SPU Isolated Modules Reverse Engineering

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.

Current repos

• https://github.com/kraiskil/anergistic.git
• http://git.gitbrew.org/ps3/anergistic.git/
• https://github.com/psfree/anergistic
• http://foxbrew.org/git/anergistic.git/
• http://git.fail0verflow.com/?p=anergistic.git

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

only emulate

./anergistic spu_elf_name.elf

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

debug

terminal 1

./anergistic -g1234 spu_elf_name.elf

simulate debug server in the local host on port 1234

terminal 2

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

Documentation

• http://publib.boulder.ibm.com/infocenter/ieduasst/stgv1r0/topic/com.ibm.iea.cbe/cbe/1.0/LinuxOnCell/L2T1H1_31_LinuxonCellToolchainGDB.pdf
• SPU specific commands
  • http://sourceware.org/gdb/onlinedocs/gdb/SPU.html

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

Customizations

See example below.

Running in aim_spu_module anergistic

Problems

Connection problem

when in debugger mode

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

Solution

Use spu-gdb.

Tools

gnuify_ida.plmirror

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.

Loading Isolated Modules in GameOS

This code kinda represents how GameOS applications load and execute isolated SPU SELFs. For example: psp emulator.

  sys_spu_initialize(1,1);
  syscall(230, sys_spu_t *id,img &iso_spuSCEself,void *arg,0,0,0);
  sys_ppu_thread_create(sys_ppu_thread_t *thread_id,void* iso_spu_handler,sys_spu_t *id, 0x64, 0x1000, 2,"iso_spu_handler");
  syscall(233, sys_spu_t *id,2,0,sys_interrupt_tag_t intrtag);   //sys_iso_spu_create_interrupt_tag?
  sys_interrupt_thread_establish(sys_interrupt_thread_handle_t *ih,sys_interrupt_tag_t intrtag,sys_ppu_thread_t t_id, 
  sys_spu_t id,0);
  syscall(234, sys_spu_t *id,2,7); //sys_iso_spu_set_int_mask?
  syscall(232, sys_spu_t *id);     //sys_iso_spu_destroy?
  ...

  iso_spu_handler(...) {
  syscall(237, sys_spu_t id,2,void *out1);  // sys_iso_spu_get_int_stat?
  syscall(240, void *out2, out1);           // sys_iso_spu_mmio_read ?
  syscall(236, sys_spu_t id,2, out1)        // sys_iso_spu_set_int_stat?
  sys_interrupt_thread_eoi()
  }

aim_spu_module

It is used to retrieve the device type, Device Id, OpenPSID and the PsCode from the EID0 data that is passed in.

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"

These messages are sent via DMA to the PPU if a debug output address is specified.

Data

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

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.

Disasm

The complete disassembly is available at [1].

Decrypting EID

Dumper iso.self

Is there one ?

Dumper Payload

• Dumper payload code
• mirror

Running aim_spu_module in anergistic

• Partial code modified to run aim_spu_module
• mirror

isoldr

Loads, decrypts, runs isolated modules, and creates through AES the required key in LS 0x0.

Debug messages

This module doesn't contain debug messages.

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)

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

• REed functions names from FW 3.41 isoldr (offsets relative to segment start).
• mirror