[strongSwan] SHA1 vs SHA256

[Dusan Ilic]

Hi Andreas,

Okey, I see. Thank you for clarifying!


Den 2017-08-04 kl. 20:50, skrev Andreas Steffen:
> Hi Dusan,
>
> the only workaround I see is to either upgrade your Linux 2.6
> kernel or fall back to a SHA-1 based ESP HMAC.
>
> Regards
>
> Andreas
>
> On 04.08.2017 20:46, Dusan Ilic wrote:
>> Hi,
>>
>> Unfortunately, I'm not following you guys :)
>> Could someone please clarify?
>>
>>
>> Den 2017-08-04 kl. 19:04, skrev Noel Kuntze:
>>> Hi,
>>>
>>> IIRC pfkey still uses the old truncation (It's mentioned in some
>>> relatively recent ticket).
>>> Try using kernel-netlink instead.
>>>
>>> Kind regards
>>>
>>> Noel
>>>
>>>
>>> On 04.08.2017 19:02, Andreas Steffen wrote:
>>>> Hi Dusan,
>>>>
>>>> hmmm, our documentation says that the correct ESP SHA256_128 HMAC
>>>> truncation was introduced with the 2.6.33 kernel but your kernel
>>>> might not be a vanilla 2.6.36 kernel:
>>>>
>>>>    https://wiki.strongswan.org/projects/strongswan/wiki/IKEv2CipherSuites
>>>>
>>>>    (ESP integrity algorithm footnote n)
>>>>
>>>> Regards
>>>>
>>>> Andreas
>>>>
>>>> On 04.08.2017 16:41, Dusan Ilic wrote:
>>>>> Hi Andreas
>>>>>
>>>>> One side is 2.6.36 and the other 3.10.20
>>>>>
>>>>>
>>>>> Den 2017-08-04 kl. 12:48, skrev Andreas Steffen:
>>>>>> Hi Dusan,
>>>>>>
>>>>>> this is a Linux kernel issue. Which kernel versions are you running
>>>>>> on the two endpoints?.
>>>>>>
>>>>>> Regards
>>>>>>
>>>>>> Andreas
>>>>>>
>>>>>> On 04.08.2017 12:41, Dusan Ilic wrote:
>>>>>>> Hi Noel,
>>>>>>>
>>>>>>> One side is Strongswan 5.2.2 and the other is 5.5.2.
>>>>>>> How do I switch?
>>>>>>>
>>>>>>>
>>>>>>> Den 2017-08-04 kl. 12:25, skrev Noel Kuntze:
>>>>>>>> the remote peer probably uses the DRAFT variant of sha2-256, which
>>>>>>>> uses 96 bit truncation. strongSwan uses the actual standardized
>>>>>>>> variant that truncates to 128 bit.
>>>>>>>> You can switch between the two in the newest version of strongSwan
>>>>>>>>
>>>>>>>> On 04.08.2017 12:23, Dusan Ilic wrote:
>>>>>>>>> Hello!
>>>>>>>>>
>>>>>>>>> I have a strange issue, with both settings below the tunnel goes up
>>>>>>>>> as it should, but only with SHA1 in ESP traffic goes through.
>>>>>>>>> When I
>>>>>>>>> ping the remote client with ESP SHA256 it times out, even though
>>>>>>>>> the
>>>>>>>>> tunnel reports as being up by Strongswan.
>>>>>>>>>
>>>>>>>>> Traffic working:
>>>>>>>>>
>>>>>>>>> ike=aes256-sha256-modp2048!
>>>>>>>>> esp=aes128-sha1-modp2048!
>>>>>>>>>
>>>>>>>>> Traffic not working:
>>>>>>>>>
>>>>>>>>> ike=aes256-sha256-modp2048!
>>>>>>>>> esp=aes256-sha256-modp2048!
>>>>>>>>>
>>>>>>>>> Below combo doesn't work either:
>>>>>>>>>
>>>>>>>>> ike=aes256-sha256-modp2048!
>>>>>>>>> esp=aes128-sha256-modp2048!
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Also, are above settings good? I'm having AES128 on ESP because
>>>>>>>>> with
>>>>>>>>> AES256 I loose too much througput. Do you have any suggestions for
>>>>>>>>> change?
>>>>>>>>>
>>>>>>>>>