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JaicraB on Cobra USB JIG Protection RTOC Trick for PS3


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159w 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:


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:


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.


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:


Subsequently, given the value 0x11DE0 to RTOC:


A r0 is given the value 0x920:


R0 is subtracted from the value of RTOC:


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


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


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:


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


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


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:


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





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Comments 694 Comments - Go to Forum Thread »

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tommasi's Avatar
#144 - tommasi - 132w ago
system crash exiting form MM can anyone confirm? running phat ps3 60GB KMEAW 3.55

smokyyuwe's Avatar
#143 - smokyyuwe - 132w ago
The way I see it, even if he did "sell out", at least this version of multiman works without the dongle so you can use it on kmeaw. To me that sounds more like the case of "this is the free version but with the pro you get these features", which, I'm perfectly fine with.

Transient's Avatar
#142 - Transient - 132w ago
Open Office is only one of many open source projects. It in itself is the combination of many other open source projects. There's literally millions of open source projects out there.

I don't fault deank if he decided to profit off Multiman. As far as I know, he contributed the vast majority of work to the project. If he solicited the help of others under the guise of open source and then turned around and sold it for a profit, then I'd have a different opinion, but as far as I know that is not the case. Would I prefer he continued with a free open source development? Of course.

Also, it's worth nothing that deank has denied allegations that he's working with Cobra. His past actions have given me no reason to believe he's anything but trustworthy. I agree the sudden stop of development appears suspicious, but there's many possible scenarios.

Maybe it's all coincidence and other factors in his personal life have stopped development. Unless you know deank personally, I don't think anyone has a right to doubt his claims. I can imagine many scenarios that he might not want to share with everyone (eg. cancer, dead relative, unemployed, etc) and it'd be terrible if people were giving him a bad name over purely circumstantial evidence.

I'm grateful for his past contribution as I know I'm entitled to nothing.

cfwprophet's Avatar
#141 - cfwprophet - 132w ago
I have said that they both dongles are doing the same. But for me guys like grafchokolo have done much more then those both teams. All the files used on this both sticks are frm dev_flash and just patched/ported and not rewritten or anything else.

But anyway it seems you haven't understood. tHeUnknOwEnSeCRet will do this all for acid cfw and even don't want fame. He only do this for helping peoples and he do this for acid cause we share the same ideology about those things.

Bartholomy's Avatar
#140 - Bartholomy - 132w ago
Or some other teams, like exetrimall

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