/* crypto/dsa/dsa_lib.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/dsa.h>
#include <openssl/asn1.h>
#ifndef OPENSSL_NO_ENGINE
#include <openssl/engine.h>
#endif
#ifndef OPENSSL_NO_DH
#include <openssl/dh.h>
#endif

#ifdef OPENSSL_FIPS
#include <openssl/fips.h>
#endif

const char DSA_version[]="DSA" OPENSSL_VERSION_PTEXT;

static const DSA_METHOD *default_DSA_method = NULL;

void DSA_set_default_method(const DSA_METHOD *meth)
	{
	default_DSA_method = meth;
	}

const DSA_METHOD *DSA_get_default_method(void)
	{
	if(!default_DSA_method)
		{
#ifdef OPENSSL_FIPS
		if (FIPS_mode())
			return FIPS_dsa_openssl();
		else
			return DSA_OpenSSL();
#else
		default_DSA_method = DSA_OpenSSL();
#endif
		}
	return default_DSA_method;
	}

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
	if (dsa->engine)
		{
		ENGINE_finish(dsa->engine);
		dsa->engine = NULL;
		}
#endif
        dsa->meth = meth;
        if (meth->init) meth->init(dsa);
        return 1;
	}

DSA *DSA_new_method(ENGINE *engine)
	{
	DSA *ret;

	ret=(DSA *)OPENSSL_malloc(sizeof(DSA));
	if (ret == NULL)
		{
		DSAerr(DSA_F_DSA_NEW_METHOD,ERR_R_MALLOC_FAILURE);
		return(NULL);
		}
	ret->meth = DSA_get_default_method();
#ifndef OPENSSL_NO_ENGINE
	if (engine)
		{
		if (!ENGINE_init(engine))
			{
			DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_ENGINE_LIB);
			OPENSSL_free(ret);
			return NULL;
			}
		ret->engine = engine;
		}
	else
		ret->engine = ENGINE_get_default_DSA();
	if(ret->engine)
		{
		ret->meth = ENGINE_get_DSA(ret->engine);
		if(!ret->meth)
			{
			DSAerr(DSA_F_DSA_NEW_METHOD,
				ERR_R_ENGINE_LIB);
			ENGINE_finish(ret->engine);
			OPENSSL_free(ret);
			return NULL;
			}
		}
#endif

	ret->pad=0;
	ret->version=0;
	ret->write_params=1;
	ret->p=NULL;
	ret->q=NULL;
	ret->g=NULL;

	ret->pub_key=NULL;
	ret->priv_key=NULL;

	ret->kinv=NULL;
	ret->r=NULL;
	ret->method_mont_p=NULL;

	ret->references=1;
	ret->flags=ret->meth->flags & ~DSA_FLAG_NON_FIPS_ALLOW;
	CRYPTO_new_ex_data(CRYPTO_EX_INDEX_DSA, ret, &ret->ex_data);
	if ((ret->meth->init != NULL) && !ret->meth->init(ret))
		{
#ifndef OPENSSL_NO_ENGINE
		if (ret->engine)
			ENGINE_finish(ret->engine);
#endif
		CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DSA, ret, &ret->ex_data);
		OPENSSL_free(ret);
		ret=NULL;
		}
	
	return(ret);
	}

void DSA_free(DSA *r)
	{
	int i;

	if (r == NULL) return;

	i=CRYPTO_add(&r->references,-1,CRYPTO_LOCK_DSA);
#ifdef REF_PRINT
	REF_PRINT("DSA",r);
#endif
	if (i > 0) return;
#ifdef REF_CHECK
	if (i < 0)
		{
		fprintf(stderr,"DSA_free, bad reference count\n");
		abort();
		}
#endif

	if(r->meth->finish)
		r->meth->finish(r);
#ifndef OPENSSL_NO_ENGINE
	if(r->engine)
		ENGINE_finish(r->engine);
#endif

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

	if (r->p != NULL) BN_clear_free(r->p);
	if (r->q != NULL) BN_clear_free(r->q);
	if (r->g != NULL) BN_clear_free(r->g);
	if (r->pub_key != NULL) BN_clear_free(r->pub_key);
	if (r->priv_key != NULL) BN_clear_free(r->priv_key);
	if (r->kinv != NULL) BN_clear_free(r->kinv);
	if (r->r != NULL) BN_clear_free(r->r);
	OPENSSL_free(r);
	}

int DSA_up_ref(DSA *r)
	{
	int i = CRYPTO_add(&r->references, 1, CRYPTO_LOCK_DSA);
#ifdef REF_PRINT
	REF_PRINT("DSA",r);
#endif
#ifdef REF_CHECK
	if (i < 2)
		{
		fprintf(stderr, "DSA_up_ref, bad reference count\n");
		abort();
		}
#endif
	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_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
	     CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
        {
	return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_DSA, argl, argp,
				new_func, dup_func, free_func);
        }

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));
	}

#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;

	if (r == NULL)
		goto err;
	ret = DH_new();
	if (ret == NULL)
		goto err;
	if (r->p != NULL) 
		if ((ret->p = BN_dup(r->p)) == NULL)
			goto err;
	if (r->q != NULL)
		{
		ret->length = BN_num_bits(r->q);
		if ((ret->q = BN_dup(r->q)) == NULL)
			goto err;
		}
	if (r->g != NULL)
		if ((ret->g = BN_dup(r->g)) == NULL)
			goto err;
	if (r->pub_key != NULL)
		if ((ret->pub_key = BN_dup(r->pub_key)) == NULL)
			goto err;
	if (r->priv_key != NULL)
		if ((ret->priv_key = BN_dup(r->priv_key)) == NULL)
			goto err;

	return ret;

 err:
	if (ret != NULL)
		DH_free(ret);
	return NULL;
	}
#endif