On Thu, Dec 17, 2015 at 12:33 PM, Hannes Frederic Sowa <han...@stressinduktion.org> wrote: > On 17.12.2015 19:10, Tom Herbert wrote: >> 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. > > That is true. Albeit for net-branch/stable I would still suggest either > this patch or restricting udp offloads just to the initial net namespace. > I would opt for the latter then.
> 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
