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--[[
Copyright (c) 2018, 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.
]]--
--[[[
-- @module lua_scanners_common
-- This module contains common external scanners functions
--]]
local rspamd_logger = require "rspamd_logger"
local lua_util = require "lua_util"
local lua_redis = require "lua_redis"
local fun = require "fun"
local exports = {}
local function match_patterns(default_sym, found, patterns)
if type(patterns) ~= 'table' then return default_sym end
if not patterns[1] then
for sym, pat in pairs(patterns) do
if pat:match(found) then
return sym
end
end
return default_sym
else
for _, p in ipairs(patterns) do
for sym, pat in pairs(p) do
if pat:match(found) then
return sym
end
end
end
return default_sym
end
end
local function yield_result(task, rule, vname, N, dyn_weight)
local all_whitelisted = true
if not dyn_weight then dyn_weight = 1.0 end
if type(vname) == 'string' then
local symname = match_patterns(rule.symbol, vname, rule.patterns)
if rule.whitelist and rule.whitelist:get_key(vname) then
rspamd_logger.infox(task, '%s: "%s" is in whitelist', N, vname)
return
end
task:insert_result(symname, 1.0, vname)
rspamd_logger.infox(task, '%s: %s found: "%s"', N, rule.detection_category, vname)
elseif type(vname) == 'table' then
for _, vn in ipairs(vname) do
local symname = match_patterns(rule.symbol, vn, rule.patterns)
if rule.whitelist and rule.whitelist:get_key(vn) then
rspamd_logger.infox(task, '%s: "%s" is in whitelist', N, vn)
else
all_whitelisted = false
task:insert_result(symname, dyn_weight, vn)
rspamd_logger.infox(task, '%s: %s found: "%s"',
N, rule.detection_category, vn)
end
end
end
if rule.action then
if type(vname) == 'table' then
if all_whitelisted then return end
vname = table.concat(vname, '; ')
end
task:set_pre_result(rule['action'],
lua_util.template(rule.message or 'Rejected', {
SCANNER = N,
VIRUS = vname,
}), N)
end
end
local function message_not_too_large(task, content, rule)
local max_size = tonumber(rule.max_size)
if not max_size then return true end
if #content > max_size then
rspamd_logger.infox(task, "skip %s check as it is too large: %s (%s is allowed)",
N, #content, max_size)
return false
end
return true
end
local function need_av_check(task, content, rule, N)
return message_not_too_large(task, content, rule, N)
end
local function check_av_cache(task, digest, rule, fn, N)
local key = digest
local function redis_av_cb(err, data)
if data and type(data) == 'string' then
-- Cached
if data ~= 'OK' then
lua_util.debugm(N, task, 'got cached result for %s: %s',
key, data)
data = lua_util.str_split(data, '\v')
yield_result(task, rule, data, N)
else
lua_util.debugm(N, task, 'got cached result for %s: %s',
key, data)
end
else
if err then
rspamd_logger.errx(task, 'got error checking cache: %s', err)
end
fn()
end
end
if rule.redis_params then
key = rule['prefix'] .. key
if lua_redis.redis_make_request(task,
rule.redis_params, -- connect params
key, -- hash key
false, -- is write
redis_av_cb, --callback
'GET', -- command
{key} -- arguments)
) then
return true
end
end
return false
end
local function save_av_cache(task, digest, rule, to_save, N)
local key = digest
local function redis_set_cb(err)
-- Do nothing
if err then
rspamd_logger.errx(task, 'failed to save %s cache for %s -> "%s": %s',
rule.detection_category, to_save, key, err)
else
lua_util.debugm(N, task, 'saved cached result for %s: %s',
key, to_save)
end
end
if type(to_save) == 'table' then
to_save = table.concat(to_save, '\v')
end
if rule.redis_params and rule.prefix then
key = rule.prefix .. key
lua_redis.redis_make_request(task,
rule.redis_params, -- connect params
key, -- hash key
true, -- is write
redis_set_cb, --callback
'SETEX', -- command
{ key, rule.cache_expire or 0, to_save }
)
end
return false
end
local function text_parts_min_words(task, min_words)
local text_parts_empty = true
local text_parts = task:get_text_parts()
local filter_func = function(p)
return p:get_words_count() >= min_words
end
fun.each(function(p)
text_parts_empty = false
end, fun.filter(filter_func, text_parts))
return text_parts_empty
end
exports.yield_result = yield_result
exports.match_patterns = match_patterns
exports.need_av_check = need_av_check
exports.check_av_cache = check_av_cache
exports.save_av_cache = save_av_cache
exports.text_parts_min_words = text_parts_min_words
setmetatable(exports, {
__call = function(t, override)
for k, v in pairs(t) do
if _G[k] ~= nil then
local msg = 'function ' .. k .. ' already exists in global scope.'
if override then
_G[k] = v
print('WARNING: ' .. msg .. ' Overwritten.')
else
print('NOTICE: ' .. msg .. ' Skipped.')
end
else
_G[k] = v
end
end
end,
})
return exports
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