What's inside the input stack?🐁

Kernel Recipes 2017

About me:

Benjamin Tissoires (irc: bentiss) • Software engineer at Red Hat • kernel hid-multitouch maintainer, hid core co-maintainer • also gives bad advice for the upper input stack

About the other guy:

Peter Hutterer (irc: whot) • Software engineer at Red Hat • libinput maintainer • Maintainer of the X.Org input stack, and evdev, synaptics, ... drivers • (99% of the time, 'we' means him and I)

Isn't it working already?

Problem is:hardware makers can be creative

And usage is changing

Outline: • Introduction • Input architecture • Talking about a bunch of devices • A little bit about security

Everything you never wanted toknow about 'how input works'

Components: • Kernel • libinput • "Wayland" or Xorg • toolkit • application

Kernel: • knows about protocols (HID, RMI4, ...) • knows about transport layer (USB, PS/2, SMBus, I2C, etc...) • talks evdev

Libinput: • because input is "easy" • relies on libevdev • does fancy things like gestures • has a global view of the input devices

Compositor (or Xorg): • loads libinput • pass incoming events to the right client

Toolkits: • relies on [see previous slides] • does fancy things like gestures too

Applications: • do something useful (hopefully)

The good, the bad and the ugly(of input devices)

Keyboards

Page left blank

Actually no...the Caps Lock LED in a TTY isbroken since UTF-8 support inthe kernel

Actually no...the Caps Lock LED in a TTY isbroken since UTF-8 support inthe kernel

pro tip: add /etc/udev/rules.d/99-kbd.rulesACTION=="add", \ SUBSYSTEM=="leds", \ ENV{DEVPATH}=="*/input*::capslock", \ ATTR{trigger}="kbd-ctrlllock"

Mice

(for the kernel)

Not much to add...

.

(for the kernel)

Not much to add...

except libratbag

libratbag:A thing to configure gaming mice

• fun project to hack on • allows for reverse engineering without the pain of breaking the kernel • supports many gaming devices: Logitech, Roccat, G-Skill, Razer (in progress)

Touchpads

Most are still using PS/2

story time: T440

story time: T440

story time: T450

story time: T450

A little bit about security(with a red background)

CVEs?: • yes, but only a few • one notable was regarding the ChromeBook injecting HID event through a web application

MouseJack

MouseJack:

Congrats, your mouse is IoT ready!

http://www.mousejack.com/

.

MouseJack:

Congrats, your mouse is IoT ready!

http://www.mousejack.com/

You have to update it

Summary: • Input architecture • some devices still need some care • security is also involved

Credits • PS/2 keyboard: CC BY Matthijs Kooijman • G600 Gaming Mouse: all rights reserved, Logitech • Lenovo X1 Carbon: CC BY-SA 2.0 Stannate • Lenovo Yoga Tablet 3 Pro: all rights reserved, Lenovo

Thanks!

benjamin.tissoires@(gmail|redhat).comIRC: bentiss @freenode @gimpnet

Summary: • Input architecture • some devices still need some care • security is also involved