Fixed issue #1390 - Broken email with huge pdf inline (lead to huge article body with bigger then 7MB) is blocking rendering of web app.

app/models/ticket/article.rb

@@ -16,8 +16,8 @@ class Ticket::Article < ApplicationModel
   belongs_to    :created_by,  class_name: 'User'
   belongs_to    :updated_by,  class_name: 'User'
   store         :preferences
-  before_create :check_subject, :check_message_id_md5
-  before_update :check_subject, :check_message_id_md5
+  before_create :check_subject, :check_body, :check_message_id_md5
+  before_update :check_subject, :check_body, :check_message_id_md5
 
   sanitized_html :body
 
@@ -284,6 +284,22 @@ returns
     true
   end
 
+  # strip body length or raise exception
+  def check_body
+    return true if body.blank?
+    limit = 1_500_000
+    current_length = body.length
+    if body.length > limit
+      if ApplicationHandleInfo.current.present? && ApplicationHandleInfo.current.split('.')[1] == 'postmaster'
+        logger.warn "WARNING: cut string because of database length #{self.class}.body(#{limit} but is #{current_length})"
+        self.body = body[0, limit]
+      else
+        raise Exceptions::UnprocessableEntity, "body if article is to large, #{current_length} chars - only #{limit} allowed"
+      end
+    end
+    true
+  end
+
   def history_log_attributes
     {
       related_o_id:           self['ticket_id'],

test/unit/ticket_article_dos_test.rb

@@ -0,0 +1,103 @@
+# encoding: utf-8
+require 'test_helper'
+
+class TicketArticleDos < ActiveSupport::TestCase
+
+  test 'check body size' do
+
+    org_community = Organization.create_if_not_exists(
+      name: 'Zammad Foundation',
+    )
+    user_community = User.create_or_update(
+      login: 'article.dos@example.org',
+      firstname: 'Article',
+      lastname: 'Dos',
+      email: 'article.dos@example.org',
+      password: '',
+      active: true,
+      roles: [ Role.find_by(name: 'Customer') ],
+      organization_id: org_community.id,
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+
+    UserInfo.current_user_id = user_community.id
+    ApplicationHandleInfo.current = 'test.postmaster'
+
+    ticket1 = Ticket.create!(
+      group_id: Group.first.id,
+      customer_id: user_community.id,
+      title: 'DoS 1!',
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+    article1 = Ticket::Article.create!(
+      ticket_id: ticket1.id,
+      type_id: Ticket::Article::Type.find_by(name: 'phone').id,
+      sender_id: Ticket::Article::Sender.find_by(name: 'Customer').id,
+      from: 'Zammad Feedback <feedback@example.org>',
+      body: Array.new(2_000_000) { [*'0'..'9', *'a'..'z', ' ', ' ', ' ', '. '].sample }.join,
+      internal: false,
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+    assert_equal(1_500_000, article1.body.length)
+
+    ticket2 = Ticket.create!(
+      group_id: Group.first.id,
+      customer_id: user_community.id,
+      title: 'DoS 2!',
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+    article2 = Ticket::Article.create!(
+      ticket_id: ticket2.id,
+      type_id: Ticket::Article::Type.find_by(name: 'phone').id,
+      sender_id: Ticket::Article::Sender.find_by(name: 'Customer').id,
+      from: 'Zammad Feedback <feedback@example.org>',
+      body: "\u0000#{Array.new(2_000_000) { [*'0'..'9', *'a'..'z', ' ', ' ', ' ', '. '].sample }.join}",
+      internal: false,
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+    assert_equal(1_500_000, article2.body.length)
+
+    ApplicationHandleInfo.current = 'web'
+
+    ticket3 = Ticket.create!(
+      group_id: Group.first.id,
+      customer_id: user_community.id,
+      title: 'DoS 3!',
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+
+    assert_raises(Exceptions::UnprocessableEntity) {
+      article3 = Ticket::Article.create!(
+        ticket_id: ticket3.id,
+        type_id: Ticket::Article::Type.find_by(name: 'phone').id,
+        sender_id: Ticket::Article::Sender.find_by(name: 'Customer').id,
+        from: 'Zammad Feedback <feedback@example.org>',
+        body: "\u0000#{Array.new(2_000_000) { [*'0'..'9', *'a'..'z', ' ', ' ', ' ', '. '].sample }.join}",
+        internal: false,
+        updated_by_id: 1,
+        created_by_id: 1,
+      )
+    }
+
+  end
+
+  test 'check body size / cut if email' do
+
+    email_raw_string = "From: me@example.com
+To: customer@example.com
+Subject: some new subject
+
+Some Text" + Array.new(2_000_000) { [*'0'..'9', *'a'..'z', ' ', ' ', ' ', '. '].sample }.join
+
+    ticket_p, article_p, user_p, mail = Channel::EmailParser.new.process({}, email_raw_string)
+    assert_equal(1_500_000, article_p.body.length)
+
+  end
+
+end