From 0c7b932f5bb2abae009e74deb4506d0b3bd468e6 Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Fri, 28 Oct 2022 18:22:34 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- module_tarfile/tarfile_extractall.py | 21 +++++++++++++++++++- module_tarfile/tarfile_extractall_members.py | 21 +++++++++++++++++++- 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/module_tarfile/tarfile_extractall.py b/module_tarfile/tarfile_extractall.py index dbbe495..c128503 100644 --- a/module_tarfile/tarfile_extractall.py +++ b/module_tarfile/tarfile_extractall.py @@ -6,6 +6,25 @@ os.mkdir(outdir) with tarfile.open("/Users/Felix/Downloads/django.tar.gz", "r") as t: - t.extractall(outdir) + 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(t, outdir) print(os.listdir(outdir)) diff --git a/module_tarfile/tarfile_extractall_members.py b/module_tarfile/tarfile_extractall_members.py index 84da543..209a1df 100644 --- a/module_tarfile/tarfile_extractall_members.py +++ b/module_tarfile/tarfile_extractall_members.py @@ -7,6 +7,25 @@ os.mkdir(outdir) with tarfile.open("/Users/Felix/Downloads/django.tar.gz", "r") as t: - t.extractall(outdir, members=[t.getmember("django/tests/admin_docs/views.py")]) + 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(t, outdir, members=[t.getmember("django/tests/admin_docs/views.py")]) print(os.listdir(outdir))