gost2001_keyx.c revision 296341 
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 */
22static 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 */
73int 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
115int 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 */
217int 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}
293