/* dsa_asn1.c */

/*

 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project

 * 2000.

 */

/* ====================================================================

 * Copyright (c) 2000-2005 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/dsa.h>

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/rand.h>

/* Override the default new methods */

static int sig_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,

                  void *exarg)

{

    if (operation == ASN1_OP_NEW_PRE) {

        DSA_SIG *sig;

        sig = OPENSSL_malloc(sizeof(DSA_SIG));

        if (!sig) {

            DSAerr(DSA_F_SIG_CB, ERR_R_MALLOC_FAILURE);

            return 0;

        }

        sig->r = NULL;

        sig->s = NULL;

        *pval = (ASN1_VALUE *)sig;

        return 2;

    }

    return 1;

}

ASN1_SEQUENCE_cb(DSA_SIG, sig_cb) = {

        ASN1_SIMPLE(DSA_SIG, r, CBIGNUM),

        ASN1_SIMPLE(DSA_SIG, s, CBIGNUM)

} ASN1_SEQUENCE_END_cb(DSA_SIG, DSA_SIG)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA_SIG, DSA_SIG, DSA_SIG)

/* Override the default free and new methods */

static int dsa_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,

                  void *exarg)

{

    if (operation == ASN1_OP_NEW_PRE) {

        *pval = (ASN1_VALUE *)DSA_new();

        if (*pval)

            return 2;

        return 0;

    } else if (operation == ASN1_OP_FREE_PRE) {

        DSA_free((DSA *)*pval);

        *pval = NULL;

        return 2;

    }

    return 1;

}

ASN1_SEQUENCE_cb(DSAPrivateKey, dsa_cb) = {

        ASN1_SIMPLE(DSA, version, LONG),

        ASN1_SIMPLE(DSA, p, BIGNUM),

        ASN1_SIMPLE(DSA, q, BIGNUM),

        ASN1_SIMPLE(DSA, g, BIGNUM),

        ASN1_SIMPLE(DSA, pub_key, BIGNUM),

        ASN1_SIMPLE(DSA, priv_key, BIGNUM)

} ASN1_SEQUENCE_END_cb(DSA, DSAPrivateKey)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPrivateKey, DSAPrivateKey)

ASN1_SEQUENCE_cb(DSAparams, dsa_cb) = {

        ASN1_SIMPLE(DSA, p, BIGNUM),

        ASN1_SIMPLE(DSA, q, BIGNUM),

        ASN1_SIMPLE(DSA, g, BIGNUM),

} ASN1_SEQUENCE_END_cb(DSA, DSAparams)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAparams, DSAparams)

/*

 * DSA public key is a bit trickier... its effectively a CHOICE type decided

 * by a field called write_params which can either write out just the public

 * key as an INTEGER or the parameters and public key in a SEQUENCE

 */

ASN1_SEQUENCE(dsa_pub_internal) = {

        ASN1_SIMPLE(DSA, pub_key, BIGNUM),

        ASN1_SIMPLE(DSA, p, BIGNUM),

        ASN1_SIMPLE(DSA, q, BIGNUM),

        ASN1_SIMPLE(DSA, g, BIGNUM)

} ASN1_SEQUENCE_END_name(DSA, dsa_pub_internal)

ASN1_CHOICE_cb(DSAPublicKey, dsa_cb) = {

        ASN1_SIMPLE(DSA, pub_key, BIGNUM),

        ASN1_EX_COMBINE(0, 0, dsa_pub_internal)

} ASN1_CHOICE_END_cb(DSA, DSAPublicKey, write_params)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPublicKey, DSAPublicKey)

DSA *DSAparams_dup(DSA *dsa)

{

    return ASN1_item_dup(ASN1_ITEM_rptr(DSAparams), dsa);

}

int DSA_sign(int type, const unsigned char *dgst, int dlen,

             unsigned char *sig, unsigned int *siglen, DSA *dsa)

{

    DSA_SIG *s;

    RAND_seed(dgst, dlen);

    s = DSA_do_sign(dgst, dlen, dsa);

    if (s == NULL) {

        *siglen = 0;

        return (0);

    }

    *siglen = i2d_DSA_SIG(s, &sig);

    DSA_SIG_free(s);

    return (1);

}

/* data has already been hashed (probably with SHA or SHA-1). */

/*-

 * returns

 *      1: correct signature

 *      0: incorrect signature

 *     -1: error

 */

int DSA_verify(int type, const unsigned char *dgst, int dgst_len,

               const unsigned char *sigbuf, int siglen, DSA *dsa)

{

    DSA_SIG *s;

    const unsigned char *p = sigbuf;

    unsigned char *der = NULL;

    int derlen = -1;

    int ret = -1;

    s = DSA_SIG_new();

    if (s == NULL)

        return (ret);

    if (d2i_DSA_SIG(&s, &p, siglen) == NULL)

        goto err;

    /* Ensure signature uses DER and doesn't have trailing garbage */

    derlen = i2d_DSA_SIG(s, &der);

    if (derlen != siglen || memcmp(sigbuf, der, derlen))

        goto err;

    ret = DSA_do_verify(dgst, dgst_len, s, dsa);

 err:

    if (derlen > 0) {

        OPENSSL_cleanse(der, derlen);

        OPENSSL_free(der);

    }

    DSA_SIG_free(s);

    return (ret);

}