# USB CCID Emulator — vsmartcard 2021-04-28 documentation

# USB CCID Emulator

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 OpenSC 2 also PACE can be performed by the emulator.

Portable smart card reader with trusted user interface

If the machine running 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.

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`

PIN verification/modification and PACE can also be started by the application transmitting (SCardTransmit) specially crafted APDUs. Only the alternative initialization of PACE using SCardControl requires patching the driver (available for libccid, see `patches`). The pseudo APDUs with no need for patches are defined as follows (see BSI TR-03119 1.3 6 p. 33-34):

| Command APDU | Response APDU
--- | --- | ---
CLA | INS | P1 | P2 | Command Data | Response Data | SW1/SW2
GetReaderPACECapabilities | `0xFF` | `0x9A` | `0x04` | `0x01` | (No Data) | `PACECapabilities` | `0x9000` or other in case of an error
EstablishPACEChannel | `0xFF` | `0x9A` | `0x04` | `0x02` | `EstablishPACEChannelInput` | `EstablishPACEChannelOutput`
DestroyPACEChannel | `0xFF` | `0x9A` | `0x04` | `0x03` | (No Data) | (No Data)
Verify/Modify PIN | `0xFF` | `0x9A` | `0x04` | `0x10` | Coding as `PC_to_RDR_Secure` | Coding as `RDR_to_PC_DataBlock`

The USB CCID Emulator is implemented using GadgetFS 1. Some fragments of the source code are based on the GadgetFS example and on the source code of the OpenSC tools.

Software stack of the USB CCID Emulator running on the OpenMoko Neo FreeRunner

Running the USB CCID Emulator has the following dependencies:

- Linux Kernel with GadgetFS 1

- OpenSC 2

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.

Implementation of a mobile smart card reader for the German ID card

## Download

You can find the latest release of USB CCID Emulator on Github. Older releases are still available on Sourceforge.

Alternatively, you can clone our git repository:

    git clone https://github.com/frankmorgner/vsmartcard.git

## Installation

### Installation on Linux, Unix and similar

The USB CCID Emulator uses the GNU Build System to compile and install. If you are unfamiliar with it, please have a look at `INSTALL`. If you can not find it, you are probably working bleeding edge in the repository. To generate the missing standard auxiliary files you need to additionally install libtool and pkg-config and run the following command in `ccid-emulator`:

    autoreconf --verbose --install

To configure (configure --help lists possible options), build and install the USB CCID Emulator now do the following:

    ./configure
    make
    make install

The USB CCID Emulator depends on libopensc, which is automatically built from a snapshot of the OpenSC source code and then statically linked.

### Hints on GadgetFS

To create a USB Gadget in both USB host and USB client mode, you need to load the kernel module gadgetfs. Here is how to get a running version of GadgetFS on a Debian system (see also OpenMoko Wiki 5):

    sudo apt-get install linux-source linux-headers-`uname -r`
    sudo tar xjf /usr/src/linux-source-*.tar.bz2
    cd linux-source-*/drivers/usb/gadget
    # build dummy_hcd and gadgetfs
    echo "KDIR := /lib/modules/`uname -r`/build" >> Makefile
    echo "PWD := `pwd`" >> Makefile
    echo "obj-m := dummy_hcd.o gadgetfs.o" >> Makefile
    echo "default: " >> Makefile
    echo -e "\t\$(MAKE) -C \$(KDIR) SUBDIRS=\$(PWD) modules" >> Makefile
    make
    # load GadgetFS with its dependencies
    sudo modprobe udc-core
    sudo insmod ./dummy_hcd.ko
    sudo insmod ./gadgetfs.ko default_uid=`id -u`
    # mount GadgetFS
    sudo mkdir /dev/gadget
    sudo mount -t gadgetfs gadgetfs /dev/gadget

On OpenMoko it is likely that you need to patch your kernel. If you also want to switch multiple times between gadgetfs and g_ether, another patch is needed.

If you are using a more recent version of dummy_hcd and get an error loading the module, you maybe want to check out this patch.

## 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 3 and the Windows USB CCID driver 4. PIN commands are supported if implemented by the driver.

New in version 0.7: USB CCID Emulator now supports the boxing commands defined in BSI TR-03119 1.3 6.

    Usage: ccid-emulator [OPTION]...
    Emulate a USB CCID compliant smart card reader

      -h, --help               Print help and exit
      -V, --version            Print version and exit
      -i, --info               Print available readers and drivers.  (default=off)
      -r, --reader=INT         Number of the PC/SC reader to use (-1 for
                                 autodetect)  (default=`-1')
          --gadgetfs=FILENAME  Directory where GadgetFS is mounted
                                 (default=`/dev/gadget')
      -v, --verbose            Use (several times) to be more verbose

    Changing the appearance on the Universal Serial Bus:
      -p, --product=INT        USB product ID  (default=`0x3010')
      -e, --vendor=INT         USB vendor ID  (default=`0x0D46')
          --serial=STRING      USB serial number  (default=`random')
          --interface=STRING   USB serial number  (default=`notification status')
          --interrupt          Add interrupt pipe for CCID  (default=off)

    Report bugs to https://github.com/frankmorgner/vsmartcard/issues

    Written by Frank Morgner <frankmorgner@gmail.com>

## Question

Do you have questions, suggestions or contributions? Feedback of any kind is more than welcome! Please use our project trackers.

## Notes and References

1(1,2)

  http://www.linux-usb.org/gadget/

2(1,2)

  https://github.com/frankmorgner/OpenSC

3

  https://ccid.apdu.fr/

4

  http://msdn.microsoft.com/en-us/windows/hardware/gg487509

5

  http://wiki.openmoko.org/wiki/Building_Gadget_USB_Module

6(1,2)

  https://www.bsi.bund.de/DE/Publikationen/TechnischeRichtlinien/tr03119/index_htm.html