From 9408222b847f440548d2cd994d9318326c6d7c44 Mon Sep 17 00:00:00 2001 From: TrellixVulnTeam Date: Sun, 27 Nov 2022 11:16:38 +0000 Subject: [PATCH] Adding tarfile member sanitization to extractall() --- cs236781/download.py | 21 ++++++++++++++++++++- tmp/hw2/cs236781/download.py | 21 ++++++++++++++++++++- 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/cs236781/download.py b/cs236781/download.py index c58001f..69b8fa4 100644 --- a/cs236781/download.py +++ b/cs236781/download.py @@ -37,7 +37,26 @@ def download_data(out_path, url, extract=True, force=False): print(f"Extracting {out_filename}...") with tarfile.open(out_filename, "r") as tarf: members = tarf.getmembers() - tarf.extractall(out_path) + 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(tarf, out_path) first_dir = next(filter(lambda ti: ti.isdir(), members)).name extracted_dir = os.path.join(out_path, os.path.dirname(first_dir)) print(f"Extracted {len(members)} to {extracted_dir}") diff --git a/tmp/hw2/cs236781/download.py b/tmp/hw2/cs236781/download.py index c58001f..69b8fa4 100644 --- a/tmp/hw2/cs236781/download.py +++ b/tmp/hw2/cs236781/download.py @@ -37,7 +37,26 @@ def download_data(out_path, url, extract=True, force=False): print(f"Extracting {out_filename}...") with tarfile.open(out_filename, "r") as tarf: members = tarf.getmembers() - tarf.extractall(out_path) + 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(tarf, out_path) first_dir = next(filter(lambda ti: ti.isdir(), members)).name extracted_dir = os.path.join(out_path, os.path.dirname(first_dir)) print(f"Extracted {len(members)} to {extracted_dir}")