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openssl/engines/ccgost/gost94_keyx.c
Dr. Stephen Henson ae7c67cace PR: 2254 
Submitted by: Ger Hobbelt <ger@hobbelt.com>
Approved by: steve@openssl.org

Check for <= 0 i2d return value.
2010-05-22 00:40:38 +00:00

287 lines
7.7 KiB
C
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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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