Lua Sandbox "hacking"

Question

So I use a program where I script mods in lua, the lua is in a sandbox state, meaning most functions are blocked like IO and OS, I can't even use REQUIRE to add libs. I need to have a function that unzips files in one of my mods and I don't seem to find a way. Is there anyway to do it? If it's not possible in an easy way, is it possible to hack the program .exe or dlls to re-enable those functions in the lua?

Thank you in advance, Regards

Answer 1

There are decompression librarys in pure Lua, you should be able to embed these in any environment that allows loading Lua scripts: http://lua-users.org/wiki/CompressionAndArchiving

If you can't access any files at all, you could try a simple packer:

#!/usr/bin/env lua
local files = arg
local w = io.write
local function pack(...) return {...} end

w("files = {\n")
for i, filename in ipairs(arg) do
    w('\t["' ..filename .. '"] = "')
    local file = assert(io.open(filename, "r"), "Can't open file!")
    local data = file:read("*a")
    data = data:gsub("\a", "\\a")
        :gsub("\\", "\\\\")
        :gsub("\f", "\\f")
        :gsub("\n", "\\n")
        :gsub("\r", "\\r")
        :gsub("\t", "\\t")
        :gsub("\v", "\\v")
        :gsub('"', '\\"')
        :gsub("'", "\\'")
    w(data, '",\n')
end
w("}\n")
w([[
function require(path)
    local data = assert(files[path..".lua"], "file not found")
    local func = assert(loadstring(data))
    local _, ret = assert(pcall(func))
    return ret
end
]])
w('require("', arg[1]:match("^(.-)%.lua$"),'")\n')

This should create a script like this:

$ ./packer.lua init.lua 
files = {
    ["init.lua"] = "for k,v in pairs(arg) do\n\tprint(k,v)\nend\n",
}
function require(path)
    local data = assert(files[path..".lua"], "file not found")
    local func = assert(loadstring(data))
    local _, ret = assert(pcall(func))
    return ret
end
require("init")