Repair Path Traversal & Symlink Escapes

The problem

Inconsistent path normalization and weak filesystem boundaries lead to critical path traversal vulnerabilities. Manual patches often fail to account for symlink escapes, TOCTOU races, or mismatched trust boundaries across the codebase.

What it does

• Identifies and repairs path traversal defects by synchronizing normalization and validation logic.
• Enforces strict workspace root boundaries for open, create, and delete operations.
• Implements TOCTOU-resistant file operations to prevent symlink-based attacks.
• Generates deterministic local fixtures and regression tests to verify boundary enforcement.
• Aligns state ownership and cleanup tasks with specific file transactions.

Why this beats prompting it yourself

General prompts often miss subtle edge cases like archive entry manipulation or symlink resolution order. This skill follows a rigorous methodology to map trust boundaries and state transitions, ensuring security fixes don't break existing storage layouts or archive policies.

Use cases

• Hardening a file upload handler against path traversal via malicious filenames.
• Restricting archive extraction logic to prevent writing files outside a designated directory.
• Refactoring filesystem utilities to resolve symlinks safely within a sandbox.
• Fixing race conditions in temporary file cleanup routines.