1 /********************************************************************** 2 * gost_keyx.c * 3 * Copyright (c) 2005-2006 Cryptocom LTD * 4 * This file is distributed under the same license as OpenSSL * 5 * * 6 * VK0 34.10-2001 key exchange and GOST R 34.10-2001 * 7 * based PKCS7/SMIME support * 8 * Requires OpenSSL 0.9.9 for compilation * 9 **********************************************************************/ 10 #include <openssl/evp.h> 11 #include <openssl/rand.h> 12 #include <string.h> 13 #include <openssl/objects.h> 14 #include "gost89.h" 15 #include "gosthash.h" 16 #include "e_gost_err.h" 17 #include "gost_keywrap.h" 18 #include "gost_lcl.h" 19 #include "gost2001_keyx.h" 20 21 22 23 /* Implementation of CryptoPro VKO 34.10-2001 algorithm */ 24 static int VKO_compute_key(unsigned char *shared_key,size_t shared_key_size,const EC_POINT *pub_key,EC_KEY *priv_key,const unsigned char *ukm) 25 { 26 unsigned char ukm_be[8],databuf[64],hashbuf[64]; 27 BIGNUM *UKM=NULL,*p=NULL,*order=NULL,*X=NULL,*Y=NULL; 28 const BIGNUM* key=EC_KEY_get0_private_key(priv_key); 29 EC_POINT *pnt=EC_POINT_new(EC_KEY_get0_group(priv_key)); 30 int i; 31 gost_hash_ctx hash_ctx; 32 BN_CTX *ctx = BN_CTX_new(); 33 34 for (i=0;i<8;i++) 35 { 36 ukm_be[7-i]=ukm[i]; 37 } 38 BN_CTX_start(ctx); 39 UKM=getbnfrombuf(ukm_be,8); 40 p=BN_CTX_get(ctx); 41 order = BN_CTX_get(ctx); 42 X=BN_CTX_get(ctx); 43 Y=BN_CTX_get(ctx); 44 EC_GROUP_get_order(EC_KEY_get0_group(priv_key),order,ctx); 45 BN_mod_mul(p,key,UKM,order,ctx); 46 EC_POINT_mul(EC_KEY_get0_group(priv_key),pnt,NULL,pub_key,p,ctx); 47 EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(priv_key), 48 pnt,X,Y,ctx); 49 /*Serialize elliptic curve point same way as we do it when saving 50 * key */ 51 store_bignum(Y,databuf,32); 52 store_bignum(X,databuf+32,32); 53 /* And reverse byte order of whole buffer */ 54 for (i=0;i<64;i++) 55 { 56 hashbuf[63-i]=databuf[i]; 57 } 58 init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet); 59 start_hash(&hash_ctx); 60 hash_block(&hash_ctx,hashbuf,64); 61 finish_hash(&hash_ctx,shared_key); 62 done_gost_hash_ctx(&hash_ctx); 63 BN_free(UKM); 64 BN_CTX_end(ctx); 65 BN_CTX_free(ctx); 66 EC_POINT_free(pnt); 67 return 32; 68 } 69 70 71 /* 72 * EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-2001 73 * algorithm 74 */ 75 int pkey_gost2001_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen) 76 { 77 /* Public key of peer in the ctx field peerkey 78 * Our private key in the ctx pkey 79 * ukm is in the algorithm specific context data 80 */ 81 EVP_PKEY *my_key = EVP_PKEY_CTX_get0_pkey(ctx); 82 EVP_PKEY *peer_key = EVP_PKEY_CTX_get0_peerkey(ctx); 83 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); 84 85 if (!data->shared_ukm) { 86 GOSTerr(GOST_F_PKEY_GOST2001_DERIVE, GOST_R_UKM_NOT_SET); 87 return 0; 88 } 89 90 if (key == NULL) { 91 *keylen = 32; 92 return 32; 93 } 94 95 *keylen=VKO_compute_key(key, 32, EC_KEY_get0_public_key(EVP_PKEY_get0(peer_key)), 96 (EC_KEY *)EVP_PKEY_get0(my_key),data->shared_ukm); 97 return 1; 98 } 99 100 101 102 103 /* 104 * EVP_PKEY_METHOD callback encrypt 105 * Implementation of GOST2001 key transport, cryptocom variation 106 */ 107 /* Generates ephemeral key based on pubk algorithm 108 * computes shared key using VKO and returns filled up 109 * GOST_KEY_TRANSPORT structure 110 */ 111 112 /* 113 * EVP_PKEY_METHOD callback encrypt 114 * Implementation of GOST2001 key transport, cryptopo variation 115 */ 116 117 int pkey_GOST01cp_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out, size_t *out_len, const unsigned char *key,size_t key_len) 118 { 119 GOST_KEY_TRANSPORT *gkt=NULL; 120 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx); 121 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx); 122 const struct gost_cipher_info *param=get_encryption_params(NULL); 123 unsigned char ukm[8], shared_key[32], crypted_key[44]; 124 int ret=0; 125 int key_is_ephemeral=1; 126 gost_ctx cctx; 127 EVP_PKEY *sec_key=EVP_PKEY_CTX_get0_peerkey(pctx); 128 if (data->shared_ukm) 129 { 130 memcpy(ukm, data->shared_ukm,8); 131 } 132 else if (out) 133 { 134 135 if (RAND_bytes(ukm,8)<=0) 136 { 137 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT, 138 GOST_R_RANDOM_GENERATOR_FAILURE); 139 return 0; 140 } 141 } 142 /* Check for private key in the peer_key of context */ 143 if (sec_key) 144 { 145 key_is_ephemeral=0; 146 if (!gost_get0_priv_key(sec_key)) 147 { 148 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT, 149 GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR); 150 goto err; 151 } 152 } 153 else 154 { 155 key_is_ephemeral=1; 156 if (out) 157 { 158 sec_key = EVP_PKEY_new(); 159 EVP_PKEY_assign(sec_key,EVP_PKEY_base_id(pubk),EC_KEY_new()); 160 EVP_PKEY_copy_parameters(sec_key,pubk); 161 if (!gost2001_keygen(EVP_PKEY_get0(sec_key))) 162 { 163 goto err; 164 } 165 } 166 } 167 if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param == gost_cipher_list) 168 { 169 param= gost_cipher_list+1; 170 } 171 if (out) 172 { 173 VKO_compute_key(shared_key,32,EC_KEY_get0_public_key(EVP_PKEY_get0(pubk)),EVP_PKEY_get0(sec_key),ukm); 174 gost_init(&cctx,param->sblock); 175 keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key); 176 } 177 gkt = GOST_KEY_TRANSPORT_new(); 178 if (!gkt) 179 { 180 goto err; 181 } 182 if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, 183 ukm,8)) 184 { 185 goto err; 186 } 187 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4)) 188 { 189 goto err; 190 } 191 if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32)) 192 { 193 goto err; 194 } 195 if (key_is_ephemeral) { 196 if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,out?sec_key:pubk)) 197 { 198 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT, 199 GOST_R_CANNOT_PACK_EPHEMERAL_KEY); 200 goto err; 201 } 202 } 203 ASN1_OBJECT_free(gkt->key_agreement_info->cipher); 204 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); 205 if (key_is_ephemeral && sec_key) EVP_PKEY_free(sec_key); 206 if (!key_is_ephemeral) 207 { 208 /* Set control "public key from client certificate used" */ 209 if (EVP_PKEY_CTX_ctrl(pctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0) 210 { 211 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT, 212 GOST_R_CTRL_CALL_FAILED); 213 goto err; 214 } 215 } 216 if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL))>0) ret =1; 217 GOST_KEY_TRANSPORT_free(gkt); 218 return ret; 219 err: 220 if (key_is_ephemeral && sec_key) EVP_PKEY_free(sec_key); 221 GOST_KEY_TRANSPORT_free(gkt); 222 return -1; 223 } 224 /* 225 * EVP_PKEY_METHOD callback decrypt 226 * Implementation of GOST2001 key transport, cryptopo variation 227 */ 228 int pkey_GOST01cp_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key, size_t * key_len, const unsigned char *in, size_t in_len) 229 { 230 const unsigned char *p = in; 231 EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx); 232 GOST_KEY_TRANSPORT *gkt = NULL; 233 int ret=0; 234 unsigned char wrappedKey[44]; 235 unsigned char sharedKey[32]; 236 gost_ctx ctx; 237 const struct gost_cipher_info *param=NULL; 238 EVP_PKEY *eph_key=NULL, *peerkey=NULL; 239 240 if (!key) 241 { 242 *key_len = 32; 243 return 1; 244 } 245 gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p, 246 in_len); 247 if (!gkt) 248 { 249 GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); 250 return -1; 251 } 252 253 /* If key transport structure contains public key, use it */ 254 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); 255 if (eph_key) 256 { 257 if (EVP_PKEY_derive_set_peer(pctx, eph_key) <= 0) 258 { 259 GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, 260 GOST_R_INCOMPATIBLE_PEER_KEY); 261 goto err; 262 } 263 } 264 else 265 { 266 /* Set control "public key from client certificate used" */ 267 if (EVP_PKEY_CTX_ctrl(pctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0) 268 { 269 GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, 270 GOST_R_CTRL_CALL_FAILED); 271 goto err; 272 } 273 } 274 peerkey = EVP_PKEY_CTX_get0_peerkey(pctx); 275 if (!peerkey) 276 { 277 GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, 278 GOST_R_NO_PEER_KEY); 279 goto err; 280 } 281 282 param = get_encryption_params(gkt->key_agreement_info->cipher); 283 if(!param){ 284 goto err; 285 } 286 287 gost_init(&ctx,param->sblock); 288 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8); 289 memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8); 290 OPENSSL_assert(gkt->key_info->encrypted_key->length==32); 291 memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32); 292 OPENSSL_assert(gkt->key_info->imit->length==4); 293 memcpy(wrappedKey+40,gkt->key_info->imit->data,4); 294 VKO_compute_key(sharedKey,32,EC_KEY_get0_public_key(EVP_PKEY_get0(peerkey)), 295 EVP_PKEY_get0(priv),wrappedKey); 296 if (!keyUnwrapCryptoPro(&ctx,sharedKey,wrappedKey,key)) 297 { 298 GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT, 299 GOST_R_ERROR_COMPUTING_SHARED_KEY); 300 goto err; 301 } 302 303 ret=1; 304 err: 305 if (eph_key) EVP_PKEY_free(eph_key); 306 if (gkt) GOST_KEY_TRANSPORT_free(gkt); 307 return ret; 308 } 309