engines/ccgost/gost94_keyx.c

   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 /* Implementation of the Diffi-Hellman key agreement scheme based on
  24  * GOST-94 keys */
  25
  26 /* Computes Diffie-Hellman key and stores it into buffer in
  27  * little-endian byte order as expected by both versions of GOST 94
  28  * algorithm
  29  */
  30 static int compute_pair_key_le(unsigned char *pair_key,BIGNUM *pub_key,DH *dh)
  31         {
  32         unsigned char be_key[128];
  33         int i,key_size;
  34         key_size=DH_compute_key(be_key,pub_key,dh);
  35         if (!key_size) return 0;
  36         memset(pair_key,0,128);
  37         for (i=0;i<key_size;i++)
  38                 {
  39                 pair_key[i]=be_key[key_size-1-i];
  40                 }
  41         return key_size;
  42         }
  43
  44 /*
  45  * Computes 256 bit Key exchange key as specified in RFC 4357
  46  */
  47 static int make_cp_exchange_key(BIGNUM *priv_key,EVP_PKEY *pubk, unsigned char *shared_key)
  48         {
  49         unsigned char dh_key [128];
  50         int ret;
  51         gost_hash_ctx hash_ctx;
  52         DH *dh = DH_new();
  53
  54         if (!dh)
  55                 return 0;
  56         memset(dh_key,0,128);
  57         dh->g = BN_dup(pubk->pkey.dsa->g);
  58         dh->p = BN_dup(pubk->pkey.dsa->p);
  59         dh->priv_key = BN_dup(priv_key);
  60         ret=compute_pair_key_le(dh_key,((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,dh) ;
  61         DH_free(dh);
  62         if (!ret)       return 0;
  63         init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
  64         start_hash(&hash_ctx);
  65         hash_block(&hash_ctx,dh_key,128);
  66         finish_hash(&hash_ctx,shared_key);
  67         done_gost_hash_ctx(&hash_ctx);
  68         return 1;
  69         }
  70
  71 /* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */
  72
  73 int pkey_gost94_derive(EVP_PKEY_CTX *ctx,unsigned char *key,size_t *keylen)
  74         {
  75                 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx);
  76                 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx);
  77                 *keylen = 32;
  78                 if (key == NULL) return 1;
  79
  80                 return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key);
  81         }
  82
  83 /* EVP_PKEY_METHOD callback encrypt for
  84  * GOST R 34.10-94 cryptopro modification
  85  */
  86
  87
  88 int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char* key, size_t key_len )
  89         {
  90         GOST_KEY_TRANSPORT *gkt=NULL;
  91         unsigned char shared_key[32], ukm[8],crypted_key[44];
  92         const struct gost_cipher_info *param=get_encryption_params(NULL);
  93         EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx);
  94         struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
  95         gost_ctx cctx;
  96         int key_is_ephemeral=1;
  97         EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx);
  98
  99         /* Do not use vizir cipher parameters with cryptopro */
 100         if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param ==  gost_cipher_list)
 101                 {
 102                 param= gost_cipher_list+1;
 103                 }
 104
 105         if (mykey)
 106                 {
 107                 /* If key already set, it is not ephemeral */
 108                 key_is_ephemeral=0;
 109                 if (!gost_get0_priv_key(mykey))
 110                         {
 111                         GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
 112                         GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR);
 113                         goto err;
 114                         }
 115                 }
 116         else
 117                 {
 118                 /* Otherwise generate ephemeral key */
 119                 key_is_ephemeral = 1;
 120                 if (out)
 121                         {
 122                         mykey = EVP_PKEY_new();
 123                         EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk),DSA_new());
 124                         EVP_PKEY_copy_parameters(mykey,pubk);
 125                         if (!gost_sign_keygen(EVP_PKEY_get0(mykey)))
 126                                 {
 127                                 goto err;
 128                                 }
 129                         }
 130                 }
 131         if (out)
 132                 make_cp_exchange_key(gost_get0_priv_key(mykey),pubk,shared_key);
 133         if (data->shared_ukm)
 134                 {
 135                 memcpy(ukm,data->shared_ukm,8);
 136                 }
 137         else if (out)
 138                 {
 139                 if (RAND_bytes(ukm,8)<=0)
 140                         {
 141                         GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
 142                                         GOST_R_RANDOM_GENERATOR_FAILURE);
 143                         goto err;
 144                         }
 145                 }
 146
 147         if (out) {
 148                 gost_init(&cctx,param->sblock);
 149                 keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key);
 150         }
 151         gkt = GOST_KEY_TRANSPORT_new();
 152         if (!gkt)
 153                 {
 154                 goto memerr;
 155                 }
 156         if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
 157                         ukm,8))
 158                 {
 159                 goto memerr;
 160                 }
 161         if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
 162                 {
 163                 goto memerr;
 164                 }
 165         if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
 166                 {
 167                 goto memerr;
 168                 }
 169         if (key_is_ephemeral) {
 170         if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,out?mykey:pubk))
 171                 {
 172                 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
 173                 goto err;
 174                 }
 175                 if (out) EVP_PKEY_free(mykey);
 176         }
 177         ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
 178         gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
 179         *outlen = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL);
 180         if (*outlen <= 0)
 181                 {
 182                 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
 183                 goto err;
 184                 }
 185         if (!key_is_ephemeral)
 186                 {
 187                 /* Set control "public key from client certificate used" */
 188                 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0)
 189                         {
 190                         GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
 191                                 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,
 202                 GOST_R_MALLOC_FAILURE);
 203         err:
 204         GOST_KEY_TRANSPORT_free(gkt);
 205         return -1;
 206         }
 207
 208
 209 /* EVP_PLEY_METHOD callback decrypt for
 210  * GOST R 34.10-94 cryptopro modification
 211  */
 212 int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *key_len,const unsigned char *in, size_t in_len) {
 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                 {
 224                 *key_len = 32;
 225                 return 1;
 226                 }
 227
 228         gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
 229                 in_len);
 230         if (!gkt)
 231                 {
 232                 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,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                 {
 238                 if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0)
 239                         {
 240                         GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
 241                                 GOST_R_INCOMPATIBLE_PEER_KEY);
 242                         goto err;
 243                         }
 244                 }
 245         else
 246                 {
 247                 /* Set control "public key from client certificate used" */
 248                 if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0)
 249                         {
 250                         GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
 251                                 GOST_R_CTRL_CALL_FAILED);
 252                         goto err;
 253                         }
 254                 }
 255         peerkey = EVP_PKEY_CTX_get0_peerkey(ctx);
 256         if (!peerkey)
 257                 {
 258                 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
 259                         GOST_R_NO_PEER_KEY);
 260                 goto err;
 261                 }
 262
 263         param = get_encryption_params(gkt->key_agreement_info->cipher);
 264     if(!param){
 265         goto err;
 266     }
 267
 268         gost_init(&cctx,param->sblock);
 269         OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
 270         memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
 271         OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
 272         memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
 273         OPENSSL_assert(gkt->key_info->imit->length==4);
 274         memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
 275         make_cp_exchange_key(gost_get0_priv_key(priv),peerkey,sharedKey);
 276         if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key))
 277                 {
 278                 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
 279                         GOST_R_ERROR_COMPUTING_SHARED_KEY);
 280                 goto err;
 281                 }
 282
 283         EVP_PKEY_free(eph_key);
 284         GOST_KEY_TRANSPORT_free(gkt);
 285         return 1;
 286 err:
 287         EVP_PKEY_free(eph_key);
 288         GOST_KEY_TRANSPORT_free(gkt);
 289         return -1;
 290         }
 291