Validate flags used in MCP server config commands

[christopherholland-workday]

Today, there is an allow-list of commands, and other validations to ensure that dangerous env vars and commands are not being used. However, flags were not validated. This PR adds a robust flag validator that covers common code execution flags that can be paired with allow-listed commands (e.g. npx -c). The validator also covers alternative syntax's like combined short flags, and "=" syntax.

[gemini-code-assist]

Summary of Changes

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This pull request significantly enhances the security posture of MCP server configurations by introducing a robust mechanism to validate command-line flags. Previously, while commands themselves were allow-listed, dangerous flags that could enable arbitrary code execution were not explicitly checked. This change closes a critical security loophole by preventing the use of such flags with otherwise legitimate commands, thereby mitigating potential attack vectors and improving the overall integrity of command execution within the system.

Highlights

• New Flag Validation Function: Introduced a new validateCommandFlags function to prevent arbitrary code execution through dangerous command-line flags.
• Comprehensive Dangerous Flag List: Defined a comprehensive list of dangerous flags for npx, node, python, python3, and docker commands that could lead to code execution.
• Robust Validation Logic: Implemented robust validation logic to detect dangerous flags, including exact matches, flags with = syntax, combined short flags (e.g., -yc), and space-separated flag values.
• Integration into Server Config: Integrated the new flag validation into the existing validateMCPServerConfig function to enhance overall security for MCP server configurations.
• Extensive Unit Tests: Added a new test file with extensive unit tests covering the new validateCommandFlags function and reinforcing existing security validations.

Changelog

• packages/components/jest.config.js
  • Updated Jest configuration to include the test directory in the roots array.
• packages/components/nodes/tools/MCP/core.ts
  • Added a new validateCommandFlags function to check for dangerous flags in command arguments.
  • Integrated validateCommandFlags into validateMCPServerConfig to apply flag validation when a command is present.
• packages/components/test/nodes/tools/MCP/core.test.ts
  • Added a new test file dedicated to MCP security validations.
  • Included comprehensive tests for the new validateCommandFlags function across various commands (npx, node, python, docker) and flag types.
  • Expanded test coverage for validateCommandInjection, validateArgsForLocalFileAccess, validateEnvironmentVariables, and validateMCPServerConfig.

Activity

• No human activity (comments, reviews, etc.) has occurred on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request introduces a robust validator for command-line flags to prevent code execution vulnerabilities when using allow-listed commands. The changes are a significant security improvement. I've identified a critical vulnerability in the flag validation logic that could allow a bypass, and I've also included a few suggestions to improve code maintainability and readability. The new tests are comprehensive but should be expanded to cover the identified vulnerability.