FIX: improve support for handling emails coming from screened email addresses

app/assets/javascripts/admin/templates/email-rejected.hbs

@@ -29,7 +29,11 @@
                 {{email.from_address}}
               {{/link-to}}
             {{else}}
-              —
+              {{#if email.from_address}}
+                <a href='mailto:{{unbound email.from_address}}'>{{email.from_address}}</a>
+              {{else}}
+                &mdash;
+              {{/if}}
             {{/if}}
           </div>
         </td>

app/controllers/admin/email_templates_controller.rb

@@ -14,6 +14,7 @@ class Admin::EmailTemplatesController < Admin::AdminController
                      "system_messages.email_reject_post_error_specified", "system_messages.email_reject_user_not_found",
                      "system_messages.email_reject_reply_key", "system_messages.email_reject_topic_closed",
                      "system_messages.email_reject_topic_not_found", "system_messages.email_reject_trust_level",
+                     "system_messages.email_reject_screened_email",
                      "system_messages.pending_users_reminder", "system_messages.post_hidden",
                      "system_messages.restore_failed", "system_messages.restore_succeeded",
                      "system_messages.spam_post_blocked", "system_messages.too_many_spam_flags",

app/jobs/scheduled/poll_mailbox.rb

@@ -55,6 +55,7 @@ module Jobs
         when Email::Receiver::EmptyEmailError             then :email_reject_empty
         when Email::Receiver::NoBodyDetectedError         then :email_reject_empty
         when Email::Receiver::UserNotFoundError           then :email_reject_user_not_found
+        when Email::Receiver::ScreenedEmailError          then :email_reject_screened_email
         when Email::Receiver::AutoGeneratedEmailError     then :email_reject_auto_generated
         when Email::Receiver::InactiveUserError           then :email_reject_inactive_user
         when Email::Receiver::BlockedUserError            then :email_reject_blocked_user

app/models/user.rb

@@ -25,6 +25,7 @@ class User < ActiveRecord::Base
   has_many :user_badges, -> { where('user_badges.badge_id IN (SELECT id FROM badges WHERE enabled)') }, dependent: :destroy
   has_many :badges, through: :user_badges
   has_many :email_logs, dependent: :delete_all
+  has_many :incoming_emails, dependent: :delete_all
   has_many :post_timings
   has_many :topic_allowed_users, dependent: :destroy
   has_many :topics_allowed, through: :topic_allowed_users, source: :topic

config/locales/server.en.yml

@@ -66,6 +66,7 @@ en:
         topic_closed_error: "Happens when a reply came in but the related topic has been closed."
         bounced_email_report: "Email is a bounced email report."
         auto_generated_email_reply: "Email contains a reply to an auto generated email."
+        screened_email_error: "Happens when the sender's email address was already screened."
 
   errors: &errors
     format: ! '%{attribute} %{message}'
@@ -1857,6 +1858,13 @@ en:
 
         Your reply was sent from an unknown email address. Try sending from another email address, or contact a staff member.
 
+    email_reject_screened_email:
+      subject_template: "[%{site_name}] Email issue -- Blocked Email"
+      text_body_template: |
+        We're sorry, but your email message to %{destination} (titled %{former_title}) didn't work.
+
+        Your reply was sent from a blocked email address. Try sending from another email address, or contact a staff member.
+
     email_reject_inactive_user:
       subject_template: "[%{site_name}] Email issue -- Inactive User"
       text_body_template: |

lib/email/receiver.rb

@@ -8,23 +8,24 @@ module Email
   class Receiver
     include ActionView::Helpers::NumberHelper
 
-    class ProcessingError             < StandardError; end
+    class ProcessingError              < StandardError; end
-    class EmptyEmailError             < ProcessingError; end
+    class EmptyEmailError              < ProcessingError; end
-    class UserNotFoundError           < ProcessingError; end
+    class ScreenedEmailError           < ProcessingError; end
-    class AutoGeneratedEmailError     < ProcessingError; end
+    class UserNotFoundError            < ProcessingError; end
+    class AutoGeneratedEmailError      < ProcessingError; end
     class AutoGeneratedEmailReplyError < ProcessingError; end
-    class BouncedEmailError           < ProcessingError; end
+    class BouncedEmailError            < ProcessingError; end
-    class NoBodyDetectedError         < ProcessingError; end
+    class NoBodyDetectedError          < ProcessingError; end
-    class InactiveUserError           < ProcessingError; end
+    class InactiveUserError            < ProcessingError; end
-    class BlockedUserError            < ProcessingError; end
+    class BlockedUserError             < ProcessingError; end
-    class BadDestinationAddress       < ProcessingError; end
+    class BadDestinationAddress        < ProcessingError; end
-    class StrangersNotAllowedError    < ProcessingError; end
+    class StrangersNotAllowedError     < ProcessingError; end
-    class InsufficientTrustLevelError < ProcessingError; end
+    class InsufficientTrustLevelError  < ProcessingError; end
-    class ReplyUserNotMatchingError   < ProcessingError; end
+    class ReplyUserNotMatchingError    < ProcessingError; end
-    class TopicNotFoundError          < ProcessingError; end
+    class TopicNotFoundError           < ProcessingError; end
-    class TopicClosedError            < ProcessingError; end
+    class TopicClosedError             < ProcessingError; end
-    class InvalidPost                 < ProcessingError; end
+    class InvalidPost                  < ProcessingError; end
-    class InvalidPostAction           < ProcessingError; end
+    class InvalidPostAction            < ProcessingError; end
 
     attr_reader :incoming_email
 
@@ -55,6 +56,8 @@ module Email
     end
 
     def process_internal
+      raise ScreenedEmailError if ScreenedEmail.should_block?(@from_email)
+
       user = find_or_create_user(@from_email, @from_display_name)
 
       raise UserNotFoundError if user.nil?
@@ -209,16 +212,20 @@ module Email
       user = nil
 
       User.transaction do
-        user = User.find_by_email(email)
+        begin
+          user = User.find_by_email(email)
 
-        if user.nil? && SiteSetting.enable_staged_users
+          if user.nil? && SiteSetting.enable_staged_users
-          username = UserNameSuggester.sanitize_username(display_name) if display_name.present?
+            username = UserNameSuggester.sanitize_username(display_name) if display_name.present?
-          user = User.create(
+            user = User.create!(
-            email: email,
+              email: email,
-            username: UserNameSuggester.suggest(username.presence || email),
+              username: UserNameSuggester.suggest(username.presence || email),
-            name: display_name.presence || User.suggest_name(email),
+              name: display_name.presence || User.suggest_name(email),
-            staged: true
+              staged: true
-          )
+            )
+          end
+        rescue
+          user = nil
         end
       end
 

spec/components/email/receiver_spec.rb

@@ -17,7 +17,12 @@ describe Email::Receiver do
     expect { Email::Receiver.new("") }.to raise_error(Email::Receiver::EmptyEmailError)
   end
 
-  it "raises and UserNotFoundError when staged users are disabled" do
+  it "raises a ScreenedEmailError when email address is screened" do
+    ScreenedEmail.expects(:should_block?).with("screened@mail.com").returns(true)
+    expect { process(:screened_email) }.to raise_error(Email::Receiver::ScreenedEmailError)
+  end
+
+  it "raises an UserNotFoundError when staged users are disabled" do
     SiteSetting.enable_staged_users = false
     expect { process(:user_not_found) }.to raise_error(Email::Receiver::UserNotFoundError)
   end

spec/fixtures/emails/screened_email.eml

@@ -0,0 +1,9 @@
+Return-Path: <screened@mail.com>
+From: Not Found <screened@mail.com>
+Date: Fri, 15 Jan 2016 00:12:43 +0100
+Message-ID: <51@foo.bar.mail>
+Mime-Version: 1.0
+Content-Type: text/plain
+Content-Transfer-Encoding: 7bit
+
+Email from a screened email address.