km_openssl/asymmetric_key.cpp

/*
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <keymaster/km_openssl/asymmetric_key.h>

#include <keymaster/new>

#include <openssl/asn1.h>
#include <openssl/stack.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

#include <keymaster/android_keymaster_utils.h>
#include <keymaster/attestation_record.h>
#include <keymaster/keymaster_context.h>
#include <keymaster/km_openssl/openssl_err.h>
#include <keymaster/km_openssl/openssl_utils.h>


namespace keymaster {

keymaster_error_t AsymmetricKey::formatted_key_material(keymaster_key_format_t format,
                                                        UniquePtr<uint8_t[]>* material,
                                                        size_t* size) const {
    if (format != KM_KEY_FORMAT_X509)
        return KM_ERROR_UNSUPPORTED_KEY_FORMAT;

    if (material == nullptr || size == nullptr)
        return KM_ERROR_OUTPUT_PARAMETER_NULL;

    EVP_PKEY_Ptr pkey(EVP_PKEY_new());
    if (!InternalToEvp(pkey.get()))
        return TranslateLastOpenSslError();

    int key_data_length = i2d_PUBKEY(pkey.get(), nullptr);
    if (key_data_length <= 0)
        return TranslateLastOpenSslError();

    material->reset(new(std::nothrow) uint8_t[key_data_length]);
    if (material->get() == nullptr)
        return KM_ERROR_MEMORY_ALLOCATION_FAILED;

    uint8_t* tmp = material->get();
    if (i2d_PUBKEY(pkey.get(), &tmp) != key_data_length) {
        material->reset();
        return TranslateLastOpenSslError();
    }

    *size = key_data_length;
    return KM_ERROR_OK;
}

}  // namespace keymaster