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Mitigation Strategies Analysis for mesonbuild/meson

Mitigation Strategy: Pin Meson Version

Description:

  1. Identify the current Meson version used in your project. Check project documentation, CI/CD configuration, or run meson --version.
  2. Explicitly declare this version as a dependency in your project's dependency management file (e.g., requirements.txt, pyproject.toml for Python projects: meson==<pinned_version>). Document the version in README or installation instructions.
  3. In CI/CD or build scripts, ensure the pinned Meson version is installed before building (e.g., pip install -r requirements.txt).
  4. Regularly review and consider upgrading the pinned version, testing for compatibility and regressions.
  • Threats Mitigated:
    • Supply Chain Attacks (High Severity): Prevents automatic upgrades to potentially compromised Meson versions.
    • Unexpected Build Breakages due to Meson Updates (Medium Severity): Ensures consistent builds by avoiding unforeseen Meson behavior changes.
  • Impact:
    • Supply Chain Attacks: High risk reduction. Significantly reduces risk of using malicious Meson.
    • Unexpected Build Breakages: Medium risk reduction. Improves build stability.
  • Currently Implemented: Yes, in requirements.txt and README.md.
  • Missing Implementation: Not enforced in CI/CD. Need to add a step to verify Meson version in CI/CD pipeline.

Mitigation Strategy: Verify Meson Installation Source

Description:

  1. Install Meson from official, trusted sources: PyPI (pip install meson) for Python, or OS package managers from official repositories (e.g., apt install meson, yum install meson).
  2. Verify package integrity if possible. PyPI provides checksums (SHA256). Compare downloaded package checksum to the official checksum. OS package managers usually handle this automatically.
  3. Avoid installing from untrusted third-party sources or source code unless necessary and you can thoroughly audit the source.
  • Threats Mitigated:
    • Supply Chain Attacks (High Severity): Reduces risk of installing compromised Meson from untrusted sources.
    • Installation of Backdoored Software (High Severity): Prevents malicious code introduction via tampered Meson installation.
  • Impact:
    • Supply Chain Attacks: High risk reduction. Significantly lowers probability of using malicious Meson.
    • Installation of Backdoored Software: High risk reduction. Prevents compromised build tools.
  • Currently Implemented: Partially. Using pip is a trusted source. Checksum verification is not performed.
  • Missing Implementation: Implement checksum verification for Meson package downloads in build scripts/documentation.

Mitigation Strategy: Dependency Scanning for Meson Itself

Description:

  1. Integrate a dependency scanning tool (e.g., pip-audit, SCA tools) into workflow/CI/CD.
  2. Configure the tool to scan Python dependencies, including Meson, for known vulnerabilities (CVE databases).
  3. Set up alerts or fail builds for vulnerabilities in Meson or dependencies above a certain severity (e.g., High, Critical).
  4. Regularly update Meson and dependencies to patch vulnerabilities.
  • Threats Mitigated:
    • Vulnerable Dependencies (Medium to High Severity): Identifies vulnerabilities in Meson's dependencies.
    • Outdated Software Components (Medium Severity): Encourages keeping Meson and dependencies updated.
  • Impact:
    • Vulnerable Dependencies: Medium to High risk reduction. Depends on tool effectiveness and patching speed.
    • Outdated Software Components: Medium risk reduction. Promotes a more secure build environment.
  • Currently Implemented: No. Dependency scanning not implemented for Meson.
  • Missing Implementation: Integrate dependency scanning into CI/CD to scan Python dependencies including Meson.

Mitigation Strategy: Code Review for meson.build Files

Description:

  1. Include meson.build files in standard code review. Treat them as code requiring scrutiny.
  2. Train developers on secure meson.build coding, emphasizing risks of external commands, file operations, and unsafe Meson functions.
  3. During reviews, check for:
    • run_command() usage without input sanitization.
    • File path manipulation leading to path traversal.
    • Unnecessary complexity in meson.build.
    • Deprecated/insecure Meson features.
  4. Use linters/static analysis tools (if available for Meson) to detect potential issues.
  • Threats Mitigated:
    • Command Injection (High Severity): Prevents malicious input injection into commands executed by meson.build.
    • File System Vulnerabilities (Medium to High Severity): Reduces path traversal, race conditions, unauthorized file access.
    • Logic Errors in Build Scripts (Medium Severity): Catches errors leading to insecure build outputs.
  • Impact:
    • Command Injection: High risk reduction. Code reviews are effective for this.
    • File System Vulnerabilities: Medium to High risk reduction. Reviews can catch many file system issues.
    • Logic Errors in Build Scripts: Medium risk reduction. Improves build script quality.
  • Currently Implemented: Yes. meson.build files are code reviewed.
  • Missing Implementation: No specific training on secure meson.build coding. No static analysis tools for meson.build.

Mitigation Strategy: Input Validation in meson.build

Description:

  1. Identify external inputs in meson.build: command-line arguments (-D), environment variables, data from files.
  2. Implement validation in meson.build to ensure inputs conform to expected formats, types, values.
  3. Use Meson functions or Python code within meson.build for validation (e.g., whitelist values, check file path directories).
  4. Sanitize inputs before using in commands/file paths (e.g., escape special characters).
  5. Raise an error and halt build for invalid input with a clear error message.
  • Threats Mitigated:
    • Command Injection (High Severity): Prevents injection via user-controlled inputs.
    • Path Traversal (Medium to High Severity): Prevents unauthorized file access by validating paths.
    • Configuration Manipulation (Medium Severity): Prevents insecure configuration changes via malicious input.
  • Impact:
    • Command Injection: High risk reduction. Input validation is crucial defense.
    • Path Traversal: Medium to High risk reduction. Limits file system access scope.
    • Configuration Manipulation: Medium risk reduction. Enforces expected build configurations.
  • Currently Implemented: Partially. Basic validation for some options, not comprehensive.
  • Missing Implementation: Systematically review meson.build and implement input validation for all external inputs, especially in commands/paths.

Mitigation Strategy: Avoid Dynamic Code Generation in meson.build (Where Possible)

Description:

  1. Minimize dynamic code generation/complex scripting in meson.build.
  2. Prefer declarative approaches and Meson built-in functions.
  3. If dynamic code generation is needed, carefully review and test generated code.
  4. Avoid external scripts for code generation in meson.build unless necessary and trusted.
  5. For complex logic, move it to separate Python modules imported by meson.build.
  • Threats Mitigated:
    • Code Injection (High Severity): Reduces risk if dynamic code generation is insecure.
    • Logic Errors and Unexpected Behavior (Medium Severity): Simplifies scripts, reducing errors.
    • Maintainability Issues (Medium Severity): Improves readability and maintainability.
  • Impact:
    • Code Injection: High risk reduction. Minimizing dynamic code generation reduces this risk.
    • Logic Errors and Unexpected Behavior: Medium risk reduction. Simpler scripts are less error-prone.
    • Maintainability Issues: Medium risk reduction. Easier to maintain simpler scripts.
  • Currently Implemented: Yes. Generally avoid complex dynamic code generation.
  • Missing Implementation: No specific missing areas, but continuous vigilance needed to maintain this principle.

Mitigation Strategy: Secure Default Build Configurations

Description:

  1. Establish secure default values for build options and feature flags in meson.build.
  2. Disable insecure/unnecessary features by default (e.g., debug symbols in release, optional features, enable security compiler flags).
  3. Require explicit opt-in for potentially risky features.
  4. Document default configurations and security implications of enabling/disabling features.
  • Threats Mitigated:
    • Exposure of Sensitive Information (Medium Severity): Prevents accidental inclusion of debug symbols in release builds.
    • Unnecessary Feature Exposure (Medium Severity): Reduces attack surface by disabling optional features.
    • Misconfiguration Vulnerabilities (Medium Severity): Establishes secure-by-default configurations.
  • Impact:
    • Exposure of Sensitive Information: Medium risk reduction. Prevents common mistakes.
    • Unnecessary Feature Exposure: Medium risk reduction. Reduces attack surface.
    • Misconfiguration Vulnerabilities: Medium risk reduction. Promotes secure defaults.
  • Currently Implemented: Partially. Some secure defaults (e.g., no debug symbols in release), but not comprehensively reviewed.
  • Missing Implementation: Thoroughly review all build options/flags in meson.build and establish secure defaults. Document defaults and security implications.

Mitigation Strategy: Input Validation for Build Options

Description:

  1. If build system accepts custom options (-D flags), validate them in meson.build.
  2. Define allowed values, types, formats for each option (e.g., file path validation, integer range).
  3. Use Meson functions or Python code in meson.build for option validation.
  4. Raise an error and halt build for invalid build options with a clear message.
  • Threats Mitigated:
    • Configuration Manipulation Attacks (Medium Severity): Prevents malicious/unexpected build options.
    • Unexpected Build Behavior (Medium Severity): Ensures options are used as intended, prevents unexpected behavior.
    • Injection Vulnerabilities (Medium Severity): Reduces injection risk if options are used in commands/paths.
  • Impact:
    • Configuration Manipulation Attacks: Medium risk reduction. Limits user influence on build process.
    • Unexpected Build Behavior: Medium risk reduction. Improves build reliability.
    • Injection Vulnerabilities: Medium risk reduction. Adds defense against injection via options.
  • Currently Implemented: Partially. Validation for some critical options, not comprehensive.
  • Missing Implementation: Systematically review user-configurable build options and implement input validation in meson.build.