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A cross-platform custom NOR firmware loader and custom IPSW generator for the iPhone

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Welcome to XPwn!

The X is for "cross", because unlike PwnageTool, this utility has no dependencies on proprietary, closed-source software and can potentially be compiled and used on any platform.

This is a special proof-of-concept version available on any platform, compiled with static libraries to minimize potential issues (which is why the executables are a bit on the heavy side).

The source is released under the terms of the GNU General Public License version 3. The full text of the license can be found in the file LICENSE. The source code itself is available at: http://github.com/planetbeing/xpwn

What XPwn is

A barebones pwnagetool implementation that is easily portable.

What XPwn is NOT

An easy-to-use tool suitable for beginners. While it is possible easy to use user interfaces will be developed for it eventually, it's mostly meant to be a toy for *nix geeks. Absolutely no support should be expected or will be given.

XPwn is also NOT winpwn. Winpwn will have things like easy package management, an actual, non-lame system of installing stuff. I've seen the code for it, and it will be pretty awesome when finished. Those tasks are outside the scope of XPwn.

Credits

This utility is merely an implementation of Pwnage, which is the work of roxfan, Turbo, wizdaz, bgm, and pumpkin. Those guys are the real heroes.

Also, the new super-awesome bootrom exploit is courtesy of wizdaz.

MuscleNerd has put a lot of work into the 3G effort. The BootNeuter unlock for first-generation iPhones packaged within is primarily his effort.

Thanks also go to gray and c1de0x for their RCE efforts. saurik is the author of Cydia, included within. bugout was the lucky guy who did our first 3G tests.

Thanks to chris for his hardware wisdom, Zf for his French humor, and pytey for the support on the serial stuff.

idevice's "ready for custom IPSW" art was graciously contributed by KinetiX

XPwn attempts to use all the same data files and patches as PwnageTool to avoid duplication of present and future labor. I believe that wizdaz probably put the most sweat into PwnageTool, and the pwnage ramdisk is the work of Turbo.

XPwn on Linux would not have been possible without libibooter, which was written by cmw, based on the Linux iPhone recovery driver written by geohot.

Dripwn was created by Munnerz, specifically for installing iDroid.

A special shout-out to cmw, who I have been helping with winpwn. He's put a lot of hard work into winpwn, and should also be credited with doing some of the initial exploratory work with the undocumented DMG format.

Usage

There are three utilities in this package, as well as the bundles and FirmwareBundles folders from PwnageTool, and Turbo's autopwn ramdisk.

Overview

The general series of steps should be to use ipsw to create a custom IPSW with the user's preferences (done once per custom ipsw required), then itunespwn (done once per computer) so that future DFU restores will be made easier. Finally, either dfu-util (Mac or Linux) or idevice (Windows) should be used as necessary on the iPhone to perform the actual exploit necessary to allow it to accept our code.

It is technically possible to skip itunespwn and just use idevice or skip idevice and just use itunespwn, but I recommend doing both.

ipsw

NOTE: Important change for 2.0: (uncompressed) tarballs rather than paths are now used for bundles

ipsw is a more complex tool to generate custom IPSWs that you can restore after using xpwn (or any other pwnage-based utility). This is important, since that's how the jailbreak actually occurs.

./ipsw <input.ipsw> <output.ipsw> [-b <bootimage.png>] [-nowipe] \
	[-bbupdate] [-s <disk0s1 size>]  [-r <recoveryimage.png>] \
	[-memory] [-e "<action to exclude>"] \
	[[-unlock] [-use39] [-use46] [-cleanup] \
	-3 <bootloader 3.9 file> -4 <bootloader 4.6 file>] \
	<package1.tar> <package2.tar>...

Yes, I know, confusing syntax. The first two options are the IPSW you want to modify, and where you want to save the modified IPSW respectively. -b and -r have the same semantics and requirements as for xpwn. You can also specify actions to exclude from the "FilesystemPatches" section of the Info.plist for your particular IPSW (in FirmwareBundles/).

The most common use of the '-e' flag is to disable automatic activation, i.e. '-e "Phone Activation"'. Note that the double-quotes are necessary.

-s allows you to specify the size of the system partition. This value is specified in megabytes (NOT mebibytes)

-memory allows you to specify that memory instead of temporary files should be used whenever possible (no longer the default).

-nowipe disables Apple's wiping of the NAND (user data), before proceeding with the restore. This allows the restore to happen much, much more quickly.

-bbupdate tells the restore ramdisk to attempt to upgrade your baseband. This is disabled by default for unlock safety reasons.

-unlock, -use39, -use46, -cleanup, -3, and -4 are valid only if you merge the BootNeuter package. These provide instructions to BootNeuter (which provides unlocking for iPhones). If you choose to use BootNeuter, you must specify the location where the 3.9 and 4.9 bootloader can be found with the -3 and -4 options. These cannot be included with xpwn due to copyright restrictions.

-unlock specifies that you wish BootNeuter to unlock the phone (if it is not already unlocked). -use39 and -use46 instructs BootNeuter to either upgrade or downgrade your bootloader (if it is not already on the version you choose). -cleanup instructs BootNeuter to delete itself off of the iPhone after it is complete. If you do not specify -cleanup, BootNeuter will be accessible via SpringBoard.

The last options are for tar-files to merge. All permissions and ownership will be preserved except for already directories that already exist. This is to prevent accidental clobbering (we're guessing you don't really want to alter permissions on existing directories). This behavior may change in the future.

Told you it was a mess.

itunespwn

This Windows utility will replace a file in your %APPDATA%\Apple Computer
Device Support folder. Subsequently, if you place your phone into DFU mode and iTunes recognizes it, Apple will automatically upload an exploit file onto your phone that will allow it to accept custom firmware (until it is turned off). This basically will allow you to restore any IPSW you want from that version of iTunes (provided you connect your phone in DFU mode).

See the following section for detailed instructions on how to enter DFU mode.

Usage:

itunespwn <custom.ipsw>

The custom.ipsw is needed for the exploited WTF that was generated during IPSW generation.

idevice

This utility replaces dfu-util for Windows, sidestepping the libusb requirement and provides a more user-friendly way of guiding them through DFU mode. Its arguments are analogous to dfu-util and more details can be read in that section. The difference is that iTunes' libraries are used rather than the non-proprietary dfu-util. Also, a user-friendly logo is made to appear on the iPhone upon successful completion, so an unambiguous cue can be given to the user that they are ready to use the IPSW they created.

Obviously, a CLI is by its very nature not very newbie friendly, so the primary purpose of this utility is to serve a mock-up for GUI implementors. All GUI implementors are strongly encouraged to reproduce this in their applications.

Usage:

idevice <custom.ipsw> <n82ap|m68ap|n45ap>

dfu-util (Not recommended on Windows)

dfu-util is an utility adapted from OpenMoko that satisfies the "pwning" stage of the process, that is, allowing the execution of our unsigned code. It relies upon an exploit in the DFU mode of the iPhone/iPod touch bootrom. This cannot be fixed by Apple on the current hardware revisions. If we can mess with the device before iTunes sees it, we can have it load a WTF with signature checking disabled with the exploit, and load an iBSS with signature checking disabled over that WTF. iTunes will see the device as a regular iPhone/iPod in recovery mode, and will happily send our custom firmware to it, which will now be accepted.

YOU MUST COMPLETELY DISABLE iTUNES WITH TASK MANAGER OR EQUIVALENT BEFORE PROCEEDING.

Only AFTERWARDS do you put your device into DFU mode. If you switch the order of these steps, iTunes will be able to load software onto your device without this vulnerability, rendering dfu-util useless.

AFTER you have disabled iTunes, iTunesHelper, etc., plug your device into the computer. Shut down the device in the normal way if necessary (Slide to shutdown). Hold down the Power and Home buttons simultaneously and count slowly to ten. (You may need to push down on power an instant before you push down on home). The iPhone will start. At around the time you count to 6, the iPhone will shut down again. KEEP HOLDING BOTH BUTTONS. Hold down both buttons until you reach 10. At this point, release the power button ONLY. Keep holding the stand-by button forever (this may take up to two minutes). Note Windows: You will know when you can stop holding the button when Windows notifies you via an audible cue that a USB device has connected. Note Linux: In terms of Linux you could do lsusb until it's seen. dfu-util is gradually being phased out anyway. This is your device in DFU mode. The screen of the device will remain completely powered off.

THEN, run dfu-util with the following syntax:

sudo ./dfu-util <custom.ipsw> <n82ap|m68ap|n45ap>

Where n82ap = 3G iPhone, m68ap = First-generation iPhone, n45ap = iPod touch. Note that you're using your CUSTOM IPSW for this stage, since we will need the patched firmware, not the stock firmware. dfu-util will pick out the right files from the ipsw and send them in the right order. If your screen powers on and then turns white, then you know it worked. You can now restore with iTunes.

xpwn (DEPRECATED)

If DFU mode is too complicated for you, and you have a first-generation phone, you can still use the legacy xpwn ramdisk method on 1.1.4 to pwn your phone. Then you can restore the custom IPSW without messing with DFU mode.

xpwn will use libibooter to bootstrap the autopwn ramdisk. This will patch NOR so that unsigned IPSWs can subsequently be used. The vulnerability used is only available in firmware version 1.1.4, so this step has to be done with that version.

./xpwn <input.ipsw> [-b <bootlogo.png>] [-r <recoverylogo.png>]

Specifying a boot logo and a recovery logo is optional. You can specify both, or just one. If you do not specify a particular boot logo, the logo will remain the same as the one you currently have.

The input IPSW should correspond with CURRENT version on the device you are trying to jailbreak. NOT the one you want to upgrade to. The reason it is necessary is to provide a kernel for the ramdisk to boot and to provide template boot logos to replace.

Note that the input IPSW must have the same name as the one on Apple's download site! That is, it will not be recognized if you have renamed it after downloading it.

Note that xpwn is not currently known to work for firmware other than 1.1.4.

The boot and recovery logos need to be PNG formatted files that less than or equal to 320x480 in dimension. Although automatic conversion will be attempted for you, the preferred format is an ARGB PNG with 8 bits per channel. NOT a paletted RGB, and an alpha channel must be present NOT binary transparency.

If you save in PNG-24 and have at least one semi-transparent (not fully transparent) pixel in your file, you ought to be in good shape.

It is safe to use xpwn multiple times consecutively, and that method can be used to swap boot logos without restoring.

A restore with a non-customized IPSW will undo what xpwn did (the NOR will be reflashed with Apple's image that does have signature checking)

Examples

Jailbreaking iPod 2.0:

./ipsw iPod1,1_2.0_5A347.ipsw custom.ipsw \
	bundles/Cydia.tar

Jailbreaking iPhone 3G:

./ipsw iPhone1,2_2.0_5A347.ipsw custom.ipsw \
	-e "Phone Activation" bundles/Cydia.tar

Jailbreaking, activating, and unlocking iPhone 2.0:

./ipsw iPhone1,1_2.0_5A347.ipsw custom.ipsw \
	-unlock -cleanup -3 bl39.bin -4 bl46.bin \
	bundles/Cydia.tar \
	bundles/BootNeuter.tar \
	bundles/YoutubeActivation.tar

Technical notes

Both xpwn and ipsw load the entire contents of the IPSW into memory before manipulating it. This is especially useful for ipsw, because it allows all the necessary transformations to be done without writing the intermediate steps to disk and slowing the process down. ipsw is hence even faster than the Mac pwnagetool.

However, hefty virtual memory requirements are necessary: 170 MB for xpwn and 500 MB for ipsw. Most modern computers should have that much to spare. Not all of it needs to be free physical, as memory is accessed in a sequential manner so thrashing should be kept to a minimum. In the worst case, it should be equivalent to just writing intermediate results to disk. In essence, virtual memory is used as an intelligent cache.

On the other hand, this also means that devices such as the iPhone itself cannot run these utilities without modification. The necessary modifications are actually relatively simple. Instead of using an AbstractFile backed by memory, an AbstractFile backed by a physical file can be used again. Contact me if this functionality is desired.

Libraries used

  • bsdiff
  • libibooter
  • libbzip2
  • libcrypto (from OpenSSL)
  • libpng
  • libusb
  • libz

These are all statically compiled in, but it should give you a good idea of the program's dependencies.

Linux Notes:

Question: Is there a way to restore the iPhone from Linux?

Answer: There is currently no way to restore an IPSW directly from Linux. The necessary reverse-engineering has already been done by pumpkin, bushing and c1de0x, so that functionality will come in the medium-term future.

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A cross-platform custom NOR firmware loader and custom IPSW generator for the iPhone

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