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From: David Miller <>
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: <> (raw)
In-Reply-To: <>

From: Paolo Abeni <>
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:
> Signed-off-by: Paolo Abeni <>

Applied and queued up for -stable.

      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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