Restrict PoC command to only run within it's directory, and on a spec…

[QuinnDACollins]

Introduce more Determinism in our PoC command, and specifically when generating concept for path traversal

• Only runs PoC within our ./gemini_security/poc directory
• When running for path traversal, generates a specific file right outside of the project directory

[github-actions]

🤖 Hi @QuinnDACollins, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.

[gemini-code-assist]

Summary of Changes

Hello @QuinnDACollins, 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!

This pull request significantly improves the security and determinism of the PoC (Proof-of-Concept) command. It introduces a critical restriction that limits PoC script execution to a dedicated, secure directory, mitigating potential risks associated with running untrusted code. Additionally, it refines the process for generating Path Traversal PoCs, ensuring a consistent and verifiable method for demonstrating this specific vulnerability, which includes strict temporary file management.

Highlights

• PoC Execution Restriction: Implemented a security measure to restrict the execution of Proof-of-Concept (PoC) scripts exclusively to the .gemini_security/poc directory, preventing arbitrary code execution from other locations.
• Path Traversal PoC Determinism: Enhanced the generation of Path Traversal PoCs to be more deterministic, specifically by requiring the creation and subsequent cleanup of a temporary file (gcli_secext_temp.txt) directly outside the project directory to demonstrate the vulnerability.
• Updated PoC Generation Instructions: The internal documentation for PoC generation has been updated to reflect the new requirements for Path Traversal vulnerabilities, emphasizing temporary file handling and cleanup.
• Test Coverage: Added new test cases to verify that PoC execution fails when attempting to access files outside the designated secure directory, and updated existing tests to align with the new PoC file path structure.

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Changelog

• mcp-server/src/index.ts
  • Updated PoC generation instructions to include specific requirements for Path Traversal vulnerabilities, detailing temporary file creation and cleanup.
• mcp-server/src/poc.test.ts
  • Enhanced mock path utilities (resolve, sep) for more robust testing of path-related logic.
  • Adjusted existing test cases to use the new .gemini_security/poc directory for PoC file paths and working directories.
  • Added a new test case to confirm that PoC execution is blocked when attempting to run a script from an unauthorized directory.
• mcp-server/src/poc.ts
  • Implemented a security validation check within the runPoc function to ensure that the provided filePath resides strictly within the .gemini_security/poc directory.

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[gemini-code-assist]

Code Review

This pull request introduces a security enhancement by restricting the execution of Proof-of-Concept (PoC) scripts to a specific directory (.gemini_security/poc), which effectively prevents path traversal attacks. The changes include validation logic in poc.ts and updated tests to cover this new security measure.

My review identifies a critical command injection vulnerability that remains in the runPoc function, which should be addressed. I've also included a couple of medium-severity suggestions to improve code maintainability by reducing code duplication in tests and centralizing hardcoded paths.

[github-actions]

📋 Review Summary

This pull request introduces a security measure to restrict the execution of Proof-of-Concept (PoC) scripts to a specific directory, preventing potential path traversal vulnerabilities. The changes are well-implemented and include corresponding tests.

🔍 General Feedback

• The addition of the security check in poc.ts is a welcome improvement.
• The new test case in poc.test.ts effectively validates the security restriction.
• The updated instructions in index.ts are clear and provide good guidance for generating PoCs for path traversal vulnerabilities.

[github-actions]

## 📋 Security Analysis Summary

The pull request introduces a command injection vulnerability in the runPoc function. The filePath parameter is used in a shell command without proper sanitization, which could allow an attacker to execute arbitrary commands.

🔍 General Feedback

• The path traversal check is a good security measure, but it's not sufficient to prevent command injection.
• It's recommended to use spawn or fork instead of exec or execAsync when dealing with user input to prevent command injection vulnerabilities.

[shrishabh]

Was this removal intentional?