On Thu, Dec 17, 2015 at 9:40 AM, Hannes Frederic Sowa <han...@stressinduktion.org> wrote: > 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. > For receive offloads we don't need to worry about checking other namespaces.
> 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
