After having analyzed the Samsung Stick firmware, it was time to make something useful out of it. When first plugged into a linux machine, it appears to be a usb Storage.
With the help of usb_modswitch, it is possible to activate the ttyUSB device, as well as the control device.Here is the output of a lsusb
The command line for the usb_modswitch would be:
Here is an output log:
So after that, a new lsusb would show us:
Modifying the linux driver
In order to have a device descriptor for the stick, we need to modify the linux driver already available.
The new file kalmia.c is present HERE
. (Special thx to Xavier Martin for his this)
and I added the Makefile that let me compile it
Now 2 new devices are present:
Now the /dev/c2xx device will give us all the debug packet, including NAS and RRC, so we could look at them with wireshark.
In order to do that, we need a wireshark dissector that: packet-c2xx.c
As seen on the following picture, the dissector takes a packet that we named c2xx.
This packet is itself composed of a header, a HDLC flag, and a frame.
Packet containing NAS are then visible