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openssl/crypto/ec/ec_ameth.c
Dr. Stephen Henson 1747fd1cc6 Add support for ECDH KARI. 
Add support for ECDH in enveloped data. The CMS ctrls for the EC ASN1
method decode/encode the appropriate parameters from the CMS ASN1 data
and send appropriate data to the EC public key method.
(cherry picked from commit 88e20b8584)
2013-10-01 14:01:18 +01:00

1037 lines
24 KiB
C
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/* 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/ec.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_CMS
#include <openssl/cms.h>
#endif
#include <openssl/asn1t.h>
#include "asn1_locl.h"
static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
{
const EC_GROUP *group;
int nid;
if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL)
{
ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
return 0;
}
if (EC_GROUP_get_asn1_flag(group)
&& (nid = EC_GROUP_get_curve_name(group)))
/* we have a 'named curve' => just set the OID */
{
*ppval = OBJ_nid2obj(nid);
*pptype = V_ASN1_OBJECT;
}
else /* explicit parameters */
{
ASN1_STRING *pstr = NULL;
pstr = ASN1_STRING_new();
if (!pstr)
return 0;
pstr->length = i2d_ECParameters(ec_key, &pstr->data);
if (pstr->length <= 0)
{
ASN1_STRING_free(pstr);
ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
return 0;
}
*ppval = pstr;
*pptype = V_ASN1_SEQUENCE;
}
return 1;
}
static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
{
EC_KEY *ec_key = pkey->pkey.ec;
void *pval = NULL;
int ptype;
unsigned char *penc = NULL, *p;
int penclen;
if (!eckey_param2type(&ptype, &pval, ec_key))
{
ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
return 0;
}
penclen = i2o_ECPublicKey(ec_key, NULL);
if (penclen <= 0)
goto err;
penc = OPENSSL_malloc(penclen);
if (!penc)
goto err;
p = penc;
penclen = i2o_ECPublicKey(ec_key, &p);
if (penclen <= 0)
goto err;
if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
ptype, pval, penc, penclen))
return 1;
err:
if (ptype == V_ASN1_OBJECT)
ASN1_OBJECT_free(pval);
else
ASN1_STRING_free(pval);
if (penc)
OPENSSL_free(penc);
return 0;
}
static EC_KEY *eckey_type2param(int ptype, void *pval)
{
EC_KEY *eckey = NULL;
if (ptype == V_ASN1_SEQUENCE)
{
ASN1_STRING *pstr = pval;
const unsigned char *pm = NULL;
int pmlen;
pm = pstr->data;
pmlen = pstr->length;
if (!(eckey = d2i_ECParameters(NULL, &pm, pmlen)))
{
ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
goto ecerr;
}
}
else if (ptype == V_ASN1_OBJECT)
{
ASN1_OBJECT *poid = pval;
EC_GROUP *group;
/* type == V_ASN1_OBJECT => the parameters are given
* by an asn1 OID
*/
if ((eckey = EC_KEY_new()) == NULL)
{
ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
goto ecerr;
}
group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
if (group == NULL)
goto ecerr;
EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
if (EC_KEY_set_group(eckey, group) == 0)
goto ecerr;
EC_GROUP_free(group);
}
else
{
ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
goto ecerr;
}
return eckey;
ecerr:
if (eckey)
EC_KEY_free(eckey);
return NULL;
}
static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
{
const unsigned char *p = NULL;
void *pval;
int ptype, pklen;
EC_KEY *eckey = NULL;
X509_ALGOR *palg;
if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
return 0;
X509_ALGOR_get0(NULL, &ptype, &pval, palg);
eckey = eckey_type2param(ptype, pval);
if (!eckey)
{
ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
return 0;
}
/* We have parameters now set public key */
if (!o2i_ECPublicKey(&eckey, &p, pklen))
{
ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
goto ecerr;
}
EVP_PKEY_assign_EC_KEY(pkey, eckey);
return 1;
ecerr:
if (eckey)
EC_KEY_free(eckey);
return 0;
}
static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
{
int r;
const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
*pb = EC_KEY_get0_public_key(b->pkey.ec);
r = EC_POINT_cmp(group, pa, pb, NULL);
if (r == 0)
return 1;
if (r == 1)
return 0;
return -2;
}
static int eckey_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
{
const unsigned char *p = NULL;
void *pval;
int ptype, pklen;
EC_KEY *eckey = NULL;
X509_ALGOR *palg;
if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
return 0;
X509_ALGOR_get0(NULL, &ptype, &pval, palg);
eckey = eckey_type2param(ptype, pval);
if (!eckey)
goto ecliberr;
/* We have parameters now set private key */
if (!d2i_ECPrivateKey(&eckey, &p, pklen))
{
ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
goto ecerr;
}
/* calculate public key (if necessary) */
if (EC_KEY_get0_public_key(eckey) == NULL)
{
const BIGNUM *priv_key;
const EC_GROUP *group;
EC_POINT *pub_key;
/* the public key was not included in the SEC1 private
* key => calculate the public key */
group = EC_KEY_get0_group(eckey);
pub_key = EC_POINT_new(group);
if (pub_key == NULL)
{
ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
goto ecliberr;
}
if (!EC_POINT_copy(pub_key, EC_GROUP_get0_generator(group)))
{
EC_POINT_free(pub_key);
ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
goto ecliberr;
}
priv_key = EC_KEY_get0_private_key(eckey);
if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, NULL))
{
EC_POINT_free(pub_key);
ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
goto ecliberr;
}
if (EC_KEY_set_public_key(eckey, pub_key) == 0)
{
EC_POINT_free(pub_key);
ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
goto ecliberr;
}
EC_POINT_free(pub_key);
}
EVP_PKEY_assign_EC_KEY(pkey, eckey);
return 1;
ecliberr:
ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
ecerr:
if (eckey)
EC_KEY_free(eckey);
return 0;
}
static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
EC_KEY *ec_key;
unsigned char *ep, *p;
int eplen, ptype;
void *pval;
unsigned int tmp_flags, old_flags;
ec_key = pkey->pkey.ec;
if (!eckey_param2type(&ptype, &pval, ec_key))
{
ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
return 0;
}
/* set the private key */
/* do not include the parameters in the SEC1 private key
* see PKCS#11 12.11 */
old_flags = EC_KEY_get_enc_flags(ec_key);
tmp_flags = old_flags | EC_PKEY_NO_PARAMETERS;
EC_KEY_set_enc_flags(ec_key, tmp_flags);
eplen = i2d_ECPrivateKey(ec_key, NULL);
if (!eplen)
{
EC_KEY_set_enc_flags(ec_key, old_flags);
ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
return 0;
}
ep = (unsigned char *) OPENSSL_malloc(eplen);
if (!ep)
{
EC_KEY_set_enc_flags(ec_key, old_flags);
ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
return 0;
}
p = ep;
if (!i2d_ECPrivateKey(ec_key, &p))
{
EC_KEY_set_enc_flags(ec_key, old_flags);
OPENSSL_free(ep);
ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
}
/* restore old encoding flags */
EC_KEY_set_enc_flags(ec_key, old_flags);
if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
ptype, pval, ep, eplen))
return 0;
return 1;
}
static int int_ec_size(const EVP_PKEY *pkey)
{
return ECDSA_size(pkey->pkey.ec);
}
static int ec_bits(const EVP_PKEY *pkey)
{
BIGNUM *order = BN_new();
const EC_GROUP *group;
int ret;
if (!order)
{
ERR_clear_error();
return 0;
}
group = EC_KEY_get0_group(pkey->pkey.ec);
if (!EC_GROUP_get_order(group, order, NULL))
{
ERR_clear_error();
return 0;
}
ret = BN_num_bits(order);
BN_free(order);
return ret;
}
static int ec_missing_parameters(const EVP_PKEY *pkey)
{
if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
return 1;
return 0;
}
static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
{
EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
if (group == NULL)
return 0;
if (EC_KEY_set_group(to->pkey.ec, group) == 0)
return 0;
EC_GROUP_free(group);
return 1;
}
static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
{
const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
*group_b = EC_KEY_get0_group(b->pkey.ec);
if (EC_GROUP_cmp(group_a, group_b, NULL))
return 0;
else
return 1;
}
static void int_ec_free(EVP_PKEY *pkey)
{
EC_KEY_free(pkey->pkey.ec);
}
static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, int ktype)
{
unsigned char *buffer=NULL;
const char *ecstr;
size_t buf_len=0, i;
int ret=0, reason=ERR_R_BIO_LIB;
BIGNUM *pub_key=NULL, *order=NULL;
BN_CTX *ctx=NULL;
const EC_GROUP *group;
const EC_POINT *public_key;
const BIGNUM *priv_key;
if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL)
{
reason = ERR_R_PASSED_NULL_PARAMETER;
goto err;
}
ctx = BN_CTX_new();
if (ctx == NULL)
{
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
if (ktype > 0)
{
public_key = EC_KEY_get0_public_key(x);
if ((pub_key = EC_POINT_point2bn(group, public_key,
EC_KEY_get_conv_form(x), NULL, ctx)) == NULL)
{
reason = ERR_R_EC_LIB;
goto err;
}
if (pub_key)
buf_len = (size_t)BN_num_bytes(pub_key);
}
if (ktype == 2)
{
priv_key = EC_KEY_get0_private_key(x);
if (priv_key && (i = (size_t)BN_num_bytes(priv_key)) > buf_len)
buf_len = i;
}
else
priv_key = NULL;
if (ktype > 0)
{
buf_len += 10;
if ((buffer = OPENSSL_malloc(buf_len)) == NULL)
{
reason = ERR_R_MALLOC_FAILURE;
goto err;
}
}
if (ktype == 2)
ecstr = "Private-Key";
else if (ktype == 1)
ecstr = "Public-Key";
else
ecstr = "ECDSA-Parameters";
if (!BIO_indent(bp, off, 128))
goto err;
if ((order = BN_new()) == NULL)
goto err;
if (!EC_GROUP_get_order(group, order, NULL))
goto err;
if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
BN_num_bits(order)) <= 0) goto err;
if ((priv_key != NULL) && !ASN1_bn_print(bp, "priv:", priv_key,
buffer, off))
goto err;
if ((pub_key != NULL) && !ASN1_bn_print(bp, "pub: ", pub_key,
buffer, off))
goto err;
if (!ECPKParameters_print(bp, group, off))
goto err;
ret=1;
err:
if (!ret)
ECerr(EC_F_DO_EC_KEY_PRINT, reason);
if (pub_key)
BN_free(pub_key);
if (order)
BN_free(order);
if (ctx)
BN_CTX_free(ctx);
if (buffer != NULL)
OPENSSL_free(buffer);
return(ret);
}
static int eckey_param_decode(EVP_PKEY *pkey,
const unsigned char **pder, int derlen)
{
EC_KEY *eckey;
if (!(eckey = d2i_ECParameters(NULL, pder, derlen)))
{
ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
return 0;
}
EVP_PKEY_assign_EC_KEY(pkey, eckey);
return 1;
}
static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
return i2d_ECParameters(pkey->pkey.ec, pder);
}
static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
ASN1_PCTX *ctx)
{
return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 0);
}
static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
ASN1_PCTX *ctx)
{
return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 1);
}
static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
ASN1_PCTX *ctx)
{
return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 2);
}
static int old_ec_priv_decode(EVP_PKEY *pkey,
const unsigned char **pder, int derlen)
{
EC_KEY *ec;
if (!(ec = d2i_ECPrivateKey (NULL, pder, derlen)))
{
ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
return 0;
}
EVP_PKEY_assign_EC_KEY(pkey, ec);
return 1;
}
static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
return i2d_ECPrivateKey(pkey->pkey.ec, pder);
}
static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
switch (op)
{
case ASN1_PKEY_CTRL_PKCS7_SIGN:
if (arg1 == 0)
{
int snid, hnid;
X509_ALGOR *alg1, *alg2;
PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
if (alg1 == NULL || alg1->algorithm == NULL)
return -1;
hnid = OBJ_obj2nid(alg1->algorithm);
if (hnid == NID_undef)
return -1;
if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
return -1;
X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
}
return 1;
#ifndef OPENSSL_NO_CMS
case ASN1_PKEY_CTRL_CMS_SIGN:
if (arg1 == 0)
{
int snid, hnid;
X509_ALGOR *alg1, *alg2;
CMS_SignerInfo_get0_algs(arg2, NULL, NULL,
&alg1, &alg2);
if (alg1 == NULL || alg1->algorithm == NULL)
return -1;
hnid = OBJ_obj2nid(alg1->algorithm);
if (hnid == NID_undef)
return -1;
if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
return -1;
X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
}
return 1;
case ASN1_PKEY_CTRL_CMS_ENVELOPE:
if (arg1 == 1)
return ecdh_cms_decrypt(arg2);
else if (arg1 == 0)
return ecdh_cms_encrypt(arg2);
return -2;
case ASN1_PKEY_CTRL_CMS_RI_TYPE:
*(int *)arg2 = CMS_RECIPINFO_AGREE;
return 1;
#endif
case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
*(int *)arg2 = NID_sha1;
return 2;
default:
return -2;
}
}
const EVP_PKEY_ASN1_METHOD eckey_asn1_meth =
{
EVP_PKEY_EC,
EVP_PKEY_EC,
0,
"EC",
"OpenSSL EC algorithm",
eckey_pub_decode,
eckey_pub_encode,
eckey_pub_cmp,
eckey_pub_print,
eckey_priv_decode,
eckey_priv_encode,
eckey_priv_print,
int_ec_size,
ec_bits,
eckey_param_decode,
eckey_param_encode,
ec_missing_parameters,
ec_copy_parameters,
ec_cmp_parameters,
eckey_param_print,
0,
int_ec_free,
ec_pkey_ctrl,
old_ec_priv_decode,
old_ec_priv_encode
};
#ifndef OPENSSL_NO_CMS
static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
{
ASN1_OBJECT *aoid;
int atype;
void *aval;
int rv = 0;
EVP_PKEY *pkpeer = NULL;
EC_KEY *ecpeer = NULL;
const unsigned char *p;
int plen;
X509_ALGOR_get0(&aoid, &atype, &aval, alg);
if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
goto err;
/* If absent parameters get group from main key */
if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL)
{
const EC_GROUP *grp;
EVP_PKEY *pk;
pk = EVP_PKEY_CTX_get0_pkey(pctx);
if (!pk)
goto err;
grp = EC_KEY_get0_group(pk->pkey.ec);
ecpeer = EC_KEY_new();
if (!ecpeer)
goto err;
if (!EC_KEY_set_group(ecpeer, grp))
goto err;
}
else
{
ecpeer = eckey_type2param(atype, aval);
if (!ecpeer)
goto err;
}
/* We have parameters now set public key */
plen = ASN1_STRING_length(pubkey);
p = ASN1_STRING_data(pubkey);
if (!p || !plen)
goto err;
if (!o2i_ECPublicKey(&ecpeer, &p, plen))
goto err;
pkpeer = EVP_PKEY_new();
if (!pkpeer)
goto err;
EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
rv = 1;
err:
if (ecpeer)
EC_KEY_free(ecpeer);
if (pkpeer)
EVP_PKEY_free(pkpeer);
return rv;
}
/* Set KDF parameters based on KDF NID */
static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
{
int kdf_nid, kdfmd_nid, cofactor;
const EVP_MD *kdf_md;
if (eckdf_nid == NID_undef)
return 0;
/* Lookup KDF type, cofactor mode and digest */
if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
return 0;
if (kdf_nid == NID_dh_std_kdf)
cofactor = 0;
else if (kdf_nid == NID_dh_cofactor_kdf)
cofactor = 1;
else return 0;
if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
return 0;
if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_62) <= 0)
return 0;
kdf_md = EVP_get_digestbynid(kdfmd_nid);
if (!kdf_md)
return 0;
if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
return 0;
return 1;
}
/* Utilities to encode the ECC_CMS_SharedInfo structure used during key
* derivation.
*/
typedef struct {
X509_ALGOR *keyInfo;
ASN1_OCTET_STRING *entityUInfo;
ASN1_OCTET_STRING *suppPubInfo;
} ECC_CMS_SharedInfo;
ASN1_SEQUENCE(ECC_CMS_SharedInfo) = {
ASN1_SIMPLE(ECC_CMS_SharedInfo, keyInfo, X509_ALGOR),
ASN1_EXP_OPT(ECC_CMS_SharedInfo, entityUInfo, ASN1_OCTET_STRING, 0),
ASN1_EXP_OPT(ECC_CMS_SharedInfo, suppPubInfo, ASN1_OCTET_STRING, 2),
} ASN1_SEQUENCE_END(ECC_CMS_SharedInfo)
static int ecdh_cms_set_ukm(EVP_PKEY_CTX *pctx,
X509_ALGOR *kekalg,
ASN1_OCTET_STRING *ukm,
int keylen)
{
union {
ECC_CMS_SharedInfo *pecsi;
ASN1_VALUE *a;
} intsi = {NULL};
unsigned char *der = NULL;
int plen;
ASN1_OCTET_STRING oklen;
unsigned char kl[4];
ECC_CMS_SharedInfo ecsi;
keylen <<= 3;
kl[0] = (keylen >> 24) & 0xff;
kl[1] = (keylen >> 16) & 0xff;
kl[2] = (keylen >> 8) & 0xff;
kl[3] = keylen & 0xff;
oklen.length = 4;
oklen.data = kl;
oklen.type = V_ASN1_OCTET_STRING;
oklen.flags = 0;
ecsi.keyInfo = kekalg;
ecsi.entityUInfo = ukm;
ecsi.suppPubInfo = &oklen;
intsi.pecsi = &ecsi;
plen = ASN1_item_i2d(intsi.a, &der, ASN1_ITEM_rptr(ECC_CMS_SharedInfo));
if (!der || !plen)
goto err;
if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
goto err;
return 1;
err:
if (der)
OPENSSL_free(der);
return 0;
}
static int ecdh_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;
int plen, keylen;
const EVP_CIPHER *kekcipher;
EVP_CIPHER_CTX *kekctx;
if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
return 0;
if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm)))
{
ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
return 0;
}
if (alg->parameter->type != V_ASN1_SEQUENCE)
return 0;
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;
keylen = EVP_CIPHER_CTX_key_length(kekctx);
if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
goto err;
if (!ecdh_cms_set_ukm(pctx, kekalg, ukm, keylen))
goto err;
rv = 1;
err:
if (kekalg)
X509_ALGOR_free(kekalg);
return rv;
}
static int ecdh_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 (!ecdh_cms_set_peerkey(pctx, alg, pubkey))
{
ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
return 0;
}
}
/* Set ECDH derivation parameters and initialise unwrap context */
if (!ecdh_cms_set_shared_info(pctx, ri))
{
ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
return 0;
}
return 1;
}
static int ecdh_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;
int penclen;
int rv = 0;
int ecdh_nid, kdf_type, kdf_nid, 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))
{
EC_KEY *eckey = pkey->pkey.ec;
/* Set the key */
unsigned char *p;
penclen = i2o_ECPublicKey(eckey, NULL);
if (penclen <= 0)
goto err;
penc = OPENSSL_malloc(penclen);
if (!penc)
goto err;
p = penc;
penclen = i2o_ECPublicKey(eckey, &p);
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_X9_62_id_ecPublicKey),
V_ASN1_UNDEF, NULL);
}
/* See if custom paraneters set */
kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
if (kdf_type <= 0)
goto err;
if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
goto err;
ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
if (ecdh_nid < 0)
goto err;
else if (ecdh_nid == 0)
ecdh_nid = NID_dh_std_kdf;
else if (ecdh_nid == 1)
ecdh_nid = NID_dh_cofactor_kdf;
if (kdf_type == EVP_PKEY_ECDH_KDF_NONE)
{
kdf_type = EVP_PKEY_ECDH_KDF_X9_62;
if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
goto err;
}
else
/* Uknown KDF */
goto err;
if (kdf_md == NULL)
{
/* Fixme later for better MD */
kdf_md = EVP_sha1();
if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
goto err;
}
if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
goto err;
/* Lookup NID for KDF+cofactor+digest */
if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
goto err;
/* Get wrap NID */
ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
wrap_nid = EVP_CIPHER_CTX_type(ctx);
keylen = EVP_CIPHER_CTX_key_length(ctx);
/* Package wrap algorithm in an AlgorithmIdentifier */
wrap_alg = X509_ALGOR_new();
if (!wrap_alg)
goto err;
X509_ALGOR_set0(wrap_alg, OBJ_nid2obj(wrap_nid), V_ASN1_UNDEF, NULL);
if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
goto err;
if (!ecdh_cms_set_ukm(pctx, wrap_alg, ukm, keylen))
goto err;
/* 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(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
rv = 1;
err:
if (penc)
OPENSSL_free(penc);
if (wrap_alg)
X509_ALGOR_free(wrap_alg);
return rv;
}
#endif
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