Rework spamassassin functions:

1) now we support some plugins, so do not refuse to parse them
2) added freemail plugin
3) rework SA functions evaluation
4) add support for eval functions
5) add freemail eval

1 files changed, 158 insertions, 18 deletions

diff --git a/src/plugins/lua/spamassassin.lua b/src/plugins/lua/spamassassin.lua
index 35e49dce1..d93104486 100644
--- a/src/plugins/lua/spamassassin.lua
+++ b/src/plugins/lua/spamassassin.lua
@@ -31,11 +31,20 @@ local rspamd_logger = require "rspamd_logger"
 local rspamd_regexp = require "rspamd_regexp"
 local rspamd_expression = require "rspamd_expression"
 local rspamd_mempool = require "rspamd_mempool"
+local rspamd_trie = require "rspamd_trie"
 local _ = require "fun"
+
 --local dumper = require 'pl.pretty'.dump
+
+-- Known plugins
+local known_plugins = {'Mail::SpamAssassin::Plugin::FreeMail'}
+
+-- Internal variables
 local rules = {}
 local atoms = {}
 local metas = {}
+local freemail_domains = {}
+local freemail_trie
 local section = rspamd_config:get_key("spamassassin")
 
 -- Minimum score to treat symbols as meta
@@ -123,6 +132,125 @@ local function handle_header_def(hline, cur_rule)
   end
 end
 
+
+local function freemail_search(input)
+  local res = false
+  local function trie_callback(number, pos)
+    rspamd_logger.debugx('Matched pattern %1 at pos %2', freemail_domains[number], pos)
+    res = true
+  end
+  
+  if input then
+    freemail_trie:match(input, trie_callback, true)
+  end
+  
+  return res
+end
+
+local function gen_eval_rule(arg)
+  local eval_funcs = {
+    {'check_freemail_from', function(task, remain) 
+        local from = task:get_from()
+        if from then
+          return freemail_search(from[1]['addr'])
+        end
+        return false 
+      end},
+    {'check_freemail_replyto', 
+      function(task, remain) 
+        return freemail_search(task:get_header('Reply-To')) 
+      end
+    },
+    {'check_freemail_header',
+      function(task, remain)
+        -- Remain here contains one or two args: header and regexp to match
+        local arg = string.match(remain, "^%(%s*['\"]([^%s]+)['\"]%s*%)$")
+        local re = nil
+        if not arg then
+          arg, re = string.match(remain, "^%(%s*['\"]([^%s]+)['\"]%s*,%s*['\"]([^%s]+)['\"]%s*%)$")
+        end
+        
+        if arg then
+          local h = task:get_header(arg)
+          if h then
+            local hdr_freemail = freemail_search(h)
+            if hdr_freemail and re then
+              r = rspamd_regexp.create_cached(re)
+              if r then
+                r:match(h)
+              else
+                rspamd_logger.infox('cannot create regexp %1', re)
+                return false
+              end
+            end
+           
+            return hdr_freemail
+          end
+        end
+        
+        return false   
+      end
+    },
+  }
+  
+  for k,f in ipairs(eval_funcs) do
+    local pat = string.format('^%s', f[1])
+    local first,last = string.find(arg, pat)
+    
+    if first then
+      local func_arg = string.sub(arg, last + 1)
+      return function(task)
+        return f[2](task, func_arg)
+      end 
+    end
+  end
+end
+
+-- Returns parser function or nil
+local function maybe_parse_sa_function(line)
+  local arg
+  local elts = split(line, '[^:]+')
+  arg = elts[2]
+  local func_cache = {}
+  
+  rspamd_logger.debugx('trying to parse SA function %1 with args %2', elts[1], elts[2])
+  local substitutions = {
+    {'^exists:', 
+      function(task) -- filter
+        if task:get_header(arg) then
+          return true
+        end
+        return false
+      end,
+    },
+    {'^eval:',
+      function(task)
+        local func = func_cache[arg]
+        if not func then
+          func = gen_eval_rule(arg)
+          func_cache[arg] = func
+        end
+        
+        if not func then
+          rspamd_logger.errx('cannot find appropriate eval rule for function %1', arg)
+        else
+          return func(task)
+        end
+        
+        return false
+      end
+    },
+  }
+  
+  for k,s in ipairs(substitutions) do
+    if string.find(line, s[1]) then
+      return s[2]
+    end
+  end
+  
+  return nil
+end
+
 local function process_sa_conf(f)
   local cur_rule = {}
   local valid_rule = false
@@ -153,7 +281,14 @@ local function process_sa_conf(f)
       return
     else
       if string.match(l, '^ifplugin') then
-        skip_to_endif = true
+        local ls = split(l)
+        
+        if not _.any(function(pl) 
+            if pl == ls[2] then return true end
+            return false
+            end, known_plugins) then
+          skip_to_endif = true
+        end
       end
     end
     
@@ -171,7 +306,7 @@ local function process_sa_conf(f)
       if valid_rule then
         insert_cur_rule()
       end
-      if slash then
+      if slash and words[4] and (words[4] == '=~' or words[4] == '!~') then
         cur_rule['type'] = 'header'
         cur_rule['symbol'] = words[2]
         
@@ -205,20 +340,16 @@ local function process_sa_conf(f)
         end
       else
         -- Maybe we know the function and can convert it
-        local s,e = string.find(words[3], 'exists:')
-        if e then
-           local h = _.foldl(function(acc, s) return acc .. s end,
-            '', _.drop_n(e, words[3]))
-           cur_rule['type'] = 'function'
-           cur_rule['symbol'] = words[2]
-           cur_rule['header'] = h
-           cur_rule['function'] = function(task)
-            if task:get_header(h) then
-              return true
-            end
-            return false
-           end
-           valid_rule = true
+        local args =  words_to_re(words, 2)
+        local func = maybe_parse_sa_function(args)
+        
+        if func then
+          cur_rule['type'] = 'function'
+          cur_rule['symbol'] = words[2]
+          cur_rule['function'] = func
+          valid_rule = true
+        else
+          rspamd_logger.infox('unknown function %1', args)
         end
       end
     elseif words[1] == "body" and slash then
@@ -261,9 +392,13 @@ local function process_sa_conf(f)
       cur_rule['meta'] = words_to_re(words, 2)
       if cur_rule['meta'] and cur_rule['symbol'] then valid_rule = true end
     elseif words[1] == "describe" and valid_rule then
-      cur_rule['description'] = words_to_re(words, 1)
+      cur_rule['description'] = words_to_re(words, 2)
     elseif words[1] == "score" and valid_rule then
       cur_rule['score'] = tonumber(words_to_re(words, 2))
+    elseif words[1] == 'freemail_domains' then
+      _.each(function(dom)
+        table.insert(freemail_domains, '@' .. dom)
+        end, _.drop_n(1, words))
     end
     end)()
   end
@@ -304,6 +439,11 @@ local function add_sole_meta(sym, rule)
   rules[sym] = r
 end
 
+if freemail_domains then
+  freemail_trie = rspamd_trie.create(freemail_domains)
+  rspamd_logger.infox('loaded %1 freemail domains definitions', #freemail_domains)
+end
+
 -- Header rules
 _.each(function(k, r)
     local f = function(task)
@@ -489,7 +629,7 @@ local function process_atom(atom, task)
     end
     return res
   else
-    --rspamd_logger.err('Cannot find atom ' .. atom)
+    rspamd_logger.err('Cannot find atom ' .. atom)
   end
   return 0
 end