1 // 2 // Copyright (C) 2020 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 16 #pragma once 17 18 #include <string> 19 20 #include <json/json.h> 21 #include <tss2/tss2_tpm2_types.h> 22 23 #include "host/commands/secure_env/gatekeeper_storage.h" 24 #include "host/commands/secure_env/tpm_resource_manager.h" 25 26 /** 27 * A GatekeeperStorage fallback implementation that is less secure. It uses an 28 * index file that is signed and encrypted by the TPM and the sensitive data 29 * is contained inside the index file. This file can be deleted or corrupted 30 * to lose access to the data inside, and is also susceptible to replay attacks. 31 * If the index file is replaced with an older version and the secure 32 * environment is restarted, it will still accept the old file with the old 33 * data. 34 * 35 * This class is not thread-safe, and should be synchronized externally if it 36 * is going to be used from multiple threads. 37 */ 38 class InsecureFallbackStorage : public GatekeeperStorage { 39 public: 40 InsecureFallbackStorage(TpmResourceManager&, const std::string& index_file); 41 ~InsecureFallbackStorage() = default; 42 43 bool Allocate(const Json::Value& key, uint16_t size) override; 44 bool HasKey(const Json::Value& key) const override; 45 46 std::unique_ptr<TPM2B_MAX_NV_BUFFER> Read(const Json::Value& key) const 47 override; 48 bool Write(const Json::Value& key, const TPM2B_MAX_NV_BUFFER& data) override; 49 private: 50 Json::Value* GetEntry(const Json::Value& key); 51 const Json::Value* GetEntry(const Json::Value& key) const; 52 53 TpmResourceManager& resource_manager_; 54 std::string index_file_; 55 Json::Value index_; 56 }; 57