1/********************************************************************** 2 * gost94_keyx.c * 3 * Copyright (c) 2005-2006 Cryptocom LTD * 4 * This file is distributed under the same license as OpenSSL * 5 * * 6 * Implements generation and parsing of GOST_KEY_TRANSPORT for * 7 * GOST R 34.10-94 algorithms * 8 * * 9 * Requires OpenSSL 0.9.9 for compilation * 10 **********************************************************************/ 11#include <string.h> 12#include <openssl/dh.h> 13#include <openssl/rand.h> 14#include <openssl/evp.h> 15#include <openssl/objects.h> 16 17#include "gost89.h" 18#include "gosthash.h" 19#include "e_gost_err.h" 20#include "gost_keywrap.h" 21#include "gost_lcl.h" 22/* Common functions for both 94 and 2001 key exchange schemes */ 23/* 24 * Implementation of the Diffi-Hellman key agreement scheme based on GOST-94 25 * keys 26 */ 27 28/* 29 * Computes Diffie-Hellman key and stores it into buffer in little-endian 30 * byte order as expected by both versions of GOST 94 algorithm 31 */ 32static int compute_pair_key_le(unsigned char *pair_key, BIGNUM *pub_key, 33 DH *dh) 34{ 35 unsigned char be_key[128]; 36 int i, key_size; 37 key_size = DH_compute_key(be_key, pub_key, dh); 38 if (!key_size) 39 return 0; 40 memset(pair_key, 0, 128); 41 for (i = 0; i < key_size; i++) { 42 pair_key[i] = be_key[key_size - 1 - i]; 43 } 44 return key_size; 45} 46 47/* 48 * Computes 256 bit Key exchange key as specified in RFC 4357 49 */ 50static int make_cp_exchange_key(BIGNUM *priv_key, EVP_PKEY *pubk, 51 unsigned char *shared_key) 52{ 53 unsigned char dh_key[128]; 54 int ret; 55 gost_hash_ctx hash_ctx; 56 DH *dh = DH_new(); 57 58 if (!dh) 59 return 0; 60 memset(dh_key, 0, 128); 61 dh->g = BN_dup(pubk->pkey.dsa->g); 62 dh->p = BN_dup(pubk->pkey.dsa->p); 63 dh->priv_key = BN_dup(priv_key); 64 ret = 65 compute_pair_key_le(dh_key, ((DSA *)(EVP_PKEY_get0(pubk)))->pub_key, 66 dh); 67 DH_free(dh); 68 if (!ret) 69 return 0; 70 init_gost_hash_ctx(&hash_ctx, &GostR3411_94_CryptoProParamSet); 71 start_hash(&hash_ctx); 72 hash_block(&hash_ctx, dh_key, 128); 73 finish_hash(&hash_ctx, shared_key); 74 done_gost_hash_ctx(&hash_ctx); 75 return 1; 76} 77 78/* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */ 79 80int pkey_gost94_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen) 81{ 82 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx); 83 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx); 84 *keylen = 32; 85 if (key == NULL) 86 return 1; 87 88 return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key); 89} 90 91/* 92 * EVP_PKEY_METHOD callback encrypt for GOST R 34.10-94 cryptopro 93 * modification 94 */ 95 96int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, 97 size_t *outlen, const unsigned char *key, 98 size_t key_len) 99{ 100 GOST_KEY_TRANSPORT *gkt = NULL; 101 unsigned char shared_key[32], ukm[8], crypted_key[44]; 102 const struct gost_cipher_info *param = get_encryption_params(NULL); 103 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx); 104 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); 105 gost_ctx cctx; 106 int key_is_ephemeral = 1; 107 int tmp_outlen; 108 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx); 109 110 /* Do not use vizir cipher parameters with cryptopro */ 111 if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) 112 && param == gost_cipher_list) { 113 param = gost_cipher_list + 1; 114 } 115 116 if (mykey) { 117 /* If key already set, it is not ephemeral */ 118 key_is_ephemeral = 0; 119 if (!gost_get0_priv_key(mykey)) { 120 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 121 GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR); 122 goto err; 123 } 124 } else { 125 /* Otherwise generate ephemeral key */ 126 key_is_ephemeral = 1; 127 if (out) { 128 mykey = EVP_PKEY_new(); 129 if (!mykey) 130 goto memerr; 131 EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk), DSA_new()); 132 EVP_PKEY_copy_parameters(mykey, pubk); 133 if (!gost_sign_keygen(EVP_PKEY_get0(mykey))) { 134 goto err; 135 } 136 } 137 } 138 if (out) 139 make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, shared_key); 140 if (data->shared_ukm) { 141 memcpy(ukm, data->shared_ukm, 8); 142 } else if (out) { 143 if (RAND_bytes(ukm, 8) <= 0) { 144 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 145 GOST_R_RANDOM_GENERATOR_FAILURE); 146 goto err; 147 } 148 } 149 150 if (out) { 151 gost_init(&cctx, param->sblock); 152 keyWrapCryptoPro(&cctx, shared_key, ukm, key, crypted_key); 153 } 154 gkt = GOST_KEY_TRANSPORT_new(); 155 if (!gkt) { 156 goto memerr; 157 } 158 if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, ukm, 8)) { 159 goto memerr; 160 } 161 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit, crypted_key + 40, 4)) { 162 goto memerr; 163 } 164 if (!ASN1_OCTET_STRING_set 165 (gkt->key_info->encrypted_key, crypted_key + 8, 32)) { 166 goto memerr; 167 } 168 if (key_is_ephemeral) { 169 if (!X509_PUBKEY_set 170 (&gkt->key_agreement_info->ephem_key, out ? mykey : pubk)) { 171 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 172 GOST_R_CANNOT_PACK_EPHEMERAL_KEY); 173 goto err; 174 } 175 if (out) 176 EVP_PKEY_free(mykey); 177 } 178 ASN1_OBJECT_free(gkt->key_agreement_info->cipher); 179 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); 180 tmp_outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL); 181 if (tmp_outlen <= 0) { 182 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 183 GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO); 184 goto err; 185 } 186 *outlen = tmp_outlen; 187 if (!key_is_ephemeral) { 188 /* Set control "public key from client certificate used" */ 189 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 190 0) { 191 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED); 192 goto err; 193 } 194 } 195 GOST_KEY_TRANSPORT_free(gkt); 196 return 1; 197 memerr: 198 if (key_is_ephemeral) { 199 EVP_PKEY_free(mykey); 200 } 201 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_MALLOC_FAILURE); 202 err: 203 GOST_KEY_TRANSPORT_free(gkt); 204 return -1; 205} 206 207/* 208 * EVP_PLEY_METHOD callback decrypt for GOST R 34.10-94 cryptopro 209 * modification 210 */ 211int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, 212 size_t *key_len, const unsigned char *in, 213 size_t in_len) 214{ 215 const unsigned char *p = in; 216 GOST_KEY_TRANSPORT *gkt = NULL; 217 unsigned char wrappedKey[44]; 218 unsigned char sharedKey[32]; 219 gost_ctx cctx; 220 const struct gost_cipher_info *param = NULL; 221 EVP_PKEY *eph_key = NULL, *peerkey = NULL; 222 EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(ctx); 223 224 if (!key) { 225 *key_len = 32; 226 return 1; 227 } 228 229 gkt = d2i_GOST_KEY_TRANSPORT(NULL, (const unsigned char **)&p, in_len); 230 if (!gkt) { 231 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 232 GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); 233 return 0; 234 } 235 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); 236 if (eph_key) { 237 if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0) { 238 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 239 GOST_R_INCOMPATIBLE_PEER_KEY); 240 goto err; 241 } 242 } else { 243 /* Set control "public key from client certificate used" */ 244 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 245 0) { 246 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_CTRL_CALL_FAILED); 247 goto err; 248 } 249 } 250 peerkey = EVP_PKEY_CTX_get0_peerkey(ctx); 251 if (!peerkey) { 252 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_NO_PEER_KEY); 253 goto err; 254 } 255 256 param = get_encryption_params(gkt->key_agreement_info->cipher); 257 if (!param) { 258 goto err; 259 } 260 261 gost_init(&cctx, param->sblock); 262 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length == 8); 263 memcpy(wrappedKey, gkt->key_agreement_info->eph_iv->data, 8); 264 OPENSSL_assert(gkt->key_info->encrypted_key->length == 32); 265 memcpy(wrappedKey + 8, gkt->key_info->encrypted_key->data, 32); 266 OPENSSL_assert(gkt->key_info->imit->length == 4); 267 memcpy(wrappedKey + 40, gkt->key_info->imit->data, 4); 268 make_cp_exchange_key(gost_get0_priv_key(priv), peerkey, sharedKey); 269 if (!keyUnwrapCryptoPro(&cctx, sharedKey, wrappedKey, key)) { 270 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 271 GOST_R_ERROR_COMPUTING_SHARED_KEY); 272 goto err; 273 } 274 275 EVP_PKEY_free(eph_key); 276 GOST_KEY_TRANSPORT_free(gkt); 277 return 1; 278 err: 279 EVP_PKEY_free(eph_key); 280 GOST_KEY_TRANSPORT_free(gkt); 281 return -1; 282} 283