ENV[MILTER_MAX_RCPT]: limits number of envelope recipients

app/ldap-acl-milter.py

@@ -1,4 +1,3 @@
-from argparse import Action
 import Milter
 from ldap3 import (
   Server, Connection, NONE, set_config_parameter
@@ -11,7 +10,6 @@ import logging
 import string
 import random
 import re
-from timeit import default_timer as timer
 import email.utils
 import authres
 
@@ -29,9 +27,7 @@ g_ldap_query = '(&(mail=%rcpt%)(allowedEnvelopeSender=%from%))'
 g_re_domain = re.compile(r'^\S*@(\S+)$')
 # http://emailregex.com/ -> Python
 g_re_email = re.compile(r"(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)")
-g_loglevel = logging.INFO
 g_milter_mode = 'test'
-g_milter_default_policy = 'reject'
 g_milter_schema = False
 g_milter_schema_wildcard_domain = False # works only if g_milter_schema == True
 g_milter_expect_auth = False
@@ -39,10 +35,14 @@ g_milter_whitelisted_rcpts = {}
 g_milter_dkim_enabled = False
 g_milter_trusted_authservid = None
 g_re_srs = re.compile(r"^SRS0=.+=.+=(\S+)=(\S+)\@.+$")
+g_milter_max_rcpt_enabled = False
+g_milter_max_rcpt = 1
 
 class LamException(Exception):
   def __init__(self, message="General exception message"):
     self.message = message
+  def __str__(self):
+    return self.message
 
 class LamSoftException(LamException):
   pass
@@ -56,8 +56,43 @@ class LdapAclMilter(Milter.Base):
     # client_addr gets overriden on any connect()
     self.client_addr = None
 
+  def do_log(self, **kwargs):
+    if 'level' not in kwargs:
+      print("do_log(): 'level' arg missing!")
+      sys.exit(1)
+    if 'log_message' not in kwargs:
+      print("do_log(): 'log_message' arg missing!")
+      sys.exit(1)
+    log_line = ''
+    if hasattr(self, 'mconn_id'):
+      log_line = "{}".format(self.mconn_id)
+    if self.queue_id != 'invalid':
+      log_line = "{0}/{1}".format(log_line, self.queue_id)
+    if self.proto_stage != 'invalid':
+      log_line = "{0}/{1}".format(log_line, self.proto_stage)
+    log_line = "{0} {1}".format(log_line, kwargs['log_message'])
+    if kwargs['level'] == 'error':
+      logging.error(log_line)
+    elif kwargs['level'] == 'warn' or kwargs['level'] == 'warning':
+      logging.warning(log_line)
+    elif kwargs['level'] == 'info':
+      logging.info(log_line)
+    elif kwargs['level'] == 'debug':
+      logging.debug(log_line)
+    else:
+      print("do_log(): invalid 'level' {}".format(kwargs['level']))
+      sys.exit(1)
+  def log_error(self, log_message):
+    self.do_log(level='error', log_message=log_message)
+  def log_warn(self, log_message):
+    self.do_log(level='warn', log_message=log_message)
+  def log_info(self, log_message):
+    self.do_log(level='info', log_message=log_message)
+  def log_debug(self, log_message):
+    self.do_log(level='debug', log_message=log_message)
+
   def reset(self):
-    self.proto_stage = 'proto-stage'
+    self.proto_stage = 'invalid'
     self.env_from = None
     self.sasl_user = None
     self.x509_subject = None
@@ -69,7 +104,7 @@ class LdapAclMilter(Milter.Base):
     self.dkim_valid = False
     self.dkim_aligned = False
     self.passed_dkim_results = []
-    logging.debug("reset(): {}".format(self.__dict__))
+    self.log_debug("reset(): {}".format(self.__dict__))
     # https://stackoverflow.com/a/2257449
     self.mconn_id = g_milter_name + ': ' + ''.join(
       random.choice(string.ascii_lowercase + string.digits) for _ in range(8)
@@ -107,37 +142,33 @@ class LdapAclMilter(Milter.Base):
     if 'reason' in kwargs:
       message = "{0} - reason: {1}".format(message, kwargs['reason'])
     if kwargs['action'] == 'reject' or kwargs['action'] == 'tmpfail':
+      self.log_info("milter_action={0} message={1}".format(
+        kwargs['action'], message
+      ))
       self.setreply(smtp_code, smtp_ecode, message)
-      logging.info(self.mconn_id + "/" +
-       self.proto_stage + ": milter_action={0} message={1}".format(kwargs['action'], message)
-      )
     return smfir
 
-  def check_policy(self, from_addr, rcpt_addr):
-    logging.info(self.mconn_id +
-      "/{0} from={1} rcpt={2}".format(
-        self.proto_stage, from_addr, rcpt_addr
-      )
-    )
+  def check_policy(self, **kwargs):
+    from_addr = kwargs['from_addr']
+    rcpt_addr = kwargs['rcpt_addr']
+    from_source = kwargs['from_source']
     m = g_re_domain.match(from_addr)
     if m == None:
-      logging.info(self.mconn_id +
-        "/{0} Could not determine domain of from={1}".format(
-          self.proto_stage, from_addr
-        )
-      )
+      self.log_info("Could not determine domain of from={0}".format(
+        from_addr
+      ))
       raise LamSoftException()
     from_domain = m.group(1)
-    logging.debug(self.mconn_id +
-      "/{0} from_domain={1}".format(self.queue_id, from_domain)
-    )
+    self.log_debug("from_domain={}".format(from_domain))
     m = g_re_domain.match(rcpt_addr)
     if m == None:
-      raise LamSoftException("Could not determine domain of rcpt={}".format(rcpt_addr))
+      raise LamHardException(
+        "Could not determine domain of rcpt={0}".format(
+          rcpt_addr
+        )
+      )
     rcpt_domain = m.group(1)
-    logging.debug(self.mconn_id +
-      "/{0} rcpt_domain={1}".format(self.queue_id, rcpt_domain)
-    )
+    self.log_debug("rcpt_domain={}".format(rcpt_domain))
     try:
       if g_milter_schema == True:
         # LDAP-ACL-Milter schema
@@ -159,9 +190,7 @@ class LdapAclMilter(Milter.Base):
             )
           else:
             auth_method = auth_method.replace('%X509_AUTH%','')
-          logging.debug(self.mconn_id +
-            " auth_method: " + auth_method
-          )
+          self.log_debug("auth_method: {}".format(auth_method))
         if g_milter_schema_wildcard_domain == True:
           # The asterisk (*) character is in term of local part
           # RFC5322 compliant and expected as a wildcard literal in this code.
@@ -211,32 +240,29 @@ class LdapAclMilter(Milter.Base):
         if len(g_ldap_conn.entries) == 0:
           # Policy not found in LDAP
           if g_milter_expect_auth == True:
-            logging.info(self.mconn_id + " " + "policy mismatch "
-              "from=" + from_addr + ", rcpt=" + rcpt_addr +
-              ", auth_method=" + auth_method
+            self.log_info(
+              "policy mismatch: from={0} from_src={1} rcpt={2} auth_method={3}".format(
+                from_addr, from_source, rcpt_addr, auth_method
+              )
             )
           else:
-            logging.info(self.mconn_id + " " + "policy mismatch "
-              "from=" + from_addr + ", rcpt=" + rcpt_addr
-            )
-          if g_milter_mode == 'reject':
-            raise LamHardException("policy not found!")
-          else:
-            logging.info(self.mconn_id + " TEST_MODE " +
-              g_milter_reject_message
+            self.log_info(
+              "policy mismatch: from={0} from_src={1} rcpt={2}".format(
+                from_addr, from_source, rcpt_addr
+              )
             )
+          raise LamHardException("policy mismatch!")
         elif len(g_ldap_conn.entries) == 1:
           # Policy found in LDAP, but which one?
           entry = g_ldap_conn.entries[0]
-          logging.info(self.mconn_id +
-            "/{0} Policy match: {1}".format(self.proto_stage, entry.policyID.value)
-          )
+          self.log_info("policy match: '{0}' from_src={1}".format(
+            entry.policyID.value, from_source
+          ))
         elif len(g_ldap_conn.entries) > 1:
           # Something went wrong!? There shouldn´t be more than one entries!
-          logging.warning(self.mconn_id + " More than one policies found! "+
-            "from=" + from_addr + ", rcpt=" + rcpt_addr +
-            ", auth_method=" + auth_method
-          )
+          self.log_warn("More than one policies found! from={0} rcpt={1} auth_method={2}".format(
+            from_addr, rcpt_addr, auth_method
+          ))
           raise LamHardException("More than one policies found!")
       else:
         # Custom LDAP schema
@@ -248,21 +274,21 @@ class LdapAclMilter(Milter.Base):
         query = query.replace("%sasl_user%", self.sasl_user)
         query = query.replace("%from_domain%", from_domain)
         query = query.replace("%rcpt_domain%", rcpt_domain)
-        logging.debug(self.mconn_id + " " + query)
+        self.log_debug("LDAP query: {}".format(query))
         g_ldap_conn.search(g_ldap_base, query)
         if len(g_ldap_conn.entries) == 0:
-          logging.info(self.mconn_id + " " + "policy mismatch "
-            "from: " + from_addr + " and rcpt: " + rcpt_addr
-          )
-          if g_milter_mode == 'reject':
-            raise LamHardException("policy mismatch")
-          else:
-            logging.info(self.mconn_id + " TEST_MODE " +
-              g_milter_reject_message
+          self.log_info(
+            "policy mismatch from={0} from_src={1} rcpt={2}".format(
+              from_addr, from_source, rcpt_addr
             )
+          )
+          raise LamHardException("policy mismatch")
+        self.log_info("policy match: '{0}' from_src={1}".format(
+          entry.policyID.value, from_source
+        ))
     except LDAPException as e:
-      logging.error(self.mconn_id + " LDAP: " + str(e))
-      raise LamSoftException(" LDAP: " + str(e)) from e;
+      self.log_error("LDAP exception: {}".format(str(e)))
+      raise LamSoftException("LDAP exception: " + str(e)) from e;
     return self.milter_action(action = 'continue')
 
   # Not registered/used callbacks
@@ -277,8 +303,8 @@ class LdapAclMilter(Milter.Base):
     self.reset()
     self.proto_stage = 'CONNECT'
     self.client_addr = hostaddr[0]
-    logging.debug(self.mconn_id +
-      "/CONNECT client_addr=[" + self.client_addr + "]:" + str(hostaddr[1])
+    self.log_debug("client_addr={0}, client_port={1}".format(
+      self.client_addr, hostaddr[1])
     )
     return self.milter_action(action = 'continue')
 
@@ -295,29 +321,29 @@ class LdapAclMilter(Milter.Base):
         x509_subject = self.getsymval('{cert_subject}')
         if x509_subject != None:
           self.x509_subject = x509_subject
-          logging.debug(self.mconn_id + "/FROM x509_subject=" + self.x509_subject)
+          self.log_debug("x509_subject={}".format(self.x509_subject))
         else:
-          logging.debug(self.mconn_id + "/FROM No x509_subject registered")
+          self.log_debug("No x509_subject registered")
         x509_issuer = self.getsymval('{cert_issuer}')
         if x509_issuer != None:
           self.x509_issuer = x509_issuer
-          logging.debug(self.mconn_id + "/FROM x509_issuer=" + self.x509_issuer)
+          self.log_debug("x509_issuer={}".format(self.x509_issuer))
         else:
-          logging.debug(self.mconn_id + "/FROM No x509_issuer registered")
+          self.log_debug("No x509_issuer registered")
       except:
-        logging.error(self.mconn_id + "/FROM x509 " + traceback.format_exc())
+        self.log_error("x509 exception: {}".format(traceback.format_exc()))
       try:
         # this may fail, if no SASL authentication preceded
         sasl_user = self.getsymval('{auth_authen}')
         if sasl_user != None:
           self.sasl_user = sasl_user
-          logging.debug(self.mconn_id + "/FROM sasl_user=" + self.sasl_user)
+          self.log_debug("sasl_user={}".format(self.sasl_user))
         else:
-          logging.debug(self.mconn_id + "/FROM No sasl_user registered")
+          self.log_debug("No sasl_user registered")
       except:
-        logging.error(self.mconn_id + "/FROM sasl_user " + traceback.format_exc())
-      logging.info(self.mconn_id + "/FROM auth: " + 
-        "client_ip={0}, x509_subject={1}, x509_issuer={2}, sasl_user={3}".format(
+        self.log_error("sasl_user exception: {}".format(traceback.format_exc()))
+      self.log_info(
+        "auth: client_ip={0} x509_subject={1} x509_issuer={2} sasl_user={3}".format(
           self.client_addr, self.x509_subject, self.x509_issuer, self.sasl_user
         )
       )
@@ -329,20 +355,16 @@ class LdapAclMilter(Milter.Base):
     # SRS (https://www.libsrs2.org/srs/srs.pdf)
     m_srs = g_re_srs.match(mailfrom)
     if m_srs != None:
-      logging.info(self.mconn_id + "/FROM " +
-        "Found SRS-encoded envelope-sender: " + mailfrom
-      )
+      self.log_info("Found SRS-encoded envelope-sender: {}".format(mailfrom))
       mailfrom = m_srs.group(2) + '@' + m_srs.group(1)
-      logging.info(self.mconn_id + "/FROM " +
-        "SRS envelope-sender replaced with: " + mailfrom
-      )
+      self.log_info("SRS envelope-sender replaced with: {}".format(mailfrom))
     self.env_from = mailfrom.lower()
-    logging.debug(self.mconn_id + "/FROM 5321.from={}".format(self.env_from))
+    self.log_debug("5321.from={}".format(self.env_from))
     m = g_re_domain.match(self.env_from)
     if m == None:
       return self.milter_action(
-        action = 'tmpfail',
-        reason = "Could not determine domain of 5321.from=" + self.env_from
+        action = 'reject',
+        reason = "Could not determine domain of 5321.from={}".format(self.env_from)
       )
     return self.milter_action(action = 'continue')
 
@@ -351,9 +373,7 @@ class LdapAclMilter(Milter.Base):
     to = to.replace("<","")
     to = to.replace(">","")
     to = to.lower()
-    logging.debug(self.mconn_id +
-      "/RCPT env_rcpt={}".format(to)
-    )
+    self.log_debug("5321.rcpt={}".format(to))
     if to in g_milter_whitelisted_rcpts:
       return self.milter_action(action = 'continue')
     if g_milter_dkim_enabled:
@@ -363,14 +383,20 @@ class LdapAclMilter(Milter.Base):
       self.env_rcpts.append(to)
     else:
       try:
-        return self.check_policy(self.env_from, to)
-      except LamSoftException as e:
-        return self.milter_action(action = 'tmpfail')
-      except LamHardException as e:
-        return self.milter_action(
-          action = 'reject',
-          reason = e.message
+        return self.check_policy(
+          from_addr=self.env_from, rcpt_addr=to, from_source='5321.from'
         )
+      except LamSoftException as e:
+        if g_milter_mode == 'reject':
+          return self.milter_action(action = 'tmpfail')
+      except LamHardException as e:
+        if g_milter_mode == 'reject':
+          return self.milter_action(
+            action = 'reject',
+            reason = e.message
+          )
+        else:
+          self.log_info("TEST-Mode: {}".format(e.message))
     return self.milter_action(action = 'continue')
 
   def header(self, hname, hval):
@@ -388,11 +414,9 @@ class LdapAclMilter(Milter.Base):
             reason = "Could not determine domain-part of 5322.from=" + self.hdr_from
           )
         self.hdr_from_domain = m.group(1)
-        logging.info(self.mconn_id + "/" + str(self.queue_id) +
-          "/HDR: 5322.from={0}, 5322.from_domain={1}".format(
-            self.hdr_from, self.hdr_from_domain
-          )
-        )
+        self.log_debug("5322.from={0}, 5322.from_domain={1}".format(
+          self.hdr_from, self.hdr_from_domain
+        ))
       # Parse RFC-7601 Authentication-Results header
       elif(hname.lower() == "Authentication-Results".lower()):
         ar = None
@@ -405,61 +429,74 @@ class LdapAclMilter(Milter.Base):
               if ar_result.method.lower() == 'dkim':
                 if ar_result.result.lower() == 'pass':
                   self.passed_dkim_results.append(ar_result.header_d.lower())
-                  logging.debug(self.mconn_id + "/" + str(self.queue_id) +
-                    "/HDR: dkim=pass sdid={0}".format(ar_result.header_d)
-                  )
+                  self.log_debug("dkim=pass sdid={}".format(ar_result.header_d))
                   self.dkim_valid = True
           else:
-            logging.debug(self.mconn_id + "/" + str(self.queue_id) +
-              "/HDR: Ignoring authentication results of {0}".format(ar.authserv_id)
+            self.log_debug("Ignoring authentication results of {}".format(
+              ar.authserv_id)
             )
         except Exception as e:
-          logging.info(self.mconn_id + "/" + str(self.queue_id) +
-            "/HDR: AR-parse exception: {0}".format(str(e))
-          )
+          self.log_info("AR-parse exception: {0}".format(str(e)))
     return self.milter_action(action = 'continue')
 
   def eom(self):
     self.proto_stage = 'EOM'
+    if g_milter_max_rcpt_enabled:
+      if len(self.env_rcpts) > int(g_milter_max_rcpt):
+        if g_milter_mode == 'reject':
+          return self.milter_action(action='reject', reason='Too many recipients!')
+        else:
+          self.do_log("TEST-Mode: Too many recipients!")
     if g_milter_dkim_enabled:
+      self.log_info("5321.from={0} 5322.from={1} 5322.from_domain={2} 5321.rcpt={3}".format(
+        self.env_from, self.hdr_from, self.hdr_from_domain, self.env_rcpts
+      ))
       if self.dkim_valid:
         # There is at least one valid DKIM signature!
         # Check if one of them is also aligned
         for passed_dkim_sdid in self.passed_dkim_results:
           if self.hdr_from_domain.lower() == passed_dkim_sdid.lower():
             self.dkim_aligned = True
-            logging.info(self.mconn_id + "/" + str(self.queue_id) +
-              "/EOM: Found aligned DKIM signature for SDID: {0}".format(
-                passed_dkim_sdid
-              ) 
-            )
+            self.log_info("Found aligned DKIM signature for SDID: {0}".format(
+              passed_dkim_sdid
+            ))
       reject_message = False
       for rcpt in self.env_rcpts:
         try:
-          # Check 5321.sender against policy
-          self.check_policy(self.env_from, rcpt)
+          # Check 5321.from against policy
+          self.check_policy(
+            from_addr=self.env_from, rcpt_addr=rcpt, from_source='5321.from'
+          )
         except LamSoftException as e:
-          return self.milter_action(action = 'tmpfail')
+          if g_milter_mode == 'reject':
+            return self.milter_action(action = 'tmpfail')
+          else:
+            self.log_info("TEST-Mode: {}".format(e.message))
         except LamHardException as e:
           if self.dkim_aligned:
             try:
-              # Check 5322.sender against policy
-              self.check_policy(self.hdr_from, rcpt)
-              logging.info(self.mconn_id +
-                "/{0}/{1} from={2} authorized by DKIM signature".format(
-                  self.queue_id, self.proto_stage, self.hdr_from
-                )
+              # Check 5322.from against policy
+              self.check_policy(
+                from_addr=self.hdr_from, rcpt_addr=rcpt, from_source='5322.from'
               )
+              self.log_info("5322.from={} authorized by DKIM signature".format(
+                self.hdr_from
+              ))
             except LamHardException as e:
               reject_message = True
           else:
             reject_message = True
 
         if reject_message:
-          return self.milter_action(
-            action = 'reject',
-            reason = 'EOM - Policy mismatch! All recipients were rejected!'
-          )
+          if g_milter_mode == 'reject':
+            return self.milter_action(
+              action = 'reject',
+              reason = 'policy mismatch! Message rejected for all recipients!'
+            )
+          else:
+            self.log_info(
+              "TEST-Mode: policy mismatch! Message would be rejected for all recipients!"
+            )
     return self.milter_action(action = 'continue')
 
   def abort(self):
@@ -475,30 +512,25 @@ class LdapAclMilter(Milter.Base):
 
 if __name__ == "__main__":
   try:
+    log_level = logging.INFO
     if 'LOG_LEVEL' in os.environ:
       if re.match(r'^info$', os.environ['LOG_LEVEL'], re.IGNORECASE):
-        g_loglevel = logging.INFO
+        log_level = logging.INFO
       elif re.match(r'^warn|warning$', os.environ['LOG_LEVEL'], re.IGNORECASE):
-        g_loglevel = logging.WARN
+        log_level = logging.WARN
       elif re.match(r'^error$', os.environ['LOG_LEVEL'], re.IGNORECASE):
-        g_loglevel = logging.ERROR
+        log_level = logging.ERROR
       elif re.match(r'debug', os.environ['LOG_LEVEL'], re.IGNORECASE):
-        g_loglevel = logging.DEBUG
+        log_level = logging.DEBUG
+    log_format = '%(asctime)s: %(levelname)s %(message)s '
     logging.basicConfig(
-      filename=None, # log to stdout
-      format='%(asctime)s: %(levelname)s %(message)s',
-      level=g_loglevel
+      filename = None, # log to stdout
+      format = log_format,
+      level = log_level
     )
     if 'MILTER_MODE' in os.environ:
       if re.match(r'^test|reject$',os.environ['MILTER_MODE'], re.IGNORECASE):
-        g_milter_mode = os.environ['MILTER_MODE']
-    if 'MILTER_DEFAULT_POLICY' in os.environ:
-      if re.match(r'^reject|permit$',os.environ['MILTER_DEFAULT_POLICY'], re.IGNORECASE):
-        g_milter_default_policy = str(os.environ['MILTER_DEFAULT_POLICY']).lower()
-      else:
-        logging.warning("MILTER_DEFAULT_POLICY invalid value: " +
-          os.environ['MILTER_DEFAULT_POLICY']
-        )
+        g_milter_mode = os.environ['MILTER_MODE'].lower()
     if 'MILTER_NAME' in os.environ:
       g_milter_name = os.environ['MILTER_NAME']
     if 'MILTER_SCHEMA' in os.environ:
@@ -508,7 +540,7 @@ if __name__ == "__main__":
           if re.match(r'^true$', os.environ['MILTER_SCHEMA_WILDCARD_DOMAIN'], re.IGNORECASE):
             g_milter_schema_wildcard_domain = True
     if 'LDAP_SERVER' not in os.environ:
-      logging.error("Missing ENV[LDAP_SERVER], e.g. " + g_ldap_server)
+      logging.error("Missing ENV[LDAP_SERVER], e.g. {}".format(g_ldap_server))
       sys.exit(1)
     g_ldap_server = os.environ['LDAP_SERVER']
     if 'LDAP_BINDDN' in os.environ:
@@ -516,7 +548,7 @@ if __name__ == "__main__":
     if 'LDAP_BINDPW' in os.environ:
       g_ldap_bindpw = os.environ['LDAP_BINDPW']
     if 'LDAP_BASE' not in os.environ:
-      logging.error("Missing ENV[LDAP_BASE], e.g. " + g_ldap_base)
+      logging.error("Missing ENV[LDAP_BASE], e.g. {}".format(g_ldap_base))
       sys.exit(1)
     g_ldap_base = os.environ['LDAP_BASE']
     if 'LDAP_QUERY' not in os.environ:
@@ -542,43 +574,57 @@ if __name__ == "__main__":
       for whitelisted_rcpt in re.split(',|\s', whitelisted_rcpts_str):
         if g_re_email.match(whitelisted_rcpt) == None:
           logging.error(
-            "ENV[MILTER_WHITELISTED_RCPTS]: invalid email address: " +
-            whitelisted_rcpt
+            "ENV[MILTER_WHITELISTED_RCPTS]: invalid email address: {}"
+            .format(whitelisted_rcpt)
           )
           sys.exit(1)
         else:
-          logging.info("ENV[MILTER_WHITELISTED_RCPTS]: " + whitelisted_rcpt)
+          logging.info("ENV[MILTER_WHITELISTED_RCPTS]: {}".format(
+            whitelisted_rcpt
+          ))
           g_milter_whitelisted_rcpts[whitelisted_rcpt] = {}
     if 'MILTER_DKIM_ENABLED' in os.environ:
       g_milter_dkim_enabled = True
       if 'MILTER_TRUSTED_AUTHSERVID' in os.environ:
         g_milter_trusted_authservid = os.environ['MILTER_TRUSTED_AUTHSERVID'].lower()
-        logging.info("ENV[MILTER_TRUSTED_AUTHSERVID]: {0}".format(g_milter_trusted_authservid))
+        logging.info("ENV[MILTER_TRUSTED_AUTHSERVID]: {0}".format(
+          g_milter_trusted_authservid
+        ))
       else:
         logging.error("ENV[MILTER_TRUSTED_AUTHSERVID] is mandatory!")
         sys.exit(1)
     logging.info("ENV[MILTER_DKIM_ENABLED]: {0}".format(g_milter_dkim_enabled))
-    set_config_parameter("RESTARTABLE_SLEEPTIME", 2)
-    set_config_parameter("RESTARTABLE_TRIES", 2)
-    server = Server(g_ldap_server, get_info=NONE)
-    g_ldap_conn = Connection(server,
-      g_ldap_binddn, g_ldap_bindpw,
-      auto_bind=True, raise_exceptions=True,
-      client_strategy='RESTARTABLE'
-    )
-    logging.info("Connected to LDAP-server: " + g_ldap_server)
+    if 'MILTER_MAX_RCPT_ENABLED' in os.environ:
+      g_milter_max_rcpt_enabled = True
+      if 'MILTER_MAX_RCPT' in os.environ:
+        if os.environ['MILTER_MAX_RCPT'].isnumeric():
+          g_milter_max_rcpt = os.environ['MILTER_MAX_RCPT']
+        else:
+          print("ENV[MILTER_MAX_RCPT] must be numeric!")
+          sys.exit(1)
+    try:
+      set_config_parameter("RESTARTABLE_SLEEPTIME", 2)
+      set_config_parameter("RESTARTABLE_TRIES", 2)
+      server = Server(g_ldap_server, get_info=NONE)
+      g_ldap_conn = Connection(server,
+        g_ldap_binddn, g_ldap_bindpw,
+        auto_bind=True, raise_exceptions=True,
+        client_strategy='RESTARTABLE'
+      )
+      logging.info("Connected to LDAP-server: " + g_ldap_server)
+    except LDAPException as e:
+      raise Exception("Connection to LDAP-server failed: {}".format(str(e))) from e
     timeout = 600
     # Register to have the Milter factory create instances of your class:
     Milter.factory = LdapAclMilter
     # Tell the MTA which features we use
     flags = Milter.ADDHDRS
     Milter.set_flags(flags)
-    logging.info("Startup " + g_milter_name +
-      "@socket: " + g_milter_socket +
-      " in mode: " + g_milter_mode
-    )
+    logging.info("Starting {0}@socket: {1} in mode {2}".format(
+      g_milter_name, g_milter_socket, g_milter_mode
+    ))
     Milter.runmilter(g_milter_name,g_milter_socket,timeout,True)
-    logging.info("Shutdown " + g_milter_name)
+    logging.info("Shutdown {}".format(g_milter_name))
   except:
-    logging.error("MAIN-EXCEPTION: " + traceback.format_exc())
+    logging.error("MAIN-EXCEPTION: {}".format(traceback.format_exc()))
     sys.exit(1)

tests/miltertest-ip-fail.lua

@@ -0,0 +1,56 @@
+-- https://mopano.github.io/sendmail-filter-api/constant-values.html#com.sendmail.milter.MilterConstants
+-- http://www.opendkim.org/miltertest.8.html
+
+-- socket must be defined as miltertest global variable (-D)
+conn = mt.connect(socket)
+if conn == nil then
+  error "mt.connect() failed"
+end
+if mt.conninfo(conn, "blubb-ip.host", "127.6.6.6") ~= nil then
+  error "mt.conninfo() failed"
+end
+
+mt.set_timeout(60)
+
+-- 5321.FROM
+if mt.mailfrom(conn, "tester-ip-fail@test.blah") ~= nil then
+  error "mt.mailfrom() failed"
+end
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("FROM-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  error("FROM-reject")
+end
+
+-- 5321.RCPT+MACROS
+mt.macro(conn, SMFIC_RCPT, "i", "4CgSNs5Q9sz7SllQ")
+if mt.rcptto(conn, "<rcpt-ip-fail@test.blubb>") ~= nil then
+  error "mt.rcptto() failed"
+end
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("RCPT-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  mt.echo("RCPT-reject")
+end
+
+-- 5322.HEADERS
+if mt.header(conn, "fRoM", '"Blah Blubb" <tester-ip-fail@test.blah>') ~= nil then
+  error "mt.header(From) failed"  
+end
+if mt.header(conn, "Authentication-REsuLTS", "my-auth-serv-id;\n  dkim=fail header.d=test.blah header.s=selector1-test-blah header.b=mumble") ~= nil then
+  error "mt.header(Authentication-Results) failed"  
+end
+
+-- EOM
+if mt.eom(conn) ~= nil then
+  error "mt.eom() failed"
+end
+mt.echo("EOM: " .. mt.getreply(conn))
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("EOM-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  mt.echo("EOM-reject")
+end
+
+-- DISCONNECT
+mt.disconnect(conn)

tests/miltertest-ip.lua

@@ -16,8 +16,10 @@ mt.set_timeout(60)
 if mt.mailfrom(conn, "tester-ip@test.blah") ~= nil then
   error "mt.mailfrom() failed"
 end
-if mt.getreply(conn) ~= SMFIR_CONTINUE then
-  error "mt.mailfrom() unexpected reply"
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("FROM-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  error("FROM-reject")
 end
 
 -- 5321.RCPT+MACROS
@@ -25,8 +27,10 @@ mt.macro(conn, SMFIC_RCPT, "i", "4CgSNs5Q9sz7SllQ")
 if mt.rcptto(conn, "<rcpt-ip@test.blubb>") ~= nil then
   error "mt.rcptto() failed"
 end
-if mt.getreply(conn) ~= SMFIR_CONTINUE then
-  error "mt.rcptto() unexpected reply"
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("RCPT-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  mt.echo("RCPT-reject")
 end
 
 -- 5322.HEADERS

tests/miltertest-sasl-wildcard.lua

@@ -0,0 +1,53 @@
+-- https://mopano.github.io/sendmail-filter-api/constant-values.html#com.sendmail.milter.MilterConstants
+-- http://www.opendkim.org/miltertest.8.html
+
+-- socket must be defined as miltertest global variable (-D)
+conn = mt.connect(socket)
+if conn == nil then
+  error "mt.connect() failed"
+end
+if mt.conninfo(conn, "localhost", "::1") ~= nil then
+  error "mt.conninfo() failed"
+end
+
+mt.set_timeout(60)
+
+-- 5321.FROM+MACROS
+mt.macro(conn, SMFIC_MAIL, "{auth_authen}", "blubb-user-wild")
+if mt.mailfrom(conn, "tester-invalid@test.blah") ~= nil then
+  error "mt.mailfrom() failed"
+end
+if mt.getreply(conn) ~= SMFIR_CONTINUE then
+  error "mt.mailfrom() unexpected reply"
+end
+
+-- 5321.RCPT+MACROS
+mt.macro(conn, SMFIC_RCPT, "i", "test-wildcard-qid")
+if mt.rcptto(conn, "<anybody-xyz@out.there>") ~= nil then
+  error "mt.rcptto() failed"
+end
+if mt.getreply(conn) ~= SMFIR_CONTINUE then
+  error "mt.rcptto() unexpected reply"
+end
+
+-- 5322.HEADERS
+if mt.header(conn, "fRoM", '"Blah Blubb" <tester@test.blah>') ~= nil then
+  error "mt.header(From) failed"  
+end
+if mt.header(conn, "Authentication-RESULTS", "my-auth-serv-id;\n  dkim=pass header.d=test.blah header.s=selector1-test-blah header.b=mumble") ~= nil then
+  error "mt.header(Authentication-Results) failed"  
+end
+
+-- EOM
+if mt.eom(conn) ~= nil then
+  error "mt.eom() failed"
+end
+mt.echo("EOM: " .. mt.getreply(conn))
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("EOM-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  mt.echo("EOM-reject")
+end
+
+-- DISCONNECT
+mt.disconnect(conn)

tests/miltertest-x509_5321-fail_dkim-pass.lua

@@ -0,0 +1,53 @@
+-- https://mopano.github.io/sendmail-filter-api/constant-values.html#com.sendmail.milter.MilterConstants
+-- http://www.opendkim.org/miltertest.8.html
+
+-- socket must be defined as miltertest global variable (-D)
+conn = mt.connect(socket)
+if conn == nil then
+  error "mt.connect() failed"
+end
+if mt.conninfo(conn, "localhost", "::1") ~= nil then
+  error "mt.conninfo() failed"
+end
+
+mt.set_timeout(60)
+
+-- 5321.FROM+MACROS
+mt.macro(conn, SMFIC_MAIL, "{cert_issuer}", "x509-issuer", "{cert_subject}", "x509-subject")
+if mt.mailfrom(conn, "tester-x509-invalid@test.blah") ~= nil then
+  error "mt.mailfrom() failed"
+end
+if mt.getreply(conn) ~= SMFIR_CONTINUE then
+  error "mt.mailfrom() unexpected reply"
+end
+
+-- 5321.RCPT+MACROS
+mt.macro(conn, SMFIC_RCPT, "i", "4CgSNs5Q9sz7SllQ")
+if mt.rcptto(conn, "<rcpt-x509@test.blubb>") ~= nil then
+  error "mt.rcptto() failed"
+end
+if mt.getreply(conn) ~= SMFIR_CONTINUE then
+  error "mt.rcptto() unexpected reply"
+end
+
+-- 5322.HEADERS
+if mt.header(conn, "fRoM", '"Blah Blubb" <tester-x509@test.blah>') ~= nil then
+  error "mt.header(From) failed"  
+end
+if mt.header(conn, "Authentication-RESULTS", "my-auth-serv-id;\n  dkim=pass header.d=test.blah header.s=selector1-test-blah header.b=mumble") ~= nil then
+  error "mt.header(Authentication-Results) failed"  
+end
+
+-- EOM
+if mt.eom(conn) ~= nil then
+  error "mt.eom() failed"
+end
+mt.echo("EOM: " .. mt.getreply(conn))
+if mt.getreply(conn) == SMFIR_CONTINUE then
+  mt.echo("EOM-continue")
+elseif mt.getreply(conn) == SMFIR_REPLYCODE then
+  mt.echo("EOM-reject")
+end
+
+-- DISCONNECT
+mt.disconnect(conn)