From: David Miller <davem@davemloft.net>
To: pabeni@redhat.com
Cc: netdev@vger.kernel.org, dsahern@gmail.com,
syzbot+91e6f9932ff122fa4410@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com, eric.dumazet@gmail.com
Subject: Re: [PATCH net v2] ipv6: the entire IPv6 header chain must fit the first fragment
Date: Sun, 25 Mar 2018 21:18:03 -0400 (EDT) [thread overview]
Message-ID: <20180325.211803.488689473146529035.davem@davemloft.net> (raw)
In-Reply-To: <43638c155545c57a4b332c64771a1e9b0238148c.1521812678.git.pabeni@redhat.com>
From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 23 Mar 2018 14:47:30 +0100
> While building ipv6 datagram we currently allow arbitrary large
> extheaders, even beyond pmtu size. The syzbot has found a way
> to exploit the above to trigger the following splat:
...
> As stated by RFC 7112 section 5:
>
> When a host fragments an IPv6 datagram, it MUST include the entire
> IPv6 Header Chain in the First Fragment.
>
> So this patch addresses the issue dropping datagrams with excessive
> extheader length. It also updates the error path to report to the
> calling socket nonnegative pmtu values.
>
> The issue apparently predates git history.
>
> v1 -> v2: cleanup error path, as per Eric's suggestion
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-by: syzbot+91e6f9932ff122fa4410@syzkaller.appspotmail.com
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Applied and queued up for -stable.
prev parent reply other threads:[~2018-03-26 1:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-23 13:47 [PATCH net v2] ipv6: the entire IPv6 header chain must fit the first fragment Paolo Abeni
2018-03-23 14:04 ` Eric Dumazet
2018-03-26 1:18 ` David Miller [this message]
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