278 lines
8.9 KiB
C
278 lines
8.9 KiB
C
/**********************************************************************
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* gost94_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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* Implements generation and parsing of GOST_KEY_TRANSPORT for *
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* GOST R 34.10-94 algorithms *
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* *
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* Requires OpenSSL 0.9.9 for compilation *
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**********************************************************************/
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#include <string.h>
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#include <openssl/dh.h>
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#include <openssl/rand.h>
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#include <openssl/evp.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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/* Common functions for both 94 and 2001 key exchange schemes */
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/*
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* Implementation of the Diffi-Hellman key agreement scheme based on GOST-94
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* keys
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*/
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/*
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* Computes Diffie-Hellman key and stores it into buffer in little-endian
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* byte order as expected by both versions of GOST 94 algorithm
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*/
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static int compute_pair_key_le(unsigned char *pair_key, BIGNUM *pub_key,
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DH *dh)
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{
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unsigned char be_key[128];
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int i, key_size;
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key_size = DH_compute_key(be_key, pub_key, dh);
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if (!key_size)
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return 0;
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memset(pair_key, 0, 128);
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for (i = 0; i < key_size; i++) {
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pair_key[i] = be_key[key_size - 1 - i];
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}
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return key_size;
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}
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/*
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* Computes 256 bit Key exchange key as specified in RFC 4357
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*/
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static int make_cp_exchange_key(BIGNUM *priv_key, EVP_PKEY *pubk,
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unsigned char *shared_key)
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{
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unsigned char dh_key[128];
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int ret;
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gost_hash_ctx hash_ctx;
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DH *dh = DH_new();
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if (!dh)
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return 0;
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memset(dh_key, 0, 128);
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dh->g = BN_dup(pubk->pkey.dsa->g);
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dh->p = BN_dup(pubk->pkey.dsa->p);
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dh->priv_key = BN_dup(priv_key);
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ret =
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compute_pair_key_le(dh_key, ((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,
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dh);
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DH_free(dh);
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if (!ret)
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return 0;
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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, dh_key, 128);
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finish_hash(&hash_ctx, shared_key);
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done_gost_hash_ctx(&hash_ctx);
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return 1;
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}
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/* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */
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int pkey_gost94_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
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{
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EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx);
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EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx);
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*keylen = 32;
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if (key == NULL)
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return 1;
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return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key);
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}
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/*
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* EVP_PKEY_METHOD callback encrypt for GOST R 34.10-94 cryptopro
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* modification
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*/
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int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out,
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size_t *outlen, 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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unsigned char shared_key[32], ukm[8], crypted_key[44];
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const struct gost_cipher_info *param = get_encryption_params(NULL);
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EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx);
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struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
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gost_ctx cctx;
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int key_is_ephemeral = 1;
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EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx);
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/* Do not use vizir cipher parameters with cryptopro */
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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 (mykey) {
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/* If key already set, it is not ephemeral */
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key_is_ephemeral = 0;
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if (!gost_get0_priv_key(mykey)) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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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/* Otherwise generate ephemeral key */
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key_is_ephemeral = 1;
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if (out) {
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mykey = EVP_PKEY_new();
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EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk), DSA_new());
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EVP_PKEY_copy_parameters(mykey, pubk);
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if (!gost_sign_keygen(EVP_PKEY_get0(mykey))) {
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goto err;
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}
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}
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}
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if (out)
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make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, shared_key);
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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_GOST94CP_ENCRYPT,
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GOST_R_RANDOM_GENERATOR_FAILURE);
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goto err;
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}
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}
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if (out) {
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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 memerr;
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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 memerr;
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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 memerr;
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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 memerr;
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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 ? mykey : pubk)) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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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if (out)
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EVP_PKEY_free(mykey);
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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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*outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL);
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if (*outlen <= 0) {
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GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
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GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
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goto err;
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}
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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(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <=
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0) {
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GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED);
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goto err;
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}
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}
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GOST_KEY_TRANSPORT_free(gkt);
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return 1;
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memerr:
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if (key_is_ephemeral) {
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EVP_PKEY_free(mykey);
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}
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GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_MALLOC_FAILURE);
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err:
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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_PLEY_METHOD callback decrypt for GOST R 34.10-94 cryptopro
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* modification
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*/
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int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, 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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GOST_KEY_TRANSPORT *gkt = NULL;
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unsigned char wrappedKey[44];
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unsigned char sharedKey[32];
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gost_ctx cctx;
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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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EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(ctx);
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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_GOST94CP_DECRYPT,
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GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
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return 0;
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}
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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(ctx, eph_key) <= 0) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <=
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0) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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(ctx);
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if (!peerkey) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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(&cctx, 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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make_cp_exchange_key(gost_get0_priv_key(priv), peerkey, sharedKey);
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if (!keyUnwrapCryptoPro(&cctx, sharedKey, wrappedKey, key)) {
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GOSTerr(GOST_F_PKEY_GOST94CP_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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EVP_PKEY_free(eph_key);
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GOST_KEY_TRANSPORT_free(gkt);
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return 1;
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err:
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EVP_PKEY_free(eph_key);
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GOST_KEY_TRANSPORT_free(gkt);
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return -1;
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}
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