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  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:   Fri, 28 Aug 2020 11:14:25 +0200
From:   Eric Dumazet <>
To:     Daniel Borkmann <>,
        Lukas Wunner <>,
        Pablo Neira Ayuso <>,
        Jozsef Kadlecsik <>,
        Florian Westphal <>
Cc:,,, Alexei Starovoitov <>,
        Eric Dumazet <>,
        Thomas Graf <>, Laura Garcia <>,
        David Miller <>
Subject: Re: [PATCH nf-next v3 0/3] Netfilter egress hook

On 8/28/20 12:14 AM, Daniel Borkmann wrote:
> Hi Lukas,
> On 8/27/20 10:55 AM, Lukas Wunner wrote:
>> Introduce a netfilter egress hook to allow filtering outbound AF_PACKETs
>> such as DHCP and to prepare for in-kernel NAT64/NAT46.
> Thinking more about this, how will this allow to sufficiently filter AF_PACKET?
> It won't. Any AF_PACKET application can freely set PACKET_QDISC_BYPASS without
> additional privileges and then dev_queue_xmit() is being bypassed in the host ns.
> This is therefore ineffective and not sufficient. (From container side these can
> be caught w/ host veth on ingress, but not in host ns, of course, so hook won't
> be invoked.)

Presumably dev_direct_xmit() could be augmented to support the hook.

dev_direct_xmit() (packet_direct_xmit()) was introduced to bypass qdisc,
not to bypass everything.

Powered by blists - more mailing lists