From 250034bb9d297d4ee05d53e60e36096b28d6dea1 Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Mon, 28 Nov 2022 06:53:06 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- axcell/helpers/unpack.py | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/axcell/helpers/unpack.py b/axcell/helpers/unpack.py index 74107ae..2a3c6ae 100644 --- a/axcell/helpers/unpack.py +++ b/axcell/helpers/unpack.py @@ -25,7 +25,29 @@ def __call__(self, source, dest): if mime == 'application/x-tar': dest.mkdir(parents=True, exist_ok=True) with tarfile.open(source, "r:*") as tar: - tar.extractall(dest) + + import os + + 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, dest) elif mime == 'text/x-tex': dest.mkdir(parents=True, exist_ok=True) with gzip.open(source, "rb") as src, open(dest / "main.tex", "wb") as dst: