From: "Horia Geantă" <horia.geanta@freescale.com>
To: Steffen Klassert <steffen.klassert@secunet.com>,
Chaoxing Lin <Chaoxing.Lin@ultra-3eti.com>
Cc: "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>
Subject: Re: authencesn compatibility problemn between software crypto and talitos driver
Date: Tue, 12 Mar 2013 19:04:42 +0200 [thread overview]
Message-ID: <513F602A.9000201@freescale.com> (raw)
In-Reply-To: <20130311071518.GD21448@secunet.com>
On 3/11/2013 9:15 AM, Steffen Klassert wrote:
> Ccing Horia Geanta, he did the esn implementation for talitos.
>
> On Fri, Mar 08, 2013 at 03:27:48PM +0000, Chaoxing Lin wrote:
>> 1. Can any one point me which RFC describe how exactly authencesn should work?
>>
>
> The ESN algorithm is described in RFC 4303 IP Encapsulating Security
> Payload (ESP).
>
>> 2. I test Ipsec with "esp=aes256-sha512-esn!" options and found compatibility issue between kernel software crypto and talitos driver.
>> Talitos <---->talitos Good
>> Soft crypto<---->soft crypto Good
>> Soft crypto<---->talitos link established but no traffic can pass through.
That's what happens when interop testing is not performed...
>>
>> 3. Looking at source code of latest stable kernel 3.8.2, I found that these two implementations don't agree on what's to be hashed in ESN case.
>> Talitos driver is more intuitive in that "assoc (SPI, SN-hi, SN-low) + IV + payload" are hashed.
>
> The ESN implementation of the talitos driver looks rather scary,
> it just renames authenc to authencesn in talitos_probe(). The
> algorithm pretends to be authencesn but still does authenc, of course.
> authencesn has to be implemented, it is not sufficient to change
> the name, really.
Seems that somehow I got confused, considering the "one/single-pass over
data" description the same as "combined mode algorithm".
I will post a fix or revert the patch if HW does not allow the correct
behaviour.
>
>> Kernel software crypto is counter-intuitive in that "hsg(SPI, SN-low) + sg(IV + payload) + tsg(SN-hi" are hashed.
>
> This might look counterintuitive, but that's what RFC 4303 describes
> for ESN if separate encryption and integrity algorithms are used.
Yes, appending the SN-hi after Payload (Next Header) is the correct way
to handle separate encryption and integrity algos.
For combined ones (AES-CCM, AES-GCM, AES-GMAC etc.), behavior is defined
separately in corresponding RFCs (4309, 4106, 4543). Usually SN-hi is
positioned between SPI and SN-lo.
next prev parent reply other threads:[~2013-03-12 17:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-08 15:27 authencesn compatibility problemn between software crypto and talitos driver Chaoxing Lin
2013-03-11 7:15 ` Steffen Klassert
2013-03-12 17:04 ` Horia Geantă [this message]
2013-03-12 20:57 ` Chaoxing Lin
2013-03-14 10:21 ` Horia Geantă
2013-03-14 23:34 ` Kim Phillips
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