It has been almost a year since last time I posted here so today we will have a quick one. I recently bought a SoloKey U2F key. It is a much cheaper and opensorce replacement for YubiKey (which is also a great product – I had a chance to use it for almost 2 years and it was flawless). In vanilla Ubuntu 18.04 when you plugin the key it gets detected correctly:

[Tue Feb 19 21:13:28 2019] usb 1-1: new full-speed USB device number 8 using xhci_hcd
[Tue Feb 19 21:13:28 2019] usb 1-1: New USB device found, idVendor=0483, idProduct=a2ca
[Tue Feb 19 21:13:28 2019] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Tue Feb 19 21:13:28 2019] usb 1-1: Product: Solo
[Tue Feb 19 21:13:28 2019] usb 1-1: Manufacturer: Solo Keys
[Tue Feb 19 21:13:28 2019] usb 1-1: SerialNumber: 0123456789ABCDEF
[Tue Feb 19 21:13:28 2019] hid-generic 0003:0483:A2CA.0008: hiddev1,hidraw3: USB HID v1.11 Device [Solo Keys Solo] on usb-0000:00:14.0-1/input0

Unfortunately permissions for device are incorrect and the key won’t be accessible from the browser:

$ ls -la /dev/hidraw*
crw------- 1 root root 243, 0 lut 19 21:03 hidraw0
crw------- 1 root root 243, 1 lut 19 21:03 hidraw1
crw------- 1 root root 243, 2 lut 19 21:03 hidraw2
crw------- 1 root root 243, 3 lut 19 21:13 hidraw3

To fix it we need a simple udev rule in /etc/udev/rules.d/90-solokey.rules:

KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="plugdev", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="a2ca"

And then reload the udev rules:

sudo udevadm control --reload-rules

Thanks to that rule it will have group set to plugdev and read/write permissions for that device. By default user created in Ubuntu is a member of such group so it will work out of the box:

$ id
uid=1000(alchemyx) gid=1000(alchemyx) grupy=1000(alchemyx),4(adm),20(dialout),24(cdrom),27(sudo),30(dip),46(plugdev),116(lpadmin),126(sambashare),128(kismet)

Now you can test it by going to demo.yubico.com using Google Chrome. Click Next on first page and allow access to the key. The LED on SoloKey should turn amber and after clicking its hardware button it will get registered correctly.

If you want to do the same from the Firefox you need to reconfigure it first. Open about:config URL and confirm that you accept the risk. Find security.webauth.u2f there and flip it to True.