SPU Isolated Modules Reverse Engineering

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[edit] anergistic

Using a static analysis (IDA) could give you a good view of what the program does, but sometimes you want to know what a program does in real time and how it reacts to different parameters, this is where anergistics becomes a powerful tool. It simulates the SPU including its communication, and storage.

[edit] Current repos

[edit] usage

anergistic can be launched in two different modes, one that only emulates (runs) the program through the SPU and the the other that lets you debug the process through gdb

[edit] only emulate

Type This
./anergistic spu_elf_name.elf

this mode runs an elf with all the parameters and actions defined on main.c, channel.c a

[edit] debug

terminal 1

Type This
./anergistic -g1234 spu_elf_name.elf

simulate debug server in the local host on port 1234

terminal 2

Type This
spu-gdb spu_elf_name.elf 
(gdb)target remote :1234

connect to the local host on port 1234

(gdb)help will give you information of the command available

[edit] Documentation

this mode performs the same as above but lets you debug the process through gdb

[edit] Customizations

see example below

Running in aim_spu_module anergistic

[edit] Problems

[edit] Connection proble

when in debugger mode

Waiting for gdb to connect...
Client connected.
recv failed: Success

[edit] Solution

use spu-gdb

[edit] Tools


Use this to convert IDA disassembly into a format suitable for GNU AS. Literals in IDA are unsigned while AS expects signed literals. Conversion of literals is a work in progress.

[edit] aim_spu_module

It is used to retrieve the device type, device id, open psid and the pscode from the EID0 data that is passed in.

[edit] Debug messages

Address Message
 ? 3.41 ? 355 CEX
0x36f0 0x3570 "(spu)start aim spu module!\n"
0x3710 0x3590 "(spu) PU DMA area start address is not align 16byte\n"
0x3750 0x35d0 "(spu) PU EID area start address is not align 16byte\n"
0x3790 0x3610 "(spu) PU DMA area size is not equall to AIM_DMA_SIZE\n"

This messages are DMAed to the ppu if a debug output address is specified.

[edit] Data

Address Message
 ? 3.41 ? 355 CEX
0x37e0 - Reference tool fallback IDPS
0x37f0 - ... 0x3650 - ... Start of AIM keys Keys#aim_keys
0x3ac0 0x3870 AES sbox (16*16 bytes)
0x3c70 0x3a20 AES inverse sbox (16*16 bytes)

[edit] Functions

Address Name Parameters Info
 3.41  CEX/DEX 355 CEX
0x9e0 stop_func unknown Stops the module execution with various stop codes.
0xa18 main_func unknown Main routine.
0xf18 response unknown Sends response to ppu over DMA.
0x1158 process_eid unknown Decrypts EID0.
0x1438 prepare_print unknown Prepares debug output.
0x1440 debug_print unknown As the name already states... (this outputs over DMA)
0x17f0 - - AES 1 Part of aes implementation.
0x1c48 aes_encrypt_ecb - AES 2 Part of aes implementation.
0x1df0 cellCryptoSpuAesCbcCfb128Decrypt - AES 3 Probably part of aes implementation.
0x20f0 aes_omac1 - AES 4 Probably part of aes implementation.
0x2300 aes_set_key_dec - AES 5 Probably part of aes implementation.
0x2418 aes_decrypt_ecb - AES 6 Part of aes implementation.
0x2608 aes_decrypt_ecb_aligned - AES 7 Part of aes implementation.
0x30c0 do_dma ls_addr:$4, dma_effective_addr:$5, size:$6, tag_id:$7, unk0:$8, unk1:$9 Used to dma data in and out of the isolated module's LS.
0x3168 write_tag_mask_bit mask_bit:$4 Used to set a specific bit in MFC_WrTagMask.

[edit] Disasm

The complete disassembly is available at [1].

[edit] Decrypting EID

[edit] Dumper iso.self

[edit] Dumper Payload

[edit] Running in aim_spu_module anergistic

//Partial code modified to run aim_spu_module

[edit] isoldr

loads, decrypts, runs isolated modules, and creates through aes the required key in LS 0x0

[edit] Debug messages

This module doesnt contain debug messages

[edit] Data

Address Message
 ? 3.41 ? 355 CEX
0x34C40 - ... 0x34d10 Start of isoldr keys Keys#Modules
0x35130 0x35050 AES sbox (16*16 bytes)
0x35300 0x35220 AES inverse sbox (16*16 bytes)

[edit] Functions

Address Name Parameters Info
 ? 3.41 ? 355 CEX
0x259E0 cleanup_jump_code unknown cleans all the registers and jump to the loader
0x259E0 main_func unknown Main routine.
0x346B0 write_tag_mask_bit mask_bit:$4 Used to set a specific bit in MFC_WrTagMask.
0x27438 aes128_cbc_decrypt
0x27508 aes128_cbc_encrypt
0x29DC0 aes_ctr
0x2BB28 aes_set_key_enc
0x2C0D0 cellCryptoSpuAesCbcCfb128Encrypt
0x2C240 cellCryptoSpuAesCbcCfb128Decrypt
0x2C540 cellCryptoSpuAesCtr
0x2C8D0 aes_omac1
0x2CAE0 sha1_buffer
0x2CB70 sha1_hmac_init
0x2CC70 sha1_hmac_update
0x2CC90 sha1_hmac_final
0x2CD28 sha1_hmac_buffer
0x2CDC8 aes_set_key_dec
0x2CEE0 aes_encrypt_ecb_aligned
0x2D7C0 aes_decrypt_ecb
0x2D9B0 aes_decrypt_ecb_aligned
0x2E450 sha1_init
0x2E4C8 sha1_update
0x2E700 sha1_final
0x2EA88 sha1_process

from isoldr 3.41 iirc -> http://pastie.org/2774207 //offsets relative to segment start