/*

 * Copyright 1995-2018 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 "internal/refcount.h"

#include <openssl/bn.h>

#include "dsa_locl.h"

#include <openssl/asn1.h>

#include <openssl/engine.h>

#include <openssl/dh.h>

DSA *DSA_new(void)

{

    return DSA_new_method(NULL);

}

int DSA_set_method(DSA *dsa, const DSA_METHOD *meth)

{

    /*

     * NB: The caller is specifically setting a method, so it's not up to us

     * to deal with which ENGINE it comes from.

     */

    const DSA_METHOD *mtmp;

    mtmp = dsa->meth;

    if (mtmp->finish)

        mtmp->finish(dsa);

#ifndef OPENSSL_NO_ENGINE

    ENGINE_finish(dsa->engine);

    dsa->engine = NULL;

#endif

    dsa->meth = meth;

    if (meth->init)

        meth->init(dsa);

    return 1;

}

const DSA_METHOD *DSA_get_method(DSA *d)

{

    return d->meth;

}

DSA *DSA_new_method(ENGINE *engine)

{

    DSA *ret = OPENSSL_zalloc(sizeof(*ret));

    if (ret == NULL) {

        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    ret->references = 1;

    ret->lock = CRYPTO_THREAD_lock_new();

    if (ret->lock == NULL) {

        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_MALLOC_FAILURE);

        OPENSSL_free(ret);

        return NULL;

    }

    ret->meth = DSA_get_default_method();

#ifndef OPENSSL_NO_ENGINE

    ret->flags = ret->meth->flags & ~DSA_FLAG_NON_FIPS_ALLOW; /* early default init */

    if (engine) {

        if (!ENGINE_init(engine)) {

            DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_ENGINE_LIB);

            goto err;

        }

        ret->engine = engine;

    } else

        ret->engine = ENGINE_get_default_DSA();

    if (ret->engine) {

        ret->meth = ENGINE_get_DSA(ret->engine);

        if (ret->meth == NULL) {

            DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_ENGINE_LIB);

            goto err;

        }

    }

#endif

    ret->flags = ret->meth->flags & ~DSA_FLAG_NON_FIPS_ALLOW;

    if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_DSA, ret, &ret->ex_data))

        goto err;

    if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {

        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_INIT_FAIL);

err:

        DSA_free(ret);

        ret = NULL;

    }

    return ret;

}

void DSA_free(DSA *r)

{

    int i;

    if (r == NULL)

        return;

    CRYPTO_DOWN_REF(&r->references, &i, r->lock);

    REF_PRINT_COUNT("DSA", r);

    if (i > 0)

        return;

    REF_ASSERT_ISNT(i < 0);

    if (r->meth->finish)

        r->meth->finish(r);

#ifndef OPENSSL_NO_ENGINE

    ENGINE_finish(r->engine);

#endif

    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DSA, r, &r->ex_data);

    CRYPTO_THREAD_lock_free(r->lock);

    BN_clear_free(r->p);

    BN_clear_free(r->q);

    BN_clear_free(r->g);

    BN_clear_free(r->pub_key);

    BN_clear_free(r->priv_key);

    OPENSSL_free(r);

}

int DSA_up_ref(DSA *r)

{

    int i;

    if (CRYPTO_UP_REF(&r->references, &i, r->lock) <= 0)

        return 0;

    REF_PRINT_COUNT("DSA", r);

    REF_ASSERT_ISNT(i < 2);

    return ((i > 1) ? 1 : 0);

}

int DSA_size(const DSA *r)

{

    int ret, i;

    ASN1_INTEGER bs;

    unsigned char buf[4];       /* 4 bytes looks really small. However,

                                 * i2d_ASN1_INTEGER() will not look beyond

                                 * the first byte, as long as the second

                                 * parameter is NULL. */

    i = BN_num_bits(r->q);

    bs.length = (i + 7) / 8;

    bs.data = buf;

    bs.type = V_ASN1_INTEGER;

    /* If the top bit is set the asn1 encoding is 1 larger. */

    buf[0] = 0xff;

    i = i2d_ASN1_INTEGER(&bs, NULL);

    i += i;                     /* r and s */

    ret = ASN1_object_size(1, i, V_ASN1_SEQUENCE);

    return ret;

}

int DSA_set_ex_data(DSA *d, int idx, void *arg)

{

    return CRYPTO_set_ex_data(&d->ex_data, idx, arg);

}

void *DSA_get_ex_data(DSA *d, int idx)

{

    return CRYPTO_get_ex_data(&d->ex_data, idx);

}

int DSA_security_bits(const DSA *d)

{

    if (d->p && d->q)

        return BN_security_bits(BN_num_bits(d->p), BN_num_bits(d->q));

    return -1;

}

#ifndef OPENSSL_NO_DH

DH *DSA_dup_DH(const DSA *r)

{

    /*

     * DSA has p, q, g, optional pub_key, optional priv_key. DH has p,

     * optional length, g, optional pub_key, optional priv_key, optional q.

     */

    DH *ret = NULL;

    BIGNUM *p = NULL, *q = NULL, *g = NULL, *pub_key = NULL, *priv_key = NULL;

    if (r == NULL)

        goto err;

    ret = DH_new();

    if (ret == NULL)

        goto err;

    if (r->p != NULL || r->g != NULL || r->q != NULL) {

        if (r->p == NULL || r->g == NULL || r->q == NULL) {

            /* Shouldn't happen */

            goto err;

        }

        p = BN_dup(r->p);

        g = BN_dup(r->g);

        q = BN_dup(r->q);

        if (p == NULL || g == NULL || q == NULL || !DH_set0_pqg(ret, p, q, g))

            goto err;

        p = g = q = NULL;

    }

    if (r->pub_key != NULL) {

        pub_key = BN_dup(r->pub_key);

        if (pub_key == NULL)

            goto err;

        if (r->priv_key != NULL) {

            priv_key = BN_dup(r->priv_key);

            if (priv_key == NULL)

                goto err;

        }

        if (!DH_set0_key(ret, pub_key, priv_key))

            goto err;

    } else if (r->priv_key != NULL) {

        /* Shouldn't happen */

        goto err;

    }

    return ret;

 err:

    BN_free(p);

    BN_free(g);

    BN_free(q);

    BN_free(pub_key);

    BN_free(priv_key);

    DH_free(ret);

    return NULL;

}

#endif

void DSA_get0_pqg(const DSA *d,

                  const BIGNUM **p, const BIGNUM **q, const BIGNUM **g)

{

    if (p != NULL)

        *p = d->p;

    if (q != NULL)

        *q = d->q;

    if (g != NULL)

        *g = d->g;

}

int DSA_set0_pqg(DSA *d, BIGNUM *p, BIGNUM *q, BIGNUM *g)

{

    /* If the fields p, q and g in d are NULL, the corresponding input

     * parameters MUST be non-NULL.

     */

    if ((d->p == NULL && p == NULL)

        || (d->q == NULL && q == NULL)

        || (d->g == NULL && g == NULL))

        return 0;

    if (p != NULL) {

        BN_free(d->p);

        d->p = p;

    }

    if (q != NULL) {

        BN_free(d->q);

        d->q = q;

    }

    if (g != NULL) {

        BN_free(d->g);

        d->g = g;

    }

    return 1;

}

void DSA_get0_key(const DSA *d,

                  const BIGNUM **pub_key, const BIGNUM **priv_key)

{

    if (pub_key != NULL)

        *pub_key = d->pub_key;

    if (priv_key != NULL)

        *priv_key = d->priv_key;

}

int DSA_set0_key(DSA *d, BIGNUM *pub_key, BIGNUM *priv_key)

{

    /* If the field pub_key in d is NULL, the corresponding input

     * parameters MUST be non-NULL.  The priv_key field may

     * be left NULL.

     */

    if (d->pub_key == NULL && pub_key == NULL)

        return 0;

    if (pub_key != NULL) {

        BN_free(d->pub_key);

        d->pub_key = pub_key;

    }

    if (priv_key != NULL) {

        BN_free(d->priv_key);

        d->priv_key = priv_key;

    }

    return 1;

}

const BIGNUM *DSA_get0_p(const DSA *d)

{

    return d->p;

}

const BIGNUM *DSA_get0_q(const DSA *d)

{

    return d->q;

}

const BIGNUM *DSA_get0_g(const DSA *d)

{

    return d->g;

}

const BIGNUM *DSA_get0_pub_key(const DSA *d)

{

    return d->pub_key;

}

const BIGNUM *DSA_get0_priv_key(const DSA *d)

{

    return d->priv_key;

}

void DSA_clear_flags(DSA *d, int flags)

{

    d->flags &= ~flags;

}

int DSA_test_flags(const DSA *d, int flags)

{

    return d->flags & flags;

}

void DSA_set_flags(DSA *d, int flags)

{

    d->flags |= flags;

}

ENGINE *DSA_get0_engine(DSA *d)

{

    return d->engine;

}

int DSA_bits(const DSA *dsa)

{

    return BN_num_bits(dsa->p);

}