engines/ccgost/gost2001_keyx.c

   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 /* Transform ECDH shared key into little endian as required by Cryptocom
  22  * key exchange */
  23 static void *make_key_le(const void *in, size_t inlen, void *out, size_t *outlen)
  24         {
  25         const char* inbuf= in;
  26         char* outbuf= out;
  27         int i;
  28         if (*outlen < inlen)
  29                 {
  30                 return NULL;
  31                 }
  32         for (i=0;i<inlen;i++)
  33                 {
  34                 outbuf[inlen-1-i]=inbuf[i];
  35                 }
  36         *outlen = inlen;
  37         return out;
  38         }
  39
  40 /* Create gost 2001 ephemeral key with same parameters as peer key */
  41 static EC_KEY *make_ec_ephemeral_key(EC_KEY *peer_key,BIGNUM *seckey)
  42         {
  43         EC_KEY *out = EC_KEY_new();
  44         EC_KEY_copy(out,peer_key);
  45         EC_KEY_set_private_key(out,seckey);
  46         gost2001_compute_public(out);
  47         return out;
  48         }
  49 /* Packs GOST elliptic curve key into EVP_PKEY setting same parameters
  50  * as in passed pubkey
  51  */
  52 static EVP_PKEY *ec_ephemeral_key_to_EVP(EVP_PKEY *pubk,int type,EC_KEY *ephemeral)
  53         {
  54         EVP_PKEY *newkey;
  55         newkey = EVP_PKEY_new();
  56         EVP_PKEY_assign(newkey,type,ephemeral);
  57         return newkey;
  58         }
  59
  60 /*
  61  * EVP_PKEY_METHOD callback encrypt
  62  * Implementation of GOST2001 key transport, cryptocom variation
  63  */
  64
  65 int pkey_GOST01cc_encrypt (EVP_PKEY_CTX *pctx,unsigned char *out,
  66         size_t *out_len, const unsigned char *key,size_t key_len)
  67         {
  68         EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx);
  69         struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
  70         GOST_KEY_TRANSPORT *gkt = NULL;
  71         int ret=0;
  72         const struct gost_cipher_info *cipher_info;
  73         gost_ctx ctx;
  74         EC_KEY *ephemeral=NULL;
  75         const EC_POINT *pub_key_point=NULL;
  76         unsigned char shared_key[32],encrypted_key[32],hmac[4],
  77                 iv[8]={0,0,0,0,0,0,0,0};
  78         ephemeral = make_ec_ephemeral_key(EVP_PKEY_get0(pubk), gost_get_priv_key(data->eph_seckey));
  79         if (!ephemeral) goto err;
  80         /* compute shared key */
  81         pub_key_point=EC_KEY_get0_public_key(EVP_PKEY_get0(pubk));
  82         if (!ECDH_compute_key(shared_key,32,pub_key_point,ephemeral,make_key_le))
  83                 {
  84                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY);
  85                 goto err;
  86                 }
  87         /* encrypt session key */
  88         cipher_info = get_encryption_params(NULL);
  89         gost_init(&ctx, cipher_info->sblock);
  90         gost_key(&ctx,shared_key);
  91         encrypt_cryptocom_key(key,key_len,encrypted_key,&ctx);
  92         /* compute hmac of session key */
  93         if (!gost_mac(&ctx,32,key,32,hmac))
  94                 {
  95                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_COMPUTING_MAC);
  96                 return -1;
  97                 }
  98         gkt = GOST_KEY_TRANSPORT_new();
  99         if (!gkt)
 100                 {
 101                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_NO_MEMORY);
 102                 return -1;
 103                 }
 104         /* Store IV which is always zero in our case */
 105         if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,iv,8))
 106                 {
 107                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_IV);
 108                 goto err;
 109                 }
 110         if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,hmac,4))
 111                 {
 112                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_MAC);
 113                 goto err;
 114                 }
 115         if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,encrypted_key,32))
 116                 {
 117                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_ENCRYPTED_KEY);
 118                 goto err;
 119                 }
 120
 121         if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,data->eph_seckey))
 122                 {
 123                 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
 124                 goto err;
 125                 }
 126         ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
 127         gkt->key_agreement_info->cipher = OBJ_nid2obj(cipher_info->nid);
 128         if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,&out))>0) ret = 1;
 129         ;
 130         err:
 131         if (gkt) GOST_KEY_TRANSPORT_free(gkt);
 132         return ret;
 133         }
 134 /*
 135  * EVP_PKEY_METHOD callback decrypt
 136  * Implementation of GOST2001 key transport, cryptocom variation
 137  */
 138 int pkey_GOST01cc_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t *key_len, const unsigned char *in, size_t in_len)
 139         {
 140         /* Form DH params from compute shared key */
 141         EVP_PKEY *priv=EVP_PKEY_CTX_get0_pkey(pctx);
 142         GOST_KEY_TRANSPORT *gkt = NULL;
 143         const unsigned char *p=in;
 144         unsigned char shared_key[32];
 145         unsigned char hmac[4],hmac_comp[4];
 146         unsigned char iv[8];
 147         int i;
 148         const struct gost_cipher_info *cipher_info;
 149         gost_ctx ctx;
 150         const EC_POINT *pub_key_point;
 151         EVP_PKEY *eph_key;
 152
 153         if (!key)
 154                 {
 155                 *key_len = 32;
 156                 return 1;
 157                 }
 158         /* Parse passed octet string and find out public key, iv and HMAC*/
 159         gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
 160                 in_len);
 161         if (!gkt)
 162                 {
 163                 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
 164                 return 0;
 165                 }
 166         eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
 167         /* Initialization vector is really ignored here */
 168         OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
 169         memcpy(iv,gkt->key_agreement_info->eph_iv->data,8);
 170         /* HMAC should be computed and checked */
 171         OPENSSL_assert(gkt->key_info->imit->length==4);
 172         memcpy(hmac,gkt->key_info->imit->data,4);
 173         /* Compute shared key */
 174         pub_key_point=EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key));
 175         i=ECDH_compute_key(shared_key,32,pub_key_point,EVP_PKEY_get0(priv),make_key_le);
 176         EVP_PKEY_free(eph_key);
 177         if (!i)
 178                 {
 179                 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY);
 180                 GOST_KEY_TRANSPORT_free(gkt);
 181                 return 0;
 182                 }
 183         /* Decrypt session key */
 184         cipher_info = get_encryption_params(gkt->key_agreement_info->cipher);
 185         gost_init(&ctx, cipher_info->sblock);
 186         gost_key(&ctx,shared_key);
 187
 188         if (!decrypt_cryptocom_key(key,*key_len,gkt->key_info->encrypted_key->data,
 189                         gkt->key_info->encrypted_key->length, &ctx))
 190                 {
 191                 GOST_KEY_TRANSPORT_free(gkt);
 192                 return 0;
 193                 }
 194         GOST_KEY_TRANSPORT_free(gkt);
 195         /* check HMAC of session key*/
 196         if (!gost_mac(&ctx,32,key,32,hmac_comp))
 197                 {
 198                 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_COMPUTING_MAC);
 199                 return 0;
 200                 }
 201         /* HMAC of session key is not correct */
 202     if (memcmp(hmac,hmac_comp,4)!=0)
 203                 {
 204                 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_SESSION_KEY_MAC_DOES_NOT_MATCH);
 205                 return 0;
 206                 }
 207         return 1;
 208         }
 209
 210 /* Implementation of CryptoPro VKO 34.10-2001 algorithm */
 211 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)
 212         {
 213         unsigned char ukm_be[8],databuf[64],hashbuf[64];
 214         BIGNUM *UKM=NULL,*p=NULL,*order=NULL,*X=NULL,*Y=NULL;
 215         const BIGNUM* key=EC_KEY_get0_private_key(priv_key);
 216         EC_POINT *pnt=EC_POINT_new(EC_KEY_get0_group(priv_key));
 217         int i;
 218         gost_hash_ctx hash_ctx;
 219         BN_CTX *ctx = BN_CTX_new();
 220
 221         for (i=0;i<8;i++)
 222                 {
 223                 ukm_be[7-i]=ukm[i];
 224                 }
 225         BN_CTX_start(ctx);
 226         UKM=getbnfrombuf(ukm_be,8);
 227         p=BN_CTX_get(ctx);
 228         order = BN_CTX_get(ctx);
 229         X=BN_CTX_get(ctx);
 230         Y=BN_CTX_get(ctx);
 231         EC_GROUP_get_order(EC_KEY_get0_group(priv_key),order,ctx);
 232         BN_mod_mul(p,key,UKM,order,ctx);
 233         EC_POINT_mul(EC_KEY_get0_group(priv_key),pnt,NULL,pub_key,p,ctx);
 234         EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(priv_key),
 235                 pnt,X,Y,ctx);
 236         /*Serialize elliptic curve point same way as we do it when saving
 237          * key */
 238         store_bignum(Y,databuf,32);
 239         store_bignum(X,databuf+32,32);
 240         /* And reverse byte order of whole buffer */
 241         for (i=0;i<64;i++)
 242                 {
 243                 hashbuf[63-i]=databuf[i];
 244                 }
 245         init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
 246         start_hash(&hash_ctx);
 247         hash_block(&hash_ctx,hashbuf,64);
 248         finish_hash(&hash_ctx,shared_key);
 249         done_gost_hash_ctx(&hash_ctx);
 250         BN_free(UKM);
 251         BN_CTX_end(ctx);
 252         BN_CTX_free(ctx);
 253         EC_POINT_free(pnt);
 254         return 32;
 255         }
 256
 257 /* Generates ephemeral key based on pubk algorithm
 258  * computes shared key using VKO and returns filled up
 259  * GOST_KEY_TRANSPORT structure
 260  */
 261 /* Public, because it would be needed in SSL implementation */
 262 GOST_KEY_TRANSPORT *make_rfc4490_keytransport_2001(EVP_PKEY *pubk,BIGNUM *eph_key,
 263         const unsigned char *key,size_t keylen, unsigned char *ukm,
 264         size_t ukm_len)
 265         {
 266
 267         const struct gost_cipher_info *param=get_encryption_params(NULL);
 268         EC_KEY *ephemeral = NULL;
 269         GOST_KEY_TRANSPORT *gkt=NULL;
 270         const EC_POINT *pub_key_point = EC_KEY_get0_public_key(EVP_PKEY_get0(pubk));
 271         unsigned char shared_key[32],crypted_key[44];
 272         gost_ctx ctx;
 273         EVP_PKEY *newkey=NULL;
 274
 275         /* Do not use vizir cipher parameters with cryptopro */
 276         if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param ==  gost_cipher_list)
 277                 {
 278                 param= gost_cipher_list+1;
 279                 }
 280         ephemeral = make_ec_ephemeral_key(EVP_PKEY_get0(pubk),eph_key);
 281     VKO_compute_key(shared_key,32,pub_key_point,ephemeral,ukm);
 282         gost_init(&ctx,param->sblock);
 283         keyWrapCryptoPro(&ctx,shared_key,ukm,key,crypted_key);
 284         gkt = GOST_KEY_TRANSPORT_new();
 285         if (!gkt)
 286                 {
 287                 goto memerr;
 288                 }
 289         if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
 290                         ukm,8))
 291                 {
 292                 goto memerr;
 293                 }
 294         if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
 295                 {
 296                 goto memerr;
 297                 }
 298         if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
 299                 {
 300                 goto memerr;
 301                 }
 302         newkey = ec_ephemeral_key_to_EVP(pubk,NID_id_GostR3410_2001,ephemeral);
 303         if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,newkey))
 304                 {
 305                 GOSTerr(GOST_F_MAKE_RFC4490_KEYTRANSPORT_2001,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
 306                 goto err;
 307                 }
 308         ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
 309         gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
 310         EVP_PKEY_free(newkey);
 311         return gkt;
 312         memerr:
 313         GOSTerr(GOST_F_MAKE_RFC4490_KEYTRANSPORT_2001,
 314                 GOST_R_MALLOC_FAILURE);
 315         err:
 316         GOST_KEY_TRANSPORT_free(gkt);
 317         return NULL;
 318         }
 319
 320 /*
 321  * EVP_PKEY_METHOD callback encrypt
 322  * Implementation of GOST2001 key transport, cryptopo variation
 323  */
 324
 325 int pkey_GOST01cp_encrypt (EVP_PKEY_CTX *pctx, unsigned char *out, size_t *out_len, const unsigned char *key,size_t key_len)
 326         {
 327         GOST_KEY_TRANSPORT *gkt=NULL;
 328         EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx);
 329         struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
 330         unsigned char ukm[8];
 331         int ret=0;
 332         if (RAND_bytes(ukm,8)<=0)
 333                 {
 334                 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT,
 335                         GOST_R_RANDOM_GENERATOR_FAILURE);
 336                 return 0;
 337                 }
 338
 339         if (!(gkt=make_rfc4490_keytransport_2001(pubk,gost_get_priv_key(data->eph_seckey),key, key_len,ukm,8)))
 340                 {
 341                 goto err;
 342                 }
 343         if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,&out))>0) ret =1;
 344         GOST_KEY_TRANSPORT_free(gkt);
 345         return ret;
 346         err:
 347         GOST_KEY_TRANSPORT_free(gkt);
 348         return -1;
 349         }
 350 /* Public, because it would be needed in SSL implementation */
 351 int decrypt_rfc4490_shared_key_2001(EVP_PKEY *priv,GOST_KEY_TRANSPORT *gkt,
 352         unsigned char *key_buf,int key_buf_len)
 353         {
 354         unsigned char wrappedKey[44];
 355         unsigned char sharedKey[32];
 356         gost_ctx ctx;
 357         const struct gost_cipher_info *param=NULL;
 358         EVP_PKEY *eph_key=NULL;
 359
 360         eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
 361         param = get_encryption_params(gkt->key_agreement_info->cipher);
 362         gost_init(&ctx,param->sblock);
 363         OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
 364         memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
 365         OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
 366         memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
 367         OPENSSL_assert(gkt->key_info->imit->length==4);
 368         memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
 369         VKO_compute_key(sharedKey,32,EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key)),
 370                 EVP_PKEY_get0(priv),wrappedKey);
 371         if (!keyUnwrapCryptoPro(&ctx,sharedKey,wrappedKey,key_buf))
 372                 {
 373                 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,
 374                         GOST_R_ERROR_COMPUTING_SHARED_KEY);
 375                 goto err;
 376                 }
 377
 378         EVP_PKEY_free(eph_key);
 379         return 32;
 380         err:
 381         EVP_PKEY_free(eph_key);
 382         return -1;
 383         }
 384 /*
 385  * EVP_PKEY_METHOD callback decrypt
 386  * Implementation of GOST2001 key transport, cryptopo variation
 387  */
 388 int pkey_GOST01cp_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t * key_len, const unsigned char *in, size_t in_len)
 389         {
 390         const unsigned char *p = in;
 391         EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
 392         GOST_KEY_TRANSPORT *gkt = NULL;
 393         int ret=0;
 394
 395         if (!key)
 396                 {
 397                 *key_len = 32;
 398                 return 1;
 399                 }
 400         gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
 401                 in_len);
 402         if (!gkt)
 403                 {
 404                 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
 405                 return -1;
 406                 }
 407         ret =   decrypt_rfc4490_shared_key_2001(priv,gkt,key,*key_len);
 408         GOST_KEY_TRANSPORT_free(gkt);
 409         return ret;
 410         }