From 6bfaf421e208b51e4cb0b5e9f13a5fa71d2a8826 Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Sun, 30 Oct 2022 19:42:29 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- chalice/utils.py | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/chalice/utils.py b/chalice/utils.py index 1bd1d61..8f03b59 100644 --- a/chalice/utils.py +++ b/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