/*
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* Copyright 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <keymaster/km_openssl/aes_key.h>
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#include <assert.h>
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#include <keymaster/new>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include "aes_operation.h"
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namespace keymaster {
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static AesOperationFactory encrypt_factory(KM_PURPOSE_ENCRYPT);
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static AesOperationFactory decrypt_factory(KM_PURPOSE_DECRYPT);
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OperationFactory* AesKeyFactory::GetOperationFactory(keymaster_purpose_t purpose) const {
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switch (purpose) {
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case KM_PURPOSE_ENCRYPT:
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return &encrypt_factory;
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case KM_PURPOSE_DECRYPT:
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return &decrypt_factory;
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default:
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return nullptr;
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}
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}
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keymaster_error_t AesKeyFactory::LoadKey(KeymasterKeyBlob&& key_material,
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const AuthorizationSet& /* additional_params */,
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AuthorizationSet&& hw_enforced,
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AuthorizationSet&& sw_enforced,
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UniquePtr<Key>* key) const {
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if (!key)
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return KM_ERROR_OUTPUT_PARAMETER_NULL;
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uint32_t min_mac_length = 0;
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if (hw_enforced.Contains(TAG_BLOCK_MODE, KM_MODE_GCM) ||
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sw_enforced.Contains(TAG_BLOCK_MODE, KM_MODE_GCM)) {
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if (!hw_enforced.GetTagValue(TAG_MIN_MAC_LENGTH, &min_mac_length) &&
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!sw_enforced.GetTagValue(TAG_MIN_MAC_LENGTH, &min_mac_length)) {
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LOG_E("AES-GCM key must have KM_TAG_MIN_MAC_LENGTH", 0);
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return KM_ERROR_INVALID_KEY_BLOB;
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}
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}
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keymaster_error_t error = KM_ERROR_OK;
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key->reset(new (std::nothrow) AesKey(move(key_material), move(hw_enforced), move(sw_enforced),
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this));
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if (!key->get())
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error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
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return error;
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}
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keymaster_error_t AesKeyFactory::validate_algorithm_specific_new_key_params(
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const AuthorizationSet& key_description) const {
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if (key_description.Contains(TAG_BLOCK_MODE, KM_MODE_GCM)) {
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uint32_t min_tag_length;
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if (!key_description.GetTagValue(TAG_MIN_MAC_LENGTH, &min_tag_length))
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return KM_ERROR_MISSING_MIN_MAC_LENGTH;
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if (min_tag_length % 8 != 0)
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return KM_ERROR_UNSUPPORTED_MIN_MAC_LENGTH;
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if (min_tag_length < kMinGcmTagLength || min_tag_length > kMaxGcmTagLength)
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return KM_ERROR_UNSUPPORTED_MIN_MAC_LENGTH;
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} else {
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// Not GCM
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if (key_description.find(TAG_MIN_MAC_LENGTH) != -1) {
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LOG_W("KM_TAG_MIN_MAC_LENGTH found for non AES-GCM key", 0);
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return KM_ERROR_INVALID_TAG;
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}
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}
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return KM_ERROR_OK;
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}
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} // namespace keymaster
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