/* rsa_x931.c */
/*
 * Written by Dr Stephen N Henson (steve@openssl.org) 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
 *    licensing@OpenSSL.org.
 *
 * 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
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#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;
}