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openssl/engines/ccgost/gost94_keyx.c
Matt Caswell 28ea6ad612 Fix error check in GOST engine 
The return value of i2d functions can be negative if an error occurs.
Therefore don't assign the return value to an unsigned type and *then*
check if it is negative.

RT#3862

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 90e7cdff3a)
2015-05-26 10:42:10 +01:00

280 lines
8.9 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;
int tmp_outlen;
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);
tmp_outlen = i2d_GOST_KEY_TRANSPORT(gkt, out ? &out : NULL);
if (tmp_outlen <= 0) {
GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
goto err;
}
*outlen = tmp_outlen;
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);
if (!param) {
goto err;
}
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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