From 82846cc9fc24d4c7c94ebde6dadac067d0b47cba Mon Sep 17 00:00:00 2001
From: Pierre-Yves Chibon <pingou@pingoured.fr>
Date: Aug 01 2020 19:06:32 +0000
Subject: Let the milter announce when it reject an email based on its address


Until now when the milter dropped an email, it did so silently.
With this commit, it will reject the email and send an error reply
whenever the reason for the rejection is an invalid email address is
used (either as recipient or as sender).

Fixes https://pagure.io/pagure/issue/4916

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>

---

diff --git a/pagure-milters/comment_email_milter.py b/pagure-milters/comment_email_milter.py
index 4085bd2..23df6e7 100644
--- a/pagure-milters/comment_email_milter.py
+++ b/pagure-milters/comment_email_milter.py
@@ -139,7 +139,7 @@ class PagureMilter(Milter.Base):
         msg_id = msg.get("In-Reply-To", None)
         if msg_id is None:
             self.log("No In-Reply-To, keep going")
-            return Milter.CONTINUE
+            return Milter.REJECT
 
         # Ensure we don't get extra lines in the message-id
         msg_id = msg_id.split("\n")[0].strip()
@@ -172,7 +172,12 @@ class PagureMilter(Milter.Base):
                 % from_email
             )
             session.remove()
-            return Milter.CONTINUE
+            self.setreply(
+                "550",
+                xcode="5.7.1",
+                msg="The sender address <%s> isn't recognized." % from_email
+            )
+            return Milter.REJECT
 
         hashes = []
         for email_obj in user.emails:
@@ -192,12 +197,12 @@ class PagureMilter(Milter.Base):
             self.log("tohash:    %s" % tohash)
             self.log("Hash does not correspond to the destination")
             session.remove()
-            return Milter.CONTINUE
+            return Milter.REJECT
 
         if msg["From"] and msg["From"] == _config.get("FROM_EMAIL"):
             self.log("Let's not process the email we send")
             session.remove()
-            return Milter.CONTINUE
+            return Milter.REJECT
 
         msg_id = clean_item(msg_id)
 
@@ -243,7 +248,7 @@ class PagureMilter(Milter.Base):
         self.log("Could not add the comment to ticket to pagure")
         self.log(req.text)
 
-        return Milter.CONTINUE
+        return Milter.REJECT
 
     def handle_request_email(self, emailobj, msg_id):
         """ Add the email as a comment on a request. """
@@ -274,7 +279,7 @@ class PagureMilter(Milter.Base):
         self.log("Could not add the comment to PR to pagure")
         self.log(req.text)
 
-        return Milter.CONTINUE
+        return Milter.REJECT
 
 
 def background():