 |
lua-l archive |
|
|
||
|
On 8 Oct 2013 02:29, "Rena" <hyperhacker@gmail.com> wrote:
>
> On Mon, Oct 7, 2013 at 9:25 PM, Sean Conner <sean@conman.org> wrote:
>>
>> It was thus said that the Great Rena once stated:
>> > Does anyone have experience running Lua safely as root? What environment
>> > variables, files, and behaviours to watch out for to avoid creating a
>> > security flaw or potentially breaking something? I recall hearing about Lua
>> > being used in the BSD kernel, so I think it should be possible.
>>
>> I do. I've written a few programs in Lua that I run as root, but they
>> have a well defined function, and none of the programs execute arbitrary Lua
>> code (in other words, I know the code being run as root).
>>
>> But I'm not sure what you are asking in particular. It's easy to create a
>> Lua jail (I've done that too), but if you are running as root, it's because
>> you want to do something that root can only do, so my question to you is:
>> what are you trying to do?
>>
>> -spc
>>
>>
>
> In particular I'm interested in reading a lot of system information from /proc and making it available to another program in a somewhat saner format for display. Some things in /proc can only be read by root.
>
The main way to make it safe is to not have any configuration or control. Then it becomes harder to subvert. Also you need to compile it into an executable to set it suid - don't make Lua suid! And make it do as little as possible eg just log the info to a file or socket and have some other program read that. Make sure that file is not in tmp and create it sanely to avoid symlink attacks. There is nothing really Lua specific, other than there is no point opening libraries you don't use eg debug to keep it minimal.
Justin