mirror of
https://github.com/xemu-project/xemu.git
synced 2024-11-24 12:09:58 +00:00
471f7e30a4
Using the file-backed smartcard backend is black magic, but it can be useful if your only smartcard bricks itself if it is accessed the wrong way too many times. Complete the documentation to include the art of creating certificates and using them with QEMU, based on Ray Strode's useful tutorial at https://blogs.gnome.org/halfline/2013/09/08/another-smartcard-post/ but with ccid-card-emulated or vscclient instead of SPICE. Cc: Ray Strode <rstrode@redhat.com> Reviewed-by: Alon Levy <alevy@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
182 lines
7.5 KiB
Plaintext
182 lines
7.5 KiB
Plaintext
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 stored in files
|
|
|
|
You must create the CA and card certificates. This is a one time process.
|
|
We use NSS certificates:
|
|
|
|
mkdir fake-smartcard
|
|
cd fake-smartcard
|
|
certutil -N -d sql:$PWD
|
|
certutil -S -d sql:$PWD -s "CN=Fake Smart Card CA" -x -t TC,TC,TC -n fake-smartcard-ca
|
|
certutil -S -d sql:$PWD -t ,, -s "CN=John Doe" -n id-cert -c fake-smartcard-ca
|
|
certutil -S -d sql:$PWD -t ,, -s "CN=John Doe (signing)" --nsCertType smime -n signing-cert -c fake-smartcard-ca
|
|
certutil -S -d sql:$PWD -t ,, -s "CN=John Doe (encryption)" --nsCertType sslClient -n encryption-cert -c fake-smartcard-ca
|
|
|
|
Note: you must have exactly three certificates.
|
|
|
|
You can use the emulated card type with the certificates backend:
|
|
|
|
qemu -usb -device usb-ccid -device ccid-card-emulated,backend=certificates,db=sql:$PWD,cert1=id-cert,cert2=signing-cert,cert3=encryption-cert
|
|
|
|
To use the certificates in the guest, export the CA certificate:
|
|
|
|
certutil -L -r -d sql:$PWD -o fake-smartcard-ca.cer -n fake-smartcard-ca
|
|
|
|
and import it in the guest:
|
|
|
|
certutil -A -d /etc/pki/nssdb -i fake-smartcard-ca.cer -t TC,TC,TC -n fake-smartcard-ca
|
|
|
|
In a Linux guest you can then use the CoolKey PKCS #11 module to access
|
|
the card:
|
|
|
|
certutil -d /etc/pki/nssdb -L -h all
|
|
|
|
It will prompt you for the PIN (which is the password you assigned to the
|
|
certificate database early on), and then show you all three certificates
|
|
together with the manually imported CA cert:
|
|
|
|
Certificate Nickname Trust Attributes
|
|
fake-smartcard-ca CT,C,C
|
|
John Doe:CAC ID Certificate u,u,u
|
|
John Doe:CAC Email Signature Certificate u,u,u
|
|
John Doe:CAC Email Encryption Certificate u,u,u
|
|
|
|
If this does not happen, CoolKey is not installed or not registered with
|
|
NSS. Registration can be done from Firefox or the command line:
|
|
|
|
modutil -dbdir /etc/pki/nssdb -add "CAC Module" -libfile /usr/lib64/pkcs11/libcoolkeypk11.so
|
|
modutil -dbdir /etc/pki/nssdb -list
|
|
|
|
|
|
5. Using ccid-card-passthru with client side hardware
|
|
|
|
on the host specify the ccid-card-passthru device with a suitable chardev:
|
|
|
|
qemu -chardev socket,server,host=0.0.0.0,port=2001,id=ccid,nowait -usb -device usb-ccid -device ccid-card-passthru,chardev=ccid
|
|
|
|
on the client run vscclient, built when you built QEMU:
|
|
|
|
vscclient <qemu-host> 2001
|
|
|
|
|
|
6. Using ccid-card-passthru with client side certificates
|
|
|
|
This case is not particularly useful, but you can use it to debug
|
|
your setup if #4 works but #5 does not.
|
|
|
|
Follow instructions as per #4, except run QEMU and vscclient as follows:
|
|
Run qemu as per #5, and run vscclient from the "fake-smartcard"
|
|
directory as follows:
|
|
|
|
qemu -chardev socket,server,host=0.0.0.0,port=2001,id=ccid,nowait -usb -device usb-ccid -device ccid-card-passthru,chardev=ccid
|
|
vscclient -e "db=\"sql:$PWD\" use_hw=no soft=(,Test,CAC,,id-cert,signing-cert,encryption-cert)" <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
|
|
|
|
Both ccid-card-emulated 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 retrieve certificates and do
|
|
any encryption. The backend can then be a real reader and card, or
|
|
certificates stored in files.
|
|
|
|
For documentation of the library see docs/libcacard.txt.
|
|
|