This repository template is deprecated in favour of the GitHub Action CodeQL Bundle Action. The repository will remain available in read-only mode, but it is advised to migrate.

The Custom CodeQL Bundle repository can be used in combination with GitHub Actions to automate customizing the behavior of the queries in the CodeQL standard library for a variety of target languages. It is currently considered the best practice for customizing the built-in CodeQL queries.

At current this repository will work with the following languages:

• Java
• Javascript
• Python
• C#
• Go

Official support for Ruby will be added when the Customizations.qll is made available in the selected CodeQL bundles specified in the bundles.json. As an unofficial workaround you can change the environment variable FORCE_CUSTOMIZATION in the .github/build-bundles.yml to "true". The forced customization will create a Customizations.qll file and prepend it to the language specific library (e.g., cpp.qll, ruby.qll).

Using the Custom CodeQL bundle involves two main steps:

1. Creating a copy of the custom-codeql-bundle repository within your organization.
2. Modifying your CodeQL action to retrieve your custom bundle during query execution.

The tooling within this repository takes care of combining your customizations here with the main codeql-bundle distribution. It uses the Customizations.qll mechanism which ensures that upstream changes are never made, thus making it possible to rebase your clone of this repository on newer versions of CodeQL without conflict.

1. To use this repository, first start by clicking the Use This Template button on GitHub.com interface located here: https://github.com/advanced-security/custom-codeql-bundle

This will allow you to create a copy of this repository that you will customize with your additions.

2. Modify bundles.json in the root of this repository. This controls the CodeQL version that will be used with your queries.

3. Add your customizations to the customizations/<language> directory within the root of this repository. You may add as many independent .qll files in these directories as you wish. They will be combined and added to the appropriate extension points within your target language.

4. Modify your codeql-analysis.yml file to point at your custom bundle. If it is private you can use the following configuration that downloads a private release using a GitHub PAT:

   - name: Download CodeQL bundle
      env:
        GITHUB_TOKEN: ${{ secrets.CODEQL_BUNDLE_PAT }}
      run: |
        gh release -R advanced-security/custom-codeql-bundle download codeql-bundle-20211005-79ff94b
    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
      uses: github/codeql-action/init@v1
      with:
        languages: ${{ matrix.language }}
        tools: codeql-bundle.tar.gz

The relevant portion of that file when the CodeQL bundle repository is private is the following:

steps:
  - name: Download CodeQL bundle
    env:
      GITHUB_TOKEN: ${{ secrets.CODEQL_BUNDLE_PAT }}
    run: |
      # Download custom CodeQL bundle as codeql-bundle.tar.gz
      gh release -R <your-clone-of-custom-codeql-bundle> download <tag>
    # Initializes the CodeQL tools for scanning.
  - name: Initialize CodeQL
    uses: github/codeql-action/init@v1
    with:
      languages: ${{ matrix.language }}
      # Specify the use of our custom CodeQL bundle
      tools: codeql-bundle.tar.gz

In the above, you set the location of your bundle as well as the tag.

If the CodeQL bundle repository is public, or the bundle is stored in a public location, then we can directly specify it in the tools configuration like:

steps:
    # Initializes the CodeQL tools for scanning.
  - name: Initialize CodeQL
    uses: github/codeql-action/init@v1
    with:
      languages: ${{ matrix.language }}
      # Specify the use of our custom CodeQL bundle
      tools: https://<url>/<version>/codeql-bundle.tar.gz

Where <version> follows the versioning scheme used in the bundles.json

Once these steps are performed, you will be able to analyze your project using your custom CodeQL bundle with your customizations in place.

To get an idea of the sorts of customizations that are possible, please see:

• https://codeql.github.com/docs/codeql-language-guides/specifying-additional-remote-flow-sources-for-javascript/
• https://codeql.github.com/docs/codeql-language-guides/analyzing-data-flow-in-csharp/#flow-sources
• https://codeql.github.com/docs/codeql-language-guides/modeling-data-flow-in-go-libraries/#sources
• https://codeql.github.com/docs/codeql-language-guides/analyzing-data-flow-in-java/#flow-sources
• https://codeql.github.com/docs/codeql-language-guides/analyzing-data-flow-in-python/#predefined-sources-and-sinks

This repository may be used to refine the behavior of the out of the box queries by:

• Extending existing abstract classes
• Adding additional sinks and sources specific to your organization

It may not be used for replacing classes within CodeQL.

Please direct your contributions to us by opening up a pull request.