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diff --git a/docs/ccid.txt b/docs/ccid.txt new file mode 100644 index 0000000..b8e504a --- /dev/null +++ b/docs/ccid.txt @@ -0,0 +1,135 @@ +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 + +Smartcard 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-emualated + +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 <qemu-host> 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)" <qemu-host> 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. + |