| /********************************************************************** |
| * gost94_keyx.c * |
| * Copyright (c) 2005-2006 Cryptocom LTD * |
| * This file is distributed under the same license as OpenSSL * |
| * * |
| * Implements generation and parsing of GOST_KEY_TRANSPORT for * |
| * GOST R 34.10-94 algorithms * |
| * * |
| * Requires OpenSSL 0.9.9 for compilation * |
| **********************************************************************/ |
| #include <string.h> |
| #include <openssl/dh.h> |
| #include <openssl/rand.h> |
| #include <openssl/evp.h> |
| #include <openssl/objects.h> |
| |
| #include "gost89.h" |
| #include "gosthash.h" |
| #include "e_gost_err.h" |
| #include "gost_keywrap.h" |
| #include "gost_lcl.h" |
| /* Common functions for both 94 and 2001 key exchange schemes */ |
| /* |
| * Implementation of the Diffi-Hellman key agreement scheme based on GOST-94 |
| * keys |
| */ |
| |
| /* |
| * Computes Diffie-Hellman key and stores it into buffer in little-endian |
| * byte order as expected by both versions of GOST 94 algorithm |
| */ |
| static int compute_pair_key_le(unsigned char *pair_key, BIGNUM *pub_key, |
| DH *dh) |
| { |
| unsigned char be_key[128]; |
| int i, key_size; |
| key_size = DH_compute_key(be_key, pub_key, dh); |
| if (!key_size) |
| return 0; |
| memset(pair_key, 0, 128); |
| for (i = 0; i < key_size; i++) { |
| pair_key[i] = be_key[key_size - 1 - i]; |
| } |
| return key_size; |
| } |
| |
| /* |
| * Computes 256 bit Key exchange key as specified in RFC 4357 |
| */ |
| static int make_cp_exchange_key(BIGNUM *priv_key, EVP_PKEY *pubk, |
| unsigned char *shared_key) |
| { |
| unsigned char dh_key[128]; |
| int ret; |
| gost_hash_ctx hash_ctx; |
| DH *dh = DH_new(); |
| |
| if (!dh) |
| return 0; |
| memset(dh_key, 0, 128); |
| dh->g = BN_dup(pubk->pkey.dsa->g); |
| dh->p = BN_dup(pubk->pkey.dsa->p); |
| dh->priv_key = BN_dup(priv_key); |
| ret = |
| compute_pair_key_le(dh_key, ((DSA *)(EVP_PKEY_get0(pubk)))->pub_key, |
| dh); |
| DH_free(dh); |
| if (!ret) |
| return 0; |
| init_gost_hash_ctx(&hash_ctx, &GostR3411_94_CryptoProParamSet); |
| start_hash(&hash_ctx); |
| hash_block(&hash_ctx, dh_key, 128); |
| finish_hash(&hash_ctx, shared_key); |
| done_gost_hash_ctx(&hash_ctx); |
| return 1; |
| } |
| |
| /* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */ |
| |
| int pkey_gost94_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen) |
| { |
| EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx); |
| EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx); |
| *keylen = 32; |
| if (key == NULL) |
| return 1; |
| |
| return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key); |
| } |
| |
| /* |
| * EVP_PKEY_METHOD callback encrypt for GOST R 34.10-94 cryptopro |
| * modification |
| */ |
| |
| int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, |
| size_t *outlen, const unsigned char *key, |
| size_t key_len) |
| { |
| GOST_KEY_TRANSPORT *gkt = NULL; |
| unsigned char shared_key[32], ukm[8], crypted_key[44]; |
| const struct gost_cipher_info *param = get_encryption_params(NULL); |
| EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx); |
| struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); |
| gost_ctx cctx; |
| int key_is_ephemeral = 1; |
| int tmp_outlen; |
| EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx); |
| |
| /* Do not use vizir cipher parameters with cryptopro */ |
| if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) |
| && param == gost_cipher_list) { |
| param = gost_cipher_list + 1; |
| } |
| |
| if (mykey) { |
| /* If key already set, it is not ephemeral */ |
| key_is_ephemeral = 0; |
| if (!gost_get0_priv_key(mykey)) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, |
| GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR); |
| goto err; |
| } |
| } else { |
| /* Otherwise generate ephemeral key */ |
| key_is_ephemeral = 1; |
| if (out) { |
| mykey = EVP_PKEY_new(); |
| EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk), DSA_new()); |
| EVP_PKEY_copy_parameters(mykey, pubk); |
| if (!gost_sign_keygen(EVP_PKEY_get0(mykey))) { |
| goto err; |
| } |
| } |
| } |
| if (out) |
| make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, shared_key); |
| if (data->shared_ukm) { |
| memcpy(ukm, data->shared_ukm, 8); |
| } else if (out) { |
| if (RAND_bytes(ukm, 8) <= 0) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, |
| GOST_R_RANDOM_GENERATOR_FAILURE); |
| goto err; |
| } |
| } |
| |
| if (out) { |
| gost_init(&cctx, param->sblock); |
| keyWrapCryptoPro(&cctx, shared_key, ukm, key, crypted_key); |
| } |
| gkt = GOST_KEY_TRANSPORT_new(); |
| if (!gkt) { |
| goto memerr; |
| } |
| if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, ukm, 8)) { |
| goto memerr; |
| } |
| if (!ASN1_OCTET_STRING_set(gkt->key_info->imit, crypted_key + 40, 4)) { |
| goto memerr; |
| } |
| if (!ASN1_OCTET_STRING_set |
| (gkt->key_info->encrypted_key, crypted_key + 8, 32)) { |
| goto memerr; |
| } |
| if (key_is_ephemeral) { |
| if (!X509_PUBKEY_set |
| (&gkt->key_agreement_info->ephem_key, out ? mykey : pubk)) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, |
| GOST_R_CANNOT_PACK_EPHEMERAL_KEY); |
| goto err; |
| } |
| if (out) |
| EVP_PKEY_free(mykey); |
| } |
| ASN1_OBJECT_free(gkt->key_agreement_info->cipher); |
| gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); |
| tmp_outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL); |
| if (tmp_outlen <= 0) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, |
| GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO); |
| goto err; |
| } |
| *outlen = tmp_outlen; |
| if (!key_is_ephemeral) { |
| /* Set control "public key from client certificate used" */ |
| if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= |
| 0) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED); |
| goto err; |
| } |
| } |
| GOST_KEY_TRANSPORT_free(gkt); |
| return 1; |
| memerr: |
| if (key_is_ephemeral) { |
| EVP_PKEY_free(mykey); |
| } |
| GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_MALLOC_FAILURE); |
| err: |
| GOST_KEY_TRANSPORT_free(gkt); |
| return -1; |
| } |
| |
| /* |
| * EVP_PLEY_METHOD callback decrypt for GOST R 34.10-94 cryptopro |
| * modification |
| */ |
| int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, |
| size_t *key_len, const unsigned char *in, |
| size_t in_len) |
| { |
| const unsigned char *p = in; |
| GOST_KEY_TRANSPORT *gkt = NULL; |
| unsigned char wrappedKey[44]; |
| unsigned char sharedKey[32]; |
| gost_ctx cctx; |
| const struct gost_cipher_info *param = NULL; |
| EVP_PKEY *eph_key = NULL, *peerkey = NULL; |
| EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(ctx); |
| |
| if (!key) { |
| *key_len = 32; |
| return 1; |
| } |
| |
| gkt = d2i_GOST_KEY_TRANSPORT(NULL, (const unsigned char **)&p, in_len); |
| if (!gkt) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, |
| GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); |
| return 0; |
| } |
| eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); |
| if (eph_key) { |
| if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, |
| GOST_R_INCOMPATIBLE_PEER_KEY); |
| goto err; |
| } |
| } else { |
| /* Set control "public key from client certificate used" */ |
| if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= |
| 0) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_CTRL_CALL_FAILED); |
| goto err; |
| } |
| } |
| peerkey = EVP_PKEY_CTX_get0_peerkey(ctx); |
| if (!peerkey) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_NO_PEER_KEY); |
| goto err; |
| } |
| |
| param = get_encryption_params(gkt->key_agreement_info->cipher); |
| if (!param) { |
| goto err; |
| } |
| |
| gost_init(&cctx, param->sblock); |
| OPENSSL_assert(gkt->key_agreement_info->eph_iv->length == 8); |
| memcpy(wrappedKey, gkt->key_agreement_info->eph_iv->data, 8); |
| OPENSSL_assert(gkt->key_info->encrypted_key->length == 32); |
| memcpy(wrappedKey + 8, gkt->key_info->encrypted_key->data, 32); |
| OPENSSL_assert(gkt->key_info->imit->length == 4); |
| memcpy(wrappedKey + 40, gkt->key_info->imit->data, 4); |
| make_cp_exchange_key(gost_get0_priv_key(priv), peerkey, sharedKey); |
| if (!keyUnwrapCryptoPro(&cctx, sharedKey, wrappedKey, key)) { |
| GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, |
| GOST_R_ERROR_COMPUTING_SHARED_KEY); |
| goto err; |
| } |
| |
| EVP_PKEY_free(eph_key); |
| GOST_KEY_TRANSPORT_free(gkt); |
| return 1; |
| err: |
| EVP_PKEY_free(eph_key); |
| GOST_KEY_TRANSPORT_free(gkt); |
| return -1; |
| } |
