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--[[
Copyright (c) 2016, 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.
]]--
-- A plugin that implements greylisting using redis
local redis_params
local whitelisted_ip
local settings = {
expire = 86400, -- 1 day by default
timeout = 300, -- 5 minutes by default
key_prefix = 'rg', -- default hash name
max_data_len = 10240, -- default data limit to hash
message = 'Try again later', -- default greylisted message
symbol = 'GREYLIST',
ipv4_mask = 19, -- Mask bits for ipv4
ipv6_mask = 64, -- Mask bits for ipv6
}
local rspamd_logger = require "rspamd_logger"
local rspamd_redis = require "rspamd_redis"
local upstream_list = require "rspamd_upstream_list"
local rspamd_util = require "rspamd_util"
local fun = require "fun"
local rspamd_cryptobox = require "rspamd_cryptobox"
local hash = require "rspamd_cryptobox_hash"
local function data_key(task)
local cached = task:get_mempool():get_variable("grey_bodyhash")
if cached then
return cached
end
local body = task:get_rawbody()
if not body then return nil end
local len = body:len()
if len > settings['max_data_len'] then
len = settings['max_data_len']
end
local h = hash.create()
h:update(body, len)
local b32 = settings['key_prefix'] .. 'b' .. h:base32():sub(1, 20)
task:get_mempool():set_variable("grey_bodyhash", b32)
return b32
end
local function envelope_key(task)
local cached = task:get_mempool():get_variable("grey_metahash")
if cached then
return cached
end
local from = task:get_from('smtp')
local h = hash.create()
local addr = '<>'
if from and from[1] then
addr = from[1]['addr']
end
h:update(addr)
local rcpt = task:get_recipients('smtp')
if rcpt then
table.sort(rcpt, function(r1, r2)
return r1['addr'] < r2['addr']
end)
fun.each(function(r)
h:update(r['addr'])
end, rcpt)
end
local ip = task:get_from_ip()
if ip and ip:is_valid() then
local s
if ip:get_version() == 4 then
s = tostring(ip:apply_mask(settings['ipv4_mask']))
else
s = tostring(ip:apply_mask(settings['ipv6_mask']))
end
h:update(s)
end
local b32 = settings['key_prefix'] .. 'm' .. h:base32():sub(1, 20)
task:get_mempool():set_variable("grey_metahash", b32)
return b32
end
-- Returns pair of booleans: found,greylisted
local function check_time(task, tm, type)
local t = tonumber(tm)
if not t then
rspamd_logger.infox(task, 'not a valid number: %s', tm)
return false,false
end
local now = rspamd_util.get_time()
if now - t < settings['timeout'] then
return true,true
else
-- We just set variable to pass when in post-filter stage
task:get_mempool():set_variable("grey_whitelisted", type)
return true,false
end
return false,false
end
local function greylist_check(task)
local ip_addr = task:get_ip()
if task:get_user() or (ip_addr and ip_addr:is_local()) then
return
end
local body_key = data_key(task)
local meta_key = envelope_key(task)
local hash_key = body_key .. meta_key
local upstream
local function redis_set_cb(task, err, data)
if not err then
upstream:ok()
else
rspamd_logger.infox(task, 'got error %s when setting greylisting record on server %s',
err, upstream:get_addr())
end
end
local function redis_get_cb(task, err, data)
local ret_body = false
local greylisted_body = false
local ret_meta = false
local greylisted_meta = false
local greylist_type
if data then
if data[1] and type(data[1]) ~= 'userdata' then
ret_body,greylisted_body = check_time(task, data[1], 'body')
if greylisted_body then
local end_time = rspamd_util.time_to_string(rspamd_util.get_time()
+ settings['timeout'])
task:get_mempool():set_variable("grey_greylisted_body", end_time)
end
end
if data[2] and type(data[2]) ~= 'userdata' then
if not ret_body or greylisted_body then
ret_meta,greylisted_meta = check_time(task, data[2], 'meta')
if greylisted_meta then
local end_time = rspamd_util.time_to_string(rspamd_util.get_time()
+ settings['timeout'])
task:get_mempool():set_variable("grey_greylisted_meta", end_time)
end
end
end
upstream:ok()
if not ret_body and not ret_meta then
local end_time = rspamd_util.time_to_string(rspamd_util.get_time()
+ settings['timeout'])
task:get_mempool():set_variable("grey_greylisted", end_time)
elseif greylisted_body and greylisted_meta then
local end_time = rspamd_util.time_to_string(rspamd_util.get_time() +
settings['timeout'])
rspamd_logger.infox(task, 'greylisted until "%s" using %s key',
end_time, type)
task:insert_result(settings['symbol'], 0.0, 'greylisted', end_time,
greylist_type)
task:set_pre_result('soft reject', settings['message'])
end
elseif err then
rspamd_logger.infox(task, 'got error while getting greylisting keys: %1', err)
upstream:fail()
end
end
local ret
ret,_,upstream = rspamd_redis_make_request(task,
redis_params, -- connect params
hash_key, -- hash key
false, -- is write
redis_get_cb, --callback
'MGET', -- command
{body_key, meta_key} -- arguments
)
if not ret then
rspamd_logger.errx(task, 'cannot make redis request to check results')
end
end
local function greylist_set(task)
local ip_addr = task:get_ip()
if task:get_user() or (ip_addr and ip_addr:is_local()) then
return
end
local is_whitelisted = task:get_mempool():get_variable("grey_whitelisted")
local do_greylisting = task:get_mempool():get_variable("grey_greylisted")
local action = task:get_metric_action('default')
if action == 'no action' or action == 'reject' then return end
local body_key = data_key(task)
local meta_key = envelope_key(task)
local upstream, ret, conn
local hash_key = body_key .. meta_key
local function redis_set_cb(task, err, data)
if not err then
upstream:ok()
else
rspamd_logger.infox(task, 'got error %s when setting greylisting record on server %s',
err, upstream:get_addr())
end
end
if is_whitelisted then
if action == 'greylist' then
-- We are going to accept message
task:set_metric_action('default', 'no action')
end
task:insert_result(settings['symbol'], 0.0, 'pass', is_whitelisted)
rspamd_logger.infox(task, 'greylisting pass (%s) until %s',
is_whitelisted,
rspamd_util.time_to_string(rspamd_util.get_time() + settings['expire']))
ret,conn,upstream = rspamd_redis_make_request(task,
redis_params, -- connect params
hash_key, -- hash key
true, -- is write
redis_set_cb, --callback
'EXPIRE', -- command
{body_key, tostring(settings['expire'])} -- arguments
)
-- Update greylisting record expire
if conn then
conn:add_cmd('EXPIRE', {
meta_key, tostring(settings['expire'])
})
else
rspamd_logger.infox(task, 'got error while connecting to redis: %1', addr)
upstream:fail()
end
elseif do_greylisting then
local t = tostring(math.floor(rspamd_util.get_time()))
local end_time = rspamd_util.time_to_string(t + settings['timeout'])
rspamd_logger.infox(task, 'greylisted until "%s", new record', end_time)
task:insert_result(settings['symbol'], 0.0, 'greylisted', end_time,
'new record')
task:set_pre_result('soft reject', settings['message'])
-- Create new record
local ret, conn
ret,conn,upstream = rspamd_redis_make_request(task,
redis_params, -- connect params
hash_key, -- hash key
true, -- is write
redis_set_cb, --callback
'SETEX', -- command
{body_key, tostring(settings['expire']), t} -- arguments
)
if conn then
conn:add_cmd('SETEX', {
meta_key, tostring(settings['expire']), t
})
local end_time = rspamd_util.time_to_string(rspamd_util.get_time()
+ settings['timeout'])
else
rspamd_logger.infox(task, 'got error while connecting to redis: %s',
upstream:get_addr())
upstream:fail()
end
else
if action ~= 'no action' and action ~= 'reject' then
local grey_res = task:get_mempool():get_variable("grey_greylisted_body")
if grey_res then
-- We need to delay message, hence set a temporary result
task:insert_result(settings['symbol'], 0.0, grey_res, 'body')
rspamd_logger.infox(task, 'greylisting delayed until "%s": body', grey_res)
else
grey_res = task:get_mempool():get_variable("grey_greylisted_meta")
if grey_res then
task:insert_result(settings['symbol'], 0.0, grey_res, 'meta')
rspamd_logger.infox(task, 'greylisting delayed until "%s": meta', grey_res)
else
task:insert_result(settings['symbol'], 0.0, 'greylisted', 'redis fail')
return
end
end
task:set_metric_action('default', 'soft reject')
task:set_pre_result('soft reject', settings['message'])
else
task:insert_result(settings['symbol'], 0.0, 'greylisted', 'passed')
end
end
end
local opts = rspamd_config:get_all_opt('greylist')
if opts then
if opts['enabled'] == false then
rspamd_logger.info('Module is disabled')
return
end
if opts['whitelisted_ip'] then
whitelisted_ip = rspamd_config:add_radix_map(opts['whitelisted_ip'],
'Greylist whitelist ip map')
end
redis_params = rspamd_parse_redis_server('greylist')
if not redis_params then
rspamd_logger.infox(rspamd_config, 'no servers are specified, disabling module')
else
rspamd_config:register_symbol({
name = 'GREYLIST_SAVE',
type = 'postfilter',
callback = greylist_set,
priority = 10
})
rspamd_config:register_symbol({
name = 'GREYLIST_CHECK',
type = 'prefilter',
callback = greylist_check,
})
end
for k,v in pairs(opts) do
settings[k] = v
end
end
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