624be586a5bbceaab80417e8ffd6c2571b983f5b
[openssl.git] / 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         gost_init(&cctx,param->sblock); 
265         OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
266         memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
267         OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
268         memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
269         OPENSSL_assert(gkt->key_info->imit->length==4);
270         memcpy(wrappedKey+40,gkt->key_info->imit->data,4);      
271         make_cp_exchange_key(gost_get0_priv_key(priv),peerkey,sharedKey);
272         if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key))
273                 {
274                 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
275                         GOST_R_ERROR_COMPUTING_SHARED_KEY);
276                 goto err;
277                 }       
278                                 
279         EVP_PKEY_free(eph_key);
280         GOST_KEY_TRANSPORT_free(gkt);
281         return 1;
282 err:
283         EVP_PKEY_free(eph_key);
284         GOST_KEY_TRANSPORT_free(gkt);
285         return -1;
286         }       
287