netdev - Re: [PATCH v5 net 0/2] net: udp: fix Fast/frag0 UDP GRO

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] [day] [month] [year] [list]

Message-ID: <20201112095922.5868d9a0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Thu, 12 Nov 2020 09:59:22 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Alexander Lobakin <alobakin@...me>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Willem de Bruijn <willemb@...gle.com>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Eric Dumazet <edumazet@...gle.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 net 0/2] net: udp: fix Fast/frag0 UDP GRO

On Wed, 11 Nov 2020 20:44:08 +0000 Alexander Lobakin wrote:
> While testing UDP GSO fraglists forwarding through driver that uses
> Fast GRO (via napi_gro_frags()), I was observing lots of out-of-order
> iperf packets:
> 
> [ ID] Interval           Transfer     Bitrate         Jitter
> [SUM]  0.0-40.0 sec  12106 datagrams received out-of-order
> 
> Simple switch to napi_gro_receive() or any other method without frag0
> shortcut completely resolved them.
> 
> I've found two incorrect header accesses in GRO receive callback(s):
>  - udp_hdr() (instead of udp_gro_udphdr()) that always points to junk
>    in "fast" mode and could probably do this in "regular".
>    This was the actual bug that caused all out-of-order delivers;
>  - udp{4,6}_lib_lookup_skb() -> ip{,v6}_hdr() (instead of
>    skb_gro_network_header()) that potentionally might return odd
>    pointers in both modes.
> 
> Each patch addresses one of these two issues.
> 
> This doesn't cover a support for nested tunnels as it's out of the
> subject and requires more invasive changes. It will be handled
> separately in net-next series.

Applied, thanks!