Free60
From Wikipedia, the free encyclopedia
Free60 is the successor to the Xbox Linux Project that aims to put Linux, BSD, or Darwin on the new Xbox 360 using a software or hardware based "hack". The Xbox 360 uses hardware encryption and will not run unsigned code out of the box.
The project's goals were met in March 2007, when shortly after the announcement of a critical software vulnerabilty in the Xbox 360 Hypervisor a loader for Linux appeared, which allowed to run a Linux ported to the Xbox 360.
To date, three main Linux distributions may be run on the Xbox 360; Gentoo, Debian and Ubuntu Linux, the last two of which are easily installable to the hard drive by scripts provided by members of the Free60 project.
[edit] Execution Method
Due to the fact that executable code on the Xbox 360 is signed, and runs underneath a hypervisor, an exploit or hack is necessary in order to execute homebrew code. On the Xbox 360, one such exploit exists, relying on and utilizing a modified DVD-ROM drive firmware, a modified burnt disc of the game King Kong (for Xbox 360), and the target console having one of two vulnerable Kernel revisions. Optionally, a homemade serial cable may be used where attached to a pin header on the motherboard of the console.
The console must launch the modified game, which will utilize the software vulnerability to load a small chunk of code that is on the disc. This code may either initialize the serial port to allow upload of further code to the console, or eject the drive tray and prepare the console to load further code from a specified point on optical media that is then placed in the drive. The code executed, in this instance is known as XeLL, short for Xenon Linux Loader. XeLL captures CPU threads and launches the Linux Kernel as its only purpose. The Linux Kernel from this point initializes most of the hardware in the console.
[edit] Limitations
- The cd read method was initially restricted to only Hitachi branded DVD-ROM drives, but now also supports Samsung branded drives. One commercially used drive, BenQ, is currently unsupported.
- An older version of the game King Kong is needed, as following the publicity of the exploit, which used a shader file in the game, Microsoft has released all newer versions of the disc as patched, so that the exploit will not work when based on the new discs.
- An older Kernel revision is required on the Xbox 360 itself, which may prove to be hard to find, since connecting to the Xbox Live service applies updates to the console, and many games include updates that must be applied before the game will run. This limitation is not as important as it once was, as it is now known to be possible to downgrade a Kernel greater than the last of the two exploitable Kernels by means of a timing attack.
