Comex, developer of the JailbreakMe 3.0 iPad 2 PDF jailbreak has posted the source code of JailbreakMe on his github page, making the latest iteration of JailbreakMe open source. Those interested can now have a look at the JailbreakMe 3.0 code.
Originally codenamed 'saffron' JailbreakMe 3.0 uses a vulnerability in mobile Safari to gain root access to the device from where the PDF payload is installed.
Two exploits are used to jailbreak Apple devices by opening a PDF file in the MobileSafari browser: initial code execution is obtained through a vulnerability in the Freetype Type 1 font parser, allowing subsequent exploitation of a kernel vulnerability to disable code signing enforcement, get root privileges and "install" the jailbreak. The same kernel vulnerability is also exploited at each reboot to provide an untethered jailbreak, using the Incomplete Codesign technique to bootstrap the kernel exploitClick here to see the JailbreakMe 3.0 source code for yourself. On another note, here's how to jailbreak iPad 2 using JailbreakMe 3.0.