🛡️ Sentinel: [CRITICAL] Fix path traversal in skill imports

.jules/sentinel.md

@@ -0,0 +1,4 @@
+## 2025-02-14 - Prevent Zip Slip Vulnerability during Extraction
+**Vulnerability:** Zip Slip (path traversal) risk when extracting `zipfile.ZipFile` archives using `extractall()` without verifying individual member paths in `helpers/skills_import.py`.
+**Learning:** Malicious zip files can contain relative paths (e.g., `../../etc/passwd`) or absolute paths that extract files outside the intended target directory. Using `extractall()` blindly trusts the paths within the zip archive, bypassing directory containment.
+**Prevention:** Explicitly iterate through every member in `z.namelist()`, construct the member's resolved absolute path, and verify it falls within the intended target directory using a safe path containment method like `Path.resolve().is_relative_to()` before proceeding with extraction.

helpers/skills_import.py

@@ -94,6 +94,10 @@ def _unzip_to_temp_dir(zip_path: Path) -> Path:
     target.mkdir(parents=True, exist_ok=True)
 
     with zipfile.ZipFile(zip_path, "r") as z:
+        for member in z.namelist():
+            member_path = (target / member).resolve()
+            if not member_path.is_relative_to(target.resolve()):
+                raise ValueError(f"Unsafe path in archive: {member}")
         z.extractall(target)
 
     # If zip contains a single top-level folder, treat that as the root