From 4e3f6f528f6f9e15e3d85d17c2e76d540f801901 Mon Sep 17 00:00:00 2001
From: Dominik Chilla <dominik@zwackl.de>
Date: Wed, 20 Nov 2019 00:56:59 +0100
Subject: [PATCH] Strip BATV-signatures out of envelope sender address

---
 app/ldap-acl-milter.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/app/ldap-acl-milter.py b/app/ldap-acl-milter.py
index 4a09ad0..c3b5cb7 100644
--- a/app/ldap-acl-milter.py
+++ b/app/ldap-acl-milter.py
@@ -100,6 +100,9 @@ class LdapAclMilter(Milter.Base):
       logging.error(self.mconn_id + "/FROM sasl_user " + traceback.format_exc())
     mailfrom = mailfrom.replace("<","")
     mailfrom = mailfrom.replace(">","")
+    # BATV (https://tools.ietf.org/html/draft-levine-smtp-batv-01)
+    # Strip out Simple Private Signature (PRVS)
+    mailfrom = re.sub(r"^prvs=.{10}=", '', mailfrom)
     self.env_from = mailfrom
     m = g_re_domain.match(self.env_from)
     if m == None: