Following up on the previous PS3 Lv0ldr / Bootldr clarifications by marcan42 and wololo, today PlayStation 3 hacker naehrwert has shared some details based on reverse-engineering the exploit used to dump it.
To quote from his blog: The Exploit
As the exploit that was used to dump lv0ldr/bootldr/howeveryouliketocallit is public now, letís have a closer look at it to understand whatís going on. Here is what I have reversed from lv0 (it shares the syscon portion of the code with its SPU counterpart):
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The syscon library implements some high level functions, e.g. to shutdown the console on panic or to read certain configuration values. Every of this functions internally uses another function to exchange packets with syscon and the exchange function uses the read_cmpl_msg one to get the answer packet. The top-level function will pass a fixed size buffer to the exchange function.
So if we are able to control syscon packets, e.g. by emulating MMIO (and thanks to IBM we are), we can change the packet size between the two packet readings and overwrite the caller stack. And if we first copy a little stub to shared LS and let the return address point to it, we can easily dump the whole 256 kB.
Nothing more left to say now, letís wait and see if this is going to be fixed in future firmware versions (we just have to check lv0 fortunately).
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