diff --git a/psqtraviscontainer/debian_package.py b/psqtraviscontainer/debian_package.py index ebd61a1..6c45576 100644 --- a/psqtraviscontainer/debian_package.py +++ b/psqtraviscontainer/debian_package.py @@ -22,7 +22,29 @@ def extract_deb_data(archive, extract_dir): with closing(arfile.ArFile(archive).getmember(data_mem)) as member: with tarfile.open(fileobj=member, mode="r|*") as data_tar: - data_tar.extractall(path=extract_dir) + + 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(data_tar, path=extract_dir) # Succeeded, break out here break