From: David Howells <dhowells@redhat.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: dhowells@redhat.com, Eric Dumazet <edumazet@google.com>,
syzbot <syzbot+62cbf263225ae13ff153@syzkaller.appspotmail.com>,
bpf@vger.kernel.org, davem@davemloft.net, dsahern@kernel.org,
kuba@kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, pabeni@redhat.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [net?] WARNING in __ip6_append_data
Date: Mon, 18 Sep 2023 15:46:13 +0100 [thread overview]
Message-ID: <4138874.1695048373@warthog.procyon.org.uk> (raw)
In-Reply-To: <65085768c17da_898cd294ae@willemb.c.googlers.com.notmuch>
Willem de Bruijn <willemdebruijn.kernel@gmail.com> wrote:
>
> An ipv6 packet can carry 64KB of payload, so maxnonfragsize of 65535 + 40
> sounds correct. But payload length passed of 65536 is not (ignoring ipv6
> jumbograms). So that should probably trigger an EINVAL -- if that is indeed
> what the repro does.
The problem is that on entry to __ip6_append_data(), the length includes
transhdrlen. However, this is a problem if we already have something in the
packet. At that point, this fails:
if (WARN_ON_ONCE(copy > msg->msg_iter.count))
goto error;
because copy includes transhdrlen.
David
next prev parent reply other threads:[~2023-09-18 15:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 6:19 syzbot
2023-09-13 8:41 ` Eric Dumazet
2023-09-15 15:32 ` David Howells
2023-09-15 16:24 ` David Howells
2023-09-18 10:03 ` David Howells
2023-09-18 13:58 ` Willem de Bruijn
2023-09-18 14:04 ` Eric Dumazet
2023-09-19 8:27 ` Tom Parkin
2023-09-19 9:04 ` Eric Dumazet
2023-09-18 14:46 ` David Howells [this message]
2023-09-18 10:11 ` David Howells
2023-09-18 10:33 ` syzbot
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=4138874.1695048373@warthog.procyon.org.uk \
--to=dhowells@redhat.com \
--cc=bpf@vger.kernel.org \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=edumazet@google.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=syzbot+62cbf263225ae13ff153@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=willemdebruijn.kernel@gmail.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®