CVE-2007-4559 Patch

chalice/utils.py

@@ -231,7 +231,26 @@ def extract_zipfile(self, zipfile_path, unpack_dir):
     def extract_tarfile(self, tarfile_path, unpack_dir):
         # type: (str, str) -> None
         with tarfile.open(tarfile_path, 'r:*') as tar:
-            tar.extractall(unpack_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(tar, unpack_dir)
 
     def directory_exists(self, path):
         # type: (str) -> bool