/* crypto/rsa/rsa_ssl.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_SSLv23(unsigned char *to, int tlen, unsigned char *from,
	     int flen)
	{
	int i,j;
	unsigned char *p;
	
	if (flen > (tlen-11))
		{
		RSAerr(RSA_F_RSA_PADDING_ADD_SSLV23,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-3-8-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++;
		}

	memset(p,3,8);
	p+=8;
	*(p++)='\0';

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

int RSA_padding_check_SSLv23(unsigned char *to, int tlen, unsigned char *from,
	     int flen, int num)
	{
	int i,j,k;
	unsigned char *p;

	p=from;
	if (flen < 10)
		{
		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_DATA_TOO_SMALL);
		return(-1);
		}
	if ((num != (flen+1)) || (*(p++) != 02))
		{
		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_BLOCK_TYPE_IS_NOT_02);
		return(-1);
		}

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

	if ((i == j) || (i < 8))
		{
		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_NULL_BEFORE_BLOCK_MISSING);
		return(-1);
		}
	for (k= -8; k<0; k++)
		{
		if (p[k] !=  0x03) break;
		}
	if (k == 0)
		{
		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_SSLV3_ROLLBACK_ATTACK);
		return(-1);
		}

	i++; /* Skip over the '\0' */
	j-=i;
	memcpy(to,p,(unsigned int)j);

	return(j);
	}