2.5 KiB
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(f, options) and sandbox.protect(f, options) are synonyms. They return a sandboxed version of f.
options is not required. So far the only possible options are env and quota (see below)
local sandboxed_f = sandbox(function() return 'hey' end)
local msg = sandboxed_f() -- msg is now 'hey'
sandbox.run(f) sanboxes a function and executes it. f can be either a string or a function
local msg = sandbox.run(function() return 'this is untrusted code' end)
local msg2 = sandbox.run("return 'this is also untrusted code'")
Only safe modules and operations can be accessed from the sandboxed mode. See the source code for a list of safe/unsafe operations.
sandbox.run(function()
return string.upper('string.upper is a safe operation.')
end)
Attempting to invoke unsafe operations (such as os.execute) is not permitted
sandbox.run(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.run('while true do end')
The amount of instructions executed can be tweaked via the quota option (default value: 500000 instructions)
sandbox.run('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.run('return foo', {env = {foo = 'This was on the environment'}})
If provided, the env variable will be heavily modified by the sanbox (adding base modules like string) The sandboxed code can also modify the env
local env = {amount = 1}
sandbox.run('amount = amount + 1', {env = env})
assert(env.amount = 2)
Finally, you may pass parameters to the sandboxed function directly in sandbox.run. Just add them after the options param.
local secret = sandbox.run(function(a,b) return a + b, {}, 1, 2)
assert(secret == 3)
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