From: Eric Dumazet <eric.dumazet@gmail.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>,
Dmitry Vyukov <dvyukov@google.com>,
David Miller <davem@davemloft.net>,
Tom Herbert <tom@herbertland.com>,
Alexander Duyck <aduyck@mirantis.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Jiri Benc <jbenc@redhat.com>,
Sabrina Dubroca <sd@queasysnail.net>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: net: GPF in eth_header
Date: Tue, 29 Nov 2016 08:15:14 -0800 [thread overview]
Message-ID: <1480436114.18162.143.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <CAAeHK+zLO=Gv33TqS6tGTTC=QUYO-HOPgSB2oS1SBOAyJzPDTQ@mail.gmail.com>
On Tue, 2016-11-29 at 16:31 +0100, Andrey Konovalov wrote:
=
> The issue is not with skb_network_offset(), but with __skb_pull()
> using skb_network_offset() as an argument.
>
No. The issue can happen with _any_ __skb_pull() with a 'negative'
argument, on 64bit arches.
skb_network_offset() is only one of the many cases this could happen if
a bug is added at some random place, including memory corruption from
a different kernel layer, or buggy hardware.
> I'm not sure what would be the beast way to fix this, to add a check
> before every __skb_pull(skb_network_offset()), to fix __skb_pull() to
> work with signed ints, to add BUG_ON()'s in __skb_pull, or something
> else.
>
> What I meant is that you fixed this very instance of the bug, and I'm
> pointing out that a similar one might hit us again.
As I said, adding a check in skb_network_offset() would not be generic
enough.
Sure, we can be proactive and add tests everywhere in the kernel, but we
also want to keep it reasonably fast.
next prev parent reply other threads:[~2016-11-29 16:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-26 17:30 net: GPF in eth_header Dmitry Vyukov
2016-11-26 18:28 ` Eric Dumazet
2016-11-26 19:07 ` Andrey Konovalov
2016-11-26 20:05 ` Eric Dumazet
2016-11-26 20:34 ` Eric Dumazet
2016-11-29 10:26 ` Andrey Konovalov
2016-11-29 14:58 ` Eric Dumazet
2016-11-29 15:31 ` Andrey Konovalov
2016-11-29 16:15 ` Eric Dumazet [this message]
2016-11-28 18:50 ` Eric Dumazet
2016-11-28 19:04 ` Andrey Konovalov
2016-11-28 19:34 ` Dmitry Vyukov
2016-11-28 19:47 ` Eric Dumazet
2016-11-28 21:05 ` Eric Dumazet
2016-11-28 21:18 ` Eric Dumazet
2016-11-28 21:34 ` Florian Westphal
2016-11-28 22:14 ` Eric Dumazet
2016-11-28 22:19 ` Florian Westphal
2016-11-28 23:16 ` Eric Dumazet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1480436114.18162.143.camel@edumazet-glaptop3.roam.corp.google.com \
--to=eric.dumazet@gmail.com \
--cc=aduyck@mirantis.com \
--cc=andreyknvl@google.com \
--cc=davem@davemloft.net \
--cc=dvyukov@google.com \
--cc=hannes@stressinduktion.org \
--cc=jbenc@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=sd@queasysnail.net \
--cc=syzkaller@googlegroups.com \
--cc=tom@herbertland.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.