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--[[
Copyright (c) 2021, defkev <defkev@gmail.com>
Copyright (c) 2018, Carsten Rosenberg <c.rosenberg@heinlein-support.de>
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 pyzor
-- This module contains pyzor access functions
--]]
local lua_util = require "lua_util"
local tcp = require "rspamd_tcp"
local upstream_list = require "rspamd_upstream_list"
local rspamd_logger = require "rspamd_logger"
local common = require "lua_scanners/common"
local N = 'pyzor'
local categories = {'pyzor','bulk', 'hash', 'scanner'}
local function pyzor_config(opts)
local pyzor_conf = {
text_part_min_words = 2,
default_port = 5953,
timeout = 15.0,
log_clean = false,
retransmits = 2,
detection_category = "hash",
cache_expire = 7200, -- expire redis in one hour
message = '${SCANNER}: Pyzor bulk message found: "${VIRUS}"',
default_score = 1,
action = false,
}
pyzor_conf = lua_util.override_defaults(pyzor_conf, opts)
if not pyzor_conf.prefix then
pyzor_conf.prefix = 'rext_' .. N .. '_'
end
if not pyzor_conf.log_prefix then
pyzor_conf.log_prefix = N .. ' (' .. pyzor_conf.detection_category .. ')'
end
if not pyzor_conf['servers'] then
rspamd_logger.errx(rspamd_config, 'no servers defined')
return nil
end
pyzor_conf['upstreams'] = upstream_list.create(rspamd_config,
pyzor_conf['servers'],
pyzor_conf.default_port)
if pyzor_conf['upstreams'] then
lua_util.add_debug_alias('external_services', N)
return pyzor_conf
end
rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
pyzor_conf['servers'])
return nil
end
local function pyzor_check(task, content, digest, rule)
local function pyzor_check_uncached ()
local upstream = rule.upstreams:get_upstream_round_robin()
local addr = upstream:get_addr()
local retransmits = rule.retransmits
local function pyzor_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: retry IP: %s:%s err: %s',
rule.log_prefix, addr, addr:get_port(), err)
tcp.request({
task = task,
host = addr:to_string(),
port = addr:get_port(),
timeout = rule['timeout'],
shutdown = true,
data = content,
callback = pyzor_callback,
})
else
rspamd_logger.errx(task, '%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
-- Parse the response
if upstream then upstream:ok() end
-- pyzor output is unicode (\x09 -> tab, \0a -> newline)
-- public.pyzor.org:24441 (200, 'OK') 21285091 206759
-- server:port Code Diag Count WL-Count
lua_util.debugm(N, task, '%s: returned data: %s', rule.log_prefix, tostring(data))
-- If pyzor would return JSON this wouldn't be necessary
local resp = {}
for v in string.gmatch(tostring(data), '[^\t]+') do
table.insert(resp, v)
end
-- rspamd_logger.infox(task, 'resp: %s', resp)
if resp[2] ~= '(200, \'OK\')' then
rspamd_logger.errx(task, "error parsing response: %s", tostring(data))
return
end
local whitelisted = tonumber(resp[4])
local reported = tonumber(resp[3])
--rspamd_logger.infox(task, "%s - count=%s wl=%s", addr:to_string(), reported, whitelisted)
--[[
@todo: Implement math function to calc the score dynamically based on return values.
Maybe check spamassassin implementation.
]] --
local entries = reported - whitelisted
local weight = 0
if entries >= 100 then
weight = 1.5
elseif entries >= 25 then
weight = 1.25
elseif entries >= 5 then
weight = 1.0
elseif entries >= 1 and whitelisted == 0 then
weight = 0.2
end
if whitelisted >= 100 then
weight = weight - 1.5
elseif whitelisted >= 25 then
weight = weight - 1.25
elseif whitelisted >= 5 then
weight = weight - 1.0
elseif whitelisted >= 1 then
weight = weight - 0.2
end
local info = string.format("count=%d wl=%d", reported, whitelisted)
local threat_string = string.format("bl_%d_wl_%d", reported, whitelisted)
if weight > 0 then
lua_util.debugm(N, task, '%s: returned result is spam - info: %s', rule.log_prefix, info)
common.yield_result(task, rule, threat_string, weight)
common.save_cache(task, digest, rule, threat_string, weight)
else
if rule.log_clean then
rspamd_logger.infox(task, '%s: clean, returned result is ham - info: %s', rule.log_prefix, info)
else
lua_util.debugm(N, task, '%s: returned result is ham - info: %s', rule.log_prefix, info)
end
common.save_cache(task, digest, rule, 'OK', weight)
end
end
end
if digest == 'da39a3ee5e6b4b0d3255bfef95601890afd80709' then
rspamd_logger.infox(task, '%s: not checking default digest', rule.log_prefix)
return
end
tcp.request({
task = task,
host = addr:to_string(),
port = addr:get_port(),
timeout = rule.timeout,
shutdown = true,
data = content,
callback = pyzor_callback,
})
end
if common.condition_check_and_continue(task, content, rule, digest, pyzor_check_uncached) then
return
else
pyzor_check_uncached()
end
end
return {
type = categories,
description = 'pyzor bulk scanner',
configure = pyzor_config,
check = pyzor_check,
name = N
}
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