Subject: Re: [RFC ipsec-next] xfrm: make sha256 icv truncation length RFC-compliant

From: Nicolas Dichtel <[email-masked]>
Date: Fri, 23 May 2014 10:06:09 +0200

Le 23/05/2014 08:28, Horia Geantă a écrit :
> On 5/22/2014 7:03 PM, Nicolas Dichtel wrote:
>> Le 22/05/2014 17:10, Horia Geanta a écrit :
>>> From: Lei Xu <[email-masked]>
>>>
>>> Currently the sha256 icv truncation length is set to 96bit
>>> while the length is defined as 128bit in RFC4868.
>>> This may result in somer errors when working with other IPsec devices
>>> with the standard truncation length.
>>> Thus, change the sha256 truncation length from 96bit to 128bit.
>> The patch was already proposed, but it was kept as-is for userspace
>> compatibility.
>>
>> See: https://lkml.org/lkml/2012/3/7/431
>
> Thanks, somehow I missed that.
>
> So this just means bad luck for user space tools (for e.g. ipsec-tools - setkey,
> racoon - and any other PF_KEY-based tool) that AFAICT cannot override the
> default truncated icv size, right?
You can change the default value with the netlink attribute
XFRMA_ALG_AUTH_TRUNC (option 'auth-trunc' in iproute2).

Regards,
Nicolas