Adding tarfile member sanitization to extractall()

tensorflow1_ipynb/helper.py

@@ -52,7 +52,26 @@ def download_and_extract_cifar(target_dir,
     sys.stdout.flush()
 
     with tarfile.open(fpath, 'r:gz') as t:
-        t.extractall(target_dir)
+        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(t, target_dir)
 
     return fpath.replace('cifar-10-python.tar.gz', 'cifar-10-batches-py')