--[[ Copyright (c) 2022, Vsevolod Stakhov Copyright (c) 2019, Carsten Rosenberg 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 spamassassin -- This module contains spamd 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 = 'spamassassin' local function spamassassin_config(opts) local spamassassin_conf = { N = N, scan_mime_parts = false, scan_text_mime = false, scan_image_mime = false, default_port = 783, timeout = 15.0, log_clean = false, retransmits = 2, cache_expire = 3600, -- expire redis in one hour symbol = "SPAMD", message = '${SCANNER}: Spamassassin bulk message found: "${VIRUS}"', detection_category = "spam", default_score = 1, action = false, extended = false, symbol_type = 'postfilter', dynamic_scan = true, } spamassassin_conf = lua_util.override_defaults(spamassassin_conf, opts) if not spamassassin_conf.prefix then spamassassin_conf.prefix = 'rs_' .. spamassassin_conf.name .. '_' end if not spamassassin_conf.log_prefix then if spamassassin_conf.name:lower() == spamassassin_conf.type:lower() then spamassassin_conf.log_prefix = spamassassin_conf.name else spamassassin_conf.log_prefix = spamassassin_conf.name .. ' (' .. spamassassin_conf.type .. ')' end end if not spamassassin_conf.servers then rspamd_logger.errx(rspamd_config, 'no servers defined') return nil end spamassassin_conf.upstreams = upstream_list.create(rspamd_config, spamassassin_conf.servers, spamassassin_conf.default_port) if spamassassin_conf.upstreams then lua_util.add_debug_alias('external_services', spamassassin_conf.N) return spamassassin_conf end rspamd_logger.errx(rspamd_config, 'cannot parse servers %s', spamassassin_conf.servers) return nil end local function spamassassin_check(task, content, digest, rule) local function spamassassin_check_uncached () local upstream = rule.upstreams:get_upstream_round_robin() local addr = upstream:get_addr() local retransmits = rule.retransmits -- Build the spamd query -- https://svn.apache.org/repos/asf/spamassassin/trunk/spamd/PROTOCOL local request_data = { "HEADERS SPAMC/1.5\r\n", "User: root\r\n", "Content-length: ".. #content .. "\r\n", "\r\n", content, } local function spamassassin_callback(err, data) local function spamassassin_requery(error) -- retry with another upstream until retransmits exceeds if retransmits > 0 then retransmits = retransmits - 1 lua_util.debugm(rule.N, task, '%s: Request Error: %s - retries left: %s', rule.log_prefix, error, retransmits) -- Select a different upstream! upstream = rule.upstreams:get_upstream_round_robin() addr = upstream:get_addr() lua_util.debugm(rule.N, task, '%s: retry IP: %s:%s', rule.log_prefix, addr, addr:get_port()) tcp.request({ task = task, host = addr:to_string(), port = addr:get_port(), upstream = upstream, timeout = rule['timeout'], data = request_data, callback = spamassassin_callback, }) else rspamd_logger.errx(task, '%s: failed to scan, maximum retransmits '.. 'exceed - err: %s', rule.log_prefix, error) common.yield_result(task, rule, 'failed to scan and retransmits exceed: ' .. error, 0.0, 'fail') end end if err then spamassassin_requery(err) else --lua_util.debugm(rule.N, task, '%s: returned result: %s', rule.log_prefix, data) --[[ patterns tested against Spamassassin 3.4.6 X-Spam-Status: No, score=1.1 required=5.0 tests=HTML_MESSAGE,MIME_HTML_ONLY, TVD_RCVD_SPACE_BRACKET,UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.6 ]] -- local header = string.gsub(tostring(data), "[\r\n]+[\t ]", " ") --lua_util.debugm(rule.N, task, '%s: returned header: %s', rule.log_prefix, header) local symbols = "" local spam_score = 0 for s in header:gmatch("[^\r\n]+") do if string.find(s, 'X%-Spam%-Status: %S+, score') then local pattern_symbols = "X%-Spam%-Status: %S+, score%=([%-%d%.]+)%s.*tests%=(.*,?)(%s*%S+)%sautolearn.*" spam_score = string.gsub(s, pattern_symbols, "%1") symbols = string.gsub(s, pattern_symbols, "%2%3") symbols = string.gsub(symbols, "%s", "") end end lua_util.debugm(rule.N, task, '%s: spam_score: %s, symbols: %s, int spam_score: |%s|, type spam_score: |%s|', rule.log_prefix, spam_score, symbols, tonumber(spam_score), type(spam_score)) if tonumber(spam_score) > 0 and #symbols > 0 and symbols ~= "none" then if rule.extended == false then common.yield_result(task, rule, symbols, spam_score) common.save_cache(task, digest, rule, symbols, spam_score) else local symbols_table = lua_util.str_split(symbols, ",") lua_util.debugm(rule.N, task, '%s: returned symbols as table: %s', rule.log_prefix, symbols_table) common.yield_result(task, rule, symbols_table, spam_score) common.save_cache(task, digest, rule, symbols_table, spam_score) end else common.save_cache(task, digest, rule, 'OK') common.log_clean(task, rule, 'no spam detected - spam score: ' .. spam_score .. ', symbols: ' .. symbols) end end end tcp.request({ task = task, host = addr:to_string(), port = addr:get_port(), upstream = upstream, timeout = rule['timeout'], data = request_data, callback = spamassassin_callback, }) end if common.condition_check_and_continue(task, content, rule, digest, spamassassin_check_uncached) then return else spamassassin_check_uncached() end end return { type = {N,'spam', 'scanner'}, description = 'spamassassin spam scanner', configure = spamassassin_config, check = spamassassin_check, name = N }