/* 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>

EXPORT_C int RSA_padding_add_SSLv23(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_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);

	}

EXPORT_C int RSA_padding_check_SSLv23(unsigned char *to, int tlen,

	const unsigned char *from, int flen, int num)

	{

	int i,j,k;

	const 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 == -1)

		{

		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_SSLV3_ROLLBACK_ATTACK);

		return(-1);

		}

	i++; /* Skip over the '\0' */

	j-=i;

	if (j > tlen)

		{

		RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_DATA_TOO_LARGE);

		return(-1);

		}

	memcpy(to,p,(unsigned int)j);

	return(j);

	}