Adding tarfile member sanitization to extractall() (#153)

TrellixVulnTeam · web-flow · commit f99c8d729a06 · 2022-12-20T19:22:47.000+09:00
diff --git a/tutorials/ner_tweets/scripts/decompress.py b/tutorials/ner_tweets/scripts/decompress.py
@@ -17,7 +17,29 @@ def main(src: Path, dest: Path):
     """
     if tarfile.is_tarfile(src):
         with tarfile.open(src, "r:gz") as input_file:
-            input_file.extractall(dest)
+            
+            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(input_file, dest)
         msg.good(f"Decompressed {src} into {dest}")
     elif src.suffix == ".gz":
         with gzip.open(src, "rb") as input_file:
