import contextlib
import io
import logging
import tarfile
from abc import ABC
from typing import List, Optional
from credsweeper.credentials.candidate import Candidate
from credsweeper.deep_scanner.abstract_scanner import AbstractScanner
from credsweeper.file_handler.data_content_provider import DataContentProvider
from credsweeper.file_handler.file_path_extractor import FilePathExtractor
from credsweeper.utils.util import Util
logger = logging.getLogger(__name__)
[docs]
class TarScanner(AbstractScanner, ABC):
"""Implements tar scanning"""
[docs]
@staticmethod
def match(data: bytes | bytearray) -> bool:
"""According https://en.wikipedia.org/wiki/List_of_file_signatures"""
if 512 <= len(data) and 257 == data.find(b"\x75\x73\x74\x61\x72", 257, 262) \
and (262 == data.find(b"\x00\x30\x30", 262, 265)
or 262 == data.find(b"\x20\x20\x00", 262, 265)):
with contextlib.suppress(Exception):
chksum = tarfile.nti(data[148:156]) # type: ignore
unsigned_chksum, signed_chksum = tarfile.calc_chksums(data) # type: ignore
if chksum == unsigned_chksum or chksum == signed_chksum:
return True
return False
[docs]
def data_scan(
self, #
data_provider: DataContentProvider, #
depth: int, #
recursive_limit_size: int) -> Optional[List[Candidate]]:
"""Extracts files one by one from tar archive and launches data_scan"""
try:
candidates = []
with tarfile.TarFile(fileobj=io.BytesIO(data_provider.data)) as tf:
for tfi in tf.getmembers():
# skip directory
if not tfi.isreg():
continue
if FilePathExtractor.check_exclude_file(self.config, tfi.name):
continue
if 0 > recursive_limit_size - tfi.size:
logger.warning("%s: size %s is over limit %s depth:%s", tfi.name, tfi.size,
recursive_limit_size, depth)
continue
with tf.extractfile(tfi) as f:
tar_content_provider = DataContentProvider(data=f.read(),
file_path=data_provider.file_path,
file_type=Util.get_type(tfi.name),
info=f"{data_provider.info}|TAR:{tfi.name}")
tar_candidates = self.recursive_scan(tar_content_provider, depth, recursive_limit_size)
candidates.extend(tar_candidates)
return candidates
except Exception as tar_exc:
# too many exception types might be produced with broken tar
logger.warning("%s:%s", data_provider.file_path, tar_exc)
return None