[Openswan dev] nss/nspr4 warning and PLUTO_SENDS_VENDORID vs HAVE_LIBNSS

[Avesh Agarwal]

On 01/05/2010 11:12 AM, Paul Wouters wrote:
> On Tue, 5 Jan 2010, Avesh Agarwal wrote:
>
>> I looked into this, and the reason for not to send vendorid during 
>> FIPS mode is that it computes MD5 hashes on the vendorid, and MD5 
>> should not be allowed in FIPS mode.
>
> But md5 here is not used as a security issue. It is used so that the 
> vendorid
> payload is of a fixed size. Other payloads in IKE are defined by the 
> IETF,
> so they have reference numbers registered at IANA that are used in the
> payloads. Vendor ID's dont have such a central registration. If you 
> look at
> vendor.c and vendor.h you will see most vendors use longer strings to
> identify their model and version number, and then hash it to get it 
> down to
> a fixed length. md5 is used as "compression" only.
>
> For example, the vendor id for "CISCO-UNITY" is:
>
> md5('CISCO-UNITY') = 12f5f28c457168a9702d9fe274cc02d4
>
> The vendorid 'NATT_IETF_00' is md5("draft-ietf-ipsec-nat-t-ike-00")
>
> These are not "secrets" or "encrypted" information.

Hi Paul,

I understand it. The only reason is that md5 calls will not be enabled 
when in FIPS mode, as that is not an alllowed algorithm as per FIPS 
requirements. can it be chanaged to SHA1 then?

>
>> As FIPS or non-FIPS mode can be setup at "run time", I coded it in 
>> the way so at run time, the sending of vendor id can be enabled and 
>> disabled depending upon non-FIPS mode or FIPS mode.
>
> What I see now is that we should send the vendorid regardless of FIPS 
> mode.
It may not be a security issue but as I said above that md5 is not 
allowed in FIPS mode.

>
>
>> If you do it at compile time like you did above then, even during 
>> non-FIPS mode, it is not possible to send vendor id which should be 
>> allowed.
>
> Changing sending the vendorid from a compile time to a runtime option is
> something we can implement, but I see it as a seperate issue from FIPS.

Actually if we can still send the vendor id in FIPS mode (may be by 
using SHA), then there is no option required as it will be sent in any 
case. As currently it is using md5, thats why I used the option to 
disable it in FIPS mode. If you see the code that I have put the code 
under Pluto_IsFIPS calls which check whether the system is in FIPS mode 
nor not.

>
>> And the reason that it does not compile with USE_VENDORID=false is 
>> not due to HAVE_LIBNSS. The problem is there even if you do not have 
>> HAVE_LIBNSS enabled.
>
> That is right, and it got fixed seperately.
>
> Thanks for the clarification of your patch. To sumarize, since the use of
> md5 here is not done in any security context, I believe we do not require
> to change our behaviour based on FIPS mode.
>
Same as above, can we then change it to SHA1 or something else?

Thanks and Regards
Avesh

> Paul