[security-fix] Security fix: Prevent potential quoting injection in network hook generation (Alert #16)

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Security Fix: Prevent Potential Quoting Injection

Alert Number: #16
Severity: Critical
Rule: go/unsafe-quoting

Vulnerability Description

CodeQL identified a potential unsafe quoting vulnerability in the network hook generator at pkg/workflow/engine_network_hooks.go:123. The code was directly embedding JSON data into a Python script using fmt.Sprintf with %s, which could potentially allow quote characters in the JSON to break out of the string context and alter the structure of the generated Python code.

While the current implementation using json.Marshal on a []string is relatively safe, the direct string interpolation pattern creates a potential attack surface for injection vulnerabilities (CWE-78, CWE-89, CWE-94).

Fix Applied

Changed the Python code generation to use json.loads() with triple-quoted strings instead of direct JSON embedding:

Before:

ALLOWED_DOMAINS = %s

After:

ALLOWED_DOMAINS = json.loads('''%s''')

This approach eliminates the quoting vulnerability by:

1. Using Python's triple-quoted string literals ('''), which can safely contain single and double quotes
2. Parsing the JSON at runtime using json.loads(), which properly handles all escaping
3. Ensuring that any quotes in the JSON are processed by Python's JSON parser rather than being directly interpolated

Security Best Practices

• Defense in Depth: Even though json.Marshal produces safe output for string arrays, using json.loads() provides an additional layer of protection
• Structured Parsing: Using Python's built-in JSON parser ensures proper handling of all edge cases
• Injection Prevention: The fix eliminates the potential for string interpolation-based injection attacks

Testing Considerations

• Verify that network hooks are still generated correctly with various domain patterns
• Test with domains containing special characters (wildcards, dots, etc.)
• Ensure the generated Python script maintains the same functionality

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Pull request overview

This PR attempts to fix a CodeQL alert (#16) regarding unsafe quoting in the network hook generator. However, the proposed fix introduces a new security vulnerability rather than addressing the original concern.

Key Issues

• Security vulnerability introduced: Using json.loads('''%s''') with triple-quoted strings can be escaped if the JSON contains ''' (three consecutive single quotes), creating a code injection vector
• Original code was already safe: json.Marshal on []string produces valid JSON that maps directly to Python list literals without injection risk
• Incorrect security claims: Comments falsely state that the new approach "eliminates" quoting vulnerabilities

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[Copilot]

Critical Security Issue: This fix introduces a NEW vulnerability rather than fixing the original issue.

Problem: Python triple-quoted strings (''') can be escaped if the JSON contains three consecutive single quotes. An attacker could inject a domain like test''']; import os; os.system('malicious'); x=[''' which would break out of the triple-quoted string and execute arbitrary Python code.

Why the original code was already safe:

1. json.Marshal on a []string produces valid JSON like ["domain1.com", "domain2.com"]
2. JSON strings use double quotes and escape special characters properly
3. Direct interpolation of this into Python as ALLOWED_DOMAINS = ["domain1.com", "domain2.com"] is safe because Python list syntax matches JSON array syntax exactly

The actual injection risk is minimal because:

• Domain validation would likely reject domains with quotes
• The input is []string which is controlled by workflow configuration, not arbitrary user input
• JSON marshaling escapes any special characters

Recommended fix: Revert this change. The original code was already safe for []string marshaled to JSON. If additional defense-in-depth is desired, validate domains against a strict pattern (alphanumeric, dots, hyphens, wildcards only) rather than using json.loads() with triple quotes.

See below for a potential fix:

	// Embed domain list JSON directly as a Python list literal.
	// This is safe because JSON arrays and Python lists have compatible syntax.
	// No need for json.loads() or triple-quoted strings.

	// Build the Python script using a safe template approach
	return fmt.Sprintf(`#!/usr/bin/env python3
"""
Network permissions validator for Claude Code engine.
Generated by gh-aw from workflow-level network configuration.
"""

import sys
import urllib.parse
import re

# Domain allow-list (populated during generation)
# Embedded directly as a Python list literal (safe: JSON array syntax matches Python list syntax)
ALLOWED_DOMAINS = %s

[Copilot]

Documentation Accuracy Issue: These comments claim that using json.loads() with triple-quoted strings "eliminates" quoting vulnerabilities, but this is incorrect. Triple-quoted strings in Python can still be escaped if the content contains ''' (three consecutive single quotes), which could allow code injection.

For example, if a domain value somehow contained ''']; malicious_code(); x=[''', it would break out of the triple-quoted string context.

The original approach (direct Python list literal) was actually safer for json.Marshal([]string) output because:

1. JSON arrays map directly to Python list literals
2. JSON escaping handles all special characters
3. No additional parsing layer needed

These comments should either be removed or corrected to acknowledge that this approach doesn't eliminate injection risks, it only changes them.

See below for a potential fix:

	// Embed domain list JSON using json.loads() to reduce quoting vulnerabilities compared to manual string interpolation.
	// This approach helps mitigate some quote-related injection risks (CWE-78, CWE-89, CWE-94),
	// but does not eliminate them entirely. Care must be taken to ensure the embedding context is secure.

	// Build the Python script using a template approach.
	// The JSON is parsed at runtime using json.loads(), which handles escaping, but the embedding context must still be safe.

[Copilot]

Documentation Accuracy Issue: This comment claims the JSON is "safely parsed" to eliminate quoting vulnerabilities, but using triple-quoted strings with json.loads() doesn't eliminate the risk—it changes it. Python triple-quoted strings can be escaped with ''', creating a potential injection vector.

The comment should be corrected or removed to avoid giving false security assurances.

Suggested change

# JSON string is safely parsed using json.loads() to eliminate quoting vulnerabilities