295 lines
9.8 KiB
C
295 lines
9.8 KiB
C
/**********************************************************************
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* gost_keyx.c *
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* Copyright (c) 2005-2006 Cryptocom LTD *
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* This file is distributed under the same license as OpenSSL *
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* *
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* VK0 34.10-2001 key exchange and GOST R 34.10-2001 *
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* based PKCS7/SMIME support *
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* Requires OpenSSL 0.9.9 for compilation *
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**********************************************************************/
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#include <openssl/evp.h>
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#include <openssl/rand.h>
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#include <string.h>
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#include <openssl/objects.h>
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#include "gost89.h"
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#include "gosthash.h"
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#include "e_gost_err.h"
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#include "gost_keywrap.h"
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#include "gost_lcl.h"
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#include "gost2001_keyx.h"
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/* Implementation of CryptoPro VKO 34.10-2001 algorithm */
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static int VKO_compute_key(unsigned char *shared_key, size_t shared_key_size,
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const EC_POINT *pub_key, EC_KEY *priv_key,
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const unsigned char *ukm)
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{
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unsigned char ukm_be[8], databuf[64], hashbuf[64];
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BIGNUM *UKM = NULL, *p = NULL, *order = NULL, *X = NULL, *Y = NULL;
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const BIGNUM *key = EC_KEY_get0_private_key(priv_key);
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EC_POINT *pnt = EC_POINT_new(EC_KEY_get0_group(priv_key));
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int i;
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gost_hash_ctx hash_ctx;
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BN_CTX *ctx = BN_CTX_new();
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for (i = 0; i < 8; i++) {
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ukm_be[7 - i] = ukm[i];
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}
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BN_CTX_start(ctx);
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UKM = getbnfrombuf(ukm_be, 8);
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p = BN_CTX_get(ctx);
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order = BN_CTX_get(ctx);
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X = BN_CTX_get(ctx);
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Y = BN_CTX_get(ctx);
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EC_GROUP_get_order(EC_KEY_get0_group(priv_key), order, ctx);
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BN_mod_mul(p, key, UKM, order, ctx);
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EC_POINT_mul(EC_KEY_get0_group(priv_key), pnt, NULL, pub_key, p, ctx);
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EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(priv_key),
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pnt, X, Y, ctx);
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/*
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* Serialize elliptic curve point same way as we do it when saving key
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*/
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store_bignum(Y, databuf, 32);
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store_bignum(X, databuf + 32, 32);
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/* And reverse byte order of whole buffer */
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for (i = 0; i < 64; i++) {
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hashbuf[63 - i] = databuf[i];
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}
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init_gost_hash_ctx(&hash_ctx, &GostR3411_94_CryptoProParamSet);
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start_hash(&hash_ctx);
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hash_block(&hash_ctx, hashbuf, 64);
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finish_hash(&hash_ctx, shared_key);
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done_gost_hash_ctx(&hash_ctx);
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BN_free(UKM);
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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EC_POINT_free(pnt);
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return 32;
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}
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/*
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* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-2001
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* algorithm
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*/
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int pkey_gost2001_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
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size_t *keylen)
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{
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/*
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* Public key of peer in the ctx field peerkey Our private key in the ctx
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* pkey ukm is in the algorithm specific context data
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*/
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EVP_PKEY *my_key = EVP_PKEY_CTX_get0_pkey(ctx);
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EVP_PKEY *peer_key = EVP_PKEY_CTX_get0_peerkey(ctx);
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struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
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if (!data->shared_ukm) {
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GOSTerr(GOST_F_PKEY_GOST2001_DERIVE, GOST_R_UKM_NOT_SET);
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return 0;
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}
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if (key == NULL) {
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*keylen = 32;
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return 32;
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}
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*keylen =
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VKO_compute_key(key, 32,
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EC_KEY_get0_public_key(EVP_PKEY_get0(peer_key)),
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(EC_KEY *)EVP_PKEY_get0(my_key), data->shared_ukm);
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return 1;
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}
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/*
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* EVP_PKEY_METHOD callback encrypt
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* Implementation of GOST2001 key transport, cryptocom variation
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*/
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/*
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* Generates ephemeral key based on pubk algorithm computes shared key using
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* VKO and returns filled up GOST_KEY_TRANSPORT structure
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*/
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/*
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* EVP_PKEY_METHOD callback encrypt
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* Implementation of GOST2001 key transport, cryptopo variation
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*/
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int pkey_GOST01cp_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
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size_t *out_len, const unsigned char *key,
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size_t key_len)
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{
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GOST_KEY_TRANSPORT *gkt = NULL;
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EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx);
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struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
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const struct gost_cipher_info *param = get_encryption_params(NULL);
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unsigned char ukm[8], shared_key[32], crypted_key[44];
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int ret = 0;
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int key_is_ephemeral = 1;
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gost_ctx cctx;
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EVP_PKEY *sec_key = EVP_PKEY_CTX_get0_peerkey(pctx);
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if (data->shared_ukm) {
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memcpy(ukm, data->shared_ukm, 8);
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} else if (out) {
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if (RAND_bytes(ukm, 8) <= 0) {
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GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT,
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GOST_R_RANDOM_GENERATOR_FAILURE);
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return 0;
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}
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}
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/* Check for private key in the peer_key of context */
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if (sec_key) {
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key_is_ephemeral = 0;
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if (!gost_get0_priv_key(sec_key)) {
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GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT,
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GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR);
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goto err;
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}
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} else {
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key_is_ephemeral = 1;
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if (out) {
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sec_key = EVP_PKEY_new();
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if (sec_key == NULL)
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goto err;
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EVP_PKEY_assign(sec_key, EVP_PKEY_base_id(pubk), EC_KEY_new());
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EVP_PKEY_copy_parameters(sec_key, pubk);
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if (!gost2001_keygen(EVP_PKEY_get0(sec_key))) {
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goto err;
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}
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}
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}
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if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS)
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&& param == gost_cipher_list) {
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param = gost_cipher_list + 1;
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}
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if (out) {
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VKO_compute_key(shared_key, 32,
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EC_KEY_get0_public_key(EVP_PKEY_get0(pubk)),
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EVP_PKEY_get0(sec_key), ukm);
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gost_init(&cctx, param->sblock);
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keyWrapCryptoPro(&cctx, shared_key, ukm, key, crypted_key);
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}
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gkt = GOST_KEY_TRANSPORT_new();
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if (!gkt) {
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goto err;
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}
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if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, ukm, 8)) {
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goto err;
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}
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if (!ASN1_OCTET_STRING_set(gkt->key_info->imit, crypted_key + 40, 4)) {
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goto err;
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}
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if (!ASN1_OCTET_STRING_set
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(gkt->key_info->encrypted_key, crypted_key + 8, 32)) {
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goto err;
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}
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if (key_is_ephemeral) {
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if (!X509_PUBKEY_set
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(&gkt->key_agreement_info->ephem_key, out ? sec_key : pubk)) {
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GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT,
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GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
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goto err;
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}
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}
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ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
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gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
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if (key_is_ephemeral && sec_key)
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EVP_PKEY_free(sec_key);
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if (!key_is_ephemeral) {
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/* Set control "public key from client certificate used" */
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if (EVP_PKEY_CTX_ctrl(pctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL)
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<= 0) {
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GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED);
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goto err;
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}
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}
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if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL)) > 0)
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ret = 1;
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GOST_KEY_TRANSPORT_free(gkt);
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return ret;
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err:
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if (key_is_ephemeral && sec_key)
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EVP_PKEY_free(sec_key);
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GOST_KEY_TRANSPORT_free(gkt);
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return -1;
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}
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/*
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* EVP_PKEY_METHOD callback decrypt
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* Implementation of GOST2001 key transport, cryptopo variation
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*/
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int pkey_GOST01cp_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key,
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size_t *key_len, const unsigned char *in,
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size_t in_len)
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{
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const unsigned char *p = in;
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EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
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GOST_KEY_TRANSPORT *gkt = NULL;
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int ret = 0;
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unsigned char wrappedKey[44];
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unsigned char sharedKey[32];
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gost_ctx ctx;
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const struct gost_cipher_info *param = NULL;
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EVP_PKEY *eph_key = NULL, *peerkey = NULL;
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if (!key) {
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*key_len = 32;
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return 1;
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}
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gkt = d2i_GOST_KEY_TRANSPORT(NULL, (const unsigned char **)&p, in_len);
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if (!gkt) {
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GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
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GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
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return -1;
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}
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/* If key transport structure contains public key, use it */
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eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
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if (eph_key) {
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if (EVP_PKEY_derive_set_peer(pctx, eph_key) <= 0) {
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GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
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GOST_R_INCOMPATIBLE_PEER_KEY);
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goto err;
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}
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} else {
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/* Set control "public key from client certificate used" */
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if (EVP_PKEY_CTX_ctrl(pctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL)
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<= 0) {
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GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, GOST_R_CTRL_CALL_FAILED);
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goto err;
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}
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}
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peerkey = EVP_PKEY_CTX_get0_peerkey(pctx);
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if (!peerkey) {
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GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, GOST_R_NO_PEER_KEY);
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goto err;
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}
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param = get_encryption_params(gkt->key_agreement_info->cipher);
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if (!param) {
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goto err;
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}
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gost_init(&ctx, param->sblock);
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OPENSSL_assert(gkt->key_agreement_info->eph_iv->length == 8);
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memcpy(wrappedKey, gkt->key_agreement_info->eph_iv->data, 8);
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OPENSSL_assert(gkt->key_info->encrypted_key->length == 32);
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memcpy(wrappedKey + 8, gkt->key_info->encrypted_key->data, 32);
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OPENSSL_assert(gkt->key_info->imit->length == 4);
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memcpy(wrappedKey + 40, gkt->key_info->imit->data, 4);
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VKO_compute_key(sharedKey, 32,
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EC_KEY_get0_public_key(EVP_PKEY_get0(peerkey)),
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EVP_PKEY_get0(priv), wrappedKey);
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if (!keyUnwrapCryptoPro(&ctx, sharedKey, wrappedKey, key)) {
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GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
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GOST_R_ERROR_COMPUTING_SHARED_KEY);
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goto err;
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}
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ret = 1;
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err:
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if (eph_key)
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EVP_PKEY_free(eph_key);
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if (gkt)
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GOST_KEY_TRANSPORT_free(gkt);
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return ret;
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}
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