (*p == '\0');
            p++;
            }

      *(p++)='\0';

      memcpy(p,from,(unsigned int)flen);
      return(1);
      }

int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
           const unsigned char *from, int flen, int num)
      {
      int i,j;
      const unsigned char *p;

      p=from;
      if ((num != (flen+1)) || (*(p++) != 02))
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_BLOCK_TYPE_IS_NOT_02);
            return(-1);
            }
#ifdef PKCS1_CHECK
      return(num-11);
#endif

      /* scan over padding data */
      j=flen-1; /* one for type. */
      for (i=0; i<j; i++)
            if (*(p++) == 0) break;

      if (i == j)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_NULL_BEFORE_BLOCK_MISSING);
            return(-1);
            }

      if (i < 8)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_BAD_PAD_BYTE_COUNT);
            return(-1);
            }
      i++; /* Skip over the '\0' */
      j-=i;
      if (j > tlen)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_DATA_TOO_LARGE);
            return(-1);
            }
      memcpy(to,p,(unsigned int)j);

      return(j);
      }


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