forked from len0rd/rockbox
e232f69214
Added fw modifications required to unpack real world player dumps. Documented more fwu header fields, magic numbers and finite field arithmetics (extended Euclidean for inverse, long division for reducing modulo field_poly). v3 encryption used is standard RC4 with the key additionally ciphered by the Elliptic Curve Integrated Encryption Scheme. Either sect233k1 (NIST K-233) or sect163r2 (NIST B-163) curves can be used, with the former overwhelmingly prevailing, being hardwired in SDK's maker.exe. Using a private/public key scheme is superfluous because both are stored in the firmware, with the added level of complexity likely serving the purpose of obfuscation. The private key is generated at random with each invokation. None of KDF or MAC from ECIES are used, RC4 key is directly xored with the shared secret. The random number r used to calculate rG isn't stored, but that's unimportant since only krG == rkG is actually used in the encryption. Change-Id: Ieacf8cc744bc90c7c5582dd724b2c10a41bfc191
34 lines
1.5 KiB
C
34 lines
1.5 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2017 Amaury Pouly
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef __FW_H__
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#define __FW_H__
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#include <stdint.h>
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/* Unpack an AFI file: the callback function will be called once for each file in the archive with
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* its name and content. If the callback returns a nonzero value, the function will stop and return
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* that value. Returns 0 on success */
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typedef int (*fw_extract_callback_t)(const char *name, uint8_t *buf, size_t size);
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int fw_unpack(uint8_t *buf, size_t size, fw_extract_callback_t cb, bool big_endian);
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/* Check if a file looks like an AFI file */
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bool fw_check(uint8_t *buf, size_t size);
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#endif /* __FW_H__ */
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