[Minor] Move mid checks to a separated rules file

1 files changed, 66 insertions, 0 deletions

diff --git a/rules/mid.lua b/rules/mid.lua
new file mode 100644
index 000000000..0b68fa612
--- /dev/null
+++ b/rules/mid.lua
@@ -0,0 +1,66 @@
+--[[
+Copyright (c) 2016, Vsevolod Stakhov <vsevolod@highsecure.ru>
+Copyright (c) 2016, Steve Freeguard
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+]]--
+
+local function mid_check_func(task)
+  local mid = task:get_header('Message-ID')
+  if not mid then return false end
+  -- Check for 'bare' IP addresses in RHS
+  if mid:find("@%d+%.%d+%.%d+%.%d+>$") then
+    task:insert_result('MID_BARE_IP', 1.0)
+  end
+  -- Check for non-FQDN RHS
+  if mid:find("@[^%.]+>?$") then
+    task:insert_result('MID_RHS_NOT_FQDN', 1.0)
+  end
+  -- Check for missing <>'s
+  if not mid:find('^<[^>]+>$') then
+    task:insert_result('MID_MISSING_BRACKETS', 1.0)
+  end
+  -- Check for IP literal in RHS
+  if mid:find("@%[%d+%.%d+%.%d+%.%d+%]") then
+    task:insert_result('MID_RHS_IP_LITERAL', 1.0)
+  end
+  -- Check From address atrributes against MID
+  local from = task:get_from(2)
+  if (from and from[1] and from[1].domain) then
+    local fd = from[1].domain:lower()
+    local _,_,md = mid:find("@([^>]+)>?$")
+    -- See if all or part of the From address
+    -- can be found in the Message-ID
+    if (mid:lower():find(from[1].addr:lower(),1,true)) then
+      task:insert_result('MID_CONTAINS_FROM', 1.0)
+    elseif (md and fd == md:lower()) then
+      task:insert_result('MID_RHS_MATCH_FROM', 1.0)
+    end
+  end
+end
+
+-- MID checks from Steve Freegard
+local check_mid_id = rspamd_config:register_callback_symbol('CHECK_MID', 1.0,
+  mid_check_func)
+rspamd_config:register_virtual_symbol('MID_BARE_IP', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_BARE_IP', 2.0, 'Message-ID RHS is a bare IP address')
+rspamd_config:register_virtual_symbol('MID_RHS_NOT_FQDN', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_RHS_NOT_FQDN', 0.5, 'Message-ID RHS is not a fully-qualified domain name')
+rspamd_config:register_virtual_symbol('MID_MISSING_BRACKETS', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_MISSING_BRACKETS', 0.5, 'Message-ID is missing <>\'s')
+rspamd_config:register_virtual_symbol('MID_RHS_IP_LITERAL', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_RHS_IP_LITERAL', 0.5, 'Message-ID RHS is an IP-literal')
+rspamd_config:register_virtual_symbol('MID_CONTAINS_FROM', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_CONTAINS_FROM', 1.0, 'Message-ID contains From address')
+rspamd_config:register_virtual_symbol('MID_RHS_MATCH_FROM', 1.0, check_mid_id)
+rspamd_config:set_metric_symbol('MID_RHS_MATCH_FROM', 1.0, 'Message-ID RHS matches From domain')
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