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