Override

local obj = {test = function()
    print("test")
end}

local copy = function(t)
    local tt = {}
    for k,v in pairs(t) do
        tt[k]=v
    end
    return tt
end

local newEnv = copy(_G)

obj = setmetatable({},{
    __index=obj,
    __newindex=function(a,b,c)
        error("nope",0)
    end,
    __metatable = false
})

newEnv["object"] = obj

newEnv = setmetatable({},{
    __index=newEnv,
    __newindex=function(a,b,c)
        error("nope",0)
    end,
    __metatable=false
})

local func = loadfile("/rom/programs/shell")

setfenv(func,newEnv)

func()