openssl/crypto/dh/dh_ameth.c

/* Written by Dr Stephen N Henson (steve@openssl.org) 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 <openssl/bn.h>
#include "asn1_locl.h"
#ifndef OPENSSL_NO_CMS
#include <openssl/cms.h>
#endif

extern const EVP_PKEY_ASN1_METHOD dhx_asn1_meth;

/* i2d/d2i like DH parameter functions which use the appropriate routine
 * for PKCS#3 DH or X9.42 DH.
 */

static DH * d2i_dhp(const EVP_PKEY *pkey, const unsigned char **pp, long length)
	{
	if (pkey->ameth == &dhx_asn1_meth)
		return d2i_DHxparams(NULL, pp, length);
	return d2i_DHparams(NULL, pp, length);
	}

static int i2d_dhp(const EVP_PKEY *pkey, const DH *a, unsigned char **pp)
	{
	if (pkey->ameth == &dhx_asn1_meth)
		return i2d_DHxparams(a, pp);
	return i2d_DHparams(a, pp);
	}

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_dhp(pkey, &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(pkey, pkey->ameth->pkey_id, dh);
	return 1;

	err:
	if (public_key)
		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_dhp(pkey, 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(pkey->ameth->pkey_id),
				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_dhp(pkey, &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(pkey, pkey->ameth->pkey_id, 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_dhp(pkey, 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(pkey->ameth->pkey_id), 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_dhp(pkey, pder, derlen)))
		{
		DHerr(DH_F_DH_PARAM_DECODE, ERR_R_DH_LIB);
		return 0;
		}
	EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
	return 1;
	}

static int dh_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
	{
	return i2d_dhp(pkey, 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(x->q, &buf_len);
	update_buflen(x->j, &buf_len);
	update_buflen(x->counter, &buf_len);
	update_buflen(pub_key, &buf_len);
	update_buflen(priv_key, &buf_len);

	if (ptype == 2)
		ktype = "DH Private-Key";
	else if (ptype == 1)
		ktype = "DH Public-Key";
	else
		ktype = "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->q && !ASN1_bn_print(bp,"subgroup order:",x->q,m,indent)) goto err;
	if (x->j && !ASN1_bn_print(bp,"subgroup factor:",x->j,m,indent))
		goto err;
	if (x->seed)
		{
		int i;
		BIO_indent(bp, indent, 128);
		BIO_puts(bp, "seed:");
		for (i=0; i < x->seedlen; i++)
			{
			if ((i%15) == 0)
				{
				if(BIO_puts(bp,"\n") <= 0
				   || !BIO_indent(bp,indent+4,128))
				    goto err;
				}
			if (BIO_printf(bp,"%02x%s", x->seed[i],
					((i+1) == x->seedlen)?"":":") <= 0)
				goto err;
			}
		if (BIO_write(bp,"\n",1) <= 0) return(0);
		}
	if (x->counter && !ASN1_bn_print(bp,"counter:",x->counter,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_DO_DH_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 if (a->ameth == &dhx_asn1_meth)
		{
		if (BN_cmp(a->pkey.dh->q,b->pkey.dh->q))
			return 0;
		}
	return 1;
	}

static int int_dh_bn_cpy(BIGNUM **dst, const BIGNUM *src)
	{
	BIGNUM *a;
	if (src)
		{
		a = BN_dup(src);
		if (!a)
			return 0;
		}
	else 
		a = NULL;
	if (*dst)
		BN_free(*dst);
	*dst = a;
	return 1;
	}

static int int_dh_param_copy(DH *to, const DH *from, int is_x942)
	{
	if (is_x942 == -1)
		is_x942 = !!from->q;
	if (!int_dh_bn_cpy(&to->p, from->p))
		return 0;
	if (!int_dh_bn_cpy(&to->g, from->g))
		return 0;
	if (is_x942)
		{
		if (!int_dh_bn_cpy(&to->q, from->q))
			return 0;
		if (!int_dh_bn_cpy(&to->j, from->j))
			return 0;
		if(to->seed)
			{
			OPENSSL_free(to->seed);
			to->seed = NULL;
			to->seedlen = 0;
			}
		if (from->seed)
			{
			to->seed = BUF_memdup(from->seed, from->seedlen);
			if (!to->seed)
				return 0;
			to->seedlen = from->seedlen;
			}
		}
	else
		to->length = from->length;
	return 1;
	}


DH *DHparams_dup(DH *dh)
	{
	DH *ret;
	ret = DH_new();
	if (!ret)
		return NULL;
	if (!int_dh_param_copy(ret, dh, -1))
		{
		DH_free(ret);
		return NULL;
		}
	return ret;
	}

static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
	{
	return int_dh_param_copy(to->pkey.dh, from->pkey.dh,
				 from->ameth == &dhx_asn1_meth);
	}

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);
	}

#ifndef OPENSSL_NO_CMS
static int dh_cms_decrypt(CMS_RecipientInfo *ri);
static int dh_cms_encrypt(CMS_RecipientInfo *ri);
#endif

static int dh_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
	{
	switch (op)
		{
#ifndef OPENSSL_NO_CMS

		case ASN1_PKEY_CTRL_CMS_ENVELOPE:
		if (arg1 == 1)
			return dh_cms_decrypt(arg2);
		else if (arg1 == 0)
			return dh_cms_encrypt(arg2);
		return -2;

		case ASN1_PKEY_CTRL_CMS_RI_TYPE:
		*(int *)arg2 = CMS_RECIPINFO_AGREE;
		return 1;
#endif
		default:
		return -2;
		}

	}

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,
	0,

	int_dh_free,
	0
	};

const EVP_PKEY_ASN1_METHOD dhx_asn1_meth = 
	{
	EVP_PKEY_DHX,
	EVP_PKEY_DHX,
	0,

	"X9.42 DH",
	"OpenSSL X9.42 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,
	0,

	int_dh_free,
	dh_pkey_ctrl
	};
#ifndef OPENSSL_NO_CMS

static int dh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
				X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
	{
	ASN1_OBJECT *aoid;
	int atype;
	void *aval;
	ASN1_INTEGER *public_key = NULL;
	int rv = 0;
	EVP_PKEY *pkpeer = NULL, *pk = NULL;
	DH *dhpeer = NULL;
	const unsigned char *p;
	int plen;

	X509_ALGOR_get0(&aoid, &atype, &aval, alg);
	if (OBJ_obj2nid(aoid) != NID_dhpublicnumber)
		goto err;
	/* Only absent parameters allowed in RFC XXXX */
	if (atype != V_ASN1_UNDEF && atype == V_ASN1_NULL)
		goto err;

	pk = EVP_PKEY_CTX_get0_pkey(pctx);
	if (!pk)
		goto err;
	if (pk->type != EVP_PKEY_DHX)
		goto err;
	/* Get parameters from parent key */
	dhpeer = DHparams_dup(pk->pkey.dh);
	/* We have parameters now set public key */
	plen = ASN1_STRING_length(pubkey);
	p = ASN1_STRING_data(pubkey);
	if (!p || !plen)
		goto err;

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

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

	pkpeer = EVP_PKEY_new();
	if (!pkpeer)
		goto err;
	EVP_PKEY_assign(pkpeer, pk->ameth->pkey_id, dhpeer);
	dhpeer = NULL;
	if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
		rv = 1;
	err:
	if (public_key)
		ASN1_INTEGER_free(public_key);
	if (pkpeer)
		EVP_PKEY_free(pkpeer);
	if (dhpeer)
		DH_free(dhpeer);
	return rv;
	}

static int dh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
	{
	int rv = 0;

	X509_ALGOR *alg, *kekalg = NULL;
	ASN1_OCTET_STRING *ukm;
	const unsigned char *p;
	unsigned char *dukm = NULL;
	size_t dukmlen = 0;
	int keylen, plen;
	const EVP_CIPHER *kekcipher;
	EVP_CIPHER_CTX *kekctx;

	if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
		goto err;

	/* For DH we only have one OID permissible. If ever any more get
	 * defined we will need something cleverer.
	 */
	if (OBJ_obj2nid(alg->algorithm) != NID_id_smime_alg_ESDH)
		{
		DHerr(DH_F_DH_CMS_SET_SHARED_INFO, DH_R_KDF_PARAMETER_ERROR);
		goto err;
		}

	if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, EVP_PKEY_DH_KDF_X9_42) <= 0)
		goto err;

	if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, EVP_sha1()) <= 0)
		goto err;

	if (alg->parameter->type != V_ASN1_SEQUENCE)
		goto err;

	p = alg->parameter->value.sequence->data;
	plen = alg->parameter->value.sequence->length;
	kekalg = d2i_X509_ALGOR(NULL, &p, plen);
	if (!kekalg)
		goto err;
	kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
	if (!kekctx)
		goto err;
	kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
	if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
		goto err;
	if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
		goto err;
	if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
		goto err;

	keylen = EVP_CIPHER_CTX_key_length(kekctx);
	if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
		goto err;
	/* Use OBJ_nid2obj to ensure we use built in OID that isn't freed */
	if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx,
				OBJ_nid2obj(EVP_CIPHER_type(kekcipher))) <= 0)
		goto err;

	if (ukm)
		{
		dukmlen = ASN1_STRING_length(ukm);
		dukm = BUF_memdup(ASN1_STRING_data(ukm), dukmlen);
		if (!dukm)
			goto err;
		}

	if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
		goto err;
	dukm = NULL;

	rv = 1;
	err:
	if (kekalg)
		X509_ALGOR_free(kekalg);
	if (dukm)
		OPENSSL_free(dukm);
	return rv;
	}

static int dh_cms_decrypt(CMS_RecipientInfo *ri)
	{
	EVP_PKEY_CTX *pctx;
	pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
	if (!pctx)
		return 0;
	/* See if we need to set peer key */
	if (!EVP_PKEY_CTX_get0_peerkey(pctx))
		{
		X509_ALGOR *alg;
		ASN1_BIT_STRING *pubkey;
		if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
							NULL, NULL, NULL))
			return 0;
		if (!alg || !pubkey)
			return 0;
		if (!dh_cms_set_peerkey(pctx, alg, pubkey))
			{
			DHerr(DH_F_DH_CMS_DECRYPT, DH_R_PEER_KEY_ERROR);
			return 0;
			}
		}
	/* Set DH derivation parameters and initialise unwrap context */
	if (!dh_cms_set_shared_info(pctx, ri))
		{
		DHerr(DH_F_DH_CMS_DECRYPT, DH_R_SHARED_INFO_ERROR);
		return 0;
		}
	return 1;
	}

static int dh_cms_encrypt(CMS_RecipientInfo *ri)
	{
	EVP_PKEY_CTX *pctx;
	EVP_PKEY *pkey;
	EVP_CIPHER_CTX *ctx;
	int keylen;
	X509_ALGOR *talg, *wrap_alg = NULL;
	ASN1_OBJECT *aoid;
	ASN1_BIT_STRING *pubkey;
	ASN1_STRING *wrap_str;
	ASN1_OCTET_STRING *ukm;
	unsigned char *penc = NULL, *dukm = NULL;
	int penclen;
	size_t dukmlen = 0;
	int rv = 0;
	int kdf_type, wrap_nid;
	const EVP_MD *kdf_md;
	pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
	if (!pctx)
		return 0;
	/* Get ephemeral key */
	pkey = EVP_PKEY_CTX_get0_pkey(pctx);
	if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
							NULL, NULL, NULL))
		goto err;
	X509_ALGOR_get0(&aoid, NULL, NULL, talg);
	/* Is everything uninitialised? */
	if (aoid == OBJ_nid2obj(NID_undef))
		{
		ASN1_INTEGER *pubk;
		pubk = BN_to_ASN1_INTEGER(pkey->pkey.dh->pub_key, NULL);
		if (!pubk)
			goto err;
		/* Set the key */

		penclen = i2d_ASN1_INTEGER(pubk, &penc);
		ASN1_INTEGER_free(pubk);
		if (penclen <= 0)
			goto err;
		ASN1_STRING_set0(pubkey, penc, penclen);
		pubkey->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07);
		pubkey->flags|=ASN1_STRING_FLAG_BITS_LEFT;

		penc = NULL;
		X509_ALGOR_set0(talg, OBJ_nid2obj(NID_dhpublicnumber),
							V_ASN1_UNDEF, NULL);
		}

	/* See if custom paraneters set */
	kdf_type = EVP_PKEY_CTX_get_dh_kdf_type(pctx);
	if (kdf_type <= 0)
		goto err;
	if (!EVP_PKEY_CTX_get_dh_kdf_md(pctx, &kdf_md))
		goto err;

	if (kdf_type == EVP_PKEY_DH_KDF_NONE)
		{
		kdf_type = EVP_PKEY_DH_KDF_X9_42;
		if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, kdf_type) <= 0)
			goto err;
		}
	else if (kdf_type != EVP_PKEY_DH_KDF_X9_42)
		/* Unknown KDF */
		goto err;
	if (kdf_md == NULL)
		{
		/* Only SHA1 supported */
		kdf_md = EVP_sha1();
		if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, kdf_md) <= 0)
			goto err;
		}
	else if (EVP_MD_type(kdf_md) != NID_sha1)
		/* Unsupported digest */
		goto err;

	if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
		goto err;

	/* Get wrap NID */
	ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
	wrap_nid = EVP_CIPHER_CTX_type(ctx);
	if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx, OBJ_nid2obj(wrap_nid)) <= 0)
		goto err;
	keylen = EVP_CIPHER_CTX_key_length(ctx);

	/* Package wrap algorithm in an AlgorithmIdentifier */

	wrap_alg = X509_ALGOR_new();
	if (!wrap_alg)
		goto err;
	wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
	wrap_alg->parameter = ASN1_TYPE_new();
	if (!wrap_alg->parameter)
		goto err;
	if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
		goto err;
	if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef)
		{
		ASN1_TYPE_free(wrap_alg->parameter);
		wrap_alg->parameter = NULL;
		}

	if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
		goto err;

	if (ukm)
		{
		dukmlen = ASN1_STRING_length(ukm);
		dukm = BUF_memdup(ASN1_STRING_data(ukm), dukmlen);
		if (!dukm)
			goto err;
		}

	if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
		goto err;
	dukm = NULL;

	/* Now need to wrap encoding of wrap AlgorithmIdentifier into
	 * parameter of another AlgorithmIdentifier.
	 */
	penc = NULL;
	penclen = i2d_X509_ALGOR(wrap_alg, &penc);
	if (!penc || !penclen)
		goto err;
	wrap_str = ASN1_STRING_new();
	if (!wrap_str)
		goto err;
	ASN1_STRING_set0(wrap_str, penc, penclen);
	penc = NULL;
	X509_ALGOR_set0(talg, OBJ_nid2obj(NID_id_smime_alg_ESDH),
						V_ASN1_SEQUENCE, wrap_str);

	rv = 1;

	err:
	if (penc)
		OPENSSL_free(penc);
	if (wrap_alg)
		X509_ALGOR_free(wrap_alg);
	return rv;
	}

#endif