From 4eba5cb3a5fb331f94d7f741fe3d0ff852c4be40 Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Sun, 30 Oct 2022 21:10:02 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- cget/util.py | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/cget/util.py b/cget/util.py index b41ac1a..710f247 100644 --- a/cget/util.py +++ b/cget/util.py @@ -258,7 +258,29 @@ def extract_ar(archive, dst, *kwargs): if sys.version_info[0] < 3 and archive.endswith('.xz'): with contextlib.closing(lzma.LZMAFile(archive)) as xz: with tarfile.open(fileobj=xz, *kwargs) as f: - f.extractall(dst) + + 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(f, dst) elif archive.endswith('.zip'): with zipfile.ZipFile(archive,'r') as f: f.extractall(dst)