From 8dc3ac64743ce87ba3f48af6ce201f898d75f8a1 Mon Sep 17 00:00:00 2001
From: Scott Kitterman <scott@kitterman.com>
Date: Fri, 12 Apr 2019 22:31:24 -0400
Subject: [PATCH] Add option to sign for subdomains - Thanks to Sagi for the
 patch

---
 dkimpy_milter/__init__.py | 12 ++++++++++++
 dkimpy_milter/config.py   |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/dkimpy_milter/__init__.py b/dkimpy_milter/__init__.py
index b58145b..64f12df 100644
--- a/dkimpy_milter/__init__.py
+++ b/dkimpy_milter/__init__.py
@@ -183,6 +183,8 @@ class dkimMilter(Milter.Base):
             domain = milterconfig.get('Domain')
         else:
             domain = ''
+        if milterconfig.get('SubDomains'):
+            self.fdomain = _get_parent_domain(self.fdomain, domain)
         if ((self.fdomain in domain) and not milterconfig.get('Mode') == 'v'
                 and not self.external_connection):
             txt = self.fp.read()
@@ -325,6 +327,16 @@ class dkimMilter(Milter.Base):
             )
         return
 
+# get parent domain to be signed for if fdomain is a subdomain
+def _get_parent_domain(fdomain, domains):
+    for domain in domains:
+        rhs = '.'+domain
+        # compare right hand side of fdomain against .domain
+        if fdomain[-len(rhs):] == rhs:
+            # return parent domain on match
+            return domain
+    # or return the fdomain itself
+    return fdomain
 
 def main():
     # Ugh, but there's no easy way around this.
diff --git a/dkimpy_milter/config.py b/dkimpy_milter/config.py
index 6198369..efa1aa1 100644
--- a/dkimpy_milter/config.py
+++ b/dkimpy_milter/config.py
@@ -49,6 +49,7 @@ defaultConfigData = {
     'MacroList': '',
     'MacroListVerify': '',
     'DNSOverride': None,
+    'SubDomains': False,
     'debugLevel': 0  # Undocumented config item for developer use
     }
 
@@ -327,6 +328,7 @@ def _readConfigFile(path, configData=None, configGlobal={}):
         'PidFile': 'str',
         'UserID': 'str',
         'Domain': 'dataset',
+        'SubDomains': 'bool',
         'KeyFile': 'str',
         'KeyFileEd25519': 'str',
         'Selector': 'str',