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--[[
Copyright (c) 2011-2015, Vsevolod Stakhov <vsevolod@highsecure.ru>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
]]--
-- Dmarc policy filter
local rspamd_regexp = require "rspamd_regexp"
local rspamd_logger = require "rspamd_logger"
local rspamd_redis = require "rspamd_redis"
local upstream_list = require "rspamd_upstream_list"
--local dumper = require 'pl.pretty'.dump
local symbols = {
spf_allow_symbol = 'R_SPF_ALLOW',
spf_deny_symbol = 'R_SPF_FAIL',
spf_softfail_symbol = 'R_SPF_SOFTFAIL',
spf_neutral_symbol = 'R_SPF_NEUTRAL',
dkim_allow_symbol = 'R_DKIM_ALLOW',
dkim_deny_symbol = 'R_DKIM_REJECT',
}
-- Default port for redis upstreams
local default_port = 6379
local upstreams = nil
local dmarc_redis_key_prefix = "dmarc_"
local elts_re = rspamd_regexp.create_cached(";\\s+")
local function dmarc_report(task, spf_ok, dkim_ok)
local ip = task:get_from_ip()
if not ip:is_valid() then
return nil
end
local res = string.format('%d:%s:%s:%s', task:get_date(0),
ip:to_string(), tostring(spf_ok), tostring(dkim_ok))
return res
end
local function dmarc_callback(task)
local from = task:get_from(2)
local function dmarc_report_cb(task, err, data)
if not err then
rspamd_logger.info(string.format('<%s> dmarc report saved for %s',
task:get_message_id(), from[1]['domain']))
else
rspamd_logger.err(string.format('<%s> dmarc report is not saved for %s: %s',
task:get_message_id(), from[1]['domain'], err))
end
end
local function dmarc_dns_cb(resolver, to_resolve, results, err, key)
local strict_spf = false
local strict_dkim = false
local strict_policy = false
local quarantine_policy = false
local rua
if results then
for _,r in ipairs(results) do
local elts = elts_re:split(r)
if elts then
for _,e in ipairs(elts) do
dkim_pol = string.match(e, '^adkim=([sr])$')
if dkim_pol and dkim_pol == 's' then
strict_dkim = true
end
spf_pol = string.match(e, '^aspf=([sr])$')
if spf_pol and spf_pol == 's' then
strict_spf = true
end
policy = string.match(e, '^p=(.*)$')
if policy then
if (policy == 'reject') then
strict_policy = true
elseif (policy == 'quarantine') then
strict_policy = true
quarantine_policy = true
end
end
pct = string.match(e, '^pct=(.*)$')
if pct then
pct = tonumber(pct)
end
if not rua then
rua = string.match(e, '^rua=([^%s]+)$')
end
end
end
end
else
return
end
-- Check dkim and spf symbols
local spf_ok = false
local dkim_ok = false
if task:get_symbol(symbols['spf_allow_symbol']) then
efrom = task:get_from(1)
if efrom and efrom[1] and efrom[1]['domain'] then
if efrom[1]['domain'] == from[1]['domain'] then
spf_ok = true
elseif not strict_spf then
-- XXX: use tld list here and generate top level domain
end
end
end
local das = task:get_symbol(symbols['dkim_allow_symbol'])
if das and das[1] and das[1]['options'] and das[1]['options'][0] then
if from[1]['domain'] == das[1]['options'][0] then
dkim_ok = true
elseif not strict_dkim then
-- XXX: use tld list here and generate top level domain
end
end
local res = 0.5
if not (spf_ok or dkim_ok) then
res = 1.0
if quarantine_policy then
if not pct or pct == 100 or (math.random(100) <= pct) then
task:insert_result('DMARC_POLICY_QUARANTINE', res)
end
elseif strict_policy then
if not pct or pct == 100 or (math.random(100) <= pct) then
task:insert_result('DMARC_POLICY_REJECT', res)
end
else
task:insert_result('DMARC_POLICY_SOFTFAIL', res)
end
else
task:insert_result('DMARC_POLICY_ALLOW', res)
end
if rua and not(spf_ok or dkim_ok) and upstreams then
-- Prepare and send redis report element
local upstream = upstreams:get_upstream_by_hash(from[1]['domain'])
local redis_key = dmarc_redis_key_prefix .. from[1]['domain']
local addr = upstream:get_addr()
local report_data = dmarc_report(task, spf_ok, dkim_ok)
if report_data then
rspamd_redis.make_request(task, addr, dmarc_report_cb,
'LPUSH', {redis_key, report_data})
end
end
-- XXX: handle rua and push data to redis
end
if from and from[1]['domain'] and not from[2] then
-- XXX: use tld list here and generate top level domain
local dmarc_domain = '_dmarc.' .. from[1]['domain']
task:get_resolver():resolve_txt(task:get_session(), task:get_mempool(),
dmarc_domain, dmarc_dns_cb)
end
end
local opts = rspamd_config:get_all_opt('dmarc')
if not opts or type(opts) ~= 'table' then
return
end
if not opts['servers'] then
rspamd_logger.err('no servers are specified for dmarc stats')
else
upstreams = upstream_list.create(opts['servers'], default_port)
if not upstreams then
rspamd_logger.err('cannot parse servers parameter')
end
end
if opts['key_prefix'] then
dmarc_redis_key_prefix = opts['key_prefix']
end
-- Check spf and dkim sections for changed symbols
local function check_mopt(var, opts, name)
if opts[name] then
symbols['var'] = tostring(opts[name])
end
end
local spf_opts = rspamd_config:get_all_opt('spf')
if spf_opts then
check_mopt('spf_deny_symbol', spf_opts, 'symbol_fail')
check_mopt('spf_allow_symbol', spf_opts, 'symbol_allow')
check_mopt('spf_softfail_symbol', spf_opts, 'symbol_softfail')
check_mopt('spf_neutral_symbol', spf_opts, 'symbol_neutral')
end
local dkim_opts = rspamd_config:get_all_opt('dkim')
if dkim_opts then
check_mopt('dkim_deny_symbol', 'symbol_reject')
check_mopt('dkim_allow_symbol', 'symbol_allow')
end
rspamd_config:register_virtual_symbol('DMARC_POLICY_ALLOW', -1)
rspamd_config:register_virtual_symbol('DMARC_POLICY_REJECT', 1)
rspamd_config:register_virtual_symbol('DMARC_POLICY_QUARANTINE', 1)
rspamd_config:register_virtual_symbol('DMARC_POLICY_SOFTFAIL', 1)
rspamd_config:register_post_filter(dmarc_callback)
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