netdev - Re: BUG:af_packet fails to TX TSO frames

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]

Message-ID: <CAF=yD-+W2tyXqCS_ueZgu11BB8ON5hdKGOZQOWtfr+HfvqW=Sg@mail.gmail.com>
Date:   Thu, 12 Oct 2017 12:30:44 -0400
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Anton Ivanov <anton.ivanov@...bridgegreys.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>
Subject: Re: BUG:af_packet fails to TX TSO frames

On Thu, Oct 12, 2017 at 11:44 AM, Anton Ivanov
<anton.ivanov@...bridgegreys.com> wrote:
> Found it.
>
> Two bugs canceling each other.
> The bind sequence in:  psock_txring_vnet.c is wrong.
>
> It does the following addr.sll_protocol =    htons(ETH_P_IP);
> before calling bind.
>
> If you set addr.sll_protocol to ETH_P_ALL where it should have been in the
> first place the test program blows up with -ENOBUFS

There is no such requirement that the socket should bind to ETH_P_ALL.

> I think what is happening is that this value is taken into account when
> looking at "what should I use to segment it with" in skb_mac_gso_segment
> which is invoked at the end of the verification chain which starts in
> packet_direct_xmit in af_packet.c

packet_snd sets skb->protocol based on the protocol that the packet
socket is bound to. Binding to ETH_P_IP is the right choice here.