ssh-audit/src/ssh_audit/banner.py
2020-10-15 14:34:23 -04:00

93 lines
3.5 KiB
Python

"""
The MIT License (MIT)
Copyright (C) 2017 Andris Raugulis (moo@arthepsy.eu)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
import re
# pylint: disable=unused-import
from typing import Dict, List, Set, Sequence, Tuple, Iterable # noqa: F401
from typing import Callable, Optional, Union, Any # noqa: F401
from ssh_audit.utils import Utils
class Banner:
_RXP, _RXR = r'SSH-\d\.\s*?\d+', r'(-\s*([^\s]*)(?:\s+(.*))?)?'
RX_PROTOCOL = re.compile(re.sub(r'\\d(\+?)', r'(\\d\g<1>)', _RXP))
RX_BANNER = re.compile(r'^({0}(?:(?:-{0})*)){1}$'.format(_RXP, _RXR))
def __init__(self, protocol: Tuple[int, int], software: Optional[str], comments: Optional[str], valid_ascii: bool) -> None:
self.__protocol = protocol
self.__software = software
self.__comments = comments
self.__valid_ascii = valid_ascii
@property
def protocol(self) -> Tuple[int, int]:
return self.__protocol
@property
def software(self) -> Optional[str]:
return self.__software
@property
def comments(self) -> Optional[str]:
return self.__comments
@property
def valid_ascii(self) -> bool:
return self.__valid_ascii
def __str__(self) -> str:
r = 'SSH-{}.{}'.format(self.protocol[0], self.protocol[1])
if self.software is not None:
r += '-{}'.format(self.software)
if bool(self.comments):
r += ' {}'.format(self.comments)
return r
def __repr__(self) -> str:
p = '{}.{}'.format(self.protocol[0], self.protocol[1])
r = 'protocol={}'.format(p)
if self.software is not None:
r += ', software={}'.format(self.software)
if bool(self.comments):
r += ', comments={}'.format(self.comments)
return '<{}({})>'.format(self.__class__.__name__, r)
@classmethod
def parse(cls, banner: str) -> Optional['Banner']:
valid_ascii = Utils.is_print_ascii(banner)
ascii_banner = Utils.to_print_ascii(banner)
mx = cls.RX_BANNER.match(ascii_banner)
if mx is None:
return None
protocol = min(re.findall(cls.RX_PROTOCOL, mx.group(1)))
protocol = (int(protocol[0]), int(protocol[1]))
software = (mx.group(3) or '').strip() or None
if software is None and (mx.group(2) or '').startswith('-'):
software = ''
comments = (mx.group(4) or '').strip() or None
if comments is not None:
comments = re.sub(r'\s+', ' ', comments)
return cls(protocol, software, comments, valid_ascii)