OpenSSH FIPS 140-2 support using OpenSSL FIPS modules?

[security veteran]

Hi Tomas,

Thanks for your answers!

So based on your answers:

1. Since Vanilla OpenSSH doesn't call FIPS_mode_set() function, it should
work just fine even if the OpenSSL libcrypto.so library has already been
changed to the FIPS version. Is that correct?

2. Looks like there is no such a flag in OpenSSH source to allow you
rebuild it and turn it into FIPS compliant mode, is that correct? In that
case is there a way to re-build OpenSSH server and client (somehow in both
the RedHat and Ubuntu, the OpenSSH is split into two (openssh-server and
openssl-client) packages, so that the non-FIPS compliant functions can be
disabled?


Thanks.

On Fri, Dec 4, 2015 at 12:39 AM, Tomas Kuthan <tomas.kuthan at oracle.com>
wrote:

> On 12/ 4/15 03:26 AM, security veteran wrote:
>
>> Hi All:
>>
>> I tried to rebuild openssl with the FIPS modules, and then install the new
>> openssl libs (lib crypto.so to be specific) on my Ubuntu 12.04 box.
>>
>> After that I noticed it seemed to break OpenSSH: I couldn't login to the
>> box using ssh, and couldn't run the client command like ssh-keygen either.
>>
>> My questions are:
>>
>> 1. Does OpenSSH support FIPS mode?
>>
>> 2. Or does OpenSSH support with OpenSSL FIPS modules?
>>
>> 3. Is there a way to re-compile OpenSSH by turning on/off some flags to
>> make it FIPS complaint?
>>
>> 4. Does the RedHat OpenSSH FIPS modules (
>> http://csrc.nist.gov/groups/STM/cmvp/documents/140-1/140sp/140sp1791.pdf)
>> also open sourced to the OpenSSH community?
>>
>
> Hi security veteran,
>
> vanilla OpenSSH doesn't support running OpenSSL in FIPS-140 mode. Some
> downstream providers patch OpenSSH they deliver with their distributions
> with changes to enable FIPS-140 mode.
>
> In general, an application that wants to run a FIPS-140 capable OpenSSL
> library in FIPS-140 mode, needs to call FIPS_mode_set() first. Otherwise it
> runs OpenSSL in default mode with non-FIPS algorithms available. From my
> experience this works, but is not FIPS-140 compliant.
>
> User Guide for the OpenSSL FIPS Object Module v2.0 [1]:
>
>> 2.6
>> FIPS Mode of Operation
>> Applications that utilize FIPS mode must call the FIPS_mode_set()
>> function. After successful
>> FIPS mode initialization, the non-FIPS algorithms will be disabled by
>> default.
>> The FIPS Object Module together with a compatible version of the OpenSSL
>> product can be used
>> in the generation of both FIPS mode and conventional applications. In
>> this sense, the combination
>> of the FIPS Object Module and the usual OpenSSL libraries constitutes a
>> “FIPS capable API”, and
>> provide both FIP approved algorithms and non-FIPS algorithms.
>>
>
> Vanilla OpenSSH obviously doesn't call FIPS_mode_set(). If switching
> underlying OpenSSL libcrypto to FIPS-140 capable instance precludes you
> from running ssh, most probably there is something wrong with the FIPS-140
> capable OpenSSL you built.
>
> Tomas
>
> [1] https://openssl.org/docs/fips/UserGuide-2.0.pdf
>
>
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