80 lines
2.6 KiB
Python
80 lines
2.6 KiB
Python
########################################################################
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# File name: plain.py
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# This file is part of: aiosasl
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#
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# LICENSE
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this program. If not, see
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# <http://www.gnu.org/licenses/>.
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#
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########################################################################
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import logging
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import typing
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from . import common, statemachine
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logger = logging.getLogger(__name__)
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class PLAIN(statemachine.SASLMechanism):
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"""
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The password-based ``PLAIN`` SASL mechanism (see :rfc:`4616`).
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.. warning::
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This is generally unsafe over unencrypted connections and should not be
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used there. Exclusion of the ``PLAIN`` mechanism over unsafe connections
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is out of scope for :mod:`aiosasl` and needs to be handled by the
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protocol implementation!
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`credential_provider` must be coroutine which returns a ``(user,
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password)`` tuple.
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"""
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def __init__(self, credential_provider: common.CredentialProvider):
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super().__init__()
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self._credential_provider = credential_provider
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@classmethod
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def any_supported(
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cls,
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mechanisms: typing.Iterable[str],
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) -> typing.Any:
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if "PLAIN" in mechanisms:
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return "PLAIN"
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return None
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async def authenticate(
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self,
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sm: statemachine.SASLStateMachine,
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mechanism: typing.Any,
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) -> None:
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logger.info("attempting PLAIN mechanism")
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username, password = await self._credential_provider()
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encoded_username = username.encode("utf8")
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encoded_password = password.encode("utf8")
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if b"\0" in encoded_username or b"\0" in encoded_password:
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raise ValueError("NUL byte in username or password is disallowed")
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state, _ = await sm.initiate(
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mechanism="PLAIN",
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payload=b"\0" + encoded_username + b"\0" + encoded_password,
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)
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if state != common.SASLState.SUCCESS:
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raise common.SASLFailure(
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None,
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text="SASL protocol violation")
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