[PATCH] Enable specific ioctl calls for ICA crypto card (s390)

[Eduardo Barretto]

On 03-03-2017 09:54, Petr Cerny wrote:
> Damien Miller wrote:
>> On Tue, 28 Feb 2017, Eduardo Barretto wrote:
>>
>>> On 13-02-2017 13:23, Eduardo Barretto wrote:
>>> > This patch enables specific ioctl calls for ICA crypto card on s390
>>> > platform. Without this patch, users using the IBMCA engine are not
>>> able
>>> > to perform ssh login as the filter blocks the communication with the
>>> > crypto card.
>>> >
>>> > Signed-off-by: Harald Freudenberger <freude at linux.vnet.ibm.com>
>>> > Signed-off-by: Eduardo Barretto <ebarretto at linux.vnet.ibm.com>
>>> > ---
>>> >  sandbox-seccomp-filter.c | 24 +++++++++++++++++++++---
>>> >  1 file changed, 21 insertions(+), 3 deletions(-)
>>> >
>>> > diff --git a/sandbox-seccomp-filter.c b/sandbox-seccomp-filter.c
>>> > index 2e1ed2c..264e146 100644
>>> > --- a/sandbox-seccomp-filter.c
>>> > +++ b/sandbox-seccomp-filter.c
>>
>> [snip]
>>
>>> Hi there,
>>>
>>> Do you have any feedback on this patch?
>>
>> It's hard to evaluate it without reference to some public documentation
>> for the crypto card and the syscalls needed to use it. Is it a standard
>> part of s390 machines or an option?
> 
> Hi,
> 
> let me step in for Eduardo so that the thread doesn't hibernate.
> 
> As far as I know it is an optional piece of hardware, that may or may
> not be present in the system. OpenSSL is typically configured to load
> the libica engine (alongside any other possibly available ones).
> 
> As for the syscalls, would
> https://sourceforge.net/p/opencryptoki/libica/ci/master/tree/src/ica_api.c
> and
> http://lxr.free-electrons.com/source/arch/s390/include/uapi/asm/zcrypt.h#L259
> be enough?
> 
>> Does it provide substantial benefit for the crypto used in the pre-auth
>> stage of the protocol? (private key operations and DH/ECDH key agreement)
> 
> It should speed up some these:
> https://sourceforge.net/p/opencryptoki/libica/ci/master/tree/doc/icainfo.1

Just adding some more information on Petr answer (Thanks Petr for
stepping in!):

The ioctls for the s390 crypto card support are documented. The crypto
device driver is part of the linux kernel and thus open source. It can be
found in the kernel in drivers/s390/crypto. The ioctl stuff required to
interact with the crypto device driver is as usual provided in the
kernel header file arch/s390/include/uapi/asm/zcrypt.h
In particular the defines for the ioctl magics intended to not
get filtered can be found there.

As Petr mentioned, the relevant user space shared library which provides
a comfortable api for applications is libica. Libica is open
source and currently hosted on sourceforge as part of the
opencryptoki project (URLs above).

At the moment the zcrypt device driver provides access
to crypto cards which are able to accelerate RSA functions.
We are currently working on acceleration for ECC functions
and planing to release this in the near future. So one
benefit is performance, another is relief of CPU by
offloading crypto operations to this dedicated hardware.

The key exchange may use DH, ECCDH. The authentication
may use RSA or ECC. All the kind of stuff where the crypto
hardware may assist.

Thanks,
Eduardo
> 
> Thanks
> Kind regards
>     Petr