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- /**********************************************************************
- * gost94_keyx.c *
- * Copyright (c) 2005-2006 Cryptocom LTD *
- * This file is distributed under the same license as OpenSSL *
- * *
- * Implements generation and parsing of GOST_KEY_TRANSPORT for *
- * GOST R 34.10-94 algorithms *
- * *
- * Requires OpenSSL 0.9.9 for compilation *
- **********************************************************************/
- #include <string.h>
- #include <openssl/dh.h>
- #include <openssl/rand.h>
- #include <openssl/evp.h>
- #include <openssl/objects.h>
- #include "gost89.h"
- #include "gosthash.h"
- #include "e_gost_err.h"
- #include "gost_keywrap.h"
- #include "gost_lcl.h"
- /* Common functions for both 94 and 2001 key exchange schemes */
- /* Implementation of the Diffi-Hellman key agreement scheme based on
- * GOST-94 keys */
- /* Computes Diffie-Hellman key and stores it into buffer in
- * little-endian byte order as expected by both versions of GOST 94
- * algorithm
- */
- static int compute_pair_key_le(unsigned char *pair_key,BIGNUM *pub_key,DH *dh)
- {
- unsigned char be_key[128];
- int i,key_size;
- key_size=DH_compute_key(be_key,pub_key,dh);
- if (!key_size) return 0;
- memset(pair_key,0,128);
- for (i=0;i<key_size;i++)
- {
- pair_key[i]=be_key[key_size-1-i];
- }
- return key_size;
- }
- /*
- * Computes 256 bit Key exchange key as specified in RFC 4357
- */
- static int make_cp_exchange_key(BIGNUM *priv_key,EVP_PKEY *pubk, unsigned char *shared_key)
- {
- unsigned char dh_key [128];
- int ret;
- gost_hash_ctx hash_ctx;
- DH *dh = DH_new();
-
- if (!dh)
- return 0;
- memset(dh_key,0,128);
- dh->g = BN_dup(pubk->pkey.dsa->g);
- dh->p = BN_dup(pubk->pkey.dsa->p);
- dh->priv_key = BN_dup(priv_key);
- ret=compute_pair_key_le(dh_key,((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,dh) ;
- DH_free(dh);
- if (!ret) return 0;
- init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
- start_hash(&hash_ctx);
- hash_block(&hash_ctx,dh_key,128);
- finish_hash(&hash_ctx,shared_key);
- done_gost_hash_ctx(&hash_ctx);
- return 1;
- }
- /* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */
- int pkey_gost94_derive(EVP_PKEY_CTX *ctx,unsigned char *key,size_t *keylen)
- {
- EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx);
- EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx);
- *keylen = 32;
- if (key == NULL) return 1;
- return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key);
- }
- /* EVP_PKEY_METHOD callback encrypt for
- * GOST R 34.10-94 cryptopro modification
- */
- int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char* key, size_t key_len )
- {
- GOST_KEY_TRANSPORT *gkt=NULL;
- unsigned char shared_key[32], ukm[8],crypted_key[44];
- const struct gost_cipher_info *param=get_encryption_params(NULL);
- EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx);
- struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
- gost_ctx cctx;
- int key_is_ephemeral=1;
- EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx);
- /* Do not use vizir cipher parameters with cryptopro */
- if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param == gost_cipher_list)
- {
- param= gost_cipher_list+1;
- }
- if (mykey)
- {
- /* If key already set, it is not ephemeral */
- key_is_ephemeral=0;
- if (!gost_get0_priv_key(mykey))
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
- GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR);
- goto err;
- }
- }
- else
- {
- /* Otherwise generate ephemeral key */
- key_is_ephemeral = 1;
- if (out)
- {
- mykey = EVP_PKEY_new();
- EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk),DSA_new());
- EVP_PKEY_copy_parameters(mykey,pubk);
- if (!gost_sign_keygen(EVP_PKEY_get0(mykey)))
- {
- goto err;
- }
- }
- }
- if (out)
- make_cp_exchange_key(gost_get0_priv_key(mykey),pubk,shared_key);
- if (data->shared_ukm)
- {
- memcpy(ukm,data->shared_ukm,8);
- }
- else if (out)
- {
- if (RAND_bytes(ukm,8)<=0)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
- GOST_R_RANDOM_GENERATOR_FAILURE);
- goto err;
- }
- }
-
- if (out) {
- gost_init(&cctx,param->sblock);
- keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key);
- }
- gkt = GOST_KEY_TRANSPORT_new();
- if (!gkt)
- {
- goto memerr;
- }
- if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
- ukm,8))
- {
- goto memerr;
- }
- if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
- {
- goto memerr;
- }
- if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
- {
- goto memerr;
- }
- if (key_is_ephemeral) {
- if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,out?mykey:pubk))
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
- goto err;
- }
- if (out) EVP_PKEY_free(mykey);
- }
- ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
- gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
- *outlen = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL);
- if (*outlen <= 0)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
- goto err;
- }
- if (!key_is_ephemeral)
- {
- /* Set control "public key from client certificate used" */
- if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
- GOST_R_CTRL_CALL_FAILED);
- goto err;
- }
- }
- GOST_KEY_TRANSPORT_free(gkt);
- return 1;
- memerr:
- if (key_is_ephemeral) {
- EVP_PKEY_free(mykey);
- }
- GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
- GOST_R_MALLOC_FAILURE);
- err:
- GOST_KEY_TRANSPORT_free(gkt);
- return -1;
- }
-
- /* EVP_PLEY_METHOD callback decrypt for
- * GOST R 34.10-94 cryptopro modification
- */
- int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *key_len,const unsigned char *in, size_t in_len) {
- const unsigned char *p = in;
- GOST_KEY_TRANSPORT *gkt = NULL;
- unsigned char wrappedKey[44];
- unsigned char sharedKey[32];
- gost_ctx cctx;
- const struct gost_cipher_info *param=NULL;
- EVP_PKEY *eph_key=NULL, *peerkey=NULL;
- EVP_PKEY *priv= EVP_PKEY_CTX_get0_pkey(ctx);
-
- if (!key)
- {
- *key_len = 32;
- return 1;
- }
-
- gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
- in_len);
- if (!gkt)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
- return 0;
- }
- eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
- if (eph_key)
- {
- if (EVP_PKEY_derive_set_peer(ctx, eph_key) <= 0)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
- GOST_R_INCOMPATIBLE_PEER_KEY);
- goto err;
- }
- }
- else
- {
- /* Set control "public key from client certificate used" */
- if (EVP_PKEY_CTX_ctrl(ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
- GOST_R_CTRL_CALL_FAILED);
- goto err;
- }
- }
- peerkey = EVP_PKEY_CTX_get0_peerkey(ctx);
- if (!peerkey)
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
- GOST_R_NO_PEER_KEY);
- goto err;
- }
- param = get_encryption_params(gkt->key_agreement_info->cipher);
- gost_init(&cctx,param->sblock);
- OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
- memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
- OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
- memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
- OPENSSL_assert(gkt->key_info->imit->length==4);
- memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
- make_cp_exchange_key(gost_get0_priv_key(priv),peerkey,sharedKey);
- if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key))
- {
- GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
- GOST_R_ERROR_COMPUTING_SHARED_KEY);
- goto err;
- }
-
- EVP_PKEY_free(eph_key);
- GOST_KEY_TRANSPORT_free(gkt);
- return 1;
- err:
- EVP_PKEY_free(eph_key);
- GOST_KEY_TRANSPORT_free(gkt);
- return -1;
- }
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