Hi,
I have an old BeagleBone Black (A5A, 2GB version), and I would like to
use it to emulate an external USB keyboard. I was thinking... I would
SSH into BBB and run some commands to send keymap data to PC through
- either mini-USB port
- or debug serial-to-USB cable.
As far as PC is concerned, it's receiving key presses.
Is this possible?
Where can I start my reading?
Yes, it is possible.
As far as where to start leaning ? Well, you need to learn libusb, and about the USB HID protocol. Passed that, you’re going to have to figure out how to write a Windows USB HID driver, prorbably also using libusb . . . It’s a fairly complex subject that I also personally did some reading on, but never finished.
err, yeah oops. Where ? Use google and keywords “USB HID protocol”, “libusb”, and just start reading everything you can find.
There may be a quick and dirty shortcut to avoid going down the “gotta learn the low-level details of usb” rabbit hole. You can use a usb gadget to make the mini usb port appear as a serial port to your BBB software. Took about 2 lines of bash if I recall. Sorry, I don’t have the details handy at the moment, I did this a while back. I think I got this from Jan Axelrod, maybe even on her website. If not, then her USB complete book.
Linux Gadget Drivers + BeagleBone hardware should allow you to emulate a USB keyboard.
http://www.armadeus.com/wiki/index.php?title=USB_Gadget
If you are emulating a keyboard, no PC driver is needed.
-Ed
I did a talk about how to do this at DEFCON this year. One device to pwn them all. Files you need here https://media.defcon.org/DEF%20CON%2023/DEF%20CON%2023%20presentations/DEFCON-23-Phil-Polstra-Extras.rar
So Phil . . . if you’re going to send files to others on the group, you may want to leave out files such as “attackWindows.py” . . .heh ! 
SO, the companion slides to go with those files: https://media.defcon.org/DEF%20CON%2023/DEF%20CON%2023%20presentations/DEFCON-23-Phil-Polstra-One-device-to-Pwn-them-all.pdf related material starts at page 22.
Great job Phil. I did not realize creating a faux USB HID device was so easy. Well, “easy” when one lays out in great detail how it’s done
Thank you. It’s been bookmarked and downloaded. I’ll start reading. I’m encouraged by the fact that you can script this.
Hello Phil,
I try executing your script would you have information on what to do if /sys/kernel/config is not available, I did search on google with no success