[Project] Add lua_urls_compose library

lualib/lua_maps.lua

@@ -72,6 +72,10 @@ local function maybe_adjust_type(data,mtype)
     {'cdb:/', 'cdb'},
   }
 
+  if mtype == 'callback' then
+    return mtype
+  end
+
   for _,t in ipairs(known_types) do
     if check_prefix(t[1], t[2]) then
       return data,mtype

lualib/lua_urls_compose.lua

@@ -0,0 +1,229 @@
+--[[
+Copyright (c) 2020, Vsevolod Stakhov <vsevolod@highsecure.ru>
+
+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.
+]]--
+
+--[[[
+-- @module lua_urls_compose
+-- This module contains functions to compose urls queries from hostname
+-- to TLD part
+--]]
+
+local N = "lua_urls_compose"
+local lua_util = require "lua_util"
+local rspamd_util = require "rspamd_util"
+local bit = require "bit"
+local rspamd_trie = require "rspamd_trie"
+local fun = require "fun"
+
+local maps_cache = {}
+
+local exports = {}
+
+local function process_url(self, log_obj, url_tld, url_host)
+  local tld_elt = self.tlds[url_tld]
+
+  if tld_elt then
+    lua_util.debugm(N, log_obj, 'found compose rule for %s (%s host)',
+        url_tld, url_host)
+
+    for _,excl in ipairs(tld_elt.except_rules) do
+      local matched,ret = excl[2](url_host)
+      if matched then
+        lua_util.debugm(N, log_obj, 'found compose exclusion for %s (%s) -> %s',
+            url_host, excl[1], ret)
+
+        return ret
+      end
+    end
+
+    if tld_elt.multipattern_compose_rules then
+      local matches = tld_elt.multipattern_compose_rules:match(url_host)
+
+      if #matches == 1 then
+        local lua_pat = tld_elt.compose_rules[matches[1]]
+
+        local matched,ret = lua_pat[2](url_host)
+
+        if not matched then
+          lua_util.debugm(N, log_obj, 'NOT found compose inclusion for %s (%s) -> %s',
+              url_host, lua_pat[1], url_tld)
+
+          return url_tld
+        else
+          lua_util.debugm(N, log_obj, 'found compose inclusion for %s (%s) -> %s',
+              url_host, lua_pat[1], ret)
+
+          return ret
+        end
+      end
+    else
+      -- Match one by one
+      for _,lua_pat in ipairs(tld_elt.compose_rules) do
+        local matched,ret = lua_pat[2](url_host)
+        if matched then
+          lua_util.debugm(N, log_obj, 'found compose inclusion for %s (%s) -> %s',
+              url_host, lua_pat[1], ret)
+
+          return ret
+        end
+      end
+    end
+
+    lua_util.debugm(N, log_obj, 'not found compose inclusion for %s in %s -> %s',
+        url_host, url_tld, url_tld)
+  end
+
+  return url_tld
+end
+
+local function tld_pattern_transform(tld_pat)
+  -- Convert tld like pattern to a lua match pattern
+  -- blah -> %.blah
+  -- *.blah -> .*%.blah
+
+  if tld_pat:sub(1, 1) == '*' then
+    tld_pat = tld_pat:gsub('%*', '.*%%') .. '$'
+  else
+    tld_pat = string.format('([^.]*%%.%s)$', tld_pat)
+  end
+
+  return tld_pat
+end
+
+local function include_elt_gen(pat)
+  pat = tld_pattern_transform(pat)
+  return function(_, host)
+    local match = pat:match(host)
+    if match then
+      return true,match
+    end
+
+    return false
+  end
+end
+
+local function exclude_elt_gen(pat)
+  pat = tld_pattern_transform(pat)
+  return function(tld, host)
+    if host:match(pat) then
+      return true,tld
+    end
+
+    return false
+  end
+end
+
+local function compose_map_cb(self, map_text)
+  local lpeg = require "lpeg"
+
+  local singleline_comment = lpeg.P '#' * (1 - lpeg.S '\r\n\f') ^ 0
+  local comments_strip_grammar = lpeg.C((1 - lpeg.P '#') ^ 1) * lpeg.S(' \t')^0 * singleline_comment^0
+
+  local function process_tld_rule(tld_elt, l)
+    if l:sub(1, 1) == '!' then
+      -- Exclusion elt
+      table.insert(tld_elt.except_rules, {l, exclude_elt_gen(l:sub(2))})
+    else
+      table.insert(tld_elt.compose_rules, {l, include_elt_gen(l)})
+    end
+  end
+
+  local function process_map_line(l)
+    -- Skip empty lines and comments
+    if #l == 0 then return end
+    l = comments_strip_grammar(l)
+    if not l or #l == 0 then return end
+
+    -- Get TLD
+    local tld = rspamd_util.get_tld(l)
+
+    if tld then
+      local tld_elt = self.tlds[tld]
+
+      if not tld_elt then
+        tld_elt = {
+          compose_rules = {},
+          except_rules = {},
+          multipattern_compose_rules = nil
+        }
+        self.tlds[tld] = tld_elt
+      end
+      process_tld_rule(tld_elt, l)
+    else
+      lua_util.debugm(N, rspamd_config, 'cannot read tld from compose map line: %s', l)
+    end
+  end
+
+  for _,line in map_text:lines() do
+    process_map_line(line)
+  end
+
+  local multipattern_threshold = 32
+  for tld,tld_elt in pairs(self.tlds) do
+    if rspamd_trie.has_hyperscan() and #tld_elt.compose_rules >= multipattern_threshold then
+      lua_util.debugm(N, rspamd_config, 'tld %s has %s rules, apply multipattern',
+          tld, #tld_elt.compose_rules)
+      local flags = bit.bor(rspamd_trie.flags.re,
+          rspamd_trie.flags.dot_all,
+          rspamd_trie.flags.no_start,
+          rspamd_trie.flags.single_match)
+
+
+      -- We now convert our internal patterns to multipattern patterns
+      local mp_table = fun.totable(fun.map(function(pat_elt)
+        local pat_str = pat_elt[1]
+        if pat_str:sub(1, 1) == '*' then
+          return '\\.?.*\\.?' .. pat_str .. '$'
+        else
+          return '\\.?' .. pat_str .. '$'
+        end
+      end))
+      tld_elt.multipattern_compose_rules = rspamd_trie.create(mp_table, flags)
+    end
+  end
+end
+
+exports.add_composition_map = function(cfg, map_obj)
+  local hash_key = map_obj
+  if type(map_obj) == 'table' then
+    hash_key = lua_util.table_digest(map_obj)
+  end
+
+  local map = maps_cache[hash_key]
+
+  if not map then
+    local ret = {
+      process_url = process_url,
+      hash = hash_key,
+      tlds = {},
+    }
+
+    map = cfg:add_map{
+      type = 'callback',
+      description = 'URL compose map',
+      url = map_obj,
+      callback = function(input) compose_map_cb(ret, input) end,
+      opaque_data = true,
+    }
+
+    ret.map = map
+    maps_cache[hash_key] = ret
+    map = ret
+  end
+
+  return map
+end
+
+return exports