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/*
* Copyright (C) 2016 Red Hat
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>
*
*/
#include "gnutls_int.h"
#include <datum.h>
#include <global.h>
#include "errors.h"
#include <common.h>
#include <x509.h>
#include <x509_b64.h>
#include "x509_int.h"
#include "pkcs7_int.h"
#include <algorithms.h>
#include <nettle/md5.h>
/* This file includes support for PKCS#8 PBES1 with DES and MD5.
* We only support decryption for compatibility with other software.
*/
int _gnutls_read_pbkdf1_params(const uint8_t * data, int data_size,
struct pbkdf2_params *kdf_params,
struct pbe_enc_params *enc_params)
{
ASN1_TYPE pasn = ASN1_TYPE_EMPTY;
int len;
int ret, result;
memset(kdf_params, 0, sizeof(*kdf_params));
memset(enc_params, 0, sizeof(*enc_params));
if ((result =
asn1_create_element(_gnutls_get_pkix(),
"PKIX1.pkcs-5-PBE-params",
&pasn)) != ASN1_SUCCESS) {
gnutls_assert();
return _gnutls_asn2err(result);
}
/* Decode the parameters.
*/
result =
_asn1_strict_der_decode(&pasn, data, data_size, NULL);
if (result != ASN1_SUCCESS) {
gnutls_assert();
ret = _gnutls_asn2err(result);
goto error;
}
ret =
_gnutls_x509_read_uint(pasn, "iterationCount",
&kdf_params->iter_count);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (kdf_params->iter_count >= MAX_ITER_COUNT || kdf_params->iter_count == 0) {
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto error;
}
len = sizeof(kdf_params->salt);
result =
asn1_read_value(pasn, "salt",
kdf_params->salt, &len);
if (result != ASN1_SUCCESS) {
gnutls_assert();
ret = _gnutls_asn2err(result);
goto error;
}
if (len != 8) {
gnutls_assert();
ret = GNUTLS_E_ILLEGAL_PARAMETER;
goto error;
}
enc_params->cipher = GNUTLS_CIPHER_DES_CBC;
ret = 0;
error:
asn1_delete_structure2(&pasn, ASN1_DELETE_FLAG_ZEROIZE);
return ret;
}
static void pbkdf1_md5(const char *password, unsigned password_len,
const uint8_t salt[8], unsigned iter_count, unsigned key_size, uint8_t *key)
{
struct md5_ctx ctx;
uint8_t tmp[16];
unsigned i;
if (key_size > sizeof(tmp))
abort();
for (i=0;i<iter_count;i++) {
md5_init(&ctx);
if (i==0) {
md5_update(&ctx, password_len, (uint8_t*)password);
md5_update(&ctx, 8, salt);
md5_digest(&ctx, 16, tmp);
} else {
md5_update(&ctx, 16, tmp);
md5_digest(&ctx, 16, tmp);
}
}
memcpy(key, tmp, key_size);
return;
}
int
_gnutls_decrypt_pbes1_des_md5_data(const char *password,
unsigned password_len,
const struct pbkdf2_params *kdf_params,
const struct pbe_enc_params *enc_params,
const gnutls_datum_t *encrypted_data,
gnutls_datum_t *decrypted_data)
{
int result;
gnutls_datum_t dkey, d_iv;
cipher_hd_st ch;
uint8_t key[16];
const unsigned block_size = 8;
if (enc_params->cipher != GNUTLS_CIPHER_DES_CBC)
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (encrypted_data->size % block_size != 0)
return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
/* generate the key
*/
pbkdf1_md5(password, password_len, kdf_params->salt, kdf_params->iter_count, sizeof(key), key);
dkey.data = key;
dkey.size = 8;
d_iv.data = &key[8];
d_iv.size = 8;
result =
_gnutls_cipher_init(&ch, cipher_to_entry(GNUTLS_CIPHER_DES_CBC),
&dkey, &d_iv, 0);
if (result < 0)
return gnutls_assert_val(result);
result = _gnutls_cipher_decrypt(&ch, encrypted_data->data, encrypted_data->size);
if (result < 0) {
gnutls_assert();
goto error;
}
if ((int)encrypted_data->size - encrypted_data->data[encrypted_data->size - 1] < 0) {
gnutls_assert();
result = GNUTLS_E_ILLEGAL_PARAMETER;
goto error;
}
decrypted_data->data = encrypted_data->data;
decrypted_data->size = encrypted_data->size - encrypted_data->data[encrypted_data->size - 1];
result = 0;
error:
_gnutls_cipher_deinit(&ch);
return result;
}
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