update bad mail checks

lib/msf/core/exploit/smtp_deliver.rb

@@ -151,11 +151,27 @@ module Exploit::Remote::SMTPDeliver
     [nsock, raw_send_recv("EHLO #{domain}\r\n", nsock)]
   end
 
+  def bad_address(address)
+    address.bytesize > 2048 || /[\r\n]/ =~ address
+  end
+
   #
   # Sends an email message, connecting to the server first if a connection is
   # not already established.
   #
   def send_message(data)
+    mailfrom = datastore['MAILFROM'].strip
+    if bad_address(mailfrom)
+      print_error "Bad from address, not sending: #{mailfrom}"
+      return nil
+    end
+
+    mailto = datastore['MAILTO'].strip
+    if bad_address(mailto)
+      print_error "Bad to address, not sending: #{mailto}"
+      return nil
+    end
+
     send_status = nil
 
     already_connected = connected?
@@ -166,9 +182,6 @@ module Exploit::Remote::SMTPDeliver
       nsock = connect_login(false)
     end
 
-    mailto = datastore['MAILTO'].strip
-    mailfrom = datastore['MAILFROM'].strip
-
     raw_send_recv("MAIL FROM: <#{mailfrom}>\r\n", nsock)
     res = raw_send_recv("RCPT TO: <#{mailto}>\r\n", nsock)
     if res[0..2] == '250'