sec-design.md

Project Design Document: Meson Build System

BUSINESS POSTURE

Meson is a build system designed to be fast and user-friendly. Its primary goal is to improve developer productivity by reducing the time spent on configuring and executing builds. The project prioritizes ease of use, cross-platform compatibility, and speed. Given its role in the software development lifecycle, incorrect builds can lead to deployment of vulnerable or non-functional software.

Business Priorities:

• Developer Productivity: Minimize time spent on build configuration and execution.
• Cross-Platform Compatibility: Support a wide range of platforms and compilers.
• Build Reproducibility: Ensure consistent and reliable builds across different environments.
• Speed: Provide fast compilation and linking times.
• Ease of Use: Offer a simple and intuitive build configuration language.

Business Goals:

• Become a widely adopted build system, replacing older, less efficient systems.
• Maintain a high level of quality and reliability to ensure trust from the user base.
• Foster a strong community to support and contribute to the project.

Most Important Business Risks:

• Incorrect Build Output: The build system producing incorrect binaries or libraries, leading to runtime errors, security vulnerabilities, or deployment failures.
• Supply Chain Attacks: Compromise of the Meson build system itself or its dependencies, leading to the injection of malicious code into projects that use Meson.
• Lack of Adoption: Failure to gain widespread adoption due to complexity, lack of features, or competition from other build systems.
• Maintainability: Difficulty in maintaining and extending the codebase as it grows and evolves.
• Security Vulnerabilities in Meson: Vulnerabilities within Meson itself that could be exploited by malicious actors.

SECURITY POSTURE

Existing Security Controls:

• security control: Code Reviews: All changes to the Meson codebase undergo code review by other developers. (Described in the project's contribution guidelines).
• security control: Static Analysis: The project uses static analysis tools to identify potential bugs and security vulnerabilities. (Mentioned in the project's documentation and CI configuration).
• security control: Testing: Meson has an extensive test suite to ensure the correctness and reliability of its functionality. (Visible in the project's repository structure and CI configuration).
• security control: Dependency Management: Meson uses a controlled set of dependencies to minimize the risk of supply chain attacks. (Implicit in the project's design and build configuration).
• security control: Secure Development Practices: Developers are encouraged to follow secure coding practices. (Implicit in the project's culture and code review process).

Accepted Risks:

• accepted risk: Limited Dynamic Analysis: While static analysis is used, there may be limited use of dynamic analysis tools, such as fuzzers.
• accepted risk: Reliance on Third-Party Libraries: Meson, like any software, relies on third-party libraries, which may have their own vulnerabilities.
• accepted risk: User-Controlled Build Scripts: Meson executes user-provided build scripts (meson.build), which could potentially contain malicious code if the user's system is compromised.

Recommended Security Controls:

• security control: Fuzzing: Implement fuzzing to test Meson's input parsing and handling of unexpected data.
• security control: Regular Security Audits: Conduct regular security audits of the codebase and dependencies.
• security control: Software Bill of Materials (SBOM): Generate and maintain an SBOM to track all dependencies and their versions.
• security control: Supply Chain Security Measures: Implement measures to verify the integrity of downloaded dependencies, such as checksum verification or signature checking.
• security control: Sandboxing: Consider sandboxing the execution of user-provided build scripts to limit the potential impact of malicious code.

Security Requirements:

• Authentication: Not directly applicable to the Meson build system itself, as it operates locally. However, authentication may be relevant when interacting with external services (e.g., package repositories).
• Authorization: Not directly applicable in the same way as for a service. However, file system permissions control access to source code and build artifacts. Meson should respect these permissions.
• Input Validation: Meson must rigorously validate all inputs, including user-provided build scripts (meson.build files), command-line arguments, and environment variables. This is crucial to prevent injection vulnerabilities.
• Cryptography: Meson should use cryptographic libraries appropriately when needed (e.g., for verifying signatures of downloaded dependencies). It should not attempt to implement its own cryptographic algorithms.

DESIGN

C4 CONTEXT

graph LR
    subgraph Meson Build System
        meson[("Meson")]
    end
    developer[("Developer")]
    os[("Operating System")]
    compiler[("Compiler")]
    linker[("Linker")]
    dependencies[("Dependencies")]
    buildartifacts[("Build Artifacts")]
    packagemanager[("Package Manager")]

    developer -- "Writes meson.build files" --> meson
    developer -- "Runs Meson commands" --> meson
    meson -- "Reads meson.build files" --> os
    meson -- "Executes compiler" --> compiler
    meson -- "Executes linker" --> linker
    meson -- "Downloads/Uses" --> dependencies
    meson -- "Produces" --> buildartifacts
    developer -- "Installs" --> packagemanager
    packagemanager -- "Consumes" --> buildartifacts
    os -- "Provides file system" --> meson

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Element Descriptions:

• Element:

  • Name: Developer
  • Type: Person
  • Description: The person writing code and using Meson to build it.
  • Responsibilities: Writing source code, writing meson.build files, running Meson commands, and installing build artifacts.
  • Security controls: Uses secure coding practices, performs code reviews.

• Element:

  • Name: Meson
  • Type: Software System
  • Description: The Meson build system itself.
  • Responsibilities: Parsing meson.build files, managing dependencies, executing build commands, and generating build artifacts.
  • Security controls: Input validation, static analysis, code reviews, testing.

• Element:

  • Name: Operating System
  • Type: Software System
  • Description: The underlying operating system (e.g., Linux, Windows, macOS).
  • Responsibilities: Providing file system access, process management, and other system resources.
  • Security controls: File system permissions, process isolation.

• Element:

  • Name: Compiler
  • Type: Software System
  • Description: The compiler used to translate source code into machine code (e.g., GCC, Clang, MSVC).
  • Responsibilities: Compiling source code files.
  • Security controls: Compiler-specific security flags (e.g., stack protection, ASLR).

• Element:

  • Name: Linker
  • Type: Software System
  • Description: The linker used to combine compiled object files into an executable or library.
  • Responsibilities: Linking object files.
  • Security controls: Linker-specific security flags.

• Element:

  • Name: Dependencies
  • Type: Software System
  • Description: External libraries and tools that the project depends on.
  • Responsibilities: Providing functionality required by the project.
  • Security controls: Dependency management, SBOM, vulnerability scanning.

• Element:

  • Name: Build Artifacts
  • Type: Data
  • Description: The output of the build process (e.g., executables, libraries, documentation).
  • Responsibilities: N/A
  • Security controls: Code signing (optional).

• Element:

  • Name: Package Manager
  • Type: Software System
  • Description: System or language specific package manager.
  • Responsibilities: Installing, updating, and managing software packages.
  • Security controls: Package signing, repository verification.

C4 CONTAINER

graph LR
    subgraph Meson Build System
        mesoncli[("Meson CLI")]
        buildsystem[("Build System Core")]
        backendninja[("Ninja Backend")]
        backendsvs[("Visual Studio Backend")]
        introspection[("Introspection API")]
    end
    developer[("Developer")]
    os[("Operating System")]
    compiler[("Compiler")]
    linker[("Linker")]
    dependencies[("Dependencies")]
    buildartifacts[("Build Artifacts")]

    developer -- "Uses" --> mesoncli
    mesoncli -- "Uses" --> buildsystem
    buildsystem -- "Uses" --> backendninja
    buildsystem -- "Uses" --> backendsvs
    buildsystem -- "Provides" --> introspection
    backendninja -- "Executes" --> compiler
    backendninja -- "Executes" --> linker
    backendsvs -- "Executes" --> compiler
    backendsvs -- "Executes" --> linker
    buildsystem -- "Reads/Writes" --> os
    buildsystem -- "Downloads/Uses" --> dependencies
    backendninja -- "Produces" --> buildartifacts
    backendsvs -- "Produces" --> buildartifacts

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Element Descriptions:

• Element:

  • Name: Meson CLI
  • Type: Application
  • Description: The command-line interface for interacting with Meson.
  • Responsibilities: Parsing command-line arguments, invoking the build system core.
  • Security controls: Input validation.

• Element:

  • Name: Build System Core
  • Type: Library
  • Description: The core logic of the Meson build system.
  • Responsibilities: Parsing meson.build files, managing dependencies, generating build configurations.
  • Security controls: Input validation, static analysis, code reviews.

• Element:

  • Name: Ninja Backend
  • Type: Library
  • Description: The backend that generates Ninja build files.
  • Responsibilities: Generating Ninja build files.
  • Security controls: Code reviews, testing.

• Element:

  • Name: Visual Studio Backend
  • Type: Library
  • Description: The backend that generates Visual Studio project files.
  • Responsibilities: Generating Visual Studio project files.
  • Security controls: Code reviews, testing.

• Element:

  • Name: Introspection API
  • Type: API
  • Description: An API for querying information about the build configuration.
  • Responsibilities: Providing build information to external tools.
  • Security controls: Input validation, access control (if applicable).

• Element:

  • Name: Developer
  • Type: Person
  • Description: The person writing code and using Meson to build it.
  • Responsibilities: Writing source code, writing meson.build files, running Meson commands, and installing build artifacts.
  • Security controls: Uses secure coding practices, performs code reviews.

• Element:

  • Name: Operating System
  • Type: Software System
  • Description: The underlying operating system (e.g., Linux, Windows, macOS).
  • Responsibilities: Providing file system access, process management, and other system resources.
  • Security controls: File system permissions, process isolation.

• Element:

  • Name: Compiler
  • Type: Software System
  • Description: The compiler used to translate source code into machine code (e.g., GCC, Clang, MSVC).
  • Responsibilities: Compiling source code files.
  • Security controls: Compiler-specific security flags (e.g., stack protection, ASLR).

• Element:

  • Name: Linker
  • Type: Software System
  • Description: The linker used to combine compiled object files into an executable or library.
  • Responsibilities: Linking object files.
  • Security controls: Linker-specific security flags.

• Element:

  • Name: Dependencies
  • Type: Software System
  • Description: External libraries and tools that the project depends on.
  • Responsibilities: Providing functionality required by the project.
  • Security controls: Dependency management, SBOM, vulnerability scanning.

• Element:

  • Name: Build Artifacts
  • Type: Data
  • Description: The output of the build process (e.g., executables, libraries, documentation).
  • Responsibilities: N/A
  • Security controls: Code signing (optional).

DEPLOYMENT

Meson itself is typically installed via a system package manager or built from source. The deployment of projects built with Meson depends entirely on the project. Here are some common deployment scenarios:

1. System Package: The project is packaged using a system package manager (e.g., apt, yum, pacman, MSI) and installed system-wide.
2. User Installation: The project is installed in the user's home directory.
3. Containerization: The project is packaged into a container image (e.g., Docker) and deployed to a container orchestration platform (e.g., Kubernetes).
4. Embedded System: The project is cross-compiled and deployed to an embedded device.
5. Web Application: The project is deployed to a web server.

We'll describe the "System Package" scenario in detail, as it's a common and relatively straightforward deployment model.

graph LR
    subgraph Deployment Environment (Target System)
        os[("Operating System")]
        packagemanager[("Package Manager")]
        filesystem[("File System")]
        installedsoftware[("Installed Software")]

        packagemanager -- "Installs to" --> filesystem
        filesystem -- "Contains" --> installedsoftware
    end
    buildserver[("Build Server")]
    package[("Package (e.g., .deb, .rpm)")]

    buildserver -- "Creates" --> package
    package -- "Uploaded to" --> packagemanager

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Element Descriptions:

• Element:

  • Name: Build Server
  • Type: Server
  • Description: A server that builds the Meson project and creates the package.
  • Responsibilities: Building the software, creating the package.
  • Security controls: Limited access, secure build environment.

• Element:

  • Name: Package (e.g., .deb, .rpm)
  • Type: Data
  • Description: The installation package for the target system.
  • Responsibilities: Containing the build artifacts and installation instructions.
  • Security controls: Package signing.

• Element:

  • Name: Operating System
  • Type: Software System
  • Description: The operating system of the target system.
  • Responsibilities: Providing the runtime environment.
  • Security controls: OS-level security features.

• Element:

  • Name: Package Manager
  • Type: Software System
  • Description: The system package manager (e.g., apt, yum, pacman).
  • Responsibilities: Installing, updating, and removing software packages.
  • Security controls: Package signature verification, repository verification.

• Element:

  • Name: File System
  • Type: Infrastructure
  • Description: The file system of the target system.
  • Responsibilities: Storing the installed software.
  • Security controls: File system permissions.

• Element:

  • Name: Installed Software
  • Type: Software System
  • Description: The software installed by the package manager.
  • Responsibilities: Providing the intended functionality.
  • Security controls: Depends on the specific software.

BUILD

Meson's build process can vary depending on how it's invoked (directly, via a script, or within a CI environment). A typical build process, including security considerations, is described below:

1. Developer writes code and meson.build files: The developer creates or modifies the source code and the Meson build definition files.
2. Code Review (Optional but Recommended): Changes are reviewed by other developers to identify potential bugs and security vulnerabilities.
3. Local Build (Developer's Machine): The developer runs Meson locally to build the project. This involves:
   • Meson parsing the meson.build files.
   • Meson resolving dependencies (potentially downloading them).
   • Meson generating build files (e.g., Ninja files).
   • Meson invoking the compiler and linker.
4. Testing: The developer runs unit tests and integration tests to verify the build.
5. CI/CD (Continuous Integration/Continuous Delivery): In a CI/CD environment (e.g., GitHub Actions, GitLab CI, Jenkins), the following steps are typically performed:
   • Code is checked out from the repository.
   • A clean build environment is created (often using containers).
   • Meson is installed (if not already present in the environment).
   • Meson is executed to build the project.
   • Static analysis tools (e.g., linters, code analyzers) are run.
   • Tests are executed.
   • If all steps are successful, build artifacts are created and potentially published (e.g., to a package repository).
6. Artifact Creation: The build process produces build artifacts (executables, libraries, etc.).
7. Artifact Storage/Publication: Build artifacts are stored locally or published to a repository.

graph LR
    subgraph Build Process
        developer[("Developer")]
        coderepo[("Code Repository")]
        buildenvironment[("Build Environment")]
        meson[("Meson Build System")]
        compiler[("Compiler")]
        linker[("Linker")]
        staticanalysis[("Static Analysis Tools")]
        tests[("Tests")]
        buildartifacts[("Build Artifacts")]
        artifactrepo[("Artifact Repository")]

        developer -- "Commits code" --> coderepo
        coderepo -- "Triggers build" --> buildenvironment
        buildenvironment -- "Installs" --> meson
        buildenvironment -- "Runs" --> meson
        meson -- "Executes" --> compiler
        meson -- "Executes" --> linker
        buildenvironment -- "Runs" --> staticanalysis
        buildenvironment -- "Runs" --> tests
        compiler -- "Produces" --> buildartifacts
        linker -- "Produces" --> buildartifacts
        tests -- "Validates" --> buildartifacts
        buildartifacts -- "Stored in" --> artifactrepo
    end

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Security Controls in the Build Process:

• security control: Clean Build Environment: Using a clean build environment (e.g., a container) ensures that builds are reproducible and prevents contamination from previous builds.
• security control: Static Analysis: Running static analysis tools helps identify potential vulnerabilities before runtime.
• security control: Dependency Management: Carefully managing dependencies and using a Software Bill of Materials (SBOM) helps mitigate supply chain risks.
• security control: Testing: Thorough testing helps ensure the correctness and reliability of the build.
• security control: Limited Access to Build Server: Restricting access to the build server reduces the risk of unauthorized modifications.
• security control: Code Signing (Optional): Signing build artifacts can help ensure their integrity and authenticity.

RISK ASSESSMENT

Critical Business Processes to Protect:

• Software Development Lifecycle: Ensuring the integrity and reliability of the build process is crucial for the entire software development lifecycle.
• Release Management: Protecting the process of releasing software to users, ensuring that only trusted and verified builds are deployed.

Data to Protect and Sensitivity:

• Source Code: Highly sensitive. Contains the intellectual property of the project and could reveal vulnerabilities if exposed.
• meson.build Files: Moderately sensitive. Contains build configuration information, which could be used to exploit vulnerabilities or understand the project's structure.
• Dependencies: Variable sensitivity. Dependencies may contain their own vulnerabilities, and their integrity must be protected.
• Build Artifacts: Variable sensitivity. Executables and libraries may contain sensitive information or be targets for malicious modification.
• Test Data: Low to moderate sensitivity. May contain sensitive data used for testing purposes.

QUESTIONS & ASSUMPTIONS

Questions:

• Are there any specific compliance requirements (e.g., industry regulations) that need to be considered?
• What is the expected frequency of builds and deployments?
• What are the specific target platforms and compilers that need to be supported?
• What is the level of expertise of the developers who will be using Meson?
• Are there any existing security tools or processes that should be integrated with Meson?
• What level of detail is required in the introspection API?
• What are the specific mechanisms used for dependency management (e.g., version pinning, checksum verification)?
• Are there any plans to support remote builds or caching?

Assumptions:

• BUSINESS POSTURE: The primary users of Meson are software developers.
• BUSINESS POSTURE: The project aims to be a general-purpose build system, not tailored to a specific industry or domain.
• SECURITY POSTURE: Developers are expected to follow basic secure coding practices.
• SECURITY POSTURE: The project has a relatively small attack surface, as it primarily operates locally.
• DESIGN: The build environment is trusted (i.e., not compromised).
• DESIGN: The operating system and compiler are correctly configured and secure.
• DESIGN: Dependencies are obtained from trusted sources.
• DESIGN: The build process is automated (at least partially) using a CI/CD system.