/*

 * Copyright 1999-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include "dsa_local.h"

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/rand.h>

ASN1_SEQUENCE(DSA_SIG) = {

        ASN1_SIMPLE(DSA_SIG, r, CBIGNUM),

        ASN1_SIMPLE(DSA_SIG, s, CBIGNUM)

} static_ASN1_SEQUENCE_END(DSA_SIG)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA_SIG, DSA_SIG, DSA_SIG)

DSA_SIG *DSA_SIG_new(void)

{

    DSA_SIG *sig = OPENSSL_zalloc(sizeof(*sig));

    if (sig == NULL)

        DSAerr(DSA_F_DSA_SIG_NEW, ERR_R_MALLOC_FAILURE);

    return sig;

}

void DSA_SIG_free(DSA_SIG *sig)

{

    if (sig == NULL)

        return;

    BN_clear_free(sig->r);

    BN_clear_free(sig->s);

    OPENSSL_free(sig);

}

void DSA_SIG_get0(const DSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps)

{

    if (pr != NULL)

        *pr = sig->r;

    if (ps != NULL)

        *ps = sig->s;

}

int DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s)

{

    if (r == NULL || s == NULL)

        return 0;

    BN_clear_free(sig->r);

    BN_clear_free(sig->s);

    sig->r = r;

    sig->s = s;

    return 1;

}

/* 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 != NULL)

            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_EMBED(DSA, version, INT32),

        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, CBIGNUM)

} static_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),

} static_ASN1_SEQUENCE_END_cb(DSA, DSAparams)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAparams, DSAparams)

ASN1_SEQUENCE_cb(DSAPublicKey, dsa_cb) = {

        ASN1_SIMPLE(DSA, pub_key, BIGNUM),

        ASN1_SIMPLE(DSA, p, BIGNUM),

        ASN1_SIMPLE(DSA, q, BIGNUM),

        ASN1_SIMPLE(DSA, g, BIGNUM)

} static_ASN1_SEQUENCE_END_cb(DSA, DSAPublicKey)

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;

    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:

    OPENSSL_clear_free(der, derlen);

    DSA_SIG_free(s);

    return ret;

}