File: //proc/1/task/1/root/usr/share/rspamd/lualib/lua_aliases.lua
--[[
Copyright (c) 2025, 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.
]] --
--[[[
-- @module lua_aliases
-- Email aliases resolution and local domains management
--
-- This module provides functionality for:
-- - Parsing Unix-style aliases (/etc/aliases format)
-- - Parsing virtual aliases (Postfix virtual format)
-- - Resolving email addresses through alias chains
-- - Detecting local vs external domains
-- - Classifying message direction (inbound/outbound/internal)
--]]
local rspamd_logger = require "rspamd_logger"
local lua_util = require "lua_util"
local lua_maps = require "lua_maps"
local N = "lua_aliases"
local exports = {}
--- Count elements in a table (including hash tables)
-- @param tbl table to count
-- @return number of elements
local function table_length(tbl)
if not tbl then return 0 end
local count = 0
for _ in pairs(tbl) do
count = count + 1
end
return count
end
-- Module state
local module_state = {
initialized = false,
config = nil,
local_domains = {}, -- Set of local domains or backend
unix_aliases = {}, -- Unix aliases map or backend
virtual_aliases = {}, -- Virtual aliases map or backend
rspamd_aliases = {}, -- Rspamd-specific aliases
cache = {}, -- Resolution cache
backends = {}, -- Storage backends instances
}
--[[ Backend abstraction ]] --
--- Backend interface:
-- backend:get(key) -> value or nil
-- backend:type() -> string
-- File backend (already implemented via parse_* functions)
local FileBackend = {}
FileBackend.__index = FileBackend
function FileBackend.new(file_path, parser_func)
local self = setmetatable({}, FileBackend)
self.file_path = file_path
self.parser_func = parser_func
self.data = nil
self.loaded = false
return self
end
function FileBackend:load()
if not self.loaded then
self.data = self.parser_func(self.file_path)
self.loaded = true
end
return self.data ~= nil
end
function FileBackend:get(key)
if not self.loaded then
self:load()
end
return self.data and self.data[key:lower()]
end
function FileBackend:type()
return "file"
end
-- Map backend (using lua_maps)
local MapBackend = {}
MapBackend.__index = MapBackend
function MapBackend.new(rspamd_config, map_config, map_type)
local self = setmetatable({}, MapBackend)
self.map_type = map_type or 'hash'
-- Create map using lua_maps
self.map = lua_maps.map_add_from_ucl(map_config, self.map_type,
'aliases map (' .. self.map_type .. ')')
if not self.map then
rspamd_logger.errx(rspamd_config, 'cannot create map from config: %s',
map_config)
return nil
end
return self
end
function MapBackend:get(key)
if not self.map then
return nil
end
local result = self.map:get_key(key:lower())
return result
end
function MapBackend:type()
return "map:" .. self.map_type
end
-- CDB backend (using existing CDB support)
local CDBBackend = {}
CDBBackend.__index = CDBBackend
function CDBBackend.new(rspamd_config, cdb_path)
local self = setmetatable({}, CDBBackend)
-- Use lua_maps CDB support
local map_config = {
cdb = cdb_path,
external = true,
}
self.map = lua_maps.map_add_from_ucl(map_config, 'cdb', 'aliases cdb')
if not self.map then
rspamd_logger.errx(rspamd_config, 'cannot load CDB from %s', cdb_path)
return nil
end
return self
end
function CDBBackend:get(key)
if not self.map then
return nil
end
return self.map:get_key(key:lower())
end
function CDBBackend:type()
return "cdb"
end
-- Forward declarations for parser functions
local parse_unix_aliases
local parse_virtual_aliases
local parse_local_domains
--- Create backend from configuration
-- @param rspamd_config rspamd config object
-- @param config backend configuration (table or string)
-- @param default_parser default parser for file backend
-- @return backend instance or nil
local function create_backend(rspamd_config, config, default_parser)
-- String path -> file backend
if type(config) == 'string' then
return FileBackend.new(config, default_parser)
end
-- Table configuration
if type(config) ~= 'table' then
return nil
end
local backend_type = config.type or 'file'
if backend_type == 'file' then
if config.path then
return FileBackend.new(config.path, default_parser)
end
elseif backend_type == 'map' then
if config.url or config.urls then
return MapBackend.new(rspamd_config, config, config.map_type or 'hash')
end
elseif backend_type == 'redis' then
rspamd_logger.errx(rspamd_config,
'Redis backend is not supported for aliases (requires async with task context). Use CDB or Map instead.')
return nil
elseif backend_type == 'cdb' then
if config.path then
return CDBBackend.new(rspamd_config, config.path)
end
end
rspamd_logger.errx(rspamd_config, 'unknown backend type or invalid config: %s', backend_type)
return nil
end
--- Initialize the module with configuration
-- @param rspamd_config rspamd config object
-- @param opts configuration options
-- @return true on success
local function init(rspamd_config, opts)
if module_state.initialized then
rspamd_logger.warnx(rspamd_config, 'lua_aliases already initialized')
return true
end
module_state.config = rspamd_config
opts = opts or {}
-- Load local domains
if opts.local_domains then
if type(opts.local_domains) == 'table' and not opts.local_domains.type then
-- Inline array of domains
for _, domain in ipairs(opts.local_domains) do
module_state.local_domains[domain:lower()] = true
end
rspamd_logger.infox(rspamd_config, 'loaded %s local domains from inline config',
#opts.local_domains)
else
-- Backend configuration
local backend = create_backend(rspamd_config, opts.local_domains, parse_local_domains)
if backend then
module_state.backends.local_domains = backend
rspamd_logger.infox(rspamd_config, 'initialized local domains backend: %s',
backend:type())
-- For file backend, load immediately
if backend.type and backend:type() == 'file' then
if backend:load() then
module_state.local_domains = backend.data
rspamd_logger.infox(rspamd_config, 'loaded %s local domains',
table_length(module_state.local_domains))
end
end
end
end
end
-- Load system aliases
if opts.system_aliases then
local backend = create_backend(rspamd_config, opts.system_aliases, parse_unix_aliases)
if backend then
module_state.backends.system_aliases = backend
rspamd_logger.infox(rspamd_config, 'initialized system aliases backend: %s',
backend:type())
-- For file backend, load immediately
if backend.type and backend:type() == 'file' then
if backend:load() then
module_state.unix_aliases = backend.data
rspamd_logger.infox(rspamd_config, 'loaded %s system aliases',
table_length(module_state.unix_aliases))
end
else
-- For other backends, keep reference
module_state.unix_aliases = backend
end
end
end
-- Load virtual aliases
if opts.virtual_aliases then
local backend = create_backend(rspamd_config, opts.virtual_aliases, parse_virtual_aliases)
if backend then
module_state.backends.virtual_aliases = backend
rspamd_logger.infox(rspamd_config, 'initialized virtual aliases backend: %s',
backend:type())
-- For file backend, load immediately
if backend.type and backend:type() == 'file' then
if backend:load() then
module_state.virtual_aliases = backend.data
rspamd_logger.infox(rspamd_config, 'loaded %s virtual aliases',
table_length(module_state.virtual_aliases))
end
else
-- For other backends, keep reference
module_state.virtual_aliases = backend
end
end
end
-- Load rspamd-specific aliases (always inline)
if opts.rspamd_aliases then
if type(opts.rspamd_aliases) == 'table' then
module_state.rspamd_aliases = opts.rspamd_aliases
rspamd_logger.infox(rspamd_config, 'loaded %s rspamd aliases from inline config',
table_length(opts.rspamd_aliases))
end
end
module_state.initialized = true
return true
end
exports.init = init
--- Parse Unix-style aliases file (/etc/aliases format)
-- Format:
-- alias: target1, target2, ...
-- # Comments
-- continuation lines with backslash \
--
-- @param file_path path to aliases file
-- @return table of aliases {alias -> {targets...}} or nil on error
function parse_unix_aliases(file_path)
local aliases = {}
local f, err = io.open(file_path, 'r')
if not f then
if module_state.config then
rspamd_logger.warnx(module_state.config,
'cannot open aliases file %s: %s', file_path, err)
end
return nil
end
local current_line = ""
local line_num = 0
for line in f:lines() do
line_num = line_num + 1
-- Strip trailing whitespace
line = line:gsub('%s+$', '')
-- Handle line continuation
if line:match('\\$') then
current_line = current_line .. line:gsub('\\$', '')
goto continue
else
current_line = current_line .. line
end
-- Skip empty lines and comments
if current_line:match('^%s*$') or current_line:match('^%s*#') then
current_line = ""
goto continue
end
-- Parse alias line: "alias: target1, target2, ..."
local alias, targets = current_line:match('^%s*([^:]+):%s*(.*)$')
if alias and targets then
alias = alias:gsub('%s+$', ''):lower() -- Normalize alias
-- Split targets by comma
local target_list = {}
for target in targets:gmatch('[^,]+') do
target = target:gsub('^%s+', ''):gsub('%s+$', '') -- Trim
-- Skip special targets for now (:include:, |program, /file)
if not target:match('^:include:') and
not target:match('^|') and
not target:match('^/') then
-- Normalize target
target = target:lower()
-- Add domain if missing and it's not email format
if not target:match('@') then
-- It's a local user, we'll handle it later
table.insert(target_list, target)
else
table.insert(target_list, target)
end
else
if module_state.config then
rspamd_logger.debugm(N, module_state.config,
'skipping special target in %s:%d: %s', file_path, line_num, target)
end
end
end
if #target_list > 0 then
aliases[alias] = target_list
end
else
if module_state.config then
rspamd_logger.debugm(N, module_state.config,
'cannot parse line %d in %s: %s', line_num, file_path, current_line)
end
end
current_line = ""
:: continue ::
end
f:close()
return aliases
end
exports.parse_unix_aliases = parse_unix_aliases
--- Parse virtual aliases file (Postfix virtual format)
-- Format:
-- user@domain.com target@domain.com
-- @catchall.com catchall@domain.com
--
-- @param file_path path to virtual aliases file
-- @return table of aliases {source -> target} or nil on error
function parse_virtual_aliases(file_path)
local aliases = {}
local f, err = io.open(file_path, 'r')
if not f then
if module_state.config then
rspamd_logger.warnx(module_state.config,
'cannot open virtual aliases file %s: %s', file_path, err)
end
return nil
end
local line_num = 0
for line in f:lines() do
line_num = line_num + 1
-- Skip empty lines and comments
if line:match('^%s*$') or line:match('^%s*#') then
goto continue
end
-- Parse: source target
local source, target = line:match('^%s*(%S+)%s+(%S+)')
if source and target then
source = source:lower()
target = target:lower()
aliases[source] = target
else
if module_state.config then
rspamd_logger.debugm(N, module_state.config,
'cannot parse line %d in %s: %s', line_num, file_path, line)
end
end
:: continue ::
end
f:close()
return aliases
end
exports.parse_virtual_aliases = parse_virtual_aliases
--- Parse local domains file (one domain per line)
-- Format:
-- example.com
-- mail.example.com
-- # comments
--
-- @param file_path path to local domains file
-- @return set of domains {domain -> true} or nil on error
function parse_local_domains(file_path)
local domains = {}
local f, err = io.open(file_path, 'r')
if not f then
if module_state.config then
rspamd_logger.warnx(module_state.config,
'cannot open local domains file %s: %s', file_path, err)
end
return nil
end
for line in f:lines() do
-- Skip empty lines and comments
if not line:match('^%s*$') and not line:match('^%s*#') then
local domain = line:match('^%s*(%S+)')
if domain then
domains[domain:lower()] = true
end
end
end
f:close()
return domains
end
exports.parse_local_domains = parse_local_domains
--- Get value from backend or table
-- @param source backend object or table
-- @param key lookup key
-- @return value or nil
local function get_from_source(source, key)
if not source then
return nil
end
-- If it's a backend object with :get() method
if type(source) == 'table' and source.get then
return source:get(key)
end
-- Otherwise treat as plain table
return source[key]
end
--- Check if a domain is local
-- @param domain domain name to check
-- @return true if domain is local, false otherwise
local function is_local_domain(domain)
if not domain then
return false
end
domain = domain:lower()
local result = get_from_source(module_state.local_domains, domain)
lua_util.debugm(N, module_state.config,
'is_local_domain: domain=%s result=%s',
domain, result)
return result ~= nil and result ~= false
end
exports.is_local_domain = is_local_domain
--- Check if an email address is local
-- @param addr email address (string or table with 'domain' field)
-- @return true if address is in local domain, false otherwise
local function is_local_address(addr)
local domain
if type(addr) == 'string' then
domain = addr:match('@([^@]+)$')
elseif type(addr) == 'table' and addr.domain then
domain = addr.domain
end
return is_local_domain(domain)
end
exports.is_local_address = is_local_address
--- Apply service-specific alias rules (Gmail, plus-aliases)
-- This replaces the old lua_util.remove_email_aliases() function
-- @param email_addr email address table with user, domain, addr fields
-- @return new_user, tags, new_domain or nil
local function apply_service_rules(email_addr)
local function check_gmail_user(addr)
-- Remove all points
local no_dots_user = string.gsub(addr.user, '%.', '')
local cap, pluses = string.match(no_dots_user, '^([^%+][^%+]*)(%+.*)$')
if cap then
return cap, lua_util.str_split(pluses, '+'), nil
elseif no_dots_user ~= addr.user then
return no_dots_user, {}, nil
end
return nil
end
local function check_address(addr)
if addr.user then
local cap, pluses = string.match(addr.user, '^([^%+][^%+]*)(%+.*)$')
if cap then
return cap, lua_util.str_split(pluses, '+'), nil
end
end
return nil
end
local function check_gmail(addr)
local nu, tags, nd = check_gmail_user(addr)
if nu then
return nu, tags, nd
end
return nil
end
local function check_googlemail(addr)
local nd = 'gmail.com'
local nu, tags = check_gmail_user(addr)
if nu then
return nu, tags, nd
end
return nil, nil, nd
end
local specific_domains = {
['gmail.com'] = check_gmail,
['googlemail.com'] = check_googlemail,
}
if email_addr then
if email_addr.domain and specific_domains[email_addr.domain] then
local nu, tags, nd = specific_domains[email_addr.domain](email_addr)
if nu or nd then
return nu, tags, nd
end
else
local nu, tags, nd = check_address(email_addr)
if nu or nd then
return nu, tags, nd
end
end
return nil
end
end
exports.apply_service_rules = apply_service_rules
--- Resolve one step of aliasing
-- @param email_str normalized email string
-- @return result (string, array of strings, or nil), rule_type
local function resolve_one_step(email_str)
-- Check virtual aliases first
local virtual_result = get_from_source(module_state.virtual_aliases, email_str)
if virtual_result then
return virtual_result, 'virtual'
end
-- Check rspamd aliases
if module_state.rspamd_aliases[email_str] then
return module_state.rspamd_aliases[email_str], 'rspamd'
end
-- Check unix aliases (user part only)
local user = email_str:match('^([^@]+)@')
if user then
local unix_result = get_from_source(module_state.unix_aliases, user)
if unix_result then
-- Normalize result to always be array
if type(unix_result) == 'string' then
unix_result = { unix_result }
end
if type(unix_result) == 'table' and #unix_result > 0 then
-- Add domain to targets that don't have one
local domain = email_str:match('@([^@]+)$')
if domain then
local normalized = {}
for _, target in ipairs(unix_result) do
if not target:match('@') then
table.insert(normalized, target .. '@' .. domain)
else
table.insert(normalized, target)
end
end
return normalized, 'unix'
else
return unix_result, 'unix'
end
end
end
end
-- No alias found
return nil, nil
end
--- Resolve email address recursively with loop detection
-- @param addr email address (string or table)
-- @param opts options: max_depth, track_chain, expand_multiple
-- @return canonical (string or array), chain, metadata
local function resolve_address_recursive(addr, opts)
opts = opts or {}
local max_depth = opts.max_depth or 10
local track_chain = opts.track_chain
local expand_multiple = opts.expand_multiple
-- Convert to normalized form
local email_str
local original_str
if type(addr) == 'string' then
original_str = addr
email_str = addr:lower()
elseif type(addr) == 'table' and addr.addr then
original_str = addr.addr
email_str = addr.addr:lower()
else
return addr, nil, { error = 'invalid address format' }
end
-- Track visited addresses for loop detection
local visited = {}
local chain = track_chain and { email_str } or nil
local rules_applied = {}
--- Recursive resolve helper
-- @param current_addr current address to resolve
-- @param depth current recursion depth
-- @param path current resolution path (for loop detection)
-- @return array of canonical addresses
local function resolve_recursive(current_addr, depth, path, orig)
path = path or {}
-- Check depth limit
if depth > max_depth then
lua_util.debugm(N, module_state.config,
'max recursion depth %s reached for %s', max_depth, email_str)
return { current_addr }
end
-- Check for loops (only in current path, not all visited)
if path[current_addr] then
lua_util.debugm(N, module_state.config,
'alias loop detected for %s at %s', email_str, current_addr)
return { current_addr }
end
-- Track in visited for metadata
visited[current_addr] = true
-- Create new path with current address
local new_path = {}
for k, v in pairs(path) do
new_path[k] = v
end
new_path[current_addr] = true
-- Try to resolve one step
local result, rule_type = resolve_one_step(current_addr)
if not result then
-- No more aliases, this is canonical
return { orig or current_addr }
end
-- Track rule application
if rule_type and not rules_applied[rule_type] then
rules_applied[rule_type] = 0
end
if rule_type then
rules_applied[rule_type] = rules_applied[rule_type] + 1
end
-- Normalize result to array
local targets
if type(result) == 'string' then
targets = { result }
elseif type(result) == 'table' then
targets = result
else
return { current_addr }
end
-- If we have multiple targets and expand_multiple is false, take first
if #targets > 1 and not expand_multiple then
if track_chain and chain then
table.insert(chain, targets[1])
end
return resolve_recursive(targets[1], depth + 1, new_path)
end
-- Expand multiple targets
local canonical_addrs = {}
for _, target in ipairs(targets) do
if track_chain and chain then
table.insert(chain, target)
end
-- Recursively resolve each target with current path
-- Each branch gets the same path, allowing convergence while detecting loops
local resolved = resolve_recursive(target, depth + 1, new_path)
for _, resolved_addr in ipairs(resolved) do
table.insert(canonical_addrs, resolved_addr)
end
end
return canonical_addrs
end
-- Start resolution
local canonical_addrs = resolve_recursive(email_str, 1, nil, original_str)
-- Build metadata
local metadata = {
depth = table_length(visited),
rules_applied = rules_applied,
expanded = #canonical_addrs > 1,
}
-- Return result
if #canonical_addrs == 1 then
return canonical_addrs[1], chain, metadata
else
return canonical_addrs, chain, metadata
end
end
--- Resolve a single email address (backward compatible, non-recursive)
-- @param addr email address (string or table)
-- @param opts options table (can specify max_depth)
-- @return canonical address or original address if no alias found
local function resolve_address(addr, opts)
opts = opts or {}
-- Use recursive resolver with specified depth (default 10 for compatibility)
local simple_opts = {
max_depth = opts.max_depth or 10,
track_chain = opts.track_chain or false,
expand_multiple = opts.expand_multiple or false,
}
local canonical = resolve_address_recursive(addr, simple_opts)
return canonical
end
exports.resolve_address = resolve_address
exports.resolve_address_recursive = resolve_address_recursive
--- Classify message direction (inbound/outbound/internal/forwarded)
-- @param task rspamd task
-- @param opts classification options
-- @return classification table with direction, from_local, to_local, canonical addresses, etc.
local function classify_message(task, opts)
opts = opts or {}
local resolve_opts = {
max_depth = opts.max_depth or 10,
track_chain = opts.track_chain or false,
expand_multiple = opts.expand_multiple or true,
}
local classification = {
direction = nil,
from_local = false,
to_local = false,
canonical_from = nil,
canonical_recipients = {},
forwarding_detected = nil,
aliases_resolved = {
from = nil,
recipients = {},
}
}
-- Get authenticated user and IP
local user = task:get_user()
local ip = task:get_ip()
local is_authenticated = user ~= nil
local is_local_ip = ip and ip:is_local()
-- Resolve From address
local from_smtp = task:get_from('smtp')
if from_smtp and from_smtp[1] then
local from_addr = from_smtp[1]
-- Check if from is local domain
classification.from_local = is_local_address(from_addr)
-- Apply service rules to extract tags (but don't modify addr in task)
local from_copy = {
addr = from_addr.addr,
user = from_addr.user,
domain = from_addr.domain,
name = from_addr.name,
}
local _, tags = apply_service_rules(from_copy)
if tags and #tags > 0 then
classification.from_tagged = tags
end
-- Resolve from address
local canonical_from, from_chain, from_meta = resolve_address_recursive(
from_addr, resolve_opts)
classification.canonical_from = canonical_from
classification.aliases_resolved.from = {
chain = from_chain,
metadata = from_meta,
}
end
-- Resolve recipients
local rcpts_smtp = task:get_recipients('smtp')
if rcpts_smtp then
local any_local = false
local rcpt_count = 0
for _, rcpt in ipairs(rcpts_smtp) do
rcpt_count = rcpt_count + 1
-- Check if recipient is local
local rcpt_is_local = is_local_address(rcpt)
if rcpt_is_local then
any_local = true
end
-- Resolve recipient
local canonical_rcpt, rcpt_chain, rcpt_meta = resolve_address_recursive(
rcpt, resolve_opts)
-- Handle multiple expansions
if type(canonical_rcpt) == 'table' then
for _, addr in ipairs(canonical_rcpt) do
table.insert(classification.canonical_recipients, addr)
end
else
table.insert(classification.canonical_recipients, canonical_rcpt)
end
table.insert(classification.aliases_resolved.recipients, {
original = rcpt.addr,
canonical = canonical_rcpt,
chain = rcpt_chain,
metadata = rcpt_meta,
is_local = rcpt_is_local,
})
end
classification.to_local = (rcpt_count > 0) and any_local
end
-- Determine direction
if classification.from_local and classification.to_local then
classification.direction = 'internal'
elseif classification.from_local and not classification.to_local then
classification.direction = 'outbound'
elseif not classification.from_local and classification.to_local then
classification.direction = 'inbound'
else
-- Neither from nor to is local - might be forwarded or external
classification.direction = 'external'
end
-- Check for forwarding (from opts if provided by plugin)
if opts.forwarding_detected then
classification.forwarding_detected = {
type = opts.forwarding_type,
info = opts.forwarding_info,
}
classification.direction = 'forwarded'
end
-- Override with authenticated/local IP logic
if is_authenticated or is_local_ip then
-- Authenticated users or local IPs sending mail = outbound
if not classification.to_local then
classification.direction = 'outbound'
elseif classification.to_local and classification.from_local then
classification.direction = 'internal'
end
end
return classification
end
exports.classify_message = classify_message
--- Get module state (for debugging)
-- @return module state table
local function get_state()
return module_state
end
exports.get_state = get_state
--- Reset module state (for testing)
local function reset()
module_state = {
initialized = false,
config = nil,
local_domains = {},
unix_aliases = {},
virtual_aliases = {},
rspamd_aliases = {},
cache = {},
backends = {},
}
end
exports.reset = reset
return exports