From 116821896d653a1505e720310ba4fc383db131af Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Sat, 15 Oct 2022 06:27:41 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- fetchy/dfs.py | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/fetchy/dfs.py b/fetchy/dfs.py index 736719b..7348b91 100644 --- a/fetchy/dfs.py +++ b/fetchy/dfs.py @@ -34,7 +34,26 @@ def _extract_image_in(self, directory): image.close() with tarfile.open(tar_file) as tar: - tar.extractall(directory) + 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, directory) def _extract_layers(self, directory): with open(os.path.join(directory, "manifest.json")) as manifest: