HDD Encryption

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Revision as of 11:10, 16 August 2012 by Glevand (talk | contribs) (→‎Test)
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Introduction

  • The following information was reverse engineered from LV1, Storage Manager in LPAR1 and sb_iso_spu_module.self.
  • I'm able to decrypt/encrypt my PS3 HDD and VFLASH on PC now.

HDD Encryption

  • XTS-AES-128 is used to encrypt all data on PS3 HDD.
  • XTS is NOT CBC !!! It's AES-ECB with tweak XORing. AES-CBC is impractical for HDD encryption. Each sector can be encrypted/decrypted independantly from other HDD sectors.
  • Good paper about XTS-AES: http://ntnu.diva-portal.org/smash/get/diva2:347753/FULLTEXT01
  • VFLASH is encrypted twice. First with ENCDEC keys and then with ATA keys.
  • Tweak and data XTS keys are of size 32 bytes but only the first 16 bytes are used.
  • You can set and clear ATA keys with my Linux ps3encdec device driver which i use to test HDD/VFLASH encryption. But be careful, never set/clear ATA keys while some HDD regions/partitions are mounted !!! You will corrupt your data on your HDD !!!

Dumping ATA Keys

  • I modified sb_iso_spu_module.self to dump ATA keys.
  • ATA keys are passed as parameters to sb_iso_spu_module.self.

Program

My SPU program to dump ATA tweak and data XTS keys to PPU memory with spuisofs: 

/*
 * Dump ATA keys
 *
 * Copyright (C) 2012 glevand <[email protected]>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published
 * by the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

.text

start:

	ila		$2, 0x3dfa0
	lr		$sp, $2

	ila		$80, 0x3e000
	lr		$81, $3

	stqd		$7, 0($80)	# store upper 16bytes of ATA data key
	stqd		$8, 0x10($80)	# store lower 16bytes of ATA data key
	stqd		$9, 0x20($80)
	stqd		$10, 0x30($80)
	stqd		$11, 0x40($80)	# store upper 16bytes of ATA tweak key
	stqd		$12, 0x50($80)	# store lower 16bytes of ATA tweak key

	lr		$3, $80
	lr		$4, $81
	il		$5, 0x60
	il		$6, 0x7
	il		$7, 0x20
	brsl		$lr, 0x10	# mfc_dma_xfer

	il		$3, 0x7
	brsl		$lr, 0x28	# mfc_dma_wait

	stop		0x666		# our evil stop code :)

/*
 * r3 - LSA
 * r4 - EA
 * r5 - size
 * r6 - tag
 * r7 - cmd
 */
mfc_dma_xfer:

	wrch		$ch16, $3
	wrch		$ch17, $4
	shlqbyi		$4, $4, 4
	wrch		$ch18, $4
	wrch		$ch19, $5
	wrch		$ch20, $6
	wrch		$ch21, $7

	bi		$lr

/*
 * r3 - tag
 */
mfc_dma_wait:

	il		$2, 0
	nop		$127
	hbra		2f, 1f
	wrch		$ch23, $2

1:

	rchcnt		$2, $ch23
	ceqi		$2, $2, 1
	nop		$127
	nop		$127
	nop		$127
	nop		$127
	nop		$127

2:

	brz		$2, 1b
	hbr		3f, $lr
	rdch		$2, $ch24
	il		$2, 1
	shl		$2, $2, $3
	wrch		$ch22, $2
	il		$2, 2
	wrch		$ch23, $2
	rdch		$2, $ch24
	nop		$127

3:

	bi		$lr

http://pastie.org/4503109

Result

[glevand@arch dump_ata_keys]$ ./dump_ata_keys ../dump_ata_keys.self ../eid4
spuisofs found at /mnt
arg1 kernel virtual address d000000000722000
shadow: spe_execution_status 7
priv2: puint_mb_R 2
shadow: spe_execution_status b
problem: spu_status_R 6660082
[glevand@arch dump_ata_keys]$ hexdump -C /mnt/arg1 
...
Here are your ATA tweak and data XTS keys
Data key is at offset 0x0 (32 bytes)
Tweak key is at offset 0x40 (32 bytes)
...

Test

  • To test your ATA XTS tweak and data keys, you need encrypted HDD sectors. You can either connect your HDD to PC and dump it or use my ps3vuart-tools on Linux and clear ATA keys and then dump it from ps3da. I tried both methods. But make sure you unmount all HDD regions before using ps3vuart-tools to clear your ATA keys.
  • I coded a small application which implements XTS-AES encryption/decryption. XTS-AES paper is a good reference how to implement it.
  • You have to pass the correct sector number in order to get correct results.
  • As you see below in my examples, i pass sector number 0 and sector 8 for VFLASH because VFLASH begins at sector 8 on HDD.
  • Another interesting fact is that you have to swap half-words after encrypting and before decrypting HDD sectors else you will get wrong results. This swapping is not necessary for VFLASH sectors.
  • Another note is that you have to decrypt VFLASH sectors with ATA keys first and then with ENCDEC keys.

Result with 1st encrypted sector from HDD: 

glevand@debian:~/xts_aes$ cat ../hdd_1st_sector_enc.bin  | \
    ./xts_aes -d -k <your ATA XTS data key> -t <your ATA XTS tweak key> -s 0 -r | hexdump -C
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000010  00 00 00 00 0f ac e0 ff  00 00 00 00 de ad fa ce  |................|
00000020  00 00 00 00 00 00 00 03  00 00 00 00 00 00 00 02  |................|
00000030  00 00 00 00 00 00 00 08  00 00 00 00 00 08 00 00  |................|
00000040  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 0b  |.p..............|
00000050  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000000c0  00 00 00 00 00 08 00 10  00 00 00 00 03 9a 8b 2d  |...............-|
000000d0  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
000000e0  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
000000f0  10 20 00 00 03 00 00 01  00 00 00 00 00 00 00 03  |. ..............|
00000100  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000150  00 00 00 00 03 a2 8b 45  00 00 00 00 00 3f ff f8  |.......E.....?..|
00000160  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000170  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000180  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001e0  00 00 00 00 03 e2 8b 46  00 00 00 00 19 39 ce 0c  |.......F.....9..|
000001f0  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000200

Dumping ENCDEC Keys

  • VFLASH is encrypted twice. First with ENCDEC keys and then with ATA keys.
  • You cannot dump ENCDEC keys with sb_iso_spu_module.self. They are set in lv1ldr only (see here: http://gitorious.ps3dev.net/reversing/lv1ldr/trees/master).
  • I used a modified lv1ldr with my Linux spuldrfs driver and dumped ENCDEC keys.
  • XTS-AES-128 with 128bit tweak key and 128bit data key, just like ATA keys.
  • ENCDEC tweak and data keys are passed to lv1ldr NOT in clear text.
  • ENCDEC keys are computed by lv1ldr with AES-CBC-256 by encrypting 32byte seeds.
  • metldr passes to lv1ldr AES-CBC-256 IV and key which are used to compute ENCDEC keys.
  • I tested my ENCDEC keys with my ps3encdec Linux driver and set them again, and VFLASH was still working fine. As soon as i changed some bits in these keys, VFLASH could not be decrypted properly anymore :) It means keys are correct.

ENCDEC Key Seeds

  • Use the dumped ENCDEC IV and key to encrypt these seeds and you will get your ENCDEC keys for VFLASH.
  • You can find these seeds in lv1ldr.

Tweak key seed: 

glevand@debian:~$ hexdump -C data1.bin
00000000  e2 d0 5d 40 71 94 5b 01  c3 6d 51 51 e8 8c b8 33  |..]@q.[..mQQ...3|
00000010  4a aa 29 80 81 d8 c4 4f  18 5d c6 60 ed 57 56 86  |J.)....O.].`.WV.|
00000020

Data key seed: 

glevand@debian:~$ hexdump -C data2.bin
00000000  02 08 32 92 c3 05 d5 38  bc 50 e6 99 71 0c 0a 3e  |..2....8.P..q..>|
00000010  55 f5 1c ba a5 35 a3 80  30 b6 7f 79 c9 05 bd a3  |U....5..0..y....|
00000020

Program

Here is my SPU program which i used to dump ENCDEC keys: 

/*
 * Dump ENCDEC keys
 *
 * Copyright (C) 2012 glevand <[email protected]>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published
 * by the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

.text

start:

	ila		$2, 0x3dfa0
	lr		$sp, $2

	ila		$3, 0x666
	wrch		$ch30, $3

	# wait until we get message from PPU

1:

	brsl		$lr, 0x54	# in_mbox_count
	brz		$3, 1b

	brsl		$lr, 0x54	# in_mbox_read

	ila		$80, 0x3e000
	lqd		$81, 0($80)	# load PPU EA
	ila		$82, 0x0

	lqd		$83, 0($82)
	stqd		$83, 0($80)	# store upper 16bytes of ENCDEC key
	lqd		$83, 0x10($82)
	stqd		$83, 0x10($80)	# store lower 16bytes of ENCDEC key
	lqd		$83, 0x20($82)
	stqd		$83, 0x20($80)	# store ENCDEC IV

	lr		$3, $80
	lr		$4, $81
	il		$5, 0x30
	il		$6, 0x7
	il		$7, 0x20
	brsl		$lr, 0x20	# mfc_dma_xfer

	il		$3, 0x7
	brsl		$lr, 0x38	# mfc_dma_wait

	stop		0x666		# our evil stop code :)

/*
 * no input parameters
 */
in_mbox_count:
	rchcnt		$3, $ch29
	bi		$lr

/*
 * no input parameters
 */
in_mbox_read:
	rdch		$3, $ch29
	bi		$lr

/*
 * r3 - LSA
 * r4 - EA
 * r5 - size
 * r6 - tag
 * r7 - cmd
 */
mfc_dma_xfer:

	wrch		$ch16, $3
	wrch		$ch17, $4
	shlqbyi		$4, $4, 4
	wrch		$ch18, $4
	wrch		$ch19, $5
	wrch		$ch20, $6
	wrch		$ch21, $7

	bi		$lr

/*
 * r3 - tag
 */
mfc_dma_wait:

	il		$2, 0
	nop		$127
	hbra		2f, 1f
	wrch		$ch23, $2

1:

	rchcnt		$2, $ch23
	ceqi		$2, $2, 1
	nop		$127
	nop		$127
	nop		$127
	nop		$127
	nop		$127

2:

	brz		$2, 1b
	hbr		3f, $lr
	rdch		$2, $ch24
	il		$2, 1
	shl		$2, $2, $3
	wrch		$ch22, $2
	il		$2, 2
	wrch		$ch23, $2
	rdch		$2, $ch24
	nop		$127

3:

	bi		$lr

http://pastie.org/4503119

Result

  • Test run with spuldrfs on Linux 3.5.1
glevand@debian:~/dump_encdec_keys$ ./dump_encdec_keys ../ps3/metldr ../dump_encdec_keys.self 
spuldrfs found at /mnt
buf1 kernel virtual address d000000004311000
buf2 kernel virtual address d000000004412000
priv2: puint_mb_R 1
problem: pu_mb_R 1
priv2: puint_mb_R 666
problem: spu_status_R 2
glevand@debian:~/dump_encdec_keys$ hexdump -C /mnt/buf2
...
Here are your ENCDEC keys
ENCDEC keys key is at offset 0x0 (32 bytes)
ENCDEC keys IV is at offset 0x20 (16 bytes)
...

Test

  • To test your ENCDEC XTS tweak and data keys, you need encrypted VFLASH sectors. You can dump it from ps3da starting with sector 8.
  • You have to pass the correct sector number in order to get correct results.
  • As you see below in my examples, i pass sector 8 for VFLASH because VFLASH begins at sector 8 on HDD.
  • The input sector was already decrypted with ATA keys.

Result with 1st encrypted sector from VFLASH: 

glevand@debian:~/xts_aes$ cat ../vflash_1st_sector_enc.bin | \
    ./xts_aes -d -k <your ENCDEC data key> -t <your ENCDEC tweak key> -s 8 | hexdump -C
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000010  00 00 00 00 0f ac e0 ff  00 00 00 00 de ad fa ce  |................|
00000020  00 00 00 00 00 00 00 03  00 00 00 00 00 00 00 02  |................|
00000030  00 00 00 00 00 00 00 08  00 00 00 00 00 00 75 f8  |..............u.|
00000040  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000000c0  00 00 00 00 00 00 78 00  00 00 00 00 00 06 3e 00  |......x.......>.|
000000d0  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
000000e0  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
000000f0  10 20 00 00 03 00 00 01  00 00 00 00 00 00 00 01  |. ..............|
00000100  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000150  00 00 00 00 00 06 b6 00  00 00 00 00 00 00 80 00  |................|
00000160  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000170  10 70 00 00 01 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000180  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001e0  00 00 00 00 00 07 36 00  00 00 00 00 00 00 04 00  |......6.........|
000001f0  10 70 00 00 02 00 00 01  00 00 00 00 00 00 00 03  |.p..............|
00000200
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