Limera1n

limera1n is geohot's jailbreak utility. It uses a previously undisclosed bootrom exploit (the limera1n Exploit) and comex's Packet Filter Kernel Exploit to achieve an untethered jailbreak on many devices. The following devices are supported:

• iPhone 3GS
• iPhone 4 (iPhone3,1)
• iPod touch 3G
• iPod touch 4G
• iPad
• Apple TV 2G (creates a bare-bones jailbreak by mounting '/' as read/write in /etc/fstab)

limera1n has been demonstrated multiple times by geohot, using blog posts on his now private blog. Geohot showed off a high-res picture of Cydia on an iPhone 4. He displayed an iPod touch 3G with an untethered jailbreak that met MuscleNerd's requirements for a good video. In addition, he took a picture of Cydia and blackra1n icons on an iPad.

• Release Date: October 9, 2010
• Supported OS's: Mac OS X, Windows
• Supported Operations: hacktivation, jailbreaking
• Supported iOS: 3.2.2-4.1

Release text

limera1n, 6 months in the making

iPhone 3GS, iPod Touch 3G, iPad, iPhone 4, iPod Touch 4G
4.0-4.1 and beyond+++
limera1n is unpatchable
untethered thanks to jailbreakme star comex
brought to you by geohot
hacktivates
Mac coming in 7 years
donations keep support alive

zero pictures of my face

Credit

• geohot - The program itself, and the bootrom exploit.
• comex - The userland exploit that allows limera1n to run untethered.

Changelog

Version	Release Date	MD5 Hash	Changelog
BETA 1	9 October 2010	2f2b09a6ed5c5613d5361d8a9d0696b6	First release.
BETA 2	10 October 2010	a70dccb3dfc0e505687424184dc3d1ce	Fixed kernel patching magic. Rerun BETA2+ over BETA1.
BETA 3	10 October 2010	81730090f7de1576268ee8c2407c3d35	Fixed an issue with iPhone 3GS (new bootrom)
BETA 4	10 October 2010	d901c4b3a544983f095b0d03eb94e4db	Uninstall fixed, respring fixed
RC1	11 October 2010	0622d99ffe4c25f75c720a689853845f	out of beta! afc2, reliability improvements, no reboot for cydia, 2kb smaller
RC1b	11 October 2010	fc6f7d696a57c3baede49bdff8a7f43f	addresses an install issue, mainly with iPads
Final	11 October 2010	fc6f7d696a57c3baede49bdff8a7f43f	(same as RC1b)

Technical Information

Basics

• limera1n has nothing to do with SHAtter at all.
• limera1n uses a bootrom exploit to achieve the tethered jailbreak and unsigned code execution.
• limera1n uses a userland exploit to make it untethered, which was developed by comex.
• limera1n uses a hacktivation dylib to perform hacktivation.

Exploits

limera1n reuses the usb_control_msg(0x21,2) but exploits a different vulnerability (see Limera1n Exploit).

Process

The jailbreak appears to execute something like the following (in no particular order):

• In recovery1,

"setenv debug-uarts 1
setenv auto-boot false
saveenv"

• In DFU Mode, it uploads a payload.
• In recovery2, it uploads another payload and its ramdisk.

"setenv auto-boot true
 reset
 geohot done"

Interesting Messages

"geohot black is the new purple"

"blackra1n start: %d current IRQ mask is %8.8X
usb irq disabled...shhh
fxns found @ %8.8X %8.8X
found iBoot @ %8.8X
i'm back from IRQland...
3g detected, kicking nor
nor kicked
memcpy done
iBoot restored!!!
found command table @ %8.8X
cmd_geohot added
time to pray...%8.8X"

"2.2X  send command(%d): %s
send exploit!!!
sent data to copy: %X
 sent shellcode: %X has real length %X
never freed: %X
sent fake data to timeout: %X
 sent exploit to heap overflow: %X
 sending file with length: 0x%X Mingw runtime failure:
  VirtualQuery failed for %d bytes at address %p      Unknown pseudo relocation protocol version %d.
    Unknown pseudo relocation bit size %d."

Controversy

The release of this jailbreak was specifically designed to pressure the Chronic Dev Team into not releasing SHAtter, and instead implement the limera1n exploit into greenpois0n; after releasing limera1n, releasing SHAtter would uselessly disclose another bootrom exploit to Apple.

Geohot's rationale was that Apple already discovered, through internal testing, the limera1n exploit, making it very likely that it will be fixed in the next bootrom revision. Because iBoot code is present both in the bootrom and firmware, and because firmware is refreshed much more often than bootrom code, any fix in this code branch would appear first in firmware. Geohot observed his limera1n exploit was closed in firmware and concluded that it would almost certainly be fixed in the next bootrom revision, whereas SHAtter still has a chance of remaining useful for an indefinite amount of time. Both vulnerabilities ended up being patched in the iPad 2. It was fixed before the release of limera1n according to the build number. This has been confirmed by p0sixninja.

limera1n's untethered userland exploit for iOS 4.0 and 4.1 was obtained by geohot under questionable circumstances from comex. Comex did end up fixing the kernel patching code by beta2, so as to not break users' devices.

Hacktivation

limera1n will copy hacktivation.dylib to /usr/lib and change entries to com.apple.mobile.lockdown.plist, whether it has been activated using iTunes or not. This, while helpful to many, can also be harmful to legitimate activators. For a guide on how to remove this hacktivation on iTunes activated devices, see the link below.

External Links

• Official domain
• The iPhone Wiki Mirror
• Limera1n RC Beta2 Dump on Mediafire provided by iH8sn0w.
• Veeence's explanation for release
• Hacktivation removal guide.