Address bruteforcing

NOTICE: Do not do this if you have a 2G Nano or the 1G Classic (80GB and 160GB models): we already have execution on them. We might not even need this done on the 2G Classic (120GB) either, but feel free to try.

The best way people can help us out right now is by helping find the correct address we need to jump to in order to execute code. This has already been done on the 2G Nano and the 1G Classic. But now we really need help with the other iPods. Regardless of technical experience, anyone can help us out and get Rockbox and iPodLinux ported to the Nano's quicker. If you find the correct return address, you can rightfully brag about being the first person to run non-Apple code on that iPod :-). I'd also like to point out that your iPod cannot be bricked by this process and the Linux4nano team will gladly help you out on IRC if you encounter any problems.

Setup

OK, so here's how to help out: first of all download a copy of sweepfreeze.7z. You will also need sweepcrash.7z. Don't be fooled by the small sizes, because uncompressed these archives are ~250MB. Each one contains every return address that can possibly be jumped to. The best way to get the files is to just extract the files you need one by one, rather than the whole thing. Also update your iPod to the latest firmware (except for the 4G Nano - update or downgrade to 1.0.3) because we want everyone to have the same version. Once you have these things set up, you are ready to go.

This process involves trying out various sweep files in the .7z archives. The files in sweepfreeze.7z will freeze if code has executed and the files in sweepcrash.7z will crash if code is executed. The files are .htm format. They are prefixed with either an 'a' or a 'b' and then the address they jump to. You should try only the A files for right now. As you can see, there are many sweep files, and only some of them will do anything interesting. If nobody has started on your iPod yet, start trying files starting at a080a2004.htm, otherwise continue where the others have left off.

Be sure to reserve a range for yourself to test in the table below. (we don't wont anyone doing the same files at the same time) Reserve small amounts at a time.

Known problems

Note: if you are using your iPod with a Mac, your note files will not do anything. You will need to reformat the iPod to FAT32, and restore using iTunes on a Windows machine.

Also, the 1.0.4 firmware release for the nano 4g has patched the notes vulnerability. Do not upgrade to it (there are no new worthwhile features). I would suggest not upgrading any other iPods either as of August 21. If you already upgraded to 1.0.4, you can follow this guide, except use this file and this file as the firmware.

Steps

1. Connect your iPod to the computer if it isn't already and browse to it's Notes directory. Clear out any previous notes files and put a new one from the sweepfreeze.7z archive in there. Unmount your iPod and disconnect it.
2. Reboot your iPod by holding the menu and center buttons for a few seconds. The apple logo will show while it is booting, and when the iPod is done booting you will see 1 of 4 scenarios:
   1. The iPod reboots automatically the instant the main menu is shown. This will lead to an endless reboot cycle until the note is taken off
   2. The iPod works completely normally. You can navigate menus, play music, etc. without any problems.
   3. The iPod seems to work normally ie. you can still navigate menus, but when you try to play a song it freezes or crashes
   4. The iPod freezes up entirely.
3. The next step is to get into disk mode in order to remove the notes file. First, you need to reboot by holding menu+center. If your note causes a type #1 behavior, the iPod is always rebooting and you do not need to reboot manually. When the apple logo shows up, hold the play and center buttons until the disk mode screen comes up. Repeat these steps for the next file, but read the paragraph below first!

Most sweep files will usually either crash(#1) or freeze(#4). If you have one/s that is not either of these, record it in the table. If you have one that crashes, you will need to test the same address again with the sweepcrash.7z archive. If the iPod crashes or does anything different this time, it is a good sign that we have execution. Definitely record any of these incidents in the table!

Table of reserved or tested files

Username	iPod generation	Firmware version	Windows/Mac	Starting filename	Ending filename	Status
Farthen	4G Nano	1.0.3	Windows	a080a2004.htm	a080a4e04.htm	Tested
watto	4G Nano	1.0.3	Windows	a080a4f04.htm	a080a7f04.htm	Tested
watto	4G Nano	1.0.3	Windows	a080b0104.htm	a080b3f04.htm	Reserved
kylemsguy	4G Nano	1.0.3	Windows	a080c0104.htm	a080c1004.htm	Tested
clueX	4G Nano	1.0.3	Windows	a080d0a04.htm	a080d0f04.htm	Tested (All #1)
clueX	4G Nano	1.0.3	Windows	a080d0104.htm	a080d1004.htm	Tested (All #1, except a080d0304 #4)
kylemsguy	4G Nano	1.0.3	Windows	a080d1104.htm	a080d2f04.htm	Reserved
Eosphere46	3G Nano	1.1.3	Windows	a080a2004.htm	a080a5004.htm	Tested! All #1 Except A080a3504, which was a #4. The SweepCrash was also a #4 for that one.
Eosphere46	3G Nano	1.1.3	Windows	a080a0a04	a080a1904	Reserved Table of non-#1 (or non-#4) behaviors If you leave an entry in here and don't normally hang out on IRC, send your email address to me at (cwalker32 AT gmail DOT com). This will give us a way to contact you if necessary. Username iPod generation Firmware version Windows/Mac Sweep filename Behavior type Notes Sto 2G Nano 1.1.3 Windows a08640568.htm #4 Direct jump to buffer 3mpty 1G Classic 1.0.3 Windows a080a2004.htm #4 Indirect - an ldmia instruction in firmware portion of ram jumps to the correct buffer location PharaohsVizier 2G Classic 2.0.1 Windows a09352f04.htm a09352a04.htm a09352b04.htm #2 Unknown, definitely check this out farthen, cmwslw, kylemsguy 4G Nano 1.0.4 Windows/Mac All #2 Not exploitable, as the bug is fixed in 1.0.4 farthen 4G Nano 1.0.3 Mac All #2 Not exploitable because it's a macpod Superandy 3G Nano Latest (idk) Windows a08010c04 Freezes when I play a song - Please try a08010c04 from http://tinyurl.com/sweepdelay and post behavior :) Ok, done that. It does the same thing, freezes. The 1st boot it froze stright away as soon as it loaded the album artwork for the menu. The second time it took about 10 seconds to freeze. Pretty cool Jwnordquist 2G Nano latest Windows a08010404.htm a08010504.htm a08010d04.htm a08010e04.htm a08010f04.htm a08011204.htm a08011304.htm a08011404.htm a08011904.htm #4 Farthen 4G Nano 1.0.3 Windows a080a2104.htm, a080a3b04.htm, a080a3e04.htm, a080a4604.htm, a080a4d04.htm #4 I don't know why I record this, *maybe* it can help. Should be of no interest but who knows... Crasher files have same result as freezer. Farthen 4G Nano 1.0.3 Windows a080a2f04.htm, a080a3a04.htm, #2 I don't know why I record this, *maybe* it can help. Should be of no interest but who knows... Crasher files have same result as freezer. watto 4G Nano 1.0.3 Windows a080a4f04.htm, a080a6c04 to a080a7504 inc. #4 Same result with crash and freeze files. watto 4G Nano 1.0.3 Windows a080a5c04.htm #2 Same result with crash and freeze files. kylemsguy 4G Nano 1.0.3 Windows a080c0304.htm #4 The results for the sweep files were the same