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|
--[[
Copyright (c) 2022, Vsevolod Stakhov <vsevolod@rspamd.com>
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.
]]--
local exports = {}
local N = "metatokens"
local ts = require("tableshape").types
local logger = require "rspamd_logger"
-- Metafunctions
local function meta_size_function(task)
local sizes = {
100,
200,
500,
1000,
2000,
4000,
10000,
20000,
30000,
100000,
200000,
400000,
800000,
1000000,
2000000,
8000000,
}
local size = task:get_size()
for i = 1, #sizes do
if sizes[i] >= size then
return { (1.0 * i) / #sizes }
end
end
return { 0 }
end
local function meta_images_function(task)
local images = task:get_images()
local ntotal = 0
local njpg = 0
local npng = 0
local nlarge = 0
local nsmall = 0
if images then
for _, img in ipairs(images) do
if img:get_type() == 'png' then
npng = npng + 1
elseif img:get_type() == 'jpeg' then
njpg = njpg + 1
end
local w = img:get_width()
local h = img:get_height()
if w > 0 and h > 0 then
if w + h > 256 then
nlarge = nlarge + 1
else
nsmall = nsmall + 1
end
end
ntotal = ntotal + 1
end
end
if ntotal > 0 then
njpg = 1.0 * njpg / ntotal
npng = 1.0 * npng / ntotal
nlarge = 1.0 * nlarge / ntotal
nsmall = 1.0 * nsmall / ntotal
end
return { ntotal, njpg, npng, nlarge, nsmall }
end
local function meta_nparts_function(task)
local nattachments = 0
local ntextparts = 0
local totalparts = 1
local tp = task:get_text_parts()
if tp then
ntextparts = #tp
end
local parts = task:get_parts()
if parts then
for _, p in ipairs(parts) do
if p:is_attachment() then
nattachments = nattachments + 1
end
totalparts = totalparts + 1
end
end
return { (1.0 * ntextparts) / totalparts, (1.0 * nattachments) / totalparts }
end
local function meta_encoding_function(task)
local nutf = 0
local nother = 0
local tp = task:get_text_parts()
if tp and #tp > 0 then
for _, p in ipairs(tp) do
if p:is_utf() then
nutf = nutf + 1
else
nother = nother + 1
end
end
return { nutf / #tp, nother / #tp }
end
return { 0, 0 }
end
local function meta_recipients_function(task)
local nmime = 0
local nsmtp = 0
if task:has_recipients('mime') then
nmime = #(task:get_recipients('mime'))
end
if task:has_recipients('smtp') then
nsmtp = #(task:get_recipients('smtp'))
end
if nmime > 0 then
nmime = 1.0 / nmime
end
if nsmtp > 0 then
nsmtp = 1.0 / nsmtp
end
return { nmime, nsmtp }
end
local function meta_received_function(task)
local count_factor = 0
local invalid_factor = 0
local rh = task:get_received_headers()
local time_factor = 0
local secure_factor = 0
local fun = require "fun"
if rh and #rh > 0 then
local ntotal = 0.0
local init_time = 0
fun.each(function(rc)
ntotal = ntotal + 1.0
if not rc.by_hostname then
invalid_factor = invalid_factor + 1.0
end
if init_time == 0 and rc.timestamp then
init_time = rc.timestamp
elseif rc.timestamp then
time_factor = time_factor + math.abs(init_time - rc.timestamp)
init_time = rc.timestamp
end
if rc.flags and (rc.flags['ssl'] or rc.flags['authenticated']) then
secure_factor = secure_factor + 1.0
end
end,
fun.filter(function(rc)
return not rc.flags or not rc.flags['artificial']
end, rh))
if ntotal > 0 then
invalid_factor = invalid_factor / ntotal
secure_factor = secure_factor / ntotal
count_factor = 1.0 / ntotal
end
if time_factor ~= 0 then
time_factor = 1.0 / time_factor
end
end
return { count_factor, invalid_factor, time_factor, secure_factor }
end
local function meta_urls_function(task)
local has_urls, nurls = task:has_urls()
if has_urls and nurls > 0 then
return { 1.0 / nurls }
end
return { 0 }
end
local function meta_words_function(task)
local avg_len = task:get_mempool():get_variable("avg_words_len", "double") or 0.0
local short_words = task:get_mempool():get_variable("short_words_cnt", "double") or 0.0
local ret_len = 0
local lens = {
2,
3,
4,
5,
6,
7,
8,
9,
10,
15,
20,
}
for i = 1, #lens do
if lens[i] >= avg_len then
ret_len = (1.0 * i) / #lens
break
end
end
local tp = task:get_text_parts()
local wres = {
0, -- spaces rate
0, -- double spaces rate
0, -- non spaces rate
0, -- ascii characters rate
0, -- non-ascii characters rate
0, -- capital characters rate
0, -- numeric characters
}
for _, p in ipairs(tp) do
local stats = p:get_stats()
local len = p:get_length()
if len > 0 then
wres[1] = wres[1] + stats['spaces'] / len
wres[2] = wres[2] + stats['double_spaces'] / len
wres[3] = wres[3] + stats['non_spaces'] / len
wres[4] = wres[4] + stats['ascii_characters'] / len
wres[5] = wres[5] + stats['non_ascii_characters'] / len
wres[6] = wres[6] + stats['capital_letters'] / len
wres[7] = wres[7] + stats['numeric_characters'] / len
end
end
local ret = {
short_words,
ret_len,
}
local divisor = 1.0
if #tp > 0 then
divisor = #tp
end
for _, wr in ipairs(wres) do
table.insert(ret, wr / divisor)
end
return ret
end
local metafunctions = {
{
cb = meta_size_function,
ninputs = 1,
names = {
"size"
},
description = 'Describes size of the message',
},
{
cb = meta_images_function,
ninputs = 5,
-- 1 - number of images,
-- 2 - number of png images,
-- 3 - number of jpeg images
-- 4 - number of large images (> 128 x 128)
-- 5 - number of small images (< 128 x 128)
names = {
'nimages',
'npng_images',
'njpeg_images',
'nlarge_images',
'nsmall_images'
},
description = [[Functions for images matching:
- number of images,
- number of png images,
- number of jpeg images
- number of large images (> 128 x 128)
- number of small images (< 128 x 128)
]]
},
{
cb = meta_nparts_function,
ninputs = 2,
-- 1 - number of text parts
-- 2 - number of attachments
names = {
'ntext_parts',
'nattachments'
},
description = [[Functions for images matching:
- number of text parts
- number of attachments
]]
},
{
cb = meta_encoding_function,
ninputs = 2,
-- 1 - number of utf parts
-- 2 - number of non-utf parts
names = {
'nutf_parts',
'nascii_parts'
},
description = [[Functions for encoding matching:
- number of utf parts
- number of non-utf parts
]]
},
{
cb = meta_recipients_function,
ninputs = 2,
-- 1 - number of mime rcpt
-- 2 - number of smtp rcpt
names = {
'nmime_rcpt',
'nsmtp_rcpt'
},
description = [[Functions for recipients data matching:
- number of mime rcpt
- number of smtp rcpt
]]
},
{
cb = meta_received_function,
ninputs = 4,
names = {
'nreceived',
'nreceived_invalid',
'nreceived_bad_time',
'nreceived_secure'
},
description = [[Functions for received headers data matching:
- number of received headers
- number of bad received headers
- number of skewed time received headers
- number of received via secured relays
]]
},
{
cb = meta_urls_function,
ninputs = 1,
names = {
'nurls'
},
description = [[Functions for urls data matching:
- number of urls
]]
},
{
cb = meta_words_function,
ninputs = 9,
names = {
'avg_words_len',
'nshort_words',
'spaces_rate',
'double_spaces_rate',
'non_spaces_rate',
'ascii_characters_rate',
'non_ascii_characters_rate',
'capital_characters_rate',
'numeric_characters'
},
description = [[Functions for words data matching:
- average length of the words
- number of short words
- rate of spaces in the text
- rate of multiple spaces
- rate of non space characters
- rate of ascii characters
- rate of non-ascii characters
- rate of capital letters
- rate of numbers
]]
},
}
local meta_schema = ts.shape {
cb = ts.func,
ninputs = ts.number,
names = ts.array_of(ts.string),
description = ts.string:is_optional()
}
local metatokens_by_name = {}
local function fill_metatokens_by_name()
metatokens_by_name = {}
for _, mt in ipairs(metafunctions) do
for i = 1, mt.ninputs do
local name = mt.names[i]
metatokens_by_name[name] = function(task)
local results = mt.cb(task)
return results[i]
end
end
end
end
local function calculate_digest()
local cr = require "rspamd_cryptobox_hash"
local h = cr.create()
for _, mt in ipairs(metafunctions) do
for i = 1, mt.ninputs do
local name = mt.names[i]
h:update(name)
end
end
exports.digest = h:hex()
end
local function rspamd_gen_metatokens(task, names)
local lua_util = require "lua_util"
local ipairs = ipairs
local metatokens = {}
if not names then
local cached = task:cache_get('metatokens')
if cached then
return cached
else
for _, mt in ipairs(metafunctions) do
local ct = mt.cb(task)
for i, tok in ipairs(ct) do
lua_util.debugm(N, task, "metatoken: %s = %s",
mt.names[i], tok)
if tok ~= tok or tok == math.huge then
logger.errx(task, 'metatoken %s returned %s; replace it with 0 for sanity',
mt.names[i], tok)
tok = 0.0
end
table.insert(metatokens, tok)
end
end
task:cache_set('metatokens', metatokens)
end
else
for _, n in ipairs(names) do
if metatokens_by_name[n] then
local tok = metatokens_by_name[n](task)
if tok ~= tok or tok == math.huge then
logger.errx(task, 'metatoken %s returned %s; replace it with 0 for sanity',
n, tok)
tok = 0.0
end
table.insert(metatokens, tok)
else
logger.errx(task, 'unknown metatoken: %s', n)
end
end
end
return metatokens
end
exports.rspamd_gen_metatokens = rspamd_gen_metatokens
exports.gen_metatokens = rspamd_gen_metatokens
local function rspamd_gen_metatokens_table(task)
local metatokens = {}
for _, mt in ipairs(metafunctions) do
local ct = mt.cb(task)
for i, tok in ipairs(ct) do
if tok ~= tok or tok == math.huge then
logger.errx(task, 'metatoken %s returned %s; replace it with 0 for sanity',
mt.names[i], tok)
tok = 0.0
end
metatokens[mt.names[i]] = tok
end
end
return metatokens
end
exports.rspamd_gen_metatokens_table = rspamd_gen_metatokens_table
exports.gen_metatokens_table = rspamd_gen_metatokens_table
local function rspamd_count_metatokens()
local ipairs = ipairs
local total = 0
for _, mt in ipairs(metafunctions) do
total = total + mt.ninputs
end
return total
end
exports.rspamd_count_metatokens = rspamd_count_metatokens
exports.count_metatokens = rspamd_count_metatokens
exports.version = 1 -- MUST be increased on each change of metatokens
exports.add_metafunction = function(tbl)
local ret, err = meta_schema(tbl)
if not ret then
logger.errx('cannot add metafunction: %s', err)
else
table.insert(metafunctions, tbl)
fill_metatokens_by_name()
calculate_digest()
end
end
fill_metatokens_by_name()
calculate_digest()
return exports
|