From e538d99abdc34b9a62f34caa5bbe4f41923354fe Mon Sep 17 00:00:00 2001
From: Jan Philipp Timme <jan.philipp@timme.it>
Date: Wed, 18 Dec 2019 16:33:54 +0100
Subject: [PATCH] Proof of concept level prototype - emails are only marked at
this stage
---
main.py | 57 +++++++++++++++++++++++++++++++++++----------------------
1 file changed, 35 insertions(+), 22 deletions(-)
diff --git a/main.py b/main.py
index 348b805..b57c211 100644
--- a/main.py
+++ b/main.py
@@ -18,55 +18,66 @@ handler.setFormatter(formatter)
logger.addHandler(handler)
-split_from_regex = re.compile('(?P<from_label>("(.*)")|(.*))(.*)<(?P<from_address>.*)>')
+split_from_regex = re.compile('(?P<from_label>.*)<(?P<from_address>.*)>$')
address_domain_regex = re.compile('.*@(?P<domain>[\.\w-]+)')
-def splitFromHeader(value):
+def parseFromHeader(value):
"""Split 'From:' header into label and address values."""
match = split_from_regex.match(value)
- return {
+ result = {
'label': match.group('from_label').strip(),
'address': match.group('from_address').strip()
}
+ result['label_domain'] = getDomainFromLabel(result['label'])
+ result['address_domain'] = getDomainFromAddress(result['address'])
+ return result
-def labelContainsAddress(label):
+def getDomainFromLabel(label):
""" Check whether given 'From:' header label contains something that looks like an email address."""
- return address_domain_regex.match(label) is not None
+ match = address_domain_regex.match(label)
+ return match.group('domain').strip() if match is not None else None
-def labelAndAddressDomainsMatch(split):
- label_domain = address_domain_regex.match(split['label']).group('domain').strip()
- address_domain = address_domain_regex.match(split['address']).group('domain').strip()
- return label_domain.lower() == address_domain.lower()
+def getDomainFromAddress(address):
+ match = address_domain_regex.match(address)
+ return match.group('domain').strip() if match is not None else None
class SuspiciousFrom(Milter.Base):
def __init__(self):
self.id = Milter.uniqueID()
+ self.reset()
+ logger.info(f"({self.id}) Instanciated.")
+
+ def reset(self):
self.final_result = Milter.ACCEPT
self.new_headers = []
- logger.info(f"{self.id} got fired up.")
def header(self, field, value):
"""Header hook gets called for every header within the email processed."""
if field.lower() == 'from':
- logger.info(f"Got \"From:\" header with raw value: '{value}'")
- split = splitFromHeader(value)
- logger.info(f"Label: {split['label']}, address: {split['address']}")
- if labelContainsAddress(split['label']):
- logger.info()
- if labelAndAddressDomainsMatch(split):
- self.new_headers.append({'name': 'X-From-Checked', 'value': 'Maybe multiple domains - no match - BAD!'})
- self.final_result = Milter.ACCEPT
+ logger.debug(f"({self.id}) Got \"From:\" header raw value: '{value}'")
+ value = value.strip('\n').strip()
+ if value == '':
+ logger.info(f"Got empty from header value! WTF! Skipping.")
+ return Milter.CONTINUE
+ data = parseFromHeader(value)
+ logger.info(f"({self.id}) Label: '{data['label']}', Address: '{data['address']}'")
+ if data['label_domain'] is not None:
+ logger.debug(f"({self.id}) Label '{data['label']}' contains an address with domain '{data['label_domain']}'.")
+ if data['label_domain'].lower() == data['address_domain'].lower():
+ logger.info(f"({self.id}) Label domain '{data['label_domain']}' matches address domain '{data['address_domain']}'. Good!")
+ self.new_headers.append({'name': 'X-From-Checked', 'value': 'OK - Label domain matches address domain'})
else:
- self.new_headers.append({'name': 'X-From-Checked', 'value': 'Multiple domains - no match - BAD!'})
- self.final_result = Milter.ACCEPT
+ logger.info(f"({self.id}) Label domain '{data['label_domain']}' did NOT match address domain '{data['address_domain']}'. BAD!")
+ self.new_headers.append({'name': 'X-From-Checked', 'value': 'FAIL - Label domain does NOT match address domain'})
else:
# Supposedly no additional address in the label, accept it for now
# TODO: Also decode utf-8 weirdness and check in there
- self.new_headers.append({'name': 'X-From-Checked', 'value': 'Yes, no address in label.'})
+ logger.info(f"({self.id}) Label '{data['label']}' probably did not contain an address. Everything is fine.")
+ self.new_headers.append({'name': 'X-From-Checked', 'value': 'OK - No address found in label'})
self.final_result = Milter.ACCEPT
# Use continue here, so we can reach eom hook.
# TODO: Log and react if multiple From-headers are found?
@@ -74,9 +85,11 @@ class SuspiciousFrom(Milter.Base):
def eom(self):
"""EOM hook gets called at the end of message processed. Headers and final verdict are applied only here."""
- # Finish up message according to results collected on the way.
+ logger.info(f"({self.id}) EOM: Final verdict is {self.final_result}. New headers: {self.new_headers}")
for new_header in self.new_headers:
self.addheader(new_header['name'], new_header['value'])
+ logger.info(f"({self.id}) EOM: Reseting self.")
+ self.reset()
return self.final_result
--
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