On 17.12.2015 18:32, Tom Herbert wrote: > On Thu, Dec 17, 2015 at 12:49 AM, Hannes Frederic Sowa > <han...@stressinduktion.org> wrote: >> With user namespaces a normal user can start a new network namespace >> with all privileges and thus add new offloads, letting the other stack >> interpret this garbage. Because the user namespace can also add >> arbitrary ip addresses to its interface, solely matching those is not >> enough. >> >> Tom any further comments? >> > I still don't think this addresses the core problem. If we're just > worried about offloads being added in a user namespace that conflict > with the those in the root space, it might be just as easy to disallow > setting offloads except in default namespace.
I am fine with that solution, too. > [...] > > To address this in the host stack the solution is pretty > straightforward, we need to decide that the packet is going to be > received before applying any offloads. Essentially we want to do an > early_demux _really_ early. If we demux and get UDP socket for > instance, then the protocol specific GRO function can be retrieved > from the socket. So this will work with single listener port like > encaps do today, and also if encapsulation is being used over a > connected socket. This also works if we want to support a user defined > GRO function like I mentioned we might want to do for QUIC etc. An approximation can be done, but I don't think it is feasible to implement this kind of checks across namespace borders, ip rules and netfilter rulesets, which could all change the outcome of the process. Bye, Hannes -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
