.. highlight:: sh
.. |libnpa| replace:: :ref:`libnpa`
.. |PACE| replace:: :abbr:`PACE (Password Authenticated Connection Establishment)`
.. _ccid-emulator:
################################################################################
USB CCID Emulator
################################################################################
:Author:
`Frank Morgner <morgner@informatik.hu-berlin.de>`_
:License:
GPL version 3
:Tested Platforms:
Linux (Debian, Ubuntu, OpenMoko)
The USB CCID Emulator forwards a locally present PC/SC smart card reader as a
standard USB CCID reader. USB CCID Emulator can be used as trusted intermediary
enabling secure PIN entry and PIN modification. In combination with the |libnpa|
also |PACE| can be performed by the emulator.
If the machine running :command:`ccid-emulator` is in USB device mode, a local
reader is forwareded via USB to another machine. If in USB host mode, the USB
CCID reader will locally be present.
Applications on Windows and Unix-like systems can access the USB CCID Emulator
through PC/SC as if it was a real smart card reader. No installation of a smart
card driver is required since USB CCID drivers are usually shipped with the
modern OS. [#f1]_
Here is a subset of USB CCID commands supported by the USB CCID Emulator with
their PC/SC counterpart:
================================== ============================================================
USB CCID PC/SC
================================== ============================================================
``PC_to_RDR_XfrBlock`` ``SCardTransmit``
``PC_to_RDR_Secure`` ``FEATURE_VERIFY_PIN_DIRECT``, ``FEATURE_MODIFY_PIN_DIRECT``
``PC_to_RDR_Secure`` (proprietary) ``FEATURE_EXECUTE_PACE``
================================== ============================================================
The USB CCID Emulator is implemented using GadgetFS_. Some fragments of the source
code are based on the GadgetFS example and on the source code of the OpenSC
tools.
.. include:: download.txt
.. include:: autotools.txt
Running the USB CCID Emulator has the following dependencies:
- Linux Kernel with GadgetFS_
- OpenSC_
- |libnpa| (only if support for |PACE| is enabled)
Whereas using the USB CCID Emulator on the host system as smart card reader only
needs a usable PC/SC middleware with USB CCID driver. This is the case for most
modern Windows and Unix-like systems by default.
=================
Hints on GadgetFS
=================
To create a USB Gadget in both USB host and USB client mode, you need to load
the kernel module :program:`gadgetfs`. A guide focused on Debian based systems
to run and compile GadgetFS, you can find in the `OpenMoko Wiki`_.
On OpenMoko it is likely that you need to `patch your kernel
<http://docs.openmoko.org/trac/ticket/2206>`_. If you also want to switch
multiple times between :program:`gadgetfs` and :program:`g_ether`, `another
patch is needed <http://docs.openmoko.org/trac/ticket/2240)>`_.
If you are using a more recent version of :program:`dummy_hcd` and get an error
loading the module, you maybe want to check out `this patch
<http://comments.gmane.org/gmane.linux.usb.general/47440>`_.
===============
Hints on OpenSC
===============
Without the |libnpa| the USB CCID Emulator needs the OpenSC components to be
installed (especially :file:`libopensc.so`). Here is an example of how to get
the standard installation of OpenSC without |PACE|::
PREFIX=/tmp/install
VSMARTCARD=vsmartcard
git clone git://vsmartcard.git.sourceforge.net/gitroot/vsmartcard $VSMARTCARD
cd $VSMARTCARD/ccid/src/opensc
autoreconf --verbose --install
./configure --prefix=$PREFIX
make install && cd -
Now :file:`libopensc.so` should be located in ``$PREFIX/lib``. Here is how to
configure the USB CCID Emulator to use it::
cd $VSMARTCARD/ccid
./configure --prefix=$PREFIX OPENSC_LIBS="-L$PREFIX/lib -lopensc"
make install && cd -
If you want |PACE| support for the emulated smart card reader the process is
similar. Install |libnpa| and it should be recognized automatically by the
:file:`configure` script.
*****
Usage
*****
The USB CCID Emulator has various command line options to customize the appearance
on the USB host. In order to run the USB CCID Emulator GadgetFS must be loaded
and mounted. The USB CCID Emulator is compatible with the unix driver libccid_
and the `Windows USB CCID driver`_. To initialize |PACE| using the PC/SC API
you need to patch libccid (see :file:`patches`). On Windows, the USB CCID Emulator
currently has no support for |PACE|.
.. program-output:: ccid-emulator --help
.. include:: questions.txt
********************
Notes and References
********************
.. target-notes::
.. _`GadgetFS`: http://www.linux-usb.org/gadget/
.. _`OpenSC`: http://www.opensc-project.org/opensc
.. _`libccid`: http://pcsclite.alioth.debian.org/ccid.html
.. _`Windows USB CCID driver`: http://msdn.microsoft.com/en-us/windows/hardware/gg487509
.. _`OpenMoko Wiki`: http://wiki.openmoko.org/wiki/Building_Gadget_USB_Module>`_
.. [#f1] Note that the heavily outdated Windows USB CCID driver does not support secure PIN entry or PIN modification. USB CCID Emulator comes with a patch for libccid to support |PACE|, because it is not yet standardised in USB CCID. However, the traditional commands can be used without restriction.
