mirror of https://github.com/jtesta/ssh-audit.git
109 lines
3.9 KiB
Python
109 lines
3.9 KiB
Python
"""
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The MIT License (MIT)
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Copyright (C) 2017 Andris Raugulis (moo@arthepsy.eu)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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"""
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import io
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import struct
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# pylint: disable=unused-import
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from typing import Dict, List, Set, Sequence, Tuple, Iterable # noqa: F401
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from typing import Callable, Optional, Union, Any # noqa: F401
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class WriteBuf:
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def __init__(self, data: Optional[bytes] = None) -> None:
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super(WriteBuf, self).__init__()
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self._wbuf = io.BytesIO(data) if data is not None else io.BytesIO()
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def write(self, data: bytes) -> 'WriteBuf':
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self._wbuf.write(data)
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return self
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def write_byte(self, v: int) -> 'WriteBuf':
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return self.write(struct.pack('B', v))
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def write_bool(self, v: bool) -> 'WriteBuf':
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return self.write_byte(1 if v else 0)
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def write_int(self, v: int) -> 'WriteBuf':
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return self.write(struct.pack('>I', v))
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def write_string(self, v: Union[bytes, str]) -> 'WriteBuf':
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if not isinstance(v, bytes):
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v = bytes(bytearray(v, 'utf-8'))
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self.write_int(len(v))
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return self.write(v)
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def write_list(self, v: List[str]) -> 'WriteBuf':
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return self.write_string(','.join(v))
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@classmethod
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def _bitlength(cls, n: int) -> int:
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try:
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return n.bit_length()
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except AttributeError:
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return len(bin(n)) - (2 if n > 0 else 3)
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@classmethod
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def _create_mpint(cls, n: int, signed: bool = True, bits: Optional[int] = None) -> bytes:
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if bits is None:
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bits = cls._bitlength(n)
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length = bits // 8 + (1 if n != 0 else 0)
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ql = (length + 7) // 8
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fmt, v2 = '>{}Q'.format(ql), [0] * ql
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for i in range(ql):
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v2[ql - i - 1] = n & 0xffffffffffffffff
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n >>= 64
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data = bytes(struct.pack(fmt, *v2)[-length:])
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if not signed:
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data = data.lstrip(b'\x00')
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elif data.startswith(b'\xff\x80'):
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data = data[1:]
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return data
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def write_mpint1(self, n: int) -> 'WriteBuf':
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# NOTE: Data Type Enc @ http://www.snailbook.com/docs/protocol-1.5.txt
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bits = self._bitlength(n)
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data = self._create_mpint(n, False, bits)
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self.write(struct.pack('>H', bits))
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return self.write(data)
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def write_mpint2(self, n: int) -> 'WriteBuf':
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# NOTE: Section 5 @ https://www.ietf.org/rfc/rfc4251.txt
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data = self._create_mpint(n)
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return self.write_string(data)
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def write_line(self, v: Union[bytes, str]) -> 'WriteBuf':
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if not isinstance(v, bytes):
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v = bytes(bytearray(v, 'utf-8'))
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v += b'\r\n'
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return self.write(v)
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def write_flush(self) -> bytes:
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payload = self._wbuf.getvalue()
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self._wbuf.truncate(0)
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self._wbuf.seek(0)
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return payload
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def reset(self) -> None:
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self._wbuf = io.BytesIO()
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