/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 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/x509.h>
#include <openssl/asn1.h>
#include <openssl/dh.h>
#include "asn1_locl.h"

static void int_dh_free(EVP_PKEY *pkey)
	{
	DH_free(pkey->pkey.dh);
	}

static int dh_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
	{
	const unsigned char *p, *pm;
	int pklen, pmlen;
	int ptype;
	void *pval;
	ASN1_STRING *pstr;
	X509_ALGOR *palg;
	ASN1_INTEGER *public_key = NULL;

	DH *dh = NULL;

	if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
		return 0;
	X509_ALGOR_get0(NULL, &ptype, &pval, palg);

	if (ptype != V_ASN1_SEQUENCE)
		{
		DHerr(DH_F_DH_PUB_DECODE, DH_R_PARAMETER_ENCODING_ERROR);
		goto err;
		}

	pstr = pval;	
	pm = pstr->data;
	pmlen = pstr->length;

	if (!(dh = d2i_DHparams(NULL, &pm, pmlen)))
		{
		DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
		goto err;
		}

	if (!(public_key=d2i_ASN1_INTEGER(NULL, &p, pklen)))
		{
		DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
		goto err;
		}

	/* We have parameters now set public key */
	if (!(dh->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)))
		{
		DHerr(DH_F_DH_PUB_DECODE, DH_R_BN_DECODE_ERROR);
		goto err;
		}

	ASN1_INTEGER_free(public_key);
	EVP_PKEY_assign_DH(pkey, dh);
	return 1;

	err:
	if (pubkey)
		ASN1_INTEGER_free(public_key);
	if (dh)
		DH_free(dh);
	return 0;

	}

static int dh_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
	{
	DH *dh;
	void *pval = NULL;
	int ptype;
	unsigned char *penc = NULL;
	int penclen;
	ASN1_STRING *str;
	ASN1_INTEGER *pub_key = NULL;

	dh=pkey->pkey.dh;

	str = ASN1_STRING_new();
	str->length = i2d_DHparams(dh, &str->data);
	if (str->length <= 0)
		{
		DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
		goto err;
		}
	pval = str;
	ptype = V_ASN1_SEQUENCE;

	pub_key = BN_to_ASN1_INTEGER(dh->pub_key, NULL);
	if (!pub_key)
		goto err;

	penclen = i2d_ASN1_INTEGER(pub_key, &penc);

	ASN1_INTEGER_free(pub_key);

	if (penclen <= 0)
		{
		DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
		goto err;
		}

	if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_DH),
				ptype, pval, penc, penclen))
		return 1;

	err:
	if (penc)
		OPENSSL_free(penc);
	if (pval)
		ASN1_STRING_free(pval);

	return 0;
	}


/* PKCS#8 DH is defined in PKCS#11 of all places. It is similar to DH in
 * that the AlgorithmIdentifier contains the paramaters, the private key
 * is explcitly included and the pubkey must be recalculated.
 */
	
static int dh_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
	{
	const unsigned char *p, *pm;
	int pklen, pmlen;
	int ptype;
	void *pval;
	ASN1_STRING *pstr;
	X509_ALGOR *palg;
	ASN1_INTEGER *privkey = NULL;

	DH *dh = NULL;

	if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
		return 0;

	X509_ALGOR_get0(NULL, &ptype, &pval, palg);

	if (ptype != V_ASN1_SEQUENCE)
			goto decerr;

	if (!(privkey=d2i_ASN1_INTEGER(NULL, &p, pklen)))
		goto decerr;


	pstr = pval;	
	pm = pstr->data;
	pmlen = pstr->length;
	if (!(dh = d2i_DHparams(NULL, &pm, pmlen)))
		goto decerr;
	/* We have parameters now set private key */
	if (!(dh->priv_key = ASN1_INTEGER_to_BN(privkey, NULL)))
		{
		DHerr(DH_F_DH_PRIV_DECODE,DH_R_BN_ERROR);
		goto dherr;
		}
	/* Calculate public key */
	if (!DH_generate_key(dh))
		goto dherr;

	EVP_PKEY_assign_DH(pkey, dh);

	ASN1_INTEGER_free(privkey);

	return 1;

	decerr:
	DHerr(DH_F_DH_PRIV_DECODE, EVP_R_DECODE_ERROR);
	dherr:
	DH_free(dh);
	return 0;
	}

static int dh_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
	ASN1_STRING *params = NULL;
	ASN1_INTEGER *prkey = NULL;
	unsigned char *dp = NULL;
	int dplen;

	params = ASN1_STRING_new();

	if (!params)
		{
		DHerr(DH_F_DH_PRIV_ENCODE,ERR_R_MALLOC_FAILURE);
		goto err;
		}

	params->length = i2d_DHparams(pkey->pkey.dh, &params->data);
	if (params->length <= 0)
		{
		DHerr(DH_F_DH_PRIV_ENCODE,ERR_R_MALLOC_FAILURE);
		goto err;
		}
	params->type = V_ASN1_SEQUENCE;

	/* Get private key into integer */
	prkey = BN_to_ASN1_INTEGER(pkey->pkey.dh->priv_key, NULL);

	if (!prkey)
		{
		DHerr(DH_F_DH_PRIV_ENCODE,DH_R_BN_ERROR);
		goto err;
		}

	dplen = i2d_ASN1_INTEGER(prkey, &dp);

	ASN1_INTEGER_free(prkey);

	if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_dhKeyAgreement), 0,
				V_ASN1_SEQUENCE, params, dp, dplen))
		goto err;

	return 1;

err:
	if (dp != NULL)
		OPENSSL_free(dp);
	if (params != NULL)
		ASN1_STRING_free(params);
	if (prkey != NULL)
		ASN1_INTEGER_free(prkey);
	return 0;
}


static void update_buflen(const BIGNUM *b, size_t *pbuflen)
	{
	size_t i;
	if (!b)
		return;
	if (*pbuflen < (i = (size_t)BN_num_bytes(b)))
			*pbuflen = i;
	}

static int dh_param_decode(EVP_PKEY *pkey,
					const unsigned char **pder, int derlen)
	{
	DH *dh;
	if (!(dh = d2i_DHparams(NULL, pder, derlen)))
		{
		DHerr(DH_F_DH_PARAM_DECODE, ERR_R_DH_LIB);
		return 0;
		}
	EVP_PKEY_assign_DH(pkey, dh);
	return 1;
	}

static int dh_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
	{
	return i2d_DHparams(pkey->pkey.dh, pder);
	}

static int do_dh_print(BIO *bp, const DH *x, int indent,
						ASN1_PCTX *ctx, int ptype)
	{
	unsigned char *m=NULL;
	int reason=ERR_R_BUF_LIB,ret=0;
	size_t buf_len=0;

	const char *ktype = NULL;

	BIGNUM *priv_key, *pub_key;

	if (ptype == 2)
		priv_key = x->priv_key;
	else
		priv_key = NULL;

	if (ptype > 0)
		pub_key = x->pub_key;
	else
		pub_key = NULL;

	update_buflen(x->p, &buf_len);

	if (buf_len == 0)
		{
		reason = ERR_R_PASSED_NULL_PARAMETER;
		goto err;
		}

	update_buflen(x->g, &buf_len);
	update_buflen(pub_key, &buf_len);
	update_buflen(priv_key, &buf_len);

	if (ptype == 2)
		ktype = "PKCS#3 DH Private-Key";
	else if (ptype == 1)
		ktype = "PKCS#3 DH Public-Key";
	else
		ktype = "PKCS#3 DH Parameters";

	m= OPENSSL_malloc(buf_len+10);
	if (m == NULL)
		{
		reason=ERR_R_MALLOC_FAILURE;
		goto err;
		}

	BIO_indent(bp, indent, 128);
	if (BIO_printf(bp,"%s: (%d bit)\n", ktype, BN_num_bits(x->p)) <= 0)
		goto err;
	indent += 4;

	if (!ASN1_bn_print(bp,"private-key:",priv_key,m,indent)) goto err;
	if (!ASN1_bn_print(bp,"public-key:",pub_key,m,indent)) goto err;

	if (!ASN1_bn_print(bp,"prime:",x->p,m,indent)) goto err;
	if (!ASN1_bn_print(bp,"generator:",x->g,m,indent)) goto err;
	if (x->length != 0)
		{
		BIO_indent(bp, indent, 128);
		if (BIO_printf(bp,"recommended-private-length: %d bits\n",
			(int)x->length) <= 0) goto err;
		}


	ret=1;
	if (0)
		{
err:
		DHerr(DH_F_DHPARAMS_PRINT,reason);
		}
	if (m != NULL) OPENSSL_free(m);
	return(ret);
	}

static int int_dh_size(const EVP_PKEY *pkey)
	{
	return(DH_size(pkey->pkey.dh));
	}

static int dh_bits(const EVP_PKEY *pkey)
	{
	return BN_num_bits(pkey->pkey.dh->p);
	}

static int dh_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
	{
	if (	BN_cmp(a->pkey.dh->p,b->pkey.dh->p) ||
		BN_cmp(a->pkey.dh->g,b->pkey.dh->g))
		return 0;
	else
		return 1;
	}

static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
	{
	BIGNUM *a;

	if ((a=BN_dup(from->pkey.dh->p)) == NULL)
		return 0;
	if (to->pkey.dh->p != NULL)
		BN_free(to->pkey.dh->p);
	to->pkey.dh->p=a;

	if ((a=BN_dup(from->pkey.dh->g)) == NULL)
		return 0;
	if (to->pkey.dh->g != NULL)
		BN_free(to->pkey.dh->g);
	to->pkey.dh->g=a;

	return 1;
	}

static int dh_missing_parameters(const EVP_PKEY *a)
	{
	if (!a->pkey.dh->p || !a->pkey.dh->g)
		return 1;
	return 0;
	}

static int dh_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
	{
	if (dh_cmp_parameters(a, b) == 0)
		return 0;
	if (BN_cmp(b->pkey.dh->pub_key,a->pkey.dh->pub_key) != 0)
		return 0;
	else
		return 1;
	}

static int dh_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_dh_print(bp, pkey->pkey.dh, indent, ctx, 0);
	}

static int dh_public_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_dh_print(bp, pkey->pkey.dh, indent, ctx, 1);
	}

static int dh_private_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_dh_print(bp, pkey->pkey.dh, indent, ctx, 2);
	}

int DHparams_print(BIO *bp, const DH *x)
	{
	return do_dh_print(bp, x, 4, NULL, 0);
	}

const EVP_PKEY_ASN1_METHOD dh_asn1_meth = 
	{
	EVP_PKEY_DH,
	EVP_PKEY_DH,
	0,

	"DH",
	"OpenSSL PKCS#3 DH method",

	dh_pub_decode,
	dh_pub_encode,
	dh_pub_cmp,
	dh_public_print,

	dh_priv_decode,
	dh_priv_encode,
	dh_private_print,

	int_dh_size,
	dh_bits,

	dh_param_decode,
	dh_param_encode,
	dh_missing_parameters,
	dh_copy_parameters,
	dh_cmp_parameters,
	dh_param_print,

	int_dh_free,
	0
	};