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--[[
Copyright (c) 2019, Vsevolod Stakhov <vsevolod@highsecure.ru>
Copyright (c) 2019, Carsten Rosenberg <c.rosenberg@heinlein-support.de>
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)
-- 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
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(),
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
-- Parse the response
if upstream then upstream:ok() end
--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(),
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
}
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