Tom Hendrikx
81 lines
2.3 KiB
Python
81 lines
2.3 KiB
Python
## A very simple milter to prevent mixing of internal and external mail.
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# Internal is defined as using one of a list of internal top level domains.
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# This code is open-source on the same terms as Python.
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from __future__ import print_function
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import Milter
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import time
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import sys
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from Milter.utils import parse_addr
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internal_tlds = ["corp", "personal"]
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## Determine if a hostname is internal or not.
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# True if internal, False otherwise
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def is_internal(hostname):
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components = hostname.split(".")
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return components.pop() in internal_tlds
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# Determine if internal and external hosts are mixed based on a list
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# of hostnames
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def are_mixed(hostnames):
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hostnames_mapped = map(is_internal, hostnames)
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# Num internals
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num_internal_hosts = hostnames_mapped.count(True)
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# Num externals
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num_external_hosts = hostnames_mapped.count(False)
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return num_external_hosts >= 1 and num_internal_hosts >= 1
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class NoMixMilter(Milter.Base):
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def __init__(self): # A new instance with each new connection.
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self.id = Milter.uniqueID() # Integer incremented with each call.
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## def envfrom(self,f,*str):
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@Milter.noreply
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def envfrom(self, mailfrom, *str):
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self.mailfrom = mailfrom
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self.domains = []
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t = parse_addr(mailfrom)
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if len(t) > 1:
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self.domains.append(t[1])
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else:
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self.domains.append('local')
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self.internal = False
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return Milter.CONTINUE
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## def envrcpt(self, to, *str):
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def envrcpt(self, to, *str):
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self.R.append(to)
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t = parse_addr(to)
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if len(t) > 1:
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self.domains.append(t[1])
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else:
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self.domains.append('local')
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if are_mixed(self.domains):
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# FIXME: log recipients collected in self.mailfrom and self.R
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self.setreply('550','5.7.1','Mixing internal and external TLDs')
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return Milter.REJECT
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return Milter.CONTINUE
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def main():
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socketname = "/var/run/nomixsock"
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timeout = 600
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# Register to have the Milter factory create instances of your class:
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Milter.factory = NoMixMilter
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print("%s milter startup" % time.strftime('%Y%b%d %H:%M:%S'))
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sys.stdout.flush()
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Milter.runmilter("nomixfilter",socketname,timeout)
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logq.put(None)
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bt.join()
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print("%s nomix milter shutdown" % time.strftime('%Y%b%d %H:%M:%S'))
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if __name__ == "__main__":
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main()
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