Can we please discuss this when I have running code to talk about? I mentioned my idea but I have not tried it yet. I agree with Benoit, forking subprocesses feels like a hack. But without working code, it is hard to judge cost vs. benefit.
On Tue, Feb 5, 2013 at 7:26 AM, Benoit Chesneau <[email protected]> wrote: > On Mon, Feb 4, 2013 at 6:58 PM, Jan Lehnardt <[email protected]> wrote: > > > > On Feb 4, 2013, at 18:47 , Benoit Chesneau <[email protected]> wrote: > > > >> On Mon, Feb 4, 2013 at 12:10 PM, Jan Lehnardt <[email protected]> wrote: > >>> > >>> On Feb 4, 2013, at 11:53 , Benoit Chesneau <[email protected]> > wrote: > >>> > >>>> On Thu, Jan 31, 2013 at 5:54 PM, Jason Smith <[email protected]> > wrote: > >>>>> > >>>>> On Thu, Jan 31, 2013 at 4:34 PM, Benoit Chesneau < > [email protected]>wrote: > >>>>> > >>>>>> > >>>>>> A javascript engine doesn't expose any IO par default. The > **framework** > >>>>>> nodejs is, this is all the point. I'm quite interested by the > existing > >>>>>> solutions to sandbox nodejs, do you know some projects that does it? > >>>>>> > >>>>> > >>>>> Correct. I am attempting to build something which satisfies your > >>>>> description: no i/o; i/o is not even possible. > >>>>> > >>>>> *How* is it implemented? Well, it doesn't matter whether we use > Node.js or > >>>>> couchjs/SM or couchjs/v8. What matters is we feel confident about > security. > >>>>> And of course, I agree, if we cannot achieve good security, then > that is a > >>>>> show stopper. > >>>>> > >>>>> Here is my current plan for sandboxing CouchJS. (Thanks to Isaac for > his > >>>>> tips.) > >>>>> > >>>>> When it is time to evaluate some code: > >>>>> > >>>>> 1. Set up an object with safe variable bindings: safe_context > >>>>> 2. fork() > >>>>> 3. Child process runs vm.runInNewContext(safe_context) > >>>>> 4. Child process communicates to the parent over stdio, through the > >>>>> approved safe_context functions > >>>>> > >>>>> The subprocess can also give extra sandboxing, such as chroot() if > >>>>> available. > >>>>> > >>>>> Yes, this causes two processes per instantiation; however I think the > >>>>> parent might only be short-lived, setting up the security, then > exiting. > >>>>> The grandchild can talk to Erlang over stdio. > >>>>> > >>>>> That is my plan. No idea how well it will work. > >>>>> > >>>>> -- > >>>>> Iris Couch > >>>> > >>>> > >>>> > >>>> Too much kool-aid imo :) > >>>> > >>>> This is not that it can't work. But are you seriously considering to > >>>> have a main couchjs process maintaining the STDIO channel and spawn a > >>>> new OS Process for a view (which what does `vm.runInNewContext`)? The > >>>> memory and latency cost can became very important, and i don't count > >>>> the chrooting cost especially if run this context on each indexation > >>>> batch or shows, lists and views requests. + the extra fds created by > >>>> each child contexts. > >>> > >>> Alternatively, if the above works and is necessary (modulo Klaus’s > >>> research), we live with the hit until we get to rewrite the view > protocol > >>> at which point we can make it 1 Erlang process -> 1 node process for > >>> dispatching -> N Node processes for indexing. > >> > >> I don't think it is necessary at all to use so many *OS* process at > >> all for our purpose. And I am really worried by such solution.There is > >> a reason why people don't try to launch too much OS processes on the > >> system, There is a reason why we are using systems like Erlang. > >> > >> I guess runInContext would work, with a custom `require` function to > >> include modules (to specifically forbid IO) . According to the doc the > >> context doesn't share anything, which is what we want. Also if we are > >> going for node i would prefer to start with a straight forward > >> solution and not introduce any new behaviours. > > > > I suggested 1 extra node process in total, if at all, as an alternative, > > if the thing Klaus and you outline doesn’t work. > > > Why doesn't it work? > > runInNewContext would imply to launch one new context / view if you > want to really run it sandboxed. > > "vm.runInNewContext compiles code, then runs it in sandbox and returns > the result.". > > I don't see any other way since you can't recycle a context in this > case. Having another I/O for this context wil be even uglier. In that > case you would have STDIO -> CHILD -> STDIO -> CHILD . Without > counting the memory usage it will add more latency than we have right > now. The more I think about that the more I'm reluctant to support > such solution. > > - benoît > -- Iris Couch
