141 lines
5.3 KiB
C++
141 lines
5.3 KiB
C++
/*
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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 "symmetric_key.h"
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#include <assert.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include <keymaster/android_keymaster_utils.h>
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#include <keymaster/logger.h>
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#include <keymaster/keymaster_context.h>
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#include "aes_key.h"
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#include "hmac_key.h"
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#include "openssl_err.h"
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namespace keymaster {
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keymaster_error_t SymmetricKeyFactory::GenerateKey(const AuthorizationSet& key_description,
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KeymasterKeyBlob* key_blob,
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AuthorizationSet* hw_enforced,
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AuthorizationSet* sw_enforced) const {
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if (!key_blob || !hw_enforced || !sw_enforced)
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return KM_ERROR_OUTPUT_PARAMETER_NULL;
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uint32_t key_size_bits;
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if (!key_description.GetTagValue(TAG_KEY_SIZE, &key_size_bits) ||
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!key_size_supported(key_size_bits))
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return KM_ERROR_UNSUPPORTED_KEY_SIZE;
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keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
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if (error != KM_ERROR_OK)
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return error;
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size_t key_data_size = key_size_bits / 8;
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KeymasterKeyBlob key_material(key_data_size);
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if (!key_material.key_material)
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return KM_ERROR_MEMORY_ALLOCATION_FAILED;
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error = context_->GenerateRandom(key_material.writable_data(), key_data_size);
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if (error != KM_ERROR_OK) {
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LOG_E("Error generating %d bit symmetric key", key_size_bits);
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return error;
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}
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return context_->CreateKeyBlob(key_description, KM_ORIGIN_GENERATED, key_material, key_blob,
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hw_enforced, sw_enforced);
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}
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keymaster_error_t SymmetricKeyFactory::ImportKey(const AuthorizationSet& key_description,
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keymaster_key_format_t input_key_material_format,
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const KeymasterKeyBlob& input_key_material,
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KeymasterKeyBlob* output_key_blob,
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AuthorizationSet* hw_enforced,
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AuthorizationSet* sw_enforced) const {
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if (!output_key_blob || !hw_enforced || !sw_enforced)
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return KM_ERROR_OUTPUT_PARAMETER_NULL;
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AuthorizationSet authorizations(key_description);
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uint32_t key_size_bits;
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if (!authorizations.GetTagValue(TAG_KEY_SIZE, &key_size_bits)) {
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// Default key size if not specified.
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key_size_bits = input_key_material.key_material_size * 8;
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authorizations.push_back(TAG_KEY_SIZE, key_size_bits);
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}
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keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
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if (error != KM_ERROR_OK)
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return error;
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if (!key_size_supported(key_size_bits))
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return KM_ERROR_UNSUPPORTED_KEY_SIZE;
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if (input_key_material_format != KM_KEY_FORMAT_RAW)
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return KM_ERROR_UNSUPPORTED_KEY_FORMAT;
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if (key_size_bits != input_key_material.key_material_size * 8) {
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LOG_E("Expected %d-bit key data but got %d bits", key_size_bits,
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input_key_material.key_material_size * 8);
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return KM_ERROR_INVALID_KEY_BLOB;
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}
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return context_->CreateKeyBlob(authorizations, KM_ORIGIN_IMPORTED, input_key_material,
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output_key_blob, hw_enforced, sw_enforced);
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}
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static const keymaster_key_format_t supported_import_formats[] = {KM_KEY_FORMAT_RAW};
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const keymaster_key_format_t*
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SymmetricKeyFactory::SupportedImportFormats(size_t* format_count) const {
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*format_count = array_length(supported_import_formats);
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return supported_import_formats;
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}
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SymmetricKey::SymmetricKey(const KeymasterKeyBlob& key_material,
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const AuthorizationSet& hw_enforced, const AuthorizationSet& sw_enforced,
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keymaster_error_t* error)
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: Key(hw_enforced, sw_enforced, error) {
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if (*error != KM_ERROR_OK)
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return;
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uint8_t* tmp = dup_buffer(key_material.key_material, key_material.key_material_size);
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if (tmp) {
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key_data_.reset(tmp);
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key_data_size_ = key_material.key_material_size;
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*error = KM_ERROR_OK;
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} else {
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*error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
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}
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}
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SymmetricKey::~SymmetricKey() {
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memset_s(key_data_.get(), 0, key_data_size_);
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}
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keymaster_error_t SymmetricKey::key_material(UniquePtr<uint8_t[]>* key_material,
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size_t* size) const {
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*size = key_data_size_;
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key_material->reset(new (std::nothrow) uint8_t[*size]);
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if (!key_material->get())
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return KM_ERROR_MEMORY_ALLOCATION_FAILED;
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memcpy(key_material->get(), key_data_.get(), *size);
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return KM_ERROR_OK;
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}
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} // namespace keymaster
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