netdev - Re: [flamebait] xdp, well meaning but pointless

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 1 Dec 2016 18:20:36 +0100
From:   Hannes Frederic Sowa <hannes@...essinduktion.org>
To:     David Miller <davem@...emloft.net>, tgraf@...g.ch
Cc:     fw@...len.de, netdev@...r.kernel.org
Subject: Re: [flamebait] xdp, well meaning but pointless

On 01.12.2016 17:19, David Miller wrote:
> Saying that ntuple filters can handle the early drop use case doesn't
> take into consideration the nature of the tables (hundreds of
> thousands of "evil" IP addresses), whether hardware can actually
> handle that (it can't), and whether simple IP address matching is the
> full extent of it (it isn't).

Yes, that is why you certainly use ntuple filters in combination with
some kind of high level business logic in user space.

I have to check but am pretty sure you can't even do the simplest thing
in XDP, parsing the apexes of DNS packets and checking them against a
hash table, because the program won't pass the verifier.