/*
* Copyright (c) 2016 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Portions Copyright (c) 2009 Apple Inc. 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE 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.
*/
#include <config.h>
#include <roken.h>
#ifdef PKINIT
/*
* As with the other *-ec.c files in Heimdal, this is a bit of a hack.
*
* The idea is to use OpenSSL for EC because hcrypto doesn't have the
* required functionality at this time. To do this we segregate
* EC-using code into separate source files and then we arrange for them
* to get the OpenSSL headers and not the conflicting hcrypto ones.
*
* Because of auto-generated *-private.h headers, we end up needing to
* make sure various types are defined before we include them, thus the
* strange header include order here.
*/
#ifdef HAVE_HCRYPTO_W_OPENSSL
#include <openssl/ec.h>
#include <openssl/ecdh.h>
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/dh.h>
#define HEIM_NO_CRYPTO_HDRS
#endif
/*
* NO_HCRYPTO_POLLUTION -> don't refer to hcrypto type/function names
* that we don't need in this file and which would clash with OpenSSL's
* in ways that are difficult to address in cleaner ways.
*
* In the medium- to long-term what we should do is move all PK in
* Heimdal to the newer EVP interfaces for PK and then nothing outside
* lib/hcrypto should ever have to include OpenSSL headers, and -more
* specifically- the only thing that should ever have to include OpenSSL
* headers is the OpenSSL backend to hcrypto.
*/
#define NO_HCRYPTO_POLLUTION
#include "krb5_locl.h"
#include <hcrypto/des.h>
#include <cms_asn1.h>
#include <pkcs8_asn1.h>
#include <pkcs9_asn1.h>
#include <pkcs12_asn1.h>
#include <pkinit_asn1.h>
#include <asn1_err.h>
#include <der.h>
krb5_error_code
_krb5_build_authpack_subjectPK_EC(krb5_context context,
krb5_pk_init_ctx ctx,
AuthPack *a)
{
#ifdef HAVE_HCRYPTO_W_OPENSSL
krb5_error_code ret;
ECParameters ecp;
unsigned char *p;
size_t size;
int xlen;
/* copy in public key, XXX find the best curve that the server support or use the clients curve if possible */
ecp.element = choice_ECParameters_namedCurve;
ret = der_copy_oid(&asn1_oid_id_ec_group_secp256r1,
&ecp.u.namedCurve);
if (ret)
return ret;
ALLOC(a->clientPublicValue->algorithm.parameters, 1);
if (a->clientPublicValue->algorithm.parameters == NULL) {
free_ECParameters(&ecp);
return krb5_enomem(context);
}
ASN1_MALLOC_ENCODE(ECParameters, p, xlen, &ecp, &size, ret);
free_ECParameters(&ecp);
if (ret)
return ret;
if ((int)size != xlen)
krb5_abortx(context, "asn1 internal error");
a->clientPublicValue->algorithm.parameters->data = p;
a->clientPublicValue->algorithm.parameters->length = size;
/* copy in public key */
ret = der_copy_oid(&asn1_oid_id_ecPublicKey,
&a->clientPublicValue->algorithm.algorithm);
if (ret)
return ret;
#ifdef HAVE_OPENSSL_30
ctx->u.eckey = EVP_EC_gen(OSSL_EC_curve_nid2name(NID_X9_62_prime256v1));
#else
ctx->u.eckey = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
if (ctx->u.eckey == NULL)
return krb5_enomem(context);
ret = EC_KEY_generate_key(ctx->u.eckey);
if (ret != 1)
return EINVAL;
#endif
#ifdef HAVE_OPENSSL_30
xlen = i2d_PublicKey(ctx->u.eckey, NULL);
#else
xlen = i2o_ECPublicKey(ctx->u.eckey, NULL);
#endif
if (xlen <= 0)
return EINVAL;
p = malloc(xlen);
if (p == NULL)
return krb5_enomem(context);
a->clientPublicValue->subjectPublicKey.data = p;
#ifdef HAVE_OPENSSL_30
xlen = i2d_PublicKey(ctx->u.eckey, &p);
#else
xlen = i2o_ECPublicKey(ctx->u.eckey, &p);
#endif
if (xlen <= 0) {
a->clientPublicValue->subjectPublicKey.data = NULL;
free(p);
return EINVAL;
}
a->clientPublicValue->subjectPublicKey.length = xlen * 8;
return 0;
/* XXX verify that this is right with RFC3279 */
#else
krb5_set_error_message(context, ENOTSUP,
N_("PKINIT: ECDH not supported", ""));
return ENOTSUP;
#endif
}
krb5_error_code
_krb5_pk_rd_pa_reply_ecdh_compute_key(krb5_context context,
krb5_pk_init_ctx ctx,
const unsigned char *in,
size_t in_sz,
unsigned char **out,
int *out_sz)
{
#ifdef HAVE_HCRYPTO_W_OPENSSL
#ifdef HAVE_OPENSSL_30
krb5_error_code ret = 0;
EVP_PKEY_CTX *pctx = NULL;
EVP_PKEY *template = NULL;
EVP_PKEY *public = NULL;
size_t shared_len = 0;
if ((template = EVP_PKEY_new()) == NULL)
ret = krb5_enomem(context);
if (ret == 0 &&
EVP_PKEY_copy_parameters(template, ctx->u.eckey) != 1)
ret = krb5_enomem(context);
if (ret == 0 && (pctx = EVP_PKEY_CTX_new(ctx->u.eckey, NULL)) == NULL)
ret = krb5_enomem(context);
if (ret == 0 && EVP_PKEY_derive_init(pctx) != 1)
ret = krb5_enomem(context);
if (ret == 0 &&
EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_NONE) != 1)
ret = krb5_enomem(context);
if (ret == 0 &&
(public = d2i_PublicKey(EVP_PKEY_EC, &template, &in, in_sz)) == NULL)
krb5_set_error_message(context,
ret = HX509_PARSING_KEY_FAILED,
"PKINIT: Can't parse the KDC's ECDH public key");
if (ret == 0 &&
EVP_PKEY_derive_set_peer_ex(pctx, public, 1) != 1)
krb5_set_error_message(context,
ret = KRB5KRB_ERR_GENERIC,
"Could not derive ECDH shared secret for PKINIT key exchange "
"(EVP_PKEY_derive_set_peer_ex)");
if (ret == 0 &&
(EVP_PKEY_derive(pctx, NULL, &shared_len) != 1 || shared_len == 0))
krb5_set_error_message(context,
ret = KRB5KRB_ERR_GENERIC,
"Could not derive ECDH shared secret for PKINIT key exchange "
"(EVP_PKEY_derive to get length)");
if (ret == 0 && shared_len > INT_MAX)
krb5_set_error_message(context,
ret = KRB5KRB_ERR_GENERIC,
"Could not derive ECDH shared secret for PKINIT key exchange "
"(shared key too large)");
if (ret == 0 && (*out = malloc(shared_len)) == NULL)
ret = krb5_enomem(context);
if (ret == 0 && EVP_PKEY_derive(pctx, *out, &shared_len) != 1)
krb5_set_error_message(context,
ret = KRB5KRB_ERR_GENERIC,
"Could not derive ECDH shared secret for PKINIT key exchange "
"(EVP_PKEY_derive)");
if (ret == 0)
*out_sz = shared_len;
EVP_PKEY_CTX_free(pctx); // move
EVP_PKEY_free(template);
return ret;
#else
krb5_error_code ret = 0;
int dh_gen_keylen;
const EC_GROUP *group;
EC_KEY *public = NULL;
group = EC_KEY_get0_group(ctx->u.eckey);
public = EC_KEY_new();
if (public == NULL)
return krb5_enomem(context);
if (EC_KEY_set_group(public, group) != 1) {
EC_KEY_free(public);
return krb5_enomem(context);
}
if (o2i_ECPublicKey(&public, &in, in_sz) == NULL) {
EC_KEY_free(public);
ret = KRB5KRB_ERR_GENERIC;
krb5_set_error_message(context, ret,
N_("PKINIT: Can't parse ECDH public key", ""));
return ret;
}
*out_sz = (EC_GROUP_get_degree(group) + 7) / 8;
if (*out_sz < 0)
return EOVERFLOW;
*out = malloc(*out_sz);
if (*out == NULL) {
EC_KEY_free(public);
return krb5_enomem(context);
}
dh_gen_keylen = ECDH_compute_key(*out, *out_sz,
EC_KEY_get0_public_key(public),
ctx->u.eckey, NULL);
EC_KEY_free(public);
if (dh_gen_keylen <= 0) {
ret = KRB5KRB_ERR_GENERIC;
dh_gen_keylen = 0;
krb5_set_error_message(context, ret,
N_("PKINIT: Can't compute ECDH public key", ""));
free(*out);
*out = NULL;
*out_sz = 0;
}
*out_sz = dh_gen_keylen;
return ret;
#endif
#else
krb5_set_error_message(context, ENOTSUP,
N_("PKINIT: ECDH not supported", ""));
return ENOTSUP;
#endif
}
void
_krb5_pk_eckey_free(void *eckey)
{
#ifdef HAVE_HCRYPTO_W_OPENSSL
#ifdef HAVE_OPENSSL_30
EVP_PKEY_free(eckey);
#else
EC_KEY_free(eckey);
#endif
#endif
}
#else
static char lib_krb5_pkinit_ec_c = '\0';
#endif