mirror of
https://github.com/mbirth/wiki.git
synced 2024-09-20 06:33:24 +01:00
137 lines
4.3 KiB
Markdown
137 lines
4.3 KiB
Markdown
---
|
|
title: Firmware Unpacking
|
|
layout: default
|
|
created: 2009-05-20 02:17:15 +0200
|
|
updated: 2009-05-24 23:27:24 +0200
|
|
toc: false
|
|
tags:
|
|
- know-how
|
|
- hardware
|
|
- apple
|
|
- iphone
|
|
- firmware
|
|
- hacking
|
|
---
|
|
Preparations
|
|
============
|
|
|
|
You'll need the following tools:
|
|
|
|
* [genpass.c](http://www.theiphonewiki.com/wiki/index.php?title=GenPass)
|
|
* [vfdecrypt-linux.tar.gz](http://code.google.com/p/iphone-elite/downloads/list)
|
|
* [Xpwn](http://www.zdziarski.com/iphone-forensics/v2.x-Base/Xpwn/)
|
|
* [OpenSSL 0.9.8h sources](http://www.openssl.org/source/openssl-0.9.8h.tar.gz)
|
|
|
|
Now compile the `genpass.c`:
|
|
|
|
1. untar `openssl-0.9.8h.tar.gz` and rename the directory to just `openssl`
|
|
1. compile OpenSSL:
|
|
|
|
cd openssl/
|
|
./config && make
|
|
|
|
1. now go one directory up (I assume this is where you put the `genpass.c`) and compile it:
|
|
|
|
gcc genpass.c openssl/libcrypto.a -o genpass -I openssl/include
|
|
|
|
1. the `vfdecrypt-linux.tar.gz` comes with a precompiled binary. If you want to compile it on your own, do it like this:
|
|
|
|
gcc vfdecrypt.c ../openssl/libcrypto.a -I ../openssl/include/ -o vfdecrypt
|
|
|
|
|
|
Unpacking the ipsw file
|
|
=======================
|
|
|
|
The ***iP**hone **S**oft**w**are* `.ipsw` files are normal ZIP files. You can extract them with e.g. *IZArc*. The archives
|
|
contain several files and some disk images: the iPhone OS itself, an Upgrade image and a Restore image. These 3 interesting
|
|
files for the iPhone OS 3.0 BETA 5 are named like this (output of `unzip -l`):
|
|
|
|
~~~
|
|
Archive: iPhone1,2_3.0_7A312g_Restore.ipsw
|
|
Length Date Time Name
|
|
-------- ---- ---- ----
|
|
208347136 05-04-09 13:09 018-4965-005.dmg
|
|
13086064 05-04-09 13:00 018-4970-005.dmg
|
|
13086064 05-04-09 13:00 018-4972-005.dmg
|
|
~~~
|
|
|
|
The larger one is the iPhone OS image, the other two are the two loader images (upgrade/restore).
|
|
|
|
|
|
Decrypt a loader image
|
|
======================
|
|
|
|
You need an *initialization vector* and a *key* for decrypting this. For now, these are posted
|
|
on [theiphonewiki.com](http://www.theiphonewiki.com/wiki/index.php?title=VFDecrypt_Keys:_3.x#iPhone_3G_5).
|
|
|
|
Do this using the **Xpwntool**:
|
|
|
|
./xpwntool 018-4972-005.dmg ramdisk.dmg -iv 5508FD2D20F22048D4BC1780A0B1CAFF -k 198FEAFD04973FC8B07A052BE75B9288
|
|
|
|
|
|
Find encryption key for iPhoneOS
|
|
================================
|
|
|
|
The key might be already posted on [theiphonewiki.com](http://www.theiphonewiki.com/wiki/index.php?title=VFDecrypt_Keys:_3.x#iPhone_3G_5),
|
|
so maybe we don't need this step.
|
|
|
|
Use the compiled `genpass.c` to extract the encryption key from the decrypted loader image:
|
|
|
|
./genpass s5l8900x ./ramdisk.dmg 018-4965-005.dmg
|
|
|
|
This will give something like this:
|
|
|
|
~~~
|
|
passphrase: fcdf5fbe3bdcaeff0c3de34430ffb473ac34cb0b55efdc087e70aa7c558a1055
|
|
not block 0
|
|
not block 1
|
|
not block 2
|
|
not block 3
|
|
not block 4
|
|
not block 5
|
|
vfdecryptk: f7b1edb0ee9196a1393dccdc8d090051308b84ab322bf860cb1d3ca566ef2e29752fa79a
|
|
~~~
|
|
|
|
|
|
Decrypt iPhoneOS
|
|
================
|
|
|
|
This was a bit tricky as the syntax for `vfdecrypt` was wrong in all other manuals and even in the syntax help of `vfdecrypt` itself.
|
|
|
|
Run this:
|
|
|
|
./vfdecrypt -i018-4965-005.dmg -kf7b1edb0ee9196a1393dccdc8d090051308b84ab322bf860cb1d3ca566ef2e29752fa79a -odmg.dmg
|
|
|
|
(Note the missing *\<SPACE\>* between the parameter's name and value.)
|
|
|
|
This will give you a file `dmg.dmg` which is the decrypted iPhoneOS image.
|
|
|
|
|
|
Uncompress iPhoneOS image
|
|
=========================
|
|
|
|
Since the `dmg.dmg` (199 MiB) is a compressed image, you can't mount it directly in Linux. You first have to unpack it.
|
|
There's a tool `dmg` among the **Xpwntools**. So use it like this:
|
|
|
|
./dmg extract dmg.dmg dmg-raw.dmg
|
|
|
|
You'll get a 441 MiB file `dmg-raw.dmg`.
|
|
|
|
|
|
Mount iPhoneOS
|
|
==============
|
|
|
|
To go exploring the iPhoneOS files, you can now mount the uncompressed image like this:
|
|
|
|
sudo mount -o loop -t hfsplus ./dmg-raw.dmg /mnt/iphoneimage
|
|
|
|
(Make sure that `/mnt/iphoneimage` exists and is an empty folder.)
|
|
|
|
|
|
Links
|
|
=====
|
|
|
|
* [mail-archive.com](http://www.mail-archive.com/linux4nano-dev@gna.org/msg00209.html) --- technical explanation
|
|
* [tungchingkai.blogspot.com](http://tungchingkai.blogspot.com/2009/04/how-to-decrypt-iphone-os-30-beta.html) --- how to decrypt the firmware file
|
|
* [theiphonewiki.com](http://www.theiphonewiki.com/wiki/index.php?title=VFDecrypt_Keys:_3.x#iPhone_3G_5) --- several encryption keys for iPhone firmware files
|