rsa_x931.c

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/* rsa_x931.c */
/* Written by Dr Stephen N Henson ([email protected]) for the OpenSSL
 * project 2005.
 */
/* ====================================================================
 * Copyright (c) 2005 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>
#include <openssl/objects.h>

int RSA_padding_add_X931(unsigned char *to, int tlen,
         const unsigned char *from, int flen)
    {
    int j;
    unsigned char *p;

    /* Absolute minimum amount of padding is 1 header nibble, 1 padding
     * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
     */

    j = tlen - flen - 2;

    if (j < 0)
        {
        RSAerr(RSA_F_RSA_PADDING_ADD_X931,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
        return -1;
        }
    
    p=(unsigned char *)to;

    /* If no padding start and end nibbles are in one byte */
    if (j == 0)
        *p++ = 0x6A;
    else
        {
        *p++ = 0x6B;
        if (j > 1)
            {
            memset(p, 0xBB, j - 1);
            p += j - 1;
            }
        *p++ = 0xBA;
        }
    memcpy(p,from,(unsigned int)flen);
    p += flen;
    *p = 0xCC;
    return(1);
    }

int RSA_padding_check_X931(unsigned char *to, int tlen,
         const unsigned char *from, int flen, int num)
    {
    int i = 0,j;
    const unsigned char *p;

    p=from;
    if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B)))
        {
        RSAerr(RSA_F_RSA_PADDING_CHECK_X931,RSA_R_INVALID_HEADER);
        return -1;
        }

    if (*p++ == 0x6B)
        {
        j=flen-3;
        for (i = 0; i < j; i++)
            {
            unsigned char c = *p++;
            if (c == 0xBA)
                break;
            if (c != 0xBB)
                {
                RSAerr(RSA_F_RSA_PADDING_CHECK_X931,
                    RSA_R_INVALID_PADDING);
                return -1;
                }
            }

        j -= i;

        if (i == 0)
            {
            RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
            return -1;
            }

        }
    else j = flen - 2;

    if (p[j] != 0xCC)
        {
        RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_TRAILER);
        return -1;
        }

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

    return(j);
    }

/* Translate between X931 hash ids and NIDs */

int RSA_X931_hash_id(int nid)
    {
    switch (nid)
        {
        case NID_sha1:
        return 0x33;

        case NID_sha256:
        return 0x34;

        case NID_sha384:
        return 0x36;

        case NID_sha512:
        return 0x35;

        }
    return -1;
    }