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JaicraB on Cobra USB JIG Protection RTOC Trick for PS3


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168w ago - Today Spanish PlayStation 3 developer JaicraB has explained the Cobra USB JIG protection RTOC trick implemented for the PS3 against cloning the device.

To quote, roughly translated: Flynn sent me this text explaining this protective carrying the Cobra, I hope it will open the eyes of those interested in reversing the dumps.

EXPLAIN RTOC COBRA TRICK

The JIG Cobra has several protective measures to ensure that your code could not be used correctly even if your code could be dumped.

This trick RTOC in the registry is the first used for this purpose in addition to hinder analysis.
Registration is initially RTOC stored in the battery to keep the RTOC of lv2 and power it back later:

[Register or Login to view code]


At this point we have to explain that the OFFSET DELTA. DELTA OFFSET is a method used in the x86 in its original moments in the creation of computer viruses, to calculate the memory address in which we are in the sea of ​​bytes in RAM.

In the original time a computer virus when I did not know where he was pulled into an executable,
depending on the executable it could be an initial site or another, for it was invented DELTA OFFSET.

DELTA OFFSET can be used in any system, the procedure is:

  • Using the record that indicates the current execution address (or the next depending on the system)
  • Reducing the size of the previous code we use the value obtained from the registry.

Knowing this, and taking for example the x86 processor where the EIP register can not be read directly invented the trick make a call to a "subfunction" which is simply the following line to the call:

[Register or Login to view code]


X86 call instruction saves the top of the stack the address of the next instruction to itself. Thus using pop draw from the top of the stack this value, and stored in eax for example, and having the memory address where we only subtract the above would be missing and we have the exact calculation.

The PowerPC can use this trick using the BL instruction is equivalent (LINK BRANCH), which jumps to a "subfunction" but before you save LR in the record the following address to BL.

[Register or Login to view code]


At this point we see the trick used for the creation of the RTOC of charges at this time. If you look both r0 and RTOC are passed to 0:

[Register or Login to view code]


Subsequently, given the value 0x11DE0 to RTOC:

[Register or Login to view code]


A r0 is given the value 0x920:

[Register or Login to view code]


R0 is subtracted from the value of RTOC:

[Register or Login to view code]


Unlike the PowerPC x86 LR register can be read directly with mflr instruction, we put in RTOC the value obtained by the delta offset:

[Register or Login to view code]


To calculate the delta offset subtract final instructions executed before the delta offset, which were 4, or 16 bytes:

[Register or Login to view code]


Finally we add the value of r0 at the end of the delta offset RTOC, storing the result in the RTOC and this already takes RTOC suitable for this hook:

[Register or Login to view code]


It takes having the RTOC stored in the stack 3 arguments that the hook received:

[Register or Login to view code]


You call the function of the charges where the first argument will check for command 0x8202 (a special command to the usual):

[Register or Login to view code]


After making the necessary steps as charged, the battery recovers the original RTOC, like the arguments the hook received, it executes the original instruction that was overwritten in the syscall entry 379 (in this case) to have our hook, and call the original syscall lv2:

[Register or Login to view code]


Upon returning to retrieve the original LR from the stack and returns to the prompt

[Register or Login to view code]





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Comments 716 Comments - Go to Forum Thread »

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cfwprophet's Avatar
#151 - cfwprophet - 140w ago
Uhmm... no it's more that kind that deank helped them with the cobra stick and it's also nearly on that team cobra. The files used are from dev_flash and just ported / modified. No offence meant to any one. But just think, deank knows about that stuff, he also knows about the emulators but his official mm would not be developed to a lv like the cobra stick mm use. But they use his source to make Cobra MM soooo... use your brain

DemonoidMaster's Avatar
#150 - DemonoidMaster - 140w ago
Alright so if i undertand this properly... MultiMan's creator deank left the scene and now Team Cobra decided to pick this up and from now on they're doing the releases ?? wtf... anyhow also...

Users that are just using any kind of jailbroken PS3 can use this even if it's meant for the dongle ??

Is it a one version release only ? or is there one MM release for the dongle and one for the non-cobra users ?... because all i see is one link and its mirror link (both the same).

DeVil3o3's Avatar
#149 - DeVil3o3 - 140w ago
As far as I know Multiman has great compatibility with lots of ps1 games built in without any dongle required, Cobra are planning to support multidisk games too though which will be the only ps1 bonus to Cobra owners, if that gets released, it probably will, then the free scene will get it too not long after.. same old story!

Prince Valiant's Avatar
#148 - Prince Valiant - 140w ago
PSP/PSOne games as well, no?

hotd54me's Avatar
#147 - hotd54me - 141w ago
the only thing you'd really want the dongle for is to play your legally owned ps2 backups, well that's what i'd get it for anyway. otherwise, multiman and kmeaw is just as good!

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