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
  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_MAKE_RFC4490_KEYTRANSPORT_2001,
 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 ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL))>0) ret =1;
 207         GOST_KEY_TRANSPORT_free(gkt);
 208         return ret;
 209         err:
 210         if (key_is_ephemeral && sec_key) EVP_PKEY_free(sec_key);
 211         GOST_KEY_TRANSPORT_free(gkt);
 212         return -1;
 213         }
 214 /*
 215  * EVP_PKEY_METHOD callback decrypt
 216  * Implementation of GOST2001 key transport, cryptopo variation
 217  */
 218 int pkey_GOST01cp_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t * key_len, const unsigned char *in, size_t in_len)
 219         {
 220         const unsigned char *p = in;
 221         EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
 222         GOST_KEY_TRANSPORT *gkt = NULL;
 223         int ret=0;
 224         unsigned char wrappedKey[44];
 225         unsigned char sharedKey[32];
 226         gost_ctx ctx;
 227         const struct gost_cipher_info *param=NULL;
 228         EVP_PKEY *eph_key=NULL;
 229
 230         if (!key)
 231                 {
 232                 *key_len = 32;
 233                 return 1;
 234                 }
 235         gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
 236                 in_len);
 237         if (!gkt)
 238                 {
 239                 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
 240                 return -1;
 241                 }
 242
 243         eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
 244         if (!eph_key) {
 245                 eph_key = EVP_PKEY_CTX_get0_peerkey(pctx);
 246                 if (! eph_key) {
 247                         GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
 248                                 GOST_R_NO_PEER_KEY);
 249                         goto err;
 250                 }
 251                 /* Increment reference count of peer key */
 252                 CRYPTO_add(&(eph_key->references),1 ,CRYPTO_LOCK_EVP_PKEY);
 253         }
 254
 255         param = get_encryption_params(gkt->key_agreement_info->cipher);
 256         gost_init(&ctx,param->sblock);
 257         OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
 258         memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
 259         OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
 260         memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
 261         OPENSSL_assert(gkt->key_info->imit->length==4);
 262         memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
 263         VKO_compute_key(sharedKey,32,EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key)),
 264                 EVP_PKEY_get0(priv),wrappedKey);
 265         if (!keyUnwrapCryptoPro(&ctx,sharedKey,wrappedKey,key))
 266                 {
 267                 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,
 268                         GOST_R_ERROR_COMPUTING_SHARED_KEY);
 269                 goto err;
 270                 }
 271
 272         EVP_PKEY_free(eph_key);
 273         GOST_KEY_TRANSPORT_free(gkt);
 274         ret=1;
 275 err:
 276         return ret;
 277         }