[Rework] Antivirus: Move antivirus routines to lua_scanners

2 files changed, 1012 insertions, 0 deletions

diff --git a/lualib/lua_scanners/antivirus.lua b/lualib/lua_scanners/antivirus.lua
new file mode 100644
index 000000000..286ef64d0
--- /dev/null
+++ b/lualib/lua_scanners/antivirus.lua
@@ -0,0 +1,986 @@
+--[[
+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_antivirus
+-- This module contains antivirus access functions
+--]]
+
+local lua_util = require "lua_util"
+local tcp = require "rspamd_tcp"
+local upstream_list = require "rspamd_upstream_list"
+local rspamd_util = require "rspamd_util"
+local lua_redis = require "lua_redis"
+local rspamd_logger = require "rspamd_logger"
+
+local N = "antivirus"
+
+local default_message = '${SCANNER}: virus found: "${VIRUS}"'
+
+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)
+  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 clamav_config(opts)
+  local clamav_conf = {
+    scan_mime_parts = true;
+    scan_text_mime = false;
+    scan_image_mime = false;
+    default_port = 3310,
+    log_clean = false,
+    timeout = 15.0, -- FIXME: this will break task_timeout!
+    retransmits = 2,
+    cache_expire = 3600, -- expire redis in one hour
+    message = default_message,
+  }
+
+  for k,v in pairs(opts) do
+    clamav_conf[k] = v
+  end
+
+  if not clamav_conf.prefix then
+    clamav_conf.prefix = 'rs_cl'
+  end
+
+  if not clamav_conf['servers'] then
+    rspamd_logger.errx(rspamd_config, 'no servers defined')
+
+    return nil
+  end
+
+  clamav_conf['upstreams'] = upstream_list.create(rspamd_config,
+      clamav_conf['servers'],
+      clamav_conf.default_port)
+
+  if clamav_conf['upstreams'] then
+    return clamav_conf
+  end
+
+  rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
+      clamav_conf['servers'])
+  return nil
+end
+
+local function fprot_config(opts)
+  local fprot_conf = {
+    scan_mime_parts = true;
+    scan_text_mime = false;
+    scan_image_mime = false;
+    default_port = 10200,
+    timeout = 15.0, -- FIXME: this will break task_timeout!
+    log_clean = false,
+    retransmits = 2,
+    cache_expire = 3600, -- expire redis in one hour
+    message = default_message,
+  }
+
+  for k,v in pairs(opts) do
+    fprot_conf[k] = v
+  end
+
+  if not fprot_conf.prefix then
+    fprot_conf.prefix = 'rs_fp'
+  end
+
+  if not fprot_conf['servers'] then
+    rspamd_logger.errx(rspamd_config, 'no servers defined')
+
+    return nil
+  end
+
+  fprot_conf['upstreams'] = upstream_list.create(rspamd_config,
+      fprot_conf['servers'],
+      fprot_conf.default_port)
+
+  if fprot_conf['upstreams'] then
+    return fprot_conf
+  end
+
+  rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
+      fprot_conf['servers'])
+  return nil
+end
+
+local function sophos_config(opts)
+  local sophos_conf = {
+    scan_mime_parts = true;
+    scan_text_mime = false;
+    scan_image_mime = false;
+    default_port = 4010,
+    timeout = 15.0,
+    log_clean = false,
+    retransmits = 2,
+    cache_expire = 3600, -- expire redis in one hour
+    message = default_message,
+    savdi_report_encrypted = false,
+    savdi_report_oversize = false,
+  }
+
+  for k,v in pairs(opts) do
+    sophos_conf[k] = v
+  end
+
+  if not sophos_conf.prefix then
+    sophos_conf.prefix = 'rs_sp'
+  end
+
+  if not sophos_conf['servers'] then
+    rspamd_logger.errx(rspamd_config, 'no servers defined')
+
+    return nil
+  end
+
+  sophos_conf['upstreams'] = upstream_list.create(rspamd_config,
+      sophos_conf['servers'],
+      sophos_conf.default_port)
+
+  if sophos_conf['upstreams'] then
+    return sophos_conf
+  end
+
+  rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
+      sophos_conf['servers'])
+  return nil
+end
+
+local function savapi_config(opts)
+  local savapi_conf = {
+    scan_mime_parts = true;
+    scan_text_mime = false;
+    scan_image_mime = false;
+    default_port = 4444, -- note: You must set ListenAddress in savapi.conf
+    product_id = 0,
+    log_clean = false,
+    timeout = 15.0, -- FIXME: this will break task_timeout!
+    retransmits = 1, -- FIXME: useless, for local files
+    cache_expire = 3600, -- expire redis in one hour
+    message = default_message,
+    tmpdir = '/tmp',
+  }
+
+  for k,v in pairs(opts) do
+    savapi_conf[k] = v
+  end
+
+  if not savapi_conf.prefix then
+    savapi_conf.prefix = 'rs_ap'
+  end
+
+  if not savapi_conf['servers'] then
+    rspamd_logger.errx(rspamd_config, 'no servers defined')
+
+    return nil
+  end
+
+  savapi_conf['upstreams'] = upstream_list.create(rspamd_config,
+      savapi_conf['servers'],
+      savapi_conf.default_port)
+
+  if savapi_conf['upstreams'] then
+    return savapi_conf
+  end
+
+  rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
+      savapi_conf['servers'])
+  return nil
+end
+
+local function kaspersky_config(opts)
+  local kaspersky_conf = {
+    scan_mime_parts = true;
+    scan_text_mime = false;
+    scan_image_mime = false;
+    product_id = 0,
+    log_clean = false,
+    timeout = 5.0,
+    retransmits = 1, -- use local files, retransmits are useless
+    cache_expire = 3600, -- expire redis in one hour
+    message = default_message,
+    tmpdir = '/tmp',
+    prefix = 'rs_ak',
+  }
+
+  kaspersky_conf = lua_util.override_defaults(kaspersky_conf, opts)
+
+  if not kaspersky_conf['servers'] then
+    rspamd_logger.errx(rspamd_config, 'no servers defined')
+
+    return nil
+  end
+
+  kaspersky_conf['upstreams'] = upstream_list.create(rspamd_config,
+      kaspersky_conf['servers'], 0)
+
+  if kaspersky_conf['upstreams'] then
+    return kaspersky_conf
+  end
+
+  rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
+      kaspersky_conf['servers'])
+  return nil
+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("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)
+  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 = rspamd_str_split(data, '\v')
+        yield_result(task, rule, data)
+      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: %1', 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)
+  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
+
+local function fprot_check(task, content, digest, rule)
+  local function fprot_check_uncached ()
+    local upstream = rule.upstreams:get_upstream_round_robin()
+    local addr = upstream:get_addr()
+    local retransmits = rule.retransmits
+    local scan_id = task:get_queue_id()
+    if not scan_id then scan_id = task:get_uid() end
+    local header = string.format('SCAN STREAM %s SIZE %d\n', scan_id,
+        #content)
+    local footer = '\n'
+
+    local function fprot_callback(err, data)
+      if err then
+        -- set current upstream to fail because an error occurred
+        upstream:fail()
+
+        -- retry with another upstream until retransmits exceeds
+        if retransmits > 0 then
+
+          retransmits = retransmits - 1
+
+          -- Select a different upstream!
+          upstream = rule.upstreams:get_upstream_round_robin()
+          addr = upstream:get_addr()
+
+          lua_util.debugm(N, task, '%s [%s]: retry IP: %s', rule['symbol'], rule['type'], addr)
+
+          tcp.request({
+            task = task,
+            host = addr:to_string(),
+            port = addr:get_port(),
+            timeout = rule['timeout'],
+            callback = fprot_callback,
+            data = { header, content, footer },
+            stop_pattern = '\n'
+          })
+        else
+          rspamd_logger.errx(task,
+              '%s [%s]: failed to scan, maximum retransmits exceed',
+              rule['symbol'], rule['type'])
+          task:insert_result(rule['symbol_fail'], 0.0,
+              'failed to scan and retransmits exceed')
+        end
+      else
+        upstream:ok()
+        data = tostring(data)
+        local cached
+        local clean = string.match(data, '^0 <clean>')
+        if clean then
+          cached = 'OK'
+          if rule['log_clean'] then
+            rspamd_logger.infox(task,
+                '%s [%s]: message or mime_part is clean',
+                rule['symbol'], rule['type'])
+          end
+        else
+          -- returncodes: 1: infected, 2: suspicious, 3: both, 4-255: some error occured
+          -- see http://www.f-prot.com/support/helpfiles/unix/appendix_c.html for more detail
+          local vname = string.match(data, '^[1-3] <[%w%s]-: (.-)>')
+          if not vname then
+            rspamd_logger.errx(task, 'Unhandled response: %s', data)
+          else
+            yield_result(task, rule, vname)
+            cached = vname
+          end
+        end
+        if cached then
+          save_av_cache(task, digest, rule, cached)
+        end
+      end
+    end
+
+    tcp.request({
+      task = task,
+      host = addr:to_string(),
+      port = addr:get_port(),
+      timeout = rule['timeout'],
+      callback = fprot_callback,
+      data = { header, content, footer },
+      stop_pattern = '\n'
+    })
+  end
+
+  if need_av_check(task, content, rule) then
+    if check_av_cache(task, digest, rule, fprot_check_uncached) then
+      return
+    else
+      fprot_check_uncached()
+    end
+  end
+end
+
+local function clamav_check(task, content, digest, rule)
+  local function clamav_check_uncached ()
+    local upstream = rule.upstreams:get_upstream_round_robin()
+    local addr = upstream:get_addr()
+    local retransmits = rule.retransmits
+    local header = rspamd_util.pack("c9 c1 >I4", "zINSTREAM", "\0",
+        #content)
+    local footer = rspamd_util.pack(">I4", 0)
+
+    local function clamav_callback(err, data)
+      if err then
+
+        -- set current upstream to fail because an error occurred
+        upstream:fail()
+
+        -- retry with another upstream until retransmits exceeds
+        if retransmits > 0 then
+
+          retransmits = retransmits - 1
+
+          -- Select a different upstream!
+          upstream = rule.upstreams:get_upstream_round_robin()
+          addr = upstream:get_addr()
+
+          lua_util.debugm(N, task, '%s [%s]: retry IP: %s', rule['symbol'], rule['type'], addr)
+
+          tcp.request({
+            task = task,
+            host = addr:to_string(),
+            port = addr:get_port(),
+            timeout = rule['timeout'],
+            callback = clamav_callback,
+            data = { header, content, footer },
+            stop_pattern = '\0'
+          })
+        else
+          rspamd_logger.errx(task, '%s [%s]: failed to scan, maximum retransmits exceed', rule['symbol'], rule['type'])
+          task:insert_result(rule['symbol_fail'], 0.0, 'failed to scan and retransmits exceed')
+        end
+
+      else
+        upstream:ok()
+        data = tostring(data)
+        local cached
+        lua_util.debugm(N, task, '%s [%s]: got reply: %s', rule['symbol'], rule['type'], data)
+        if data == 'stream: OK' then
+          cached = 'OK'
+          if rule['log_clean'] then
+            rspamd_logger.infox(task, '%s [%s]: message or mime_part is clean', rule['symbol'], rule['type'])
+          else
+            lua_util.debugm(N, task, '%s [%s]: message or mime_part is clean', rule['symbol'], rule['type'])
+          end
+        else
+          local vname = string.match(data, 'stream: (.+) FOUND')
+          if vname then
+            yield_result(task, rule, vname)
+            cached = vname
+          else
+            rspamd_logger.errx(task, 'unhandled response: %s', data)
+            task:insert_result(rule['symbol_fail'], 0.0, 'unhandled response')
+          end
+        end
+        if cached then
+          save_av_cache(task, digest, rule, cached)
+        end
+      end
+    end
+
+    tcp.request({
+      task = task,
+      host = addr:to_string(),
+      port = addr:get_port(),
+      timeout = rule['timeout'],
+      callback = clamav_callback,
+      data = { header, content, footer },
+      stop_pattern = '\0'
+    })
+  end
+
+  if need_av_check(task, content, rule) then
+    if check_av_cache(task, digest, rule, clamav_check_uncached) then
+      return
+    else
+      clamav_check_uncached()
+    end
+  end
+end
+
+local function sophos_check(task, content, digest, rule)
+  local function sophos_check_uncached ()
+    local upstream = rule.upstreams:get_upstream_round_robin()
+    local addr = upstream:get_addr()
+    local retransmits = rule.retransmits
+    local protocol = 'SSSP/1.0\n'
+    local streamsize = string.format('SCANDATA %d\n', #content)
+    local bye = 'BYE\n'
+
+    local function sophos_callback(err, data, conn)
+
+      if err then
+        -- set current upstream to fail because an error occurred
+        upstream:fail()
+
+        -- retry with another upstream until retransmits exceeds
+        if retransmits > 0 then
+
+          retransmits = retransmits - 1
+
+          -- Select a different upstream!
+          upstream = rule.upstreams:get_upstream_round_robin()
+          addr = upstream:get_addr()
+
+          lua_util.debugm(N, task, '%s [%s]: retry IP: %s', rule['symbol'], rule['type'], addr)
+
+          tcp.request({
+            task = task,
+            host = addr:to_string(),
+            port = addr:get_port(),
+            timeout = rule['timeout'],
+            callback = sophos_callback,
+            data = { protocol, streamsize, content, bye }
+          })
+        else
+          rspamd_logger.errx(task, '%s [%s]: failed to scan, maximum retransmits exceed', rule['symbol'], rule['type'])
+          task:insert_result(rule['symbol_fail'], 0.0, 'failed to scan and retransmits exceed')
+        end
+      else
+        upstream:ok()
+        data = tostring(data)
+        lua_util.debugm(N, task, '%s [%s]: got reply: %s', rule['symbol'], rule['type'], data)
+        local vname = string.match(data, 'VIRUS (%S+) ')
+        if vname then
+          yield_result(task, rule, vname)
+          save_av_cache(task, digest, rule, vname)
+        else
+          if string.find(data, 'DONE OK') then
+            if rule['log_clean'] then
+              rspamd_logger.infox(task, '%s [%s]: message or mime_part is clean', rule['symbol'], rule['type'])
+            else
+              lua_util.debugm(N, task, '%s [%s]: message or mime_part is clean', rule['symbol'], rule['type'])
+            end
+            save_av_cache(task, digest, rule, 'OK')
+            -- not finished - continue
+          elseif string.find(data, 'ACC') or string.find(data, 'OK SSSP') then
+            conn:add_read(sophos_callback)
+            -- set pseudo virus if configured, else do nothing since it's no fatal
+          elseif string.find(data, 'FAIL 0212') then
+            rspamd_logger.infox(task, 'Message is ENCRYPTED (0212 SOPHOS_SAVI_ERROR_FILE_ENCRYPTED): %s', data)
+            if rule['savdi_report_encrypted'] then
+              yield_result(task, rule, "SAVDI_FILE_ENCRYPTED")
+              save_av_cache(task, digest, rule, "SAVDI_FILE_ENCRYPTED")
+            end
+            -- set pseudo virus if configured, else set fail since part was not scanned
+          elseif string.find(data, 'REJ 4') then
+            if rule['savdi_report_oversize'] then
+              rspamd_logger.infox(task, 'SAVDI: Message is OVERSIZED (SSSP reject code 4): %s', data)
+              yield_result(task, rule, "SAVDI_FILE_OVERSIZED")
+              save_av_cache(task, digest, rule, "SAVDI_FILE_OVERSIZED")
+            else
+              rspamd_logger.errx(task, 'SAVDI: Message is OVERSIZED (SSSP reject code 4): %s', data)
+              task:insert_result(rule['symbol_fail'], 0.0, 'Message is OVERSIZED (SSSP reject code 4):' .. data)
+            end
+            -- excplicitly set REJ1 message when SAVDIreports a protocol error
+          elseif string.find(data, 'REJ 1') then
+            rspamd_logger.errx(task, 'SAVDI (Protocol error (REJ 1)): %s', data)
+            task:insert_result(rule['symbol_fail'], 0.0, 'SAVDI (Protocol error (REJ 1)):' .. data)
+          else
+            rspamd_logger.errx(task, 'unhandled response: %s', data)
+            task:insert_result(rule['symbol_fail'], 0.0, 'unhandled response')
+          end
+
+        end
+      end
+    end
+
+    tcp.request({
+      task = task,
+      host = addr:to_string(),
+      port = addr:get_port(),
+      timeout = rule['timeout'],
+      callback = sophos_callback,
+      data = { protocol, streamsize, content, bye }
+    })
+  end
+
+  if need_av_check(task, content, rule) then
+    if check_av_cache(task, digest, rule, sophos_check_uncached) then
+      return
+    else
+      sophos_check_uncached()
+    end
+  end
+end
+
+local function savapi_check(task, content, digest, rule)
+  local function savapi_check_uncached ()
+    local upstream = rule.upstreams:get_upstream_round_robin()
+    local addr = upstream:get_addr()
+    local retransmits = rule.retransmits
+    local fname = string.format('%s/%s.tmp',
+        rule.tmpdir, rspamd_util.random_hex(32))
+    local message_fd = rspamd_util.create_file(fname)
+
+    if not message_fd then
+      rspamd_logger.errx('cannot store file for savapi scan: %s', fname)
+      return
+    end
+
+    if type(content) == 'string' then
+      -- Create rspamd_text
+      local rspamd_text = require "rspamd_text"
+      content = rspamd_text.fromstring(content)
+    end
+    content:save_in_file(message_fd)
+
+    -- Ensure cleanup
+    task:get_mempool():add_destructor(function()
+      os.remove(fname)
+      rspamd_util.close_file(message_fd)
+    end)
+
+    local vnames = {}
+
+    -- Forward declaration for recursive calls
+    local savapi_scan1_cb
+
+    local function savapi_fin_cb(err, conn)
+      local vnames_reordered = {}
+      -- Swap table
+      for virus,_ in pairs(vnames) do
+        table.insert(vnames_reordered, virus)
+      end
+      lua_util.debugm(N, task, "%s: number of virus names found %s", rule['type'], #vnames_reordered)
+      if #vnames_reordered > 0 then
+        local vname = {}
+        for _,virus in ipairs(vnames_reordered) do
+          table.insert(vname, virus)
+        end
+
+        yield_result(task, rule, vname)
+        save_av_cache(task, digest, rule, vname)
+      end
+      if conn then
+        conn:close()
+      end
+    end
+
+    local function savapi_scan2_cb(err, data, conn)
+      local result = tostring(data)
+      lua_util.debugm(N, task, "%s: got reply: %s",
+          rule['type'], result)
+
+      -- Terminal response - clean
+      if string.find(result, '200') or string.find(result, '210') then
+        if rule['log_clean'] then
+          rspamd_logger.infox(task, '%s: message or mime_part is clean', rule['type'])
+        end
+        save_av_cache(task, digest, rule, 'OK')
+        conn:add_write(savapi_fin_cb, 'QUIT\n')
+
+        -- Terminal response - infected
+      elseif string.find(result, '319') then
+        conn:add_write(savapi_fin_cb, 'QUIT\n')
+
+        -- Non-terminal response
+      elseif string.find(result, '310') then
+        local virus
+        virus = result:match "310.*<<<%s(.*)%s+;.*;.*"
+        if not virus then
+          virus = result:match "310%s(.*)%s+;.*;.*"
+          if not virus then
+            rspamd_logger.errx(task, "%s: virus result unparseable: %s",
+                rule['type'], result)
+            return
+          end
+        end
+        -- Store unique virus names
+        vnames[virus] = 1
+        -- More content is expected
+        conn:add_write(savapi_scan1_cb, '\n')
+      end
+    end
+
+    savapi_scan1_cb = function(err, conn)
+      conn:add_read(savapi_scan2_cb, '\n')
+    end
+
+    -- 100 PRODUCT:xyz
+    local function savapi_greet2_cb(err, data, conn)
+      local result = tostring(data)
+      if string.find(result, '100 PRODUCT') then
+        lua_util.debugm(N, task, "%s: scanning file: %s",
+            rule['type'], fname)
+        conn:add_write(savapi_scan1_cb, {string.format('SCAN %s\n',
+            fname)})
+      else
+        rspamd_logger.errx(task, '%s: invalid product id %s', rule['type'],
+            rule['product_id'])
+        conn:add_write(savapi_fin_cb, 'QUIT\n')
+      end
+    end
+
+    local function savapi_greet1_cb(err, conn)
+      conn:add_read(savapi_greet2_cb, '\n')
+    end
+
+    local function savapi_callback_init(err, data, conn)
+      if err then
+
+        -- set current upstream to fail because an error occurred
+        upstream:fail()
+
+        -- retry with another upstream until retransmits exceeds
+        if retransmits > 0 then
+
+          retransmits = retransmits - 1
+
+          -- Select a different upstream!
+          upstream = rule.upstreams:get_upstream_round_robin()
+          addr = upstream:get_addr()
+
+          lua_util.debugm(N, task, '%s [%s]: retry IP: %s', rule['symbol'], rule['type'], addr)
+
+          tcp.request({
+            task = task,
+            host = addr:to_string(),
+            port = addr:get_port(),
+            timeout = rule['timeout'],
+            callback = savapi_callback_init,
+            stop_pattern = {'\n'},
+          })
+        else
+          rspamd_logger.errx(task, '%s [%s]: failed to scan, maximum retransmits exceed', rule['symbol'], rule['type'])
+          task:insert_result(rule['symbol_fail'], 0.0, 'failed to scan and retransmits exceed')
+        end
+      else
+        upstream:ok()
+        local result = tostring(data)
+
+        -- 100 SAVAPI:4.0 greeting
+        if string.find(result, '100') then
+          conn:add_write(savapi_greet1_cb, {string.format('SET PRODUCT %s\n', rule['product_id'])})
+        end
+      end
+    end
+
+    tcp.request({
+      task = task,
+      host = addr:to_string(),
+      port = addr:get_port(),
+      timeout = rule['timeout'],
+      callback = savapi_callback_init,
+      stop_pattern = {'\n'},
+    })
+  end
+
+  if need_av_check(task, content, rule) then
+    if check_av_cache(task, digest, rule, savapi_check_uncached) then
+      return
+    else
+      savapi_check_uncached()
+    end
+  end
+end
+
+local function kaspersky_check(task, content, digest, rule)
+  local function kaspersky_check_uncached ()
+    local upstream = rule.upstreams:get_upstream_round_robin()
+    local addr = upstream:get_addr()
+    local retransmits = rule.retransmits
+    local fname = string.format('%s/%s.tmp',
+        rule.tmpdir, rspamd_util.random_hex(32))
+    local message_fd = rspamd_util.create_file(fname)
+    local clamav_compat_cmd = string.format("nSCAN %s\n", fname)
+
+    if not message_fd then
+      rspamd_logger.errx('cannot store file for kaspersky scan: %s', fname)
+      return
+    end
+
+    if type(content) == 'string' then
+      -- Create rspamd_text
+      local rspamd_text = require "rspamd_text"
+      content = rspamd_text.fromstring(content)
+    end
+    content:save_in_file(message_fd)
+
+    -- Ensure file cleanup
+    task:get_mempool():add_destructor(function()
+      os.remove(fname)
+      rspamd_util.close_file(message_fd)
+    end)
+
+
+    local function kaspersky_callback(err, data)
+      if err then
+        -- set current upstream to fail because an error occurred
+        upstream:fail()
+
+        -- retry with another upstream until retransmits exceeds
+        if retransmits > 0 then
+
+          retransmits = retransmits - 1
+
+          -- Select a different upstream!
+          upstream = rule.upstreams:get_upstream_round_robin()
+          addr = upstream:get_addr()
+
+          lua_util.debugm(N, task,
+              '%s [%s]: retry IP: %s', rule['symbol'], rule['type'], addr)
+
+          tcp.request({
+            task = task,
+            host = addr:to_string(),
+            port = addr:get_port(),
+            timeout = rule['timeout'],
+            callback = kaspersky_callback,
+            data = { clamav_compat_cmd },
+            stop_pattern = '\n'
+          })
+        else
+          rspamd_logger.errx(task,
+              '%s [%s]: failed to scan, maximum retransmits exceed',
+              rule['symbol'], rule['type'])
+          task:insert_result(rule['symbol_fail'], 0.0,
+              'failed to scan and retransmits exceed')
+        end
+
+      else
+        upstream:ok()
+        data = tostring(data)
+        local cached
+        lua_util.debugm(N, task, '%s [%s]: got reply: %s',
+            rule['symbol'], rule['type'], data)
+        if data == 'stream: OK' then
+          cached = 'OK'
+          if rule['log_clean'] then
+            rspamd_logger.infox(task, '%s [%s]: message or mime_part is clean',
+                rule['symbol'], rule['type'])
+          else
+            lua_util.debugm(N, task, '%s [%s]: message or mime_part is clean',
+                rule['symbol'], rule['type'])
+          end
+        else
+          local vname = string.match(data, ': (.+) FOUND')
+          if vname then
+            yield_result(task, rule, vname)
+            cached = vname
+          else
+            rspamd_logger.errx(task, 'unhandled response: %s', data)
+            task:insert_result(rule['symbol_fail'], 0.0, 'unhandled response')
+          end
+        end
+        if cached then
+          save_av_cache(task, digest, rule, cached)
+        end
+      end
+    end
+
+    tcp.request({
+      task = task,
+      host = addr:to_string(),
+      port = addr:get_port(),
+      timeout = rule['timeout'],
+      callback = kaspersky_callback,
+      data = { clamav_compat_cmd },
+      stop_pattern = '\n'
+    })
+  end
+
+  if need_av_check(task, content, rule) then
+    if check_av_cache(task, digest, rule, kaspersky_check_uncached) then
+      return
+    else
+      kaspersky_check_uncached()
+    end
+  end
+end
+
+local exports = {
+  av_types = {
+    clamav = {
+      configure = clamav_config,
+      check = clamav_check
+    },
+    fprot = {
+      configure = fprot_config,
+      check = fprot_check
+    },
+    sophos = {
+      configure = sophos_config,
+      check = sophos_check
+    },
+    savapi = {
+      configure = savapi_config,
+      check = savapi_check
+    },
+    kaspersky = {
+      configure = kaspersky_config,
+      check = kaspersky_check
+    }
+  },
+  -- Some utilities
+  match_patterns = match_patterns,
+  check_av_cache = check_av_cache,
+  save_av_cache = save_av_cache,
+}
+
+exports.add_antivirus = function(name, conf_func, check_func)
+  assert(type(conf_func) == 'function' and type(check_func) == 'function',
+      'bad arguments')
+  exports.av_types[name] = {
+    configure = conf_func,
+    check = check_func,
+  }
+end
+
+return exports
\ No newline at end of file
diff --git a/lualib/lua_scanners/init.lua b/lualib/lua_scanners/init.lua
new file mode 100644
index 000000000..5c76ada49
--- /dev/null
+++ b/lualib/lua_scanners/init.lua
@@ -0,0 +1,26 @@
+--[[
+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
+-- This module contains external scanners functions
+--]]
+
+local exports = {
+  antivirus = require "antivirus",
+}
+
+return exports
\ No newline at end of file