QEMU CCID Device Documentation. Contents 1. USB CCID device 2. Building 3. Using ccid-card-emulated with hardware 4. Using ccid-card-emulated with certificates 5. Using ccid-card-passthru with client side hardware 6. Using ccid-card-passthru with client side certificates 7. Passthrough protocol scenario 8. libcacard 1. USB CCID device The USB CCID device is a USB device implementing the CCID specification, which lets one connect smart card readers that implement the same spec. For more information see the specification: Universal Serial Bus Device Class: Smart Card CCID Specification for Integrated Circuit(s) Cards Interface Devices Revision 1.1 April 22rd, 2005 Smartcards are used for authentication, single sign on, decryption in public/private schemes and digital signatures. A smartcard reader on the client cannot be used on a guest with simple usb passthrough since it will then not be available on the client, possibly locking the computer when it is "removed". On the other hand this device can let you use the smartcard on both the client and the guest machine. It is also possible to have a completely virtual smart card reader and smart card (i.e. not backed by a physical device) using this device. 2. Building The cryptographic functions and access to the physical card is done via NSS. Installing NSS: In redhat/fedora: yum install nss-devel In ubuntu/debian: apt-get install libnss3-dev (not tested on ubuntu) Configuring and building: ./configure --enable-smartcard && make 3. Using ccid-card-emulated with hardware Assuming you have a working smartcard on the host with the current user, using NSS, qemu acts as another NSS client using ccid-card-emulated: qemu -usb -device usb-ccid -device ccid-card-emulated 4. Using ccid-card-emulated with certificates You must create the certificates. This is a one time process. We use NSS certificates: certutil -d /etc/pki/nssdb -x -t "CT,CT,CT" -S -s "CN=cert1" -n cert1 Note: you must have exactly three certificates. Assuming the current user can access the certificates (use certutil -L to verify), you can use the emulated card type with the certificates backend: qemu -usb -device usb-ccid -device ccid-card-emulated,backend=certificates,cert1=cert1,cert2=cert2,cert3=cert3 5. Using ccid-card-passthru with client side hardware on the host specify the ccid-card-passthru device with a suitable chardev: qemu -chardev socket,server,host=0.0.0.0,port=2001,id=ccid,nowait -usb -device usb-ccid -device ccid-card-passthru,chardev=ccid on the client run vscclient, built when you built the libcacard library: libcacard/vscclient 2001 6. Using ccid-card-passthru with client side certificates Run qemu as per #5, and run vscclient as follows: (Note: vscclient command line interface is in a state of change) libcacard/vscclient -e "db=\"/etc/pki/nssdb\" use_hw=no soft=(,Test,CAC,,cert1,cert2,cert3)" 2001 7. Passthrough protocol scenario This is a typical interchange of messages when using the passthru card device. usb-ccid is a usb device. It defaults to an unattached usb device on startup. usb-ccid expects a chardev and expects the protocol defined in cac_card/vscard_common.h to be passed over that. The usb-ccid device can be in one of three modes: * detached * attached with no card * attached with card A typical interchange is: (the arrow shows who started each exchange, it can be client originated or guest originated) client event | vscclient | passthru | usb-ccid | guest event ---------------------------------------------------------------------------------------------- | VSC_Init | | | | VSC_ReaderAdd | | attach | | | | | sees new usb device. card inserted -> | | | | | VSC_ATR | insert | insert | see new card | | | | | VSC_APDU | VSC_APDU | | <- guest sends APDU client<->physical | | | | card APDU exchange| | | | client response ->| VSC_APDU | VSC_APDU | | receive APDU response ... [APDU<->APDU repeats several times] ... card removed -> | | | | | VSC_CardRemove | remove | remove | card removed ... [(card insert, apdu's, card remove) repeat] ... kill/quit | | | | vscclient | | | | | VSC_ReaderRemove | | detach | | | | | usb device removed. 8. libcacard ccid-card-passthru and vscclient use libcacard as the card emulator. libcacard implements a completely virtual CAC (DoD standard for smart cards) compliant card and uses NSS to actually retrive certificates and do any encryption using the backend (real reader + card or file backed certificates). For documentation of cac_card see README in libcacard subdirectory.