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