1238384Sjkim/********************************************************************** 2238384Sjkim * gost94_keyx.c * 3238384Sjkim * Copyright (c) 2005-2006 Cryptocom LTD * 4238384Sjkim * This file is distributed under the same license as OpenSSL * 5238384Sjkim * * 6238384Sjkim * Implements generation and parsing of GOST_KEY_TRANSPORT for * 7280297Sjkim * GOST R 34.10-94 algorithms * 8280297Sjkim * * 9238384Sjkim * Requires OpenSSL 0.9.9 for compilation * 10238384Sjkim **********************************************************************/ 11238384Sjkim#include <string.h> 12238384Sjkim#include <openssl/dh.h> 13238384Sjkim#include <openssl/rand.h> 14238384Sjkim#include <openssl/evp.h> 15238384Sjkim#include <openssl/objects.h> 16238384Sjkim 17238384Sjkim#include "gost89.h" 18238384Sjkim#include "gosthash.h" 19238384Sjkim#include "e_gost_err.h" 20238384Sjkim#include "gost_keywrap.h" 21238384Sjkim#include "gost_lcl.h" 22238384Sjkim/* Common functions for both 94 and 2001 key exchange schemes */ 23280297Sjkim/* 24280297Sjkim * Implementation of the Diffi-Hellman key agreement scheme based on GOST-94 25280297Sjkim * keys 26280297Sjkim */ 27238384Sjkim 28280297Sjkim/* 29280297Sjkim * Computes Diffie-Hellman key and stores it into buffer in little-endian 30280297Sjkim * byte order as expected by both versions of GOST 94 algorithm 31238384Sjkim */ 32280297Sjkimstatic int compute_pair_key_le(unsigned char *pair_key, BIGNUM *pub_key, 33280297Sjkim DH *dh) 34280297Sjkim{ 35280297Sjkim unsigned char be_key[128]; 36280297Sjkim int i, key_size; 37280297Sjkim key_size = DH_compute_key(be_key, pub_key, dh); 38280297Sjkim if (!key_size) 39280297Sjkim return 0; 40280297Sjkim memset(pair_key, 0, 128); 41280297Sjkim for (i = 0; i < key_size; i++) { 42280297Sjkim pair_key[i] = be_key[key_size - 1 - i]; 43280297Sjkim } 44280297Sjkim return key_size; 45280297Sjkim} 46238384Sjkim 47238384Sjkim/* 48280297Sjkim * Computes 256 bit Key exchange key as specified in RFC 4357 49238384Sjkim */ 50280297Sjkimstatic int make_cp_exchange_key(BIGNUM *priv_key, EVP_PKEY *pubk, 51280297Sjkim unsigned char *shared_key) 52280297Sjkim{ 53280297Sjkim unsigned char dh_key[128]; 54280297Sjkim int ret; 55280297Sjkim gost_hash_ctx hash_ctx; 56280297Sjkim DH *dh = DH_new(); 57238384Sjkim 58280297Sjkim if (!dh) 59280297Sjkim return 0; 60280297Sjkim memset(dh_key, 0, 128); 61280297Sjkim dh->g = BN_dup(pubk->pkey.dsa->g); 62280297Sjkim dh->p = BN_dup(pubk->pkey.dsa->p); 63280297Sjkim dh->priv_key = BN_dup(priv_key); 64280297Sjkim ret = 65280297Sjkim compute_pair_key_le(dh_key, ((DSA *)(EVP_PKEY_get0(pubk)))->pub_key, 66280297Sjkim dh); 67280297Sjkim DH_free(dh); 68280297Sjkim if (!ret) 69280297Sjkim return 0; 70280297Sjkim init_gost_hash_ctx(&hash_ctx, &GostR3411_94_CryptoProParamSet); 71280297Sjkim start_hash(&hash_ctx); 72280297Sjkim hash_block(&hash_ctx, dh_key, 128); 73280297Sjkim finish_hash(&hash_ctx, shared_key); 74280297Sjkim done_gost_hash_ctx(&hash_ctx); 75280297Sjkim return 1; 76280297Sjkim} 77280297Sjkim 78238384Sjkim/* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */ 79238384Sjkim 80280297Sjkimint pkey_gost94_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen) 81280297Sjkim{ 82280297Sjkim EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx); 83280297Sjkim EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx); 84280297Sjkim *keylen = 32; 85280297Sjkim if (key == NULL) 86280297Sjkim return 1; 87238384Sjkim 88280297Sjkim return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key); 89280297Sjkim} 90238384Sjkim 91280297Sjkim/* 92280297Sjkim * EVP_PKEY_METHOD callback encrypt for GOST R 34.10-94 cryptopro 93280297Sjkim * modification 94238384Sjkim */ 95238384Sjkim 96280297Sjkimint pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, 97280297Sjkim size_t *outlen, const unsigned char *key, 98280297Sjkim size_t key_len) 99280297Sjkim{ 100280297Sjkim GOST_KEY_TRANSPORT *gkt = NULL; 101280297Sjkim unsigned char shared_key[32], ukm[8], crypted_key[44]; 102280297Sjkim const struct gost_cipher_info *param = get_encryption_params(NULL); 103280297Sjkim EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx); 104280297Sjkim struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); 105280297Sjkim gost_ctx cctx; 106280297Sjkim int key_is_ephemeral = 1; 107284283Sjkim int tmp_outlen; 108280297Sjkim EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx); 109238384Sjkim 110280297Sjkim /* Do not use vizir cipher parameters with cryptopro */ 111280297Sjkim if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) 112280297Sjkim && param == gost_cipher_list) { 113280297Sjkim param = gost_cipher_list + 1; 114280297Sjkim } 115238384Sjkim 116280297Sjkim if (mykey) { 117280297Sjkim /* If key already set, it is not ephemeral */ 118280297Sjkim key_is_ephemeral = 0; 119280297Sjkim if (!gost_get0_priv_key(mykey)) { 120280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 121280297Sjkim GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR); 122280297Sjkim goto err; 123280297Sjkim } 124280297Sjkim } else { 125280297Sjkim /* Otherwise generate ephemeral key */ 126280297Sjkim key_is_ephemeral = 1; 127280297Sjkim if (out) { 128280297Sjkim mykey = EVP_PKEY_new(); 129306198Sjkim if (!mykey) 130306198Sjkim goto memerr; 131280297Sjkim EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk), DSA_new()); 132280297Sjkim EVP_PKEY_copy_parameters(mykey, pubk); 133280297Sjkim if (!gost_sign_keygen(EVP_PKEY_get0(mykey))) { 134280297Sjkim goto err; 135280297Sjkim } 136280297Sjkim } 137280297Sjkim } 138280297Sjkim if (out) 139280297Sjkim make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, shared_key); 140280297Sjkim if (data->shared_ukm) { 141280297Sjkim memcpy(ukm, data->shared_ukm, 8); 142280297Sjkim } else if (out) { 143280297Sjkim if (RAND_bytes(ukm, 8) <= 0) { 144280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 145280297Sjkim GOST_R_RANDOM_GENERATOR_FAILURE); 146280297Sjkim goto err; 147280297Sjkim } 148280297Sjkim } 149238384Sjkim 150280297Sjkim if (out) { 151280297Sjkim gost_init(&cctx, param->sblock); 152280297Sjkim keyWrapCryptoPro(&cctx, shared_key, ukm, key, crypted_key); 153280297Sjkim } 154280297Sjkim gkt = GOST_KEY_TRANSPORT_new(); 155280297Sjkim if (!gkt) { 156280297Sjkim goto memerr; 157280297Sjkim } 158280297Sjkim if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, ukm, 8)) { 159280297Sjkim goto memerr; 160280297Sjkim } 161280297Sjkim if (!ASN1_OCTET_STRING_set(gkt->key_info->imit, crypted_key + 40, 4)) { 162280297Sjkim goto memerr; 163280297Sjkim } 164280297Sjkim if (!ASN1_OCTET_STRING_set 165280297Sjkim (gkt->key_info->encrypted_key, crypted_key + 8, 32)) { 166280297Sjkim goto memerr; 167280297Sjkim } 168280297Sjkim if (key_is_ephemeral) { 169280297Sjkim if (!X509_PUBKEY_set 170280297Sjkim (&gkt->key_agreement_info->ephem_key, out ? mykey : pubk)) { 171280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 172280297Sjkim GOST_R_CANNOT_PACK_EPHEMERAL_KEY); 173280297Sjkim goto err; 174280297Sjkim } 175280297Sjkim if (out) 176280297Sjkim EVP_PKEY_free(mykey); 177280297Sjkim } 178280297Sjkim ASN1_OBJECT_free(gkt->key_agreement_info->cipher); 179280297Sjkim gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); 180284283Sjkim tmp_outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL); 181284283Sjkim if (tmp_outlen <= 0) { 182280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 183280297Sjkim GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO); 184280297Sjkim goto err; 185280297Sjkim } 186284283Sjkim *outlen = tmp_outlen; 187280297Sjkim if (!key_is_ephemeral) { 188280297Sjkim /* Set control "public key from client certificate used" */ 189280297Sjkim if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 190280297Sjkim 0) { 191280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED); 192280297Sjkim goto err; 193280297Sjkim } 194280297Sjkim } 195280297Sjkim GOST_KEY_TRANSPORT_free(gkt); 196280297Sjkim return 1; 197280297Sjkim memerr: 198280297Sjkim if (key_is_ephemeral) { 199280297Sjkim EVP_PKEY_free(mykey); 200280297Sjkim } 201280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_MALLOC_FAILURE); 202280297Sjkim err: 203280297Sjkim GOST_KEY_TRANSPORT_free(gkt); 204280297Sjkim return -1; 205280297Sjkim} 206238384Sjkim 207280297Sjkim/* 208280297Sjkim * EVP_PLEY_METHOD callback decrypt for GOST R 34.10-94 cryptopro 209280297Sjkim * modification 210238384Sjkim */ 211280297Sjkimint pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, 212280297Sjkim size_t *key_len, const unsigned char *in, 213280297Sjkim size_t in_len) 214280297Sjkim{ 215280297Sjkim const unsigned char *p = in; 216280297Sjkim GOST_KEY_TRANSPORT *gkt = NULL; 217280297Sjkim unsigned char wrappedKey[44]; 218280297Sjkim unsigned char sharedKey[32]; 219280297Sjkim gost_ctx cctx; 220280297Sjkim const struct gost_cipher_info *param = NULL; 221280297Sjkim EVP_PKEY *eph_key = NULL, *peerkey = NULL; 222280297Sjkim EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(ctx); 223238384Sjkim 224280297Sjkim if (!key) { 225280297Sjkim *key_len = 32; 226280297Sjkim return 1; 227280297Sjkim } 228280297Sjkim 229280297Sjkim gkt = d2i_GOST_KEY_TRANSPORT(NULL, (const unsigned char **)&p, in_len); 230280297Sjkim if (!gkt) { 231280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 232280297Sjkim GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); 233280297Sjkim return 0; 234280297Sjkim } 235280297Sjkim eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); 236280297Sjkim if (eph_key) { 237280297Sjkim if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0) { 238280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 239280297Sjkim GOST_R_INCOMPATIBLE_PEER_KEY); 240280297Sjkim goto err; 241280297Sjkim } 242280297Sjkim } else { 243280297Sjkim /* Set control "public key from client certificate used" */ 244280297Sjkim if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 245280297Sjkim 0) { 246280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_CTRL_CALL_FAILED); 247280297Sjkim goto err; 248280297Sjkim } 249280297Sjkim } 250280297Sjkim peerkey = EVP_PKEY_CTX_get0_peerkey(ctx); 251280297Sjkim if (!peerkey) { 252280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_NO_PEER_KEY); 253238384Sjkim goto err; 254238384Sjkim } 255238384Sjkim 256280297Sjkim param = get_encryption_params(gkt->key_agreement_info->cipher); 257280297Sjkim if (!param) { 258280297Sjkim goto err; 259280297Sjkim } 260280297Sjkim 261280297Sjkim gost_init(&cctx, param->sblock); 262280297Sjkim OPENSSL_assert(gkt->key_agreement_info->eph_iv->length == 8); 263280297Sjkim memcpy(wrappedKey, gkt->key_agreement_info->eph_iv->data, 8); 264280297Sjkim OPENSSL_assert(gkt->key_info->encrypted_key->length == 32); 265280297Sjkim memcpy(wrappedKey + 8, gkt->key_info->encrypted_key->data, 32); 266280297Sjkim OPENSSL_assert(gkt->key_info->imit->length == 4); 267280297Sjkim memcpy(wrappedKey + 40, gkt->key_info->imit->data, 4); 268280297Sjkim make_cp_exchange_key(gost_get0_priv_key(priv), peerkey, sharedKey); 269280297Sjkim if (!keyUnwrapCryptoPro(&cctx, sharedKey, wrappedKey, key)) { 270280297Sjkim GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 271280297Sjkim GOST_R_ERROR_COMPUTING_SHARED_KEY); 272280297Sjkim goto err; 273280297Sjkim } 274280297Sjkim 275280297Sjkim EVP_PKEY_free(eph_key); 276280297Sjkim GOST_KEY_TRANSPORT_free(gkt); 277280297Sjkim return 1; 278280297Sjkim err: 279280297Sjkim EVP_PKEY_free(eph_key); 280280297Sjkim GOST_KEY_TRANSPORT_free(gkt); 281280297Sjkim return -1; 282280297Sjkim} 283