[Rework] Lua_scanners: Further library split

1 files changed, 199 insertions, 0 deletions

diff --git a/lualib/lua_scanners/common.lua b/lualib/lua_scanners/common.lua
new file mode 100644
index 000000000..ad99137a2
--- /dev/null
+++ b/lualib/lua_scanners/common.lua
@@ -0,0 +1,199 @@
+--[[
+Copyright (c) 2018, 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_scanners_common
+-- This module contains common external scanners functions
+--]]
+
+local rspamd_logger = require "rspamd_logger"
+local lua_util = require "lua_util"
+local lua_redis = require "lua_redis"
+
+local exports = {}
+
+local function match_patterns(default_sym, found, patterns)
+  if type(patterns) ~= 'table' then return default_sym end
+  if not patterns[1] then
+    for sym, pat in pairs(patterns) do
+      if pat:match(found) then
+        return sym
+      end
+    end
+    return default_sym
+  else
+    for _, p in ipairs(patterns) do
+      for sym, pat in pairs(p) do
+        if pat:match(found) then
+          return sym
+        end
+      end
+    end
+    return default_sym
+  end
+end
+
+local function yield_result(task, rule, vname, N)
+  local all_whitelisted = true
+  if type(vname) == 'string' then
+    local symname = match_patterns(rule['symbol'], vname, rule['patterns'])
+    if rule['whitelist'] and rule['whitelist']:get_key(vname) then
+      rspamd_logger.infox(task, '%s: "%s" is in whitelist', rule['type'], vname)
+      return
+    end
+    task:insert_result(symname, 1.0, vname)
+    rspamd_logger.infox(task, '%s: virus found: "%s"', rule['type'], vname)
+  elseif type(vname) == 'table' then
+    for _, vn in ipairs(vname) do
+      local symname = match_patterns(rule['symbol'], vn, rule['patterns'])
+      if rule['whitelist'] and rule['whitelist']:get_key(vn) then
+        rspamd_logger.infox(task, '%s: "%s" is in whitelist', rule['type'], vn)
+      else
+        all_whitelisted = false
+        task:insert_result(symname, 1.0, vn)
+        rspamd_logger.infox(task, '%s: virus found: "%s"', rule['type'], vn)
+      end
+    end
+  end
+  if rule['action'] then
+    if type(vname) == 'table' then
+      if all_whitelisted then return end
+      vname = table.concat(vname, '; ')
+    end
+    task:set_pre_result(rule['action'],
+        lua_util.template(rule.message or 'Rejected', {
+          SCANNER = rule['type'],
+          VIRUS = vname,
+        }), N)
+  end
+end
+
+local function message_not_too_large(task, content, rule)
+  local max_size = tonumber(rule.max_size)
+  if not max_size then return true end
+  if #content > max_size then
+    rspamd_logger.infox(task, "skip %s AV check as it is too large: %s (%s is allowed)",
+        rule.type, #content, max_size)
+    return false
+  end
+  return true
+end
+
+local function need_av_check(task, content, rule)
+  return message_not_too_large(task, content, rule)
+end
+
+local function check_av_cache(task, digest, rule, fn, N)
+  local key = digest
+
+  local function redis_av_cb(err, data)
+    if data and type(data) == 'string' then
+      -- Cached
+      if data ~= 'OK' then
+        lua_util.debugm(N, task, 'got cached result for %s: %s',
+            key, data)
+        data = lua_util.str_split(data, '\v')
+        yield_result(task, rule, data, N)
+      else
+        lua_util.debugm(N, task, 'got cached result for %s: %s',
+            key, data)
+      end
+    else
+      if err then
+        rspamd_logger.errx(task, 'got error checking cache: %s', err)
+      end
+      fn()
+    end
+  end
+
+  if rule.redis_params then
+
+    key = rule['prefix'] .. key
+
+    if lua_redis.redis_make_request(task,
+        rule.redis_params, -- connect params
+        key, -- hash key
+        false, -- is write
+        redis_av_cb, --callback
+        'GET', -- command
+        {key} -- arguments)
+    ) then
+      return true
+    end
+  end
+
+  return false
+end
+
+local function save_av_cache(task, digest, rule, to_save, N)
+  local key = digest
+
+  local function redis_set_cb(err)
+    -- Do nothing
+    if err then
+      rspamd_logger.errx(task, 'failed to save virus cache for %s -> "%s": %s',
+          to_save, key, err)
+    else
+      lua_util.debugm(N, task, 'saved cached result for %s: %s',
+          key, to_save)
+    end
+  end
+
+  if type(to_save) == 'table' then
+    to_save = table.concat(to_save, '\v')
+  end
+
+  if rule.redis_params then
+    key = rule['prefix'] .. key
+
+    lua_redis.redis_make_request(task,
+        rule.redis_params, -- connect params
+        key, -- hash key
+        true, -- is write
+        redis_set_cb, --callback
+        'SETEX', -- command
+        { key, rule['cache_expire'], to_save }
+    )
+  end
+
+  return false
+end
+
+exports.yield_result = yield_result
+exports.match_patterns = match_patterns
+exports.need_av_check = need_av_check
+exports.check_av_cache = check_av_cache
+exports.save_av_cache = save_av_cache
+
+setmetatable(exports, {
+  __call = function(t, override)
+    for k, v in pairs(t) do
+      if _G[k] ~= nil then
+        local msg = 'function ' .. k .. ' already exists in global scope.'
+        if override then
+          _G[k] = v
+          print('WARNING: ' .. msg .. ' Overwritten.')
+        else
+          print('NOTICE: ' .. msg .. ' Skipped.')
+        end
+      else
+        _G[k] = v
+      end
+    end
+  end,
+})
+
+return exports
\ No newline at end of file