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--[[
Iptables file dumper for Alpine Wall
Copyright (C) 2012-2020 Kaarle Ritvanen
See LICENSE file for license details
]]--
local class = require('awall.class')
local ACTIVE = require('awall.family').ACTIVE
local raise = require('awall.uerror').raise
local util = require('awall.util')
local printmsg = util.printmsg
local sortedkeys = util.sortedkeys
local lpc = require('lpc')
local posix = require('posix')
local M = {}
local families = {
inet={
cmd='iptables', file='rules-save', procfile='/proc/net/ip_tables_names'
},
inet6={
cmd='ip6tables',
file='rules6-save',
procfile='/proc/net/ip6_tables_names'
}
}
M.builtin = {
filter={'FORWARD', 'INPUT', 'OUTPUT'},
mangle={'FORWARD', 'INPUT', 'OUTPUT', 'POSTROUTING', 'PREROUTING'},
nat={'INPUT', 'OUTPUT', 'POSTROUTING', 'PREROUTING'},
raw={'OUTPUT', 'PREROUTING'},
security={'FORWARD', 'INPUT', 'OUTPUT'}
}
local backupdir = '/var/run/awall'
local _actfamilies
local function actfamilies()
if _actfamilies then return _actfamilies end
_actfamilies = {}
for _, family in ipairs(ACTIVE) do
if posix.stat(families[family].procfile) then
table.insert(_actfamilies, family)
else printmsg('Warning: firewall not enabled for '..family) end
end
return _actfamilies
end
function M.isenabled() return #actfamilies() > 0 end
local BaseIPTables = class()
function BaseIPTables:print()
for _, family in sortedkeys(families) do
self:dumpfile(family, io.output())
io.write('\n')
end
end
function BaseIPTables:dump(dir)
for family, tbls in pairs(families) do
local file = io.open(dir..'/'..families[family].file, 'w')
self:dumpfile(family, file)
file:close()
end
end
function BaseIPTables:restorecmd(family, test)
local cmd = {families[family].cmd..'-restore'}
if test then table.insert(cmd, '-t') end
return table.unpack(cmd)
end
function BaseIPTables:restore(test)
for _, family in ipairs(actfamilies()) do
local pid, stdin, stdout = lpc.run(self:restorecmd(family, test))
stdout:close()
self:dumpfile(family, stdin)
stdin:close()
assert(lpc.wait(pid) == 0)
end
end
function BaseIPTables:activate()
self:flush()
self:restore(false)
end
function BaseIPTables:test() self:restore(true) end
function BaseIPTables:flush() M.flush() end
M.IPTables = class(BaseIPTables)
function M.IPTables:init()
self.config = {}
setmetatable(
self.config,
{
__index=function(t, k)
t[k] = {}
setmetatable(t[k], getmetatable(t))
return t[k]
end
}
)
end
function M.IPTables:dumpfile(family, iptfile)
iptfile:write('# '..families[family].file..' generated by awall\n')
local tables = self.config[family]
for _, tbl in sortedkeys(tables) do
iptfile:write('*'..tbl..'\n')
local chains = tables[tbl]
for _, chain in sortedkeys(chains) do
local policy = '-'
if util.contains(M.builtin[tbl], chain) then
policy = tbl == 'filter' and 'DROP' or 'ACCEPT'
end
iptfile:write(':'..chain..' '..policy..' [0:0]\n')
end
for _, chain in sortedkeys(chains) do
for _, rule in ipairs(chains[chain]) do
iptfile:write('-A '..chain..' '..rule..'\n')
end
end
iptfile:write('COMMIT\n')
end
end
local Current = class(BaseIPTables)
function Current:dumpfile(family, iptfile)
local pid, stdin, stdout = lpc.run(families[family].cmd..'-save')
stdin:close()
for line in stdout:lines() do iptfile:write(line..'\n') end
stdout:close()
assert(lpc.wait(pid) == 0)
end
local Backup = class(BaseIPTables)
function Backup:dumpfile(family, iptfile)
for line in io.lines(backupdir..'/'..families[family].file) do
iptfile:write(line..'\n')
end
end
function M.backup()
posix.mkdir(backupdir)
Current():dump(backupdir)
end
function M.revert() Backup():activate() end
function M.flush()
local empty = M.IPTables()
for _, family in pairs(actfamilies()) do
for tbl in io.lines(families[family].procfile) do
if M.builtin[tbl] then
for _, chain in ipairs(M.builtin[tbl]) do
empty.config[family][tbl][chain] = {}
end
else printmsg('Warning: not flushing unknown table: '..tbl) end
end
end
empty:restore(false)
end
return M
|
