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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.
]]--
-- This module contains 'selectors' implementation: code to extract data
-- from Rspamd tasks and compose those together
--[[[
-- @module lua_selectors
-- This module contains 'selectors' implementation: code to extract data
-- from Rspamd tasks and compose those together.
-- Typical selector looks like this: header(User).lower.substring(1, 2):ip
--]]
local exports = {}
local logger = require 'rspamd_logger'
local fun = require 'fun'
local lua_util = require "lua_util"
local M = "lua_selectors"
local E = {}
local extractors = {
-- Get source IP address
['ip'] = {
['type'] = 'ip',
['get_value'] = function(task)
local ip = task:get_ip()
if ip and ip:is_valid() then return tostring(ip) end
return nil
end,
},
-- Get SMTP from
['smtp_from'] = {
['type'] = 'email',
['get_value'] = function(task)
local from = task:get_from(0)
if ((from or E)[1] or E).addr then
return from[1]
end
return nil
end,
},
-- Get MIME from
['mime_from'] = {
['type'] = 'email',
['get_value'] = function(task)
local from = task:get_from(0)
if ((from or E)[1] or E).addr then
return from[1]
end
return nil
end,
},
-- Get country (ASN module must be executed first)
['country'] = {
['type'] = 'string',
['get_value'] = function(task)
local asn = task:get_mempool():get_variable('asn')
if not asn then
return nil
else
return asn
end
end,
},
-- Get ASN number
['asn'] = {
['type'] = 'string',
['get_value'] = function(task)
local asn = task:get_mempool():get_variable('asn')
if not asn then
return nil
else
return asn
end
end,
},
-- Get authenticated username
['user'] = {
['type'] = 'string',
['get_value'] = function(task)
local auser = task:get_user()
if not auser then
return nil
else
return auser
end
end,
},
-- Get principal recipient
['to'] = {
['type'] = 'email',
['get_value'] = function(task)
return task:get_principal_recipient()
end,
},
-- Get content digest
['digest'] = {
['type'] = 'string',
['get_value'] = function(task)
return task:get_digest()
end,
},
-- Get list of all attachments digests
['attachments'] = {
['type'] = 'string_list',
['get_value'] = function(task)
local parts = task:get_parts() or E
local digests = {}
for _,p in ipairs(parts) do
if p:get_filename() then
table.insert(digests, p:get_digest())
end
end
if #digests > 0 then
return digests
end
return nil
end,
},
-- Get all attachments files
['files'] = {
['type'] = 'string_list',
['get_value'] = function(task)
local parts = task:get_parts() or E
local files = {}
for _,p in ipairs(parts) do
local fname = p:get_filename()
if fname then
table.insert(files, fname)
end
end
if #files > 0 then
return files
end
return nil
end,
},
-- Get helo value
['helo'] = {
['type'] = 'string',
['get_value'] = function(task)
return task:get_helo()
end,
},
-- Get header with the name that is expected as an argument. Returns list of
-- headers with this name
['header'] = {
['type'] = 'kv_list',
['get_value'] = function(task, args)
return task:get_header_full(args[1])
end,
},
-- Get list of received headers (returns list of tables)
['received'] = {
['type'] = 'kv_list',
['get_value'] = function(task)
return task:get_received_headers()
end,
},
-- Get all urls
['urls'] = {
['type'] = 'url_list',
['get_value'] = function(task)
return task:get_urls()
end,
},
-- Get all emails
['emails'] = {
['type'] = 'url_list',
['get_value'] = function(task)
return task:get_emails()
end,
},
-- Get specific pool var. The first argument must be variable name,
-- the second argument is optional and defines the type (string by default)
['pool_var'] = {
['type'] = 'string',
['get_value'] = function(task, args)
return task:get_mempool():get_variable(args[1], args[2])
end,
},
-- Get specific HTTP request header. The first argument must be header name.
['request_header'] = {
['type'] = 'string',
['get_value'] = function(task, args)
local hdr = task:get_request_header(args[1])
if hdr then
return tostring(hdr)
end
return nil
end
},
-- Get task date, optionally formatted
['time'] = {
['type'] = 'string',
['get_value'] = function(task, args)
local what = args[1] or 'message'
local dt = task:get_date{format = what, gmt = true}
if dt then
if args[2] then
-- Should be in format !xxx, as dt is in GMT
return os.date(args[2], dt)
end
return tostring(dt)
end
return nil
end
}
}
local transform_function = {
-- Get hostname from url or a list of urls
['get_host'] = {
['types'] = {
['url'] = true
},
['map_type'] = 'string',
['process'] = function(inp, t)
return inp:get_host(),'string'
end
},
-- Get tld from url or a list of urls
['get_tld'] = {
['types'] = {
['url'] = true
},
['map_type'] = 'string',
['process'] = function(inp, t)
return inp:get_tld()
end
},
-- Get address
['get_addr'] = {
['types'] = {
['email'] = true
},
['map_type'] = 'string',
['process'] = function(inp, _)
return inp:get_addr()
end
},
-- Returns the lowercased string
['lower'] = {
['types'] = {
['string'] = true,
},
['map_type'] = 'string',
['process'] = function(inp, _)
return inp:lower(),'string'
end
},
-- Returns the first element
['first'] = {
['types'] = {
['url_list'] = true,
['kv_list'] = true,
['received_list'] = true,
['string_list'] = true
},
['process'] = function(inp, t)
local pure_type = t:match('^(.*)_list$')
return inp[1],pure_type
end
},
-- Returns the last element
['last'] = {
['types'] = {
['url_list'] = true,
['kv_list'] = true,
['string_list'] = true
},
['process'] = function(inp, t)
local pure_type = t:match('^(.*)_list$')
return inp[#inp],pure_type
end
},
-- Returns the nth element
['nth'] = {
['types'] = {
['url_list'] = true,
['kv_list'] = true,
['string_list'] = true
},
['process'] = function(inp, t, args)
local pure_type = t:match('^(.*)_list$')
return inp[tonumber(args[1])],pure_type
end
},
-- Joins strings into a single string using separator in the argument
['join'] = {
['types'] = {
['string_list'] = true
},
['process'] = function(inp, _, args)
return table.concat(inp, args[1] or ''), 'string'
end
},
-- Create a digest from string or a list of strings
['digest'] = {
['types'] = {
['string'] = true
},
['map_type'] = 'hash',
['process'] = function(inp, _, args)
local hash = require 'rspamd_cryptobox_hash'
local ht = args[1] or 'blake2'
return hash:create_specific(ht):update(inp), 'hash'
end
},
-- Encode hash to string (using hex encoding by default)
['encode'] = {
['types'] = {
['hash'] = true
},
['map_type'] = 'string',
['process'] = function(inp, _, args)
local how = args[1] or 'hex'
if how == 'hex' then
return inp:hex()
elseif how == 'base32' then
return inp:base32()
elseif how == 'base64' then
return inp:base64()
end
end
},
-- Extracts substring
['substring'] = {
['types'] = {
['string'] = true
},
['map_type'] = 'string',
['process'] = function(inp, _, args)
local start_pos = args[1] or 1
local end_pos = args[2] or -1
return inp:sub(start_pos, end_pos), 'string'
end
},
-- Extracts table value from key-value list
['elt'] = {
['types'] = {
['kv'] = true,
},
['map_type'] = 'string',
['process'] = function(inp, t, args)
return inp[args[1]],'string'
end
},
-- Call specific userdata method
['method'] = {
['types'] = {
['email'] = true,
['url'] = true,
['ip'] = true,
},
['map_type'] = 'string',
['process'] = function(inp, _, args)
return inp[args[1]](inp)
end
},
-- Boolean function in, returns either nil or its input if input is in args list
['in'] = {
['types'] = {
['string'] = true,
},
['map_type'] = 'string',
['process'] = function(inp, t, args)
for _,a in ipairs(args) do if a == inp then return inp,t end end
return nil
end
},
['not_in'] = {
['types'] = {
['string'] = true,
},
['map_type'] = 'string',
['process'] = function(inp, t, args)
for _,a in ipairs(args) do if a == inp then return nil end end
return inp,t
end
},
}
local function process_selector(task, sel)
local input = sel.selector.get_value(task, sel.selector.args)
if not input then return nil end
-- Now we fold elements using left fold
local function fold_function(acc, x)
if acc == nil or acc[1] == nil then return nil end
local value = acc[1]
local t = acc[2]
if not x.types[t] then
-- Additional case for map
local pure_type = t:match('^(.*)_list$')
if pure_type and x.map_type and x.types[pure_type] then
return {fun.map(function(list_elt)
local ret, _ = x.process(list_elt, pure_type, x.args)
return ret
end, value), x.map_type}
end
logger.errx(task, 'cannot apply transform %s for type %s', x.name, t)
return nil
end
return {x.process(value, t, x.args)}
end
local res = fun.foldl(fold_function,
{input, sel.selector.type},
sel.processor_pipe)
if not res or not res[1] then return nil end -- Pipeline failed
if not (res[2] == 'string' or res[2] == 'string_list') then
logger.errx(task, 'transform pipeline has returned bad type: %s, string expected: res = %s, sel: %s',
res[2], res, sel)
return nil
end
if res[2] == 'string_list' then
-- Convert to table as it might have a functional form
return fun.totable(res[1])
end
return res[1]
end
local function make_grammar()
local l = require "lpeg"
local spc = l.S(" \t\n")^0
local atom = l.C((l.R("az") + l.R("AZ") + l.R("09") + l.S("_-"))^1)
local singlequoted_string = l.P "'" * l.C(((1 - l.S "'\r\n\f\\") + (l.P'\\' * 1))^0) * "'"
local doublequoted_string = l.P '"' * l.C(((1 - l.S'"\r\n\f\\') + (l.P'\\' * 1))^0) * '"'
local argument = atom + singlequoted_string + doublequoted_string
local dot = l.P(".")
local obrace = "(" * spc
local ebrace = spc * ")"
local comma = spc * "," * spc
local sel_separator = l.S":;"
return l.P{
"LIST";
LIST = l.Ct(l.V("EXPR")) * (sel_separator * l.Ct(l.V("EXPR")))^0,
EXPR = l.V("FUNCTION") * (dot * l.V("PROCESSOR"))^0,
PROCESSOR = l.Ct(atom * spc * (obrace * l.V("ARG_LIST") * ebrace)^0),
FUNCTION = l.Ct(atom * spc * (obrace * l.V("ARG_LIST") * ebrace)^0),
ARG_LIST = l.Ct((argument * comma^0)^0)
}
end
local parser = make_grammar()
--[[[
-- @function lua_selectors.parse_selectors(cfg, str)
--]]
exports.parse_selector = function(cfg, str)
local parsed = {parser:match(str)}
local output = {}
if not parsed then return nil end
local function shallowcopy(orig)
local orig_type = type(orig)
local copy
if orig_type == 'table' then
copy = {}
for orig_key, orig_value in pairs(orig) do
copy[orig_key] = orig_value
end
else
copy = orig
end
return copy
end
-- Output AST format is the following:
-- table of individual selectors
-- each selector: list of functions
-- each function: function name + optional list of arguments
for _,sel in ipairs(parsed) do
local res = {
selector = {},
processor_pipe = {},
}
local selector_tbl = sel[1]
if not selector_tbl then
logger.errx(cfg, 'no selector represented')
return nil
end
if not extractors[selector_tbl[1]] then
logger.errx(cfg, 'selector %s is unknown', selector_tbl[1])
return nil
end
res.selector = shallowcopy(extractors[selector_tbl[1]])
res.selector.name = selector_tbl[1]
res.selector.args = selector_tbl[2] or {}
lua_util.debugm(M, cfg, 'processed selector %s, args: %s',
res.selector.name, res.selector.arg)
-- Now process processors pipe
fun.each(function(proc_tbl)
local proc_name = proc_tbl[1]
if not transform_function[proc_name] then
logger.errx(cfg, 'processor %s is unknown', proc_name)
return nil
end
local processor = shallowcopy(transform_function[proc_name])
processor.name = proc_name
processor.args = proc_tbl[2]
lua_util.debugm(M, cfg, 'attached processor %s to selector %s, args: %s',
proc_name, res.selector.name, processor.args)
table.insert(res.processor_pipe, processor)
end, fun.tail(sel))
table.insert(output, res)
end
return output
end
--[[[
-- @function lua_selectors.register_selector(cfg, name, selector)
--]]
exports.register_selector = function(cfg, name, selector)
if selector.get_value and selector.type then
if extractors[name] then
logger.warnx(cfg, 'redefining selector %s', name)
end
extractors[name] = selector
return true
end
logger.errx(cfg, 'bad selector %s', name)
return false
end
--[[[
-- @function lua_selectors.register_transform(cfg, name, transform)
--]]
exports.register_transform = function(cfg, name, transform)
if transform.process and transform.types then
if transform_function[name] then
logger.warnx(cfg, 'redefining transform function %s', name)
end
transform_function[name] = transform
return true
end
logger.errx(cfg, 'bad transform function %s', name)
return false
end
--[[[
-- @function lua_selectors.process_selectors(task, selectors_pipe)
--]]
exports.process_selectors = function(task, selectors_pipe)
local ret = {}
for _,sel in ipairs(selectors_pipe) do
local r = process_selector(task, sel)
-- If any element is nil, then the whole selector is nil
if not r then return nil end
table.insert(ret, r)
end
return ret
end
--[[[
-- @function lua_selectors.combine_selectors(task, selectors, delimiter)
--]]
exports.combine_selectors = function(_, selectors, delimiter)
if not delimiter then delimiter = '' end
if not selectors then return nil end
local all_strings = fun.all(function(s) return type(s) == 'string' end, selectors)
if all_strings then
return table.concat(selectors, delimiter)
else
-- We need to do a spill on each table selector
-- e.g. s:tbl:s -> s:telt1:s + s:telt2:s ...
local prefix = {}
local tbl = {}
local suffix = {}
local res = {}
local in_prefix = true
for _,s in ipairs(selectors) do
if in_prefix then
if type(s) == 'string' then
table.insert(prefix, s)
else
in_prefix = false
table.insert(tbl, s)
end
else
if type(s) == 'string' then
table.insert(suffix, s)
else
table.insert(tbl, s)
end
end
end
prefix = table.concat(prefix, delimiter)
suffix = table.concat(suffix, delimiter)
for _,t in ipairs(tbl) do
fun.each(function(...)
table.insert(res, table.concat({...}, delimiter))
end, fun.zip(fun.duplicate(prefix), t, fun.duplicate(suffix)))
end
return res
end
end
return exports
|