reboost blog

Oct 02, 2018

Provisioning Titan Security Keys From Linux

Google has released their own multifactor authentication hardware tokens: Titan Security Keys. Configuring your Google account to require the hardware keys is typically pretty straightforward but they must be added from a computer. When I was trying from my Linux system the process would always error out, just stating "something went wrong". I eventually found directions from Google that look pretty straight forward, but did not resolve the issue. Turns out a few tweaks were required.

Official Method

The initial directions as listed are as follows:

  1. Create a file called /etc/udev/rules.d/titan-key.rules
  2. Populate the file with the following:
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="18d1", ATTRS{idProduct}=="5026", TAG+="uaccess"
  1. Save
  2. Reboot


Even after following the above, I was getting the same error. Looking more closely at the rule as configured gave me some clues as to why. Essentially, the rule as written says that when a device is inserted that has a vendorID of 18d1 and a productID of 5026, add the "uaccess" tag. This allows Chrome to communicate directly with the USB device. That is required by since FIDO U2F, the protocol in use, actually utilizes the URL when creating the challenge–response authentication request. Plugging a key in and checking dmesg reveals the issue:

[ 5866.626801] usb 1-2: new full-speed USB device number 16 using xhci_hcd
[ 5866.775955] usb 1-2: New USB device found, idVendor=096e, idProduct=0858, bcdDevice=44.00
[ 5866.775962] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 5866.775966] usb 1-2: Product: U2F
[ 5866.775969] usb 1-2: Manufacturer: FT

Checking both keys from the set I received confirmed that neither the vendor or product matches Google's documentation. This makes some sense as the keys are actually manufactured by a company called Feitian with Google's own firmware.

After looking at a few different articles I found you can configure udev rules to match multiple options in a given field. Additionally, my version of udev did not seem to recognize rules unless the file name was prefixed with a number.

Fixed Directions

  1. Create a file called /etc/udev/rules.d/70-titan-key.rules
  2. Populate with the following:
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="18d1|096e", ATTRS{idProduct}=="5026|0858|085b", TAG+="uaccess"
  1. Save
  2. Run sudo udevadm control --reload-rules

Provisioning the key should now work from your Linux machine.

These directions were tested and confirmed working on openSUSE Tumbleweed with udev version 237. Additional tweaking may be required for other versions of udev.

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