76 lines
2.4 KiB
Python
76 lines
2.4 KiB
Python
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# -*- coding: utf-8 -*-
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import re
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import logging
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logger = logging.getLogger(__name__)
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from django import forms
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from django.conf import settings
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from django.utils.translation import ugettext_lazy as _
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from registration.forms import RegistrationForm
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import dns.resolver
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import dns.name
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resolver = dns.resolver.Resolver()
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resolver.search = [dns.name.root, ]
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resolver.lifetime = 5.0
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resolver.nameservers = settings.NAMESERVERS
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maildomain_blacklist = settings.MAILDOMAIN_BLACKLIST.strip().splitlines()
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def check_mx(domain):
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valid = False
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try:
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mx_answers = resolver.query(domain, 'MX')
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# domain exists in DNS, domain has MX
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mx_entries = sorted([(mx_rdata.preference, mx_rdata.exchange) for mx_rdata in mx_answers])
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for preference, mx in mx_entries:
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try:
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addr_answers = resolver.query(mx, 'A')
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except dns.resolver.NoAnswer:
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addr_answers = resolver.query(mx, 'AAAA')
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# MX has IP addr
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mx_addrs = [addr_rdata.address for addr_rdata in addr_answers]
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for mx_addr in mx_addrs:
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if mx_addr not in (u'127.0.0.1', u'::1', u'0.0.0.0', ):
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valid = True
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break
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if valid:
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break
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except (dns.resolver.Timeout, dns.resolver.NoAnswer, dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, ):
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# expected exceptions (e.g. due to non-existing or misconfigured crap domains)
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pass
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return valid
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def check_blacklist(domain):
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for blacklisted_re in maildomain_blacklist:
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if re.search(blacklisted_re, domain):
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return False
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return True
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class RegistrationFormValidateEmail(RegistrationForm):
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def clean_email(self):
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"""
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Validate the supplied email address to avoid undeliverable email and mailer daemon spam.
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"""
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email = self.cleaned_data.get('email')
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valid_mx = False
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try:
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domain = email.split('@')[1]
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valid_mx = check_mx(domain)
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except Exception as e:
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logger.exception('RegistrationFormValidateEmail raised an exception:')
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not_blacklisted = check_blacklist(domain)
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if valid_mx and not_blacklisted:
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return email
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logger.info('RegistrationFormValidateEmail: rejecting email address %r' % email)
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raise forms.ValidationError(_("Enter a valid email address."))
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