feat(cloudkms): Add single tenant hsm scripts

[brandonluong-lgtm]

Description

Fixes #

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• I have followed Sample Guidelines from AUTHORING_GUIDE.MD
• README is updated to include all relevant information
• Tests pass: nox -s py-3.9 (see Test Environment Setup)
• Lint pass: nox -s lint (see Test Environment Setup)
• These samples need a new API enabled in testing projects to pass (let us know which ones)
• These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• Please merge this PR for me once it is approved

[gemini-code-assist]

Hello @brandonluong-lgtm, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request adds scripts and documentation for setting up and approving Single Tenant HSM instances in Google Cloud KMS. It includes a setup.py script for building a custom gcloud CLI and generating RSA keys on YubiKeys, and an approve_proposal.py script for fetching, signing, and submitting HSM instance proposal challenges. Additionally, it introduces supporting modules for interacting with gcloud and YubiKeys, along with comprehensive testing and a README for usage instructions.

Highlights

• Custom gcloud Build: The pull request introduces a setup.py script that builds a custom gcloud CLI tailored for Single Tenant HSM, streamlining the setup process.
• HSM Proposal Approval: The pull request implements approve_proposal.py, a script designed to automate the approval of Single Tenant HSM instance proposals by fetching challenges, signing them using a YubiKey, and submitting the signed challenges back to gcloud.
• YubiKey Integration: The pull request integrates with YubiKeys for secure signing of HSM proposal challenges, enhancing the security posture of the approval process.
• Testing and Mocking: The pull request includes comprehensive testing using pytest and pytest-mock, with mocking of subprocess calls and YubiKey interactions to ensure the reliability of the scripts.

Changelog

Click here to see the changelog

• kms/singletenanthsm/README.rst
  • Added a README file providing instructions on how to use the setup and approval scripts for Single Tenant HSM instances.
• kms/singletenanthsm/approve_proposal.py
  • Created a script to fetch challenges from a Single Tenant HSM instance proposal, sign them using a YubiKey, and send the signed challenges back to gcloud for approval.
  • Implements functions to parse challenges from gcloud output, sign them using ykman-utils, and submit the signed challenges.
  • Includes argument parsing for specifying the proposal resource.
• kms/singletenanthsm/approve_proposal_test.py
  • Added tests for approve_proposal.py, mocking gcloud commands and YubiKey interactions to ensure proper functionality.
  • Includes tests for fetching challenges, signing them, and verifying the signatures.
• kms/singletenanthsm/challenges/challenge1.txt
  • Added a challenge file for testing purposes.
• kms/singletenanthsm/challenges/challenge2.txt
  • Added a challenge file for testing purposes.
• kms/singletenanthsm/challenges/challenge3.txt
  • Added a challenge file for testing purposes.
• kms/singletenanthsm/challenges/public_key1.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/challenges/public_key2.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/challenges/public_key3.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/gcloud_commands.py
  • Created a module to encapsulate gcloud commands for building a custom gcloud CLI and interacting with Single Tenant HSM proposals.
  • Implements functions to build the custom gcloud CLI, fetch challenges, and send signed challenges.
• kms/singletenanthsm/gcloud_commands_test.py
  • Added tests for gcloud_commands.py, mocking subprocess calls to ensure proper command execution and error handling.
  • Includes tests for building the custom gcloud CLI, fetching challenges, and sending signed challenges.
• kms/singletenanthsm/requirements.txt
  • Added dependencies required for the scripts, including yubikey-manager, cryptography, and testing libraries.
• kms/singletenanthsm/setup.py
  • Created a script to build a custom gcloud CLI and generate RSA keys on YubiKeys.
  • Implements argument parsing for specifying the operation type (build custom gcloud, generate RSA keys, or both).
• kms/singletenanthsm/signed_challenges/public_key_1.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/signed_challenges/public_key_2.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/signed_challenges/public_key_3.pem
  • Added a public key file for testing purposes.
• kms/singletenanthsm/signed_challenges/signed_challenge1.bin
  • Added a signed challenge file for testing purposes.
• kms/singletenanthsm/ykman_fake.py
  • Created a fake ykman module to mock yubikey interactions for testing purposes.
• kms/singletenanthsm/ykman_utils.py
  • Created a module to provide utility functions for interacting with YubiKeys, including generating private keys, signing challenges, and verifying signatures.
  • Implements functions to populate challenges from files, sign them using a YubiKey, and verify the signatures.
• kms/singletenanthsm/ykman_utils_test.py
  • Added tests for ykman_utils.py, mocking YubiKey interactions to ensure proper functionality.
  • Includes tests for signing challenges, verifying signatures, and handling errors.

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---

A key's born of challenge,
Signed by Yubi's embrace,
HSM's gate swings.

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[gemini-code-assist]

Code Review

The pull request introduces scripts for managing Single Tenant HSM instances, including building a custom gcloud environment and approving proposals. The code appears well-structured and includes tests. However, there are several areas where improvements can be made to enhance clarity, maintainability, and security.

Summary of Findings

• Error Handling: The error handling in parse_challenges_into_files and signed_challenges_to_files is basic. Consider logging the full exception with a traceback for better debugging.
• Security: Hardcoded Credentials: The ykman_utils.py script contains hardcoded default management key and PIN. These should be removed and instead be passed in as arguments, or retrieved from environment variables.
• Code Duplication: There is duplicated code for directory creation in parse_challenges_into_files and signed_challenges_to_files. Consider refactoring this into a reusable function.
• Test Coverage: The test coverage for approve_proposal.py is limited. More comprehensive tests are needed, especially around failure scenarios.

Merge Readiness

The pull request is not yet ready for merging. The hardcoded credentials in ykman_utils.py pose a significant security risk and must be addressed. Additionally, the error handling and code duplication issues should be resolved to improve maintainability. I am unable to approve this pull request, and recommend that it not be merged until the critical and high severity issues are addressed, and that others review and approve this code before merging.

[brandonluong-lgtm]

The kokoro presubmits are failing as libpcsclite-dev is not installed. This is needed to communicate with smartcards. Is there a way to ensure that the machines running the test have it installed?

In the read me the users would install it using the command sudo apt install libpcsclite-dev