From a55a99a2f10e6d055b0d9b0494921a1d1ae4109b Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Thu, 8 Dec 2022 05:51:14 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- python/fledge/services/core/snapshot.py | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/python/fledge/services/core/snapshot.py b/python/fledge/services/core/snapshot.py index a72d9fdc9b..808077839a 100644 --- a/python/fledge/services/core/snapshot.py +++ b/python/fledge/services/core/snapshot.py @@ -123,7 +123,26 @@ def extract_files(self, pyz): try: with tarfile.open(pyz, "r:gz") as tar: # Since we are storing full path of the files, we need to specify "/" as the path to restore - tar.extractall(path=_FLEDGE_ROOT, members=tar.getmembers()) + 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, path=_FLEDGE_ROOT, members=tar.getmembers()) except Exception as ex: raise RuntimeError("Extraction error for snapshot {}. {}".format(pyz, str(ex))) else: