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
