sandbox.lua

A pure-lua solution for running untrusted Lua code.

For now, sandbox.lua only works with Lua 5.1.x.

Usage

local sandbox = require 'sandbox'

-- sandbox can handle both strings and functions
local msg  = sandbox(function() return 'this is untrusted code' end)
local msg2 = sandbox("return 'this is also untrusted code'")

sandbox(function()
  -- see sandbox.lua for a list of safe and unsafe operations
  return ('I can use safe operations, like string.upper'):upper()
end)

-- Attempting to invoke unsafe operations (such as os.execute) is not possible
sandbox(function()
  os.execute('rm -rf /') -- this will throw an error, no damage don
end)

-- It is not possible to exhaust the machine with infinite loops; the following
-- will throw an error after invoking 500000 instructions:
sandbox('while true do end')

-- The amount of instructions executed can be tweaked via the quota option
sandbox('while true do end', {quota=10000}) -- throw error after 10000 instructions

-- It is also possible to use the env option to add additional variables to the environment
sandbox('return foo', {env = {foo = 'This was on the environment'}})

-- The variables defined on the env are deep-copied and changes on them will not be persisted
local env = {foo = "can't touch this"}
sandbox('foo = "bar"', {env = env})
assert(env.foo = "can't touch this")

-- If you want to modify variables from inside the sandbox, use the refs option:
local refs = {foo = "kindof insecure"}
sandbox('foo = "changed"', {refs = refs})
assert(refs.foo = "changed")

Installation

Just copy sandbox.lua wherever you need it.

License

This library is released under the MIT license. See MIT-LICENSE.txt for details

Specs

This project uses busted for its specs. In order to run them, install busted and then:

cd /path/to/where/the/spec/folder/is
busted