sec-design.md

BUSINESS POSTURE

• Business Priorities and Goals:

• Provide a central, open-source platform for home automation.

• Support a wide range of smart home devices and protocols.

• Offer users local control and privacy for their smart home data.

• Foster a vibrant community of users and developers.

• Enable advanced automation and customization through scripting and integrations.

• Business Risks:

• Security vulnerabilities in the platform could compromise user privacy and security.

• Lack of reliability could disrupt critical home automation functions.

• Compatibility issues with new devices or protocols could limit platform adoption.

• Dependence on community contributions could lead to inconsistent quality or feature gaps.

• Negative publicity from security breaches or privacy incidents could damage reputation.

SECURITY POSTURE

• Existing Security Controls:

• security control: HTTPS for web interface access (implementation location: web server configuration).

• security control: User authentication (username/password, API keys) (implementation location: core application code).

• security control: Authorization based on user roles and permissions (implementation location: core application code).

• security control: Input validation on user inputs via web interface and APIs (implementation location: core application code).

• security control: Code reviews by maintainers and community contributors (implementation location: GitHub pull request process).

• security control: Static code analysis tools used in development (implementation location: CI/CD pipelines, if configured by developers).

• security control: Dependency scanning for known vulnerabilities (implementation location: CI/CD pipelines, if configured by developers).

• security control: Regular updates and security patches (implementation location: project release cycle and user update process).

• accepted risk: Reliance on user responsibility for secure deployment environment (e.g., network security, operating system security).

• accepted risk: Potential vulnerabilities in third-party integrations and custom components.

• Recommended Security Controls:

• security control: Implement automated security testing (SAST, DAST) in CI/CD pipelines.

• security control: Enhance input validation and sanitization to prevent injection attacks.

• security control: Implement rate limiting and防禦 mechanisms against brute-force attacks.

• security control: Provide guidance and tools for users to securely configure their deployments.

• security control: Establish a formal security incident response plan.

• security control: Conduct regular penetration testing or security audits.

• security control: Implement Content Security Policy (CSP) and other browser security headers.

• security control: Improve secrets management practices within the codebase and for user configurations.

• Security Requirements:

• Authentication:

• Requirement: Securely authenticate users accessing the web interface and APIs.

• Requirement: Support strong password policies and multi-factor authentication (MFA) options.

• Requirement: Implement secure session management to prevent session hijacking.

• Authorization:

• Requirement: Implement fine-grained authorization to control access to different features and entities based on user roles and permissions.

• Requirement: Enforce least privilege principle for user access.

• Requirement: Audit authorization decisions for security monitoring and incident response.

• Input Validation:

• Requirement: Validate all user inputs from web interface, APIs, and integrations to prevent injection attacks (e.g., SQL injection, command injection, cross-site scripting).

• Requirement: Sanitize user inputs before processing and storing them.

• Requirement: Implement input validation on both client-side and server-side.

• Cryptography:

• Requirement: Use strong cryptography for storing sensitive data (e.g., passwords, API keys).

• Requirement: Securely manage cryptographic keys.

• Requirement: Use TLS/SSL for all communication channels involving sensitive data.

• Requirement: Implement secure communication protocols for integrations with external devices and services.

DESIGN

• C4 CONTEXT

graph LR
    subgraph "Home Automation System"
        center "Home Assistant Core"
    end
    User[/"User"/] -- Uses --> center
    SmartHomeDevices[/"Smart Home Devices"/] -- Interacts with --> center
    ExternalServices[/"External Services (Cloud APIs, etc.)"/] -- Interacts with --> center
    Developer[/"Developer"/] -- Extends --> center

    style center fill:#f9f,stroke:#333,stroke-width:2px

Loading

• C4 CONTEXT Elements:

• • Name: User
  • Type: Person
  • Description: End-users who interact with Home Assistant Core to control and monitor their smart home.
  • Responsibilities:
  • Configure and manage their smart home devices through Home Assistant Core.
  • Create and manage automations and dashboards.
  • Monitor the status of their smart home.
  • Security controls:
  • security control: Strong passwords or MFA for user accounts.
  • security control: User access control and permissions within Home Assistant Core.
• • Name: Home Assistant Core
  • Type: Software System
  • Description: The central open-source home automation platform. It acts as a hub to control and automate smart home devices and integrate with external services.
  • Responsibilities:
  • Manage and control smart home devices.
  • Execute user-defined automations.
  • Provide a user interface for monitoring and control.
  • Integrate with external services and APIs.
  • Store and process smart home data.
  • Security controls:
  • security control: Authentication and authorization for user access.
  • security control: Input validation and sanitization.
  • security control: Secure storage of sensitive data.
  • security control: HTTPS for web interface.
  • security control: Regular security updates.
• • Name: Smart Home Devices
  • Type: External System
  • Description: Physical devices in the user's home that are controlled and monitored by Home Assistant Core (e.g., lights, sensors, thermostats, cameras).
  • Responsibilities:
  • Execute commands from Home Assistant Core.
  • Report status and sensor data to Home Assistant Core.
  • Communicate using various smart home protocols (e.g., Zigbee, Z-Wave, Wi-Fi, Bluetooth).
  • Security controls:
  • security control: Device-specific security features (varies by device).
  • security control: Network security to protect communication between devices and Home Assistant Core.
  • security control: Secure pairing and onboarding processes.
• • Name: External Services (Cloud APIs, etc.)
  • Type: External System
  • Description: Cloud-based services and APIs that Home Assistant Core integrates with to extend functionality (e.g., weather services, voice assistants, cloud storage).
  • Responsibilities:
  • Provide data and services to Home Assistant Core.
  • Authenticate and authorize Home Assistant Core's access.
  • Communicate over network APIs (e.g., REST, WebSockets).
  • Security controls:
  • security control: API authentication and authorization mechanisms (API keys, OAuth).
  • security control: Secure communication protocols (HTTPS).
  • security control: Data privacy and security policies of external service providers.
• • Name: Developer
  • Type: Person
  • Description: Software developers who contribute to the Home Assistant Core project by developing integrations, custom components, and core features.
  • Responsibilities:
  • Develop and maintain integrations for new devices and services.
  • Contribute to the core codebase.
  • Participate in code reviews and testing.
  • Security controls:
  • security control: Code review process to identify and mitigate security vulnerabilities.
  • security control: Secure development practices.
  • security control: Access control to the codebase and development infrastructure (GitHub).

• C4 CONTAINER

graph LR
    subgraph "Home Assistant Core"
        WebUI[/"Web UI Container"/]
        API[/"API Container"/]
        AutomationEngine[/"Automation Engine Container"/]
        DeviceIntegration[/"Device Integration Container"/]
        EventBus[/"Event Bus Container"/]
        Configuration[/"Configuration Container"/]
        Database[/"Database Container"/]

        WebUI -- Uses API
        API -- Uses AutomationEngine
        API -- Uses DeviceIntegration
        AutomationEngine -- Uses EventBus
        DeviceIntegration -- Uses EventBus
        DeviceIntegration -- Uses Configuration
        API -- Uses Configuration
        AutomationEngine -- Uses Configuration
        EventBus -- Uses Database
        Configuration -- Uses Database
    end
    User[/"User"/] -- Uses --> WebUI
    User -- Uses --> API
    SmartHomeDevices[/"Smart Home Devices"/] -- Interacts with --> DeviceIntegration
    ExternalServices[/"External Services"/] -- Interacts with --> DeviceIntegration

    style WebUI fill:#f9f,stroke:#333,stroke-width:2px
    style API fill:#f9f,stroke:#333,stroke-width:2px
    style AutomationEngine fill:#f9f,stroke:#333,stroke-width:2px
    style DeviceIntegration fill:#f9f,stroke:#333,stroke-width:2px
    style EventBus fill:#f9f,stroke:#333,stroke-width:2px
    style Configuration fill:#f9f,stroke:#333,stroke-width:2px
    style Database fill:#f9f,stroke:#333,stroke-width:2px

Loading

• C4 CONTAINER Elements:

• • Name: Web UI Container
  • Type: Web Application
  • Description: Provides the user interface for interacting with Home Assistant Core through a web browser.
  • Responsibilities:
  • Presenting dashboards and visualizations of smart home data.
  • Allowing users to control devices and manage automations.
  • Handling user authentication and authorization for web access.
  • Security controls:
  • security control: HTTPS for secure communication.
  • security control: Input validation on user inputs from the UI.
  • security control: Content Security Policy (CSP) to mitigate XSS attacks.
  • security control: Session management and protection against session hijacking.
• • Name: API Container
  • Type: API Application
  • Description: Exposes a RESTful API for programmatic access to Home Assistant Core functionalities. Used by the Web UI, mobile apps, and external integrations.
  • Responsibilities:
  • Providing endpoints for device control, automation management, and data retrieval.
  • Handling API authentication and authorization (API keys, tokens).
  • Rate limiting to prevent abuse.
  • Security controls:
  • security control: API authentication and authorization mechanisms.
  • security control: Input validation on API requests.
  • security control: Rate limiting and防禦 mechanisms.
  • security control: Secure API documentation and access control.
• • Name: Automation Engine Container
  • Type: Application Logic
  • Description: Processes and executes user-defined automations based on triggers and conditions.
  • Responsibilities:
  • Evaluating automation rules.
  • Triggering actions based on events and conditions.
  • Managing automation workflows.
  • Security controls:
  • security control: Secure processing of automation logic to prevent unintended actions.
  • security control: Authorization checks before executing sensitive actions.
  • security control: Logging and auditing of automation executions.
• • Name: Device Integration Container
  • Type: Integration Component
  • Description: Manages communication and integration with various smart home devices and protocols. Includes different integration modules for Zigbee, Z-Wave, Wi-Fi devices, etc.
  • Responsibilities:
  • Discovering and onboarding new devices.
  • Translating commands and data between Home Assistant Core and devices.
  • Handling device communication protocols.
  • Security controls:
  • security control: Secure device pairing and onboarding processes.
  • security control: Secure communication with devices (where protocols allow).
  • security control: Input validation of data received from devices.
  • security control: Isolation of integration modules to limit the impact of vulnerabilities.
• • Name: Event Bus Container
  • Type: Message Broker
  • Description: A central component for inter-container communication within Home Assistant Core. Facilitates asynchronous communication between different parts of the system.
  • Responsibilities:
  • Routing events and messages between containers.
  • Decoupling components and enabling event-driven architecture.
  • Security controls:
  • security control: Access control to the event bus to prevent unauthorized message publishing or consumption.
  • security control: Message integrity and confidentiality (if required for sensitive data).
• • Name: Configuration Container
  • Type: Data Store
  • Description: Manages the configuration of Home Assistant Core, including user settings, device configurations, and automation rules.
  • Responsibilities:
  • Storing and retrieving configuration data.
  • Providing configuration management APIs.
  • Security controls:
  • security control: Secure storage of configuration data, including sensitive information (e.g., API keys, passwords).
  • security control: Access control to configuration data.
  • security control: Backup and recovery mechanisms for configuration data.
• • Name: Database Container
  • Type: Data Store
  • Description: Stores historical data, event logs, and potentially some configuration data for Home Assistant Core.
  • Responsibilities:
  • Persisting data for long-term storage and analysis.
  • Providing data query and retrieval capabilities.
  • Security controls:
  • security control: Secure database configuration and access control.
  • security control: Encryption of sensitive data at rest (if required).
  • security control: Regular database backups.

• DEPLOYMENT

• Deployment Solution: Docker Container Deployment on User-Managed Infrastructure

graph LR
    subgraph "User Infrastructure"
        HostOS[/"Host OS (Linux, etc.)"/]
        DockerEngine[/"Docker Engine"/]
        subgraph "Home Assistant Core Deployment"
            HomeAssistantContainer[/"Home Assistant Core Container"/]
        end
        HostOS -- Runs --> DockerEngine
        DockerEngine -- Runs --> HomeAssistantContainer
    end
    UserNetwork[/"User Network"/] -- Connects to --> HostOS
    SmartHomeDevices[/"Smart Home Devices"/] -- Connects to --> UserNetwork
    ExternalServices[/"External Services"/] -- Connects to --> UserNetwork

    style HostOS fill:#ccf,stroke:#333,stroke-width:2px
    style DockerEngine fill:#ccf,stroke:#333,stroke-width:2px
    style HomeAssistantContainer fill:#f9f,stroke:#333,stroke-width:2px

Loading

• DEPLOYMENT Elements:

• • Name: Host OS (Linux, etc.)
  • Type: Infrastructure - Operating System
  • Description: The operating system running on the user's hardware (e.g., Linux, Raspberry Pi OS). Provides the base environment for Docker and Home Assistant Core.
  • Responsibilities:
  • Providing system resources (CPU, memory, storage).
  • Managing network connectivity.
  • Providing OS-level security features.
  • Security controls:
  • security control: Regular OS updates and patching.
  • security control: Host-based firewall.
  • security control: Secure OS configuration (e.g., disabling unnecessary services, strong passwords).
• • Name: Docker Engine
  • Type: Infrastructure - Container Runtime
  • Description: The container runtime environment used to run the Home Assistant Core Docker container.
  • Responsibilities:
  • Managing container lifecycle (creation, start, stop, deletion).
  • Providing container isolation and resource management.
  • Handling container networking and storage.
  • Security controls:
  • security control: Docker security best practices (e.g., using least privilege containers, image scanning).
  • security control: Docker daemon configuration and access control.
  • security control: Container image security scanning and vulnerability management.
• • Name: Home Assistant Core Container
  • Type: Software Container
  • Description: A Docker container encapsulating all the components of Home Assistant Core (Web UI, API, Automation Engine, etc.).
  • Responsibilities:
  • Running the Home Assistant Core application.
  • Exposing ports for web access and device communication.
  • Managing application-level security controls.
  • Security controls:
  • security control: Application-level security controls as described in previous sections (authentication, authorization, input validation, etc.).
  • security control: Container image built from trusted base images and regularly updated.
  • security control: Container resource limits to prevent resource exhaustion.
• • Name: User Network
  • Type: Network Infrastructure
  • Description: The user's home network, typically a private network behind a router/firewall. Connects Home Assistant Core, smart home devices, and external services.
  • Responsibilities:
  • Providing network connectivity for Home Assistant Core and devices.
  • Protecting the home network from external threats.
  • Security controls:
  • security control: Firewall to protect the network from external access.
  • security control: Wi-Fi security (WPA2/WPA3 encryption).
  • security control: Network segmentation (optional, for isolating smart home devices).

• BUILD

graph LR
    Developer[/"Developer"/] --> CodeChanges[/"Code Changes"/]
    CodeChanges --> GitHub[/"GitHub Repository"/]
    GitHub --> CI[/"CI System (GitHub Actions)"/]
    CI --> BuildProcess[/"Build Process (Automated)"/]
    BuildProcess --> SecurityChecks[/"Security Checks (SAST, Linters, Dependency Scan)"/]
    SecurityChecks --> BuildArtifacts[/"Build Artifacts (Docker Image, Python Package)"/]
    BuildArtifacts --> ContainerRegistry[/"Container Registry (Docker Hub)"/]
    BuildArtifacts --> PackageRegistry[/"Package Registry (PyPI)"/]

    style CI fill:#ccf,stroke:#333,stroke-width:2px
    style BuildProcess fill:#ccf,stroke:#333,stroke-width:2px
    style SecurityChecks fill:#ccf,stroke:#333,stroke-width:2px
    style BuildArtifacts fill:#ccf,stroke:#333,stroke-width:2px
    style ContainerRegistry fill:#ccf,stroke:#333,stroke-width:2px
    style PackageRegistry fill:#ccf,stroke:#333,stroke-width:2px

Loading

• BUILD Elements:

• • Name: Developer
  • Type: Person
  • Description: Developers contributing code changes to the Home Assistant Core project.
  • Responsibilities:
  • Writing and testing code.
  • Submitting code changes via pull requests.
  • Participating in code reviews.
  • Security controls:
  • security control: Secure development practices.
  • security control: Code review process to identify security vulnerabilities.
  • security control: Access control to the codebase (GitHub).
• • Name: GitHub Repository
  • Type: Code Repository
  • Description: The central repository for the Home Assistant Core source code, hosted on GitHub.
  • Responsibilities:
  • Storing and versioning the codebase.
  • Managing pull requests and code contributions.
  • Triggering CI/CD pipelines.
  • Security controls:
  • security control: Access control to the repository (authentication and authorization).
  • security control: Branch protection rules to enforce code review and security checks.
  • security control: Audit logging of repository activities.
• • Name: CI System (GitHub Actions)
  • Type: Automation System
  • Description: The Continuous Integration system used to automate the build, test, and security check processes for Home Assistant Core. GitHub Actions is assumed as a common CI for GitHub projects.
  • Responsibilities:
  • Automating the build process.
  • Running automated tests.
  • Performing security checks (SAST, dependency scanning).
  • Publishing build artifacts.
  • Security controls:
  • security control: Secure CI/CD pipeline configuration.
  • security control: Access control to CI/CD workflows and secrets.
  • security control: Audit logging of CI/CD activities.
• • Name: Build Process (Automated)
  • Type: Automation Process
  • Description: The automated process of compiling, packaging, and preparing Home Assistant Core for distribution.
  • Responsibilities:
  • Compiling code.
  • Building Docker images.
  • Creating Python packages.
  • Running unit and integration tests.
  • Security controls:
  • security control: Reproducible builds to ensure build integrity.
  • security control: Secure build environment.
  • security control: Minimizing dependencies and supply chain risks.
• • Name: Security Checks (SAST, Linters, Dependency Scan)
  • Type: Security Tooling
  • Description: Automated security checks integrated into the build process to identify potential vulnerabilities. Includes Static Application Security Testing (SAST), linters, and dependency vulnerability scanning.
  • Responsibilities:
  • Identifying potential security flaws in the code.
  • Detecting vulnerable dependencies.
  • Enforcing code quality and security standards.
  • Security controls:
  • security control: Regularly updated security scanning tools and rulesets.
  • security control: Automated reporting and alerting on security findings.
  • security control: Integration of security findings into the development workflow.
• • Name: Build Artifacts (Docker Image, Python Package)
  • Type: Software Artifacts
  • Description: The packaged outputs of the build process, including Docker images and Python packages, ready for distribution and deployment.
  • Responsibilities:
  • Providing deployable artifacts for users.
  • Ensuring artifact integrity and authenticity.
  • Security controls:
  • security control: Signing and verifying build artifacts.
  • security control: Secure storage of build artifacts.
  • security control: Vulnerability scanning of build artifacts before publication.
• • Name: Container Registry (Docker Hub)
  • Type: Artifact Repository
  • Description: A public or private container registry (e.g., Docker Hub) used to store and distribute Docker images of Home Assistant Core.
  • Responsibilities:
  • Hosting Docker images.
  • Providing access control to images.
  • Image versioning and tagging.
  • Security controls:
  • security control: Access control to the container registry.
  • security control: Image scanning and vulnerability management in the registry.
  • security control: Secure image distribution (HTTPS).
• • Name: Package Registry (PyPI)
  • Type: Artifact Repository
  • Description: The Python Package Index (PyPI) used to distribute Python packages for Home Assistant Core and its integrations.
  • Responsibilities:
  • Hosting Python packages.
  • Providing access to packages.
  • Package versioning.
  • Security controls:
  • security control: Account security for package publishers.
  • security control: Package signing and verification (if implemented).
  • security control: Monitoring for malicious packages.

RISK ASSESSMENT

• Critical Business Processes:

• Home Automation Control: Controlling lights, appliances, security systems, and other smart home devices. Disruption can lead to inconvenience, security risks (e.g., disabled security system), and potential property damage (e.g., malfunctioning heating system).

• Automation Execution: Running scheduled automations and responding to triggers. Failure can lead to missed schedules, non-responsive smart home, and user dissatisfaction.

• Data Collection and Storage: Collecting sensor data and user preferences. Compromise can lead to privacy breaches and misuse of personal information.

• Remote Access: Allowing users to control their home remotely. Insecure remote access can lead to unauthorized control and security breaches.

• Data Sensitivity:

• User Credentials: Usernames, passwords, API keys - Highly Sensitive. Compromise leads to account takeover and unauthorized access.

• Personal Information: User names, locations, preferences - Sensitive. Compromise leads to privacy violations.

• Smart Home Device Data: Sensor readings, device status, usage patterns - Sensitive to Confidential. Can reveal user habits and activities.

• Automation Rules: User-defined automation logic - Sensitive to Integrity. Tampering can lead to unexpected and potentially harmful actions.

• Configuration Data: System settings, integration configurations - Sensitive to Integrity and Availability. Corruption can disrupt system functionality.

QUESTIONS & ASSUMPTIONS

• BUSINESS POSTURE Questions:

• What is the acceptable downtime for the Home Assistant Core service?

• What are the key performance indicators (KPIs) for success?

• What is the budget allocated for security enhancements?

• BUSINESS POSTURE Assumptions:

• The primary business goal is to provide a reliable and secure open-source home automation platform.

• User privacy and security are high priorities.

• The project relies on community contributions for development and maintenance.

• SECURITY POSTURE Questions:

• Are there any specific compliance requirements (e.g., GDPR, CCPA) that need to be considered?

• What is the current security maturity level of the project?

• Are there any existing security policies or guidelines?

• Is there a dedicated security team or point of contact?

• SECURITY POSTURE Assumptions:

• Security is a shared responsibility between the project developers and the users deploying Home Assistant Core.

• Users are expected to have some level of technical expertise to deploy and configure the system securely.

• Open-source nature allows for community scrutiny and contribution to security.

• DESIGN Questions:

• What are the expected scalability requirements for Home Assistant Core?

• What are the performance requirements for different components?

• Are there any specific technology constraints or preferences?

• What are the long-term maintenance and upgrade strategies?

• DESIGN Assumptions:

• Docker container deployment is a common and recommended deployment method.

• The system is designed for local network deployment, with optional remote access.

• The architecture is modular and event-driven for flexibility and extensibility.

• GitHub Actions is used for CI/CD.