netdev - Re: [PATCH V2 net] net: fix tcp reset packet flowlabel for ipv6

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Message-ID: <20170725213506.jfnbinozo6mzyzpc@kernel.org>
Date:   Tue, 25 Jul 2017 14:35:06 -0700
From:   Shaohua Li <shli@...nel.org>
To:     David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, Kernel-team@...com, shli@...com,
        eric.dumazet@...il.com, flo@...rcot.fr
Subject: Re: [PATCH V2 net] net: fix tcp reset packet flowlabel for ipv6

On Mon, Jul 24, 2017 at 01:34:55PM -0700, David Miller wrote:
> From: Shaohua Li <shli@...nel.org>
> Date: Tue, 18 Jul 2017 12:03:37 -0700
> 
> > +	/* Since this is being sent on the wire obfuscate hash a bit
> > +	 * to minimize possbility that any useful information to an
> > +	 * attacker is leaked. Only lower 20 bits are relevant.
> > +	 */
> > +	rol32(hash, 16);
> 
> This doesn't help anything at all.
> 
> I don't like things that try to give a sense of security (however
> little) but actually don't give any at all.
> 
> I'd rather, therefore, that you remove this altogether.

ok, so you suggest removing the rol32() for ip6_make_flowlabel too, right? just
want to make sure.

Thanks,
Shaohua