diff --git a/code_generator/checkpointer.py b/code_generator/checkpointer.py
index 29249f4..c362594 100644
--- a/code_generator/checkpointer.py
+++ b/code_generator/checkpointer.py
@@ -1,12 +1,28 @@
+import re
from pathlib import Path
+# Slugs are used to build filesystem paths and originate from config that may be
+# LLM-generated from an untrusted GitHub repo tree, so restrict them to a safe
+# character set to prevent path traversal (e.g. a "../" slug escaping the root).
+_SLUG_RE = re.compile(r"^[a-z0-9][a-z0-9-]*$")
+
+
+def _validate_slug(slug: str) -> str:
+ if not isinstance(slug, str) or not _SLUG_RE.match(slug):
+ raise ValueError(f"Unsafe slug: {slug!r}")
+ return slug
+
class Checkpointer:
def __init__(self, output_dir: str):
- self.root = Path(output_dir)
+ self.root = Path(output_dir).resolve()
def path_for(self, program_slug: str, file_slug: str) -> Path:
- return self.root / program_slug / f"{file_slug}.md"
+ path = (self.root / _validate_slug(program_slug) / f"{_validate_slug(file_slug)}.md").resolve()
+ # Defense in depth: ensure the resolved path stays within the root.
+ if self.root not in path.parents:
+ raise ValueError(f"Path escapes output root: {path}")
+ return path
def is_done(self, program_slug: str, file_slug: str) -> bool:
return self.path_for(program_slug, file_slug).exists()
diff --git a/public/index.html b/public/index.html
index 2a281ea..a0d221f 100644
--- a/public/index.html
+++ b/public/index.html
@@ -14,10 +14,10 @@
-
-
-
-
+
+
+
+