From: Paolo Abeni <pab...@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+91e6f9932ff122fa4...@syzkaller.appspotmail.com
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
Applied and queued up for -stable.
