gost94_keyx.c revision 296341
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 EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk), DSA_new()); 130 EVP_PKEY_copy_parameters(mykey, pubk); 131 if (!gost_sign_keygen(EVP_PKEY_get0(mykey))) { 132 goto err; 133 } 134 } 135 } 136 if (out) 137 make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, shared_key); 138 if (data->shared_ukm) { 139 memcpy(ukm, data->shared_ukm, 8); 140 } else if (out) { 141 if (RAND_bytes(ukm, 8) <= 0) { 142 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 143 GOST_R_RANDOM_GENERATOR_FAILURE); 144 goto err; 145 } 146 } 147 148 if (out) { 149 gost_init(&cctx, param->sblock); 150 keyWrapCryptoPro(&cctx, shared_key, ukm, key, crypted_key); 151 } 152 gkt = GOST_KEY_TRANSPORT_new(); 153 if (!gkt) { 154 goto memerr; 155 } 156 if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, ukm, 8)) { 157 goto memerr; 158 } 159 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit, crypted_key + 40, 4)) { 160 goto memerr; 161 } 162 if (!ASN1_OCTET_STRING_set 163 (gkt->key_info->encrypted_key, crypted_key + 8, 32)) { 164 goto memerr; 165 } 166 if (key_is_ephemeral) { 167 if (!X509_PUBKEY_set 168 (&gkt->key_agreement_info->ephem_key, out ? mykey : pubk)) { 169 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 170 GOST_R_CANNOT_PACK_EPHEMERAL_KEY); 171 goto err; 172 } 173 if (out) 174 EVP_PKEY_free(mykey); 175 } 176 ASN1_OBJECT_free(gkt->key_agreement_info->cipher); 177 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); 178 tmp_outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL); 179 if (tmp_outlen <= 0) { 180 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, 181 GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO); 182 goto err; 183 } 184 *outlen = tmp_outlen; 185 if (!key_is_ephemeral) { 186 /* Set control "public key from client certificate used" */ 187 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 188 0) { 189 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_CTRL_CALL_FAILED); 190 goto err; 191 } 192 } 193 GOST_KEY_TRANSPORT_free(gkt); 194 return 1; 195 memerr: 196 if (key_is_ephemeral) { 197 EVP_PKEY_free(mykey); 198 } 199 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, GOST_R_MALLOC_FAILURE); 200 err: 201 GOST_KEY_TRANSPORT_free(gkt); 202 return -1; 203} 204 205/* 206 * EVP_PLEY_METHOD callback decrypt for GOST R 34.10-94 cryptopro 207 * modification 208 */ 209int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, 210 size_t *key_len, const unsigned char *in, 211 size_t in_len) 212{ 213 const unsigned char *p = in; 214 GOST_KEY_TRANSPORT *gkt = NULL; 215 unsigned char wrappedKey[44]; 216 unsigned char sharedKey[32]; 217 gost_ctx cctx; 218 const struct gost_cipher_info *param = NULL; 219 EVP_PKEY *eph_key = NULL, *peerkey = NULL; 220 EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(ctx); 221 222 if (!key) { 223 *key_len = 32; 224 return 1; 225 } 226 227 gkt = d2i_GOST_KEY_TRANSPORT(NULL, (const unsigned char **)&p, in_len); 228 if (!gkt) { 229 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 230 GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); 231 return 0; 232 } 233 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); 234 if (eph_key) { 235 if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0) { 236 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 237 GOST_R_INCOMPATIBLE_PEER_KEY); 238 goto err; 239 } 240 } else { 241 /* Set control "public key from client certificate used" */ 242 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 243 0) { 244 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_CTRL_CALL_FAILED); 245 goto err; 246 } 247 } 248 peerkey = EVP_PKEY_CTX_get0_peerkey(ctx); 249 if (!peerkey) { 250 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, GOST_R_NO_PEER_KEY); 251 goto err; 252 } 253 254 param = get_encryption_params(gkt->key_agreement_info->cipher); 255 if (!param) { 256 goto err; 257 } 258 259 gost_init(&cctx, param->sblock); 260 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length == 8); 261 memcpy(wrappedKey, gkt->key_agreement_info->eph_iv->data, 8); 262 OPENSSL_assert(gkt->key_info->encrypted_key->length == 32); 263 memcpy(wrappedKey + 8, gkt->key_info->encrypted_key->data, 32); 264 OPENSSL_assert(gkt->key_info->imit->length == 4); 265 memcpy(wrappedKey + 40, gkt->key_info->imit->data, 4); 266 make_cp_exchange_key(gost_get0_priv_key(priv), peerkey, sharedKey); 267 if (!keyUnwrapCryptoPro(&cctx, sharedKey, wrappedKey, key)) { 268 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, 269 GOST_R_ERROR_COMPUTING_SHARED_KEY); 270 goto err; 271 } 272 273 EVP_PKEY_free(eph_key); 274 GOST_KEY_TRANSPORT_free(gkt); 275 return 1; 276 err: 277 EVP_PKEY_free(eph_key); 278 GOST_KEY_TRANSPORT_free(gkt); 279 return -1; 280} 281