forked from len0rd/rockbox
6ffd42548b
Instead of verifying the CRC before every access of the boot data, verify the CRC once at startup and set a flag to indicate the boot data is valid. Also add a framework to support multiple boot protocol versions. Firmware declares the maximum supported protocol version using a version byte in the boot data header. The bootloader chooses the highest version supported by it and the firmware when deciding what boot protocol to use. Change-Id: I810194625dc0833f026d2a23b8d64ed467fa6aca
74 lines
2.1 KiB
C
74 lines
2.1 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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*
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* Copyright (C) 2022 by Aidan MacDonald
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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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#include "bootdata.h"
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#include "crc32.h"
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#include <stddef.h>
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#ifdef BOOTLOADER
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# error "not to be included in bootloader builds"
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#endif
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bool boot_data_valid;
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static bool verify_boot_data_v0(void) INIT_ATTR;
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static bool verify_boot_data_v0(void)
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{
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/* validate protocol version */
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if (boot_data.version != 0)
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return false;
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/* validate length */
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if (boot_data.length != 4)
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return false;
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return true;
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}
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struct verify_bd_entry
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{
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int version;
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bool (*verify) (void);
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};
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static const struct verify_bd_entry verify_bd[] INITDATA_ATTR = {
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{ 0, verify_boot_data_v0 },
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};
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void verify_boot_data(void)
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{
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/* verify payload with checksum - all protocol versions */
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uint32_t crc = crc_32(boot_data.payload, boot_data.length, 0xffffffff);
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if (crc != boot_data.crc)
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return;
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/* apply verification specific to the protocol version */
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for (size_t i = 0; i < ARRAYLEN(verify_bd); ++i)
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{
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const struct verify_bd_entry *e = &verify_bd[i];
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if (e->version == boot_data.version)
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{
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if (e->verify())
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boot_data_valid = true;
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return;
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}
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}
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}
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