118 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			Python
		
	
	
# Copyright 2018 New Vector Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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import re
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import typing
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if typing.TYPE_CHECKING:
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    from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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# it's unclear what the maximum length of an email address is. RFC3696 (as corrected
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# by errata) says:
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#    the upper limit on address lengths should normally be considered to be 254.
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#
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# In practice, mail servers appear to be more tolerant and allow 400 characters
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# or so. Let's allow 500, which should be plenty for everyone.
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#
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MAX_EMAIL_ADDRESS_LENGTH = 500
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async def check_3pid_allowed(
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    hs: "HomeServer",
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    medium: str,
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    address: str,
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    registration: bool = False,
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) -> bool:
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    """Checks whether a given format of 3PID is allowed to be used on this HS
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    Args:
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        hs: server
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        medium: 3pid medium - e.g. email, msisdn
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        address: address within that medium (e.g. "wotan@matrix.org")
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            msisdns need to first have been canonicalised
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        registration: whether we want to bind the 3PID as part of registering a new user.
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    Returns:
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        whether the 3PID medium/address is allowed to be added to this HS
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    """
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    if not await hs.get_password_auth_provider().is_3pid_allowed(
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        medium, address, registration
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    ):
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        return False
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    if hs.config.registration.allowed_local_3pids:
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        for constraint in hs.config.registration.allowed_local_3pids:
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            logger.debug(
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                "Checking 3PID %s (%s) against %s (%s)",
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                address,
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                medium,
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                constraint["pattern"],
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                constraint["medium"],
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            )
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            if medium == constraint["medium"] and re.match(
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                constraint["pattern"], address
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            ):
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                return True
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    else:
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        return True
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    return False
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def canonicalise_email(address: str) -> str:
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    """'Canonicalise' email address
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    Case folding of local part of email address and lowercase domain part
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    See MSC2265, https://github.com/matrix-org/matrix-doc/pull/2265
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    Args:
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        address: email address to be canonicalised
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    Returns:
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        The canonical form of the email address
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    Raises:
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        ValueError if the address could not be parsed.
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    """
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    address = address.strip()
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    parts = address.split("@")
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    if len(parts) != 2:
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        logger.debug("Couldn't parse email address %s", address)
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        raise ValueError("Unable to parse email address")
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    return parts[0].casefold() + "@" + parts[1].lower()
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def validate_email(address: str) -> str:
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    """Does some basic validation on an email address.
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    Returns the canonicalised email, as returned by `canonicalise_email`.
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    Raises a ValueError if the email is invalid.
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    """
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    # First we try canonicalising in case that fails
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    address = canonicalise_email(address)
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    # Email addresses have to be at least 3 characters.
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    if len(address) < 3:
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        raise ValueError("Unable to parse email address")
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    if len(address) > MAX_EMAIL_ADDRESS_LENGTH:
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        raise ValueError("Unable to parse email address")
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    return address
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