Adding tarfile member sanitization to extractall()

scripts/convert_imdb_reviews.py

@@ -32,7 +32,29 @@ def main():
 
     if not PATH_DATASETS_IMDB_EXTRACTED.exists():
         with tarfile.open(PATH_DATASETS_IMDB) as mytar:
-            mytar.extractall(PATH_DATASETS_IMDB_EXTRACTED)
+
+            import os
+
+            def is_within_directory(directory, target):
+
+                abs_directory = os.path.abspath(directory)
+                abs_target = os.path.abspath(target)
+
+                prefix = os.path.commonprefix([abs_directory, abs_target])
+
+                return prefix == abs_directory
+
+            def safe_extract(tar, path=".", members=None, *, numeric_owner=False):
+
+                for member in tar.getmembers():
+                    member_path = os.path.join(path, member.name)
+                    if not is_within_directory(path, member_path):
+                        raise Exception("Attempted Path Traversal in Tar File")
+
+                tar.extractall(path, members, numeric_owner=numeric_owner) 
+
+
+            safe_extract(mytar, PATH_DATASETS_IMDB_EXTRACTED)
 
     positive = [(p, "positive") for p in (PATH_DATASETS_IMDB_TRAIN / "pos").iterdir()]
     negative = [(p, "negative") for p in (PATH_DATASETS_IMDB_TRAIN / "neg").iterdir()]