mirror of
https://github.com/trezor/trezor-firmware.git
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85 lines
3.3 KiB
C
85 lines
3.3 KiB
C
/*
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* This file is part of the Trezor project, https://trezor.io/
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*
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* Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "memory.h"
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#include <libopencm3/stm32/flash.h>
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#include <stdint.h>
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#include "sha2.h"
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#define FLASH_OPTION_BYTES_1 (*(const uint64_t *)0x1FFFC000)
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#define FLASH_OPTION_BYTES_2 (*(const uint64_t *)0x1FFFC008)
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void memory_protect(void) {
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#if MEMORY_PROTECT
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// Reference STM32F205 Flash programming manual revision 5
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// http://www.st.com/resource/en/programming_manual/cd00233952.pdf Section 2.6
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// Option bytes
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// set RDP level 2 WRP for sectors 0 and
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// 1 flash option control register matches
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if (((FLASH_OPTION_BYTES_1 & 0xFFEC) == 0xCCEC) &&
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((FLASH_OPTION_BYTES_2 & 0xFFF) == 0xFFC) &&
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(FLASH_OPTCR == 0x0FFCCCED)) {
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return; // already set up correctly - bail out
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}
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flash_unlock();
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for (int i = FLASH_STORAGE_SECTOR_FIRST; i <= FLASH_STORAGE_SECTOR_LAST;
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i++) {
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flash_erase_sector(i, FLASH_CR_PROGRAM_X32);
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}
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flash_lock();
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flash_unlock_option_bytes();
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// Section 2.8.6 Flash option control register (FLASH_OPTCR)
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// Bits 31:28 Reserved, must be kept cleared.
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// Bits 27:16 nWRP: Not write protect: write protect bootloader code in
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// flash main memory sectors 0 and 1 (Section 2.3; table 2) Bits 15:8 RDP:
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// Read protect: level 2 chip read protection active Bits 7:5 USER: User
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// option bytes: no reset on standby, no reset on stop, software watchdog
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// Bit 4 Reserved, must be kept cleared.
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// Bits 3:2 BOR_LEV: BOR reset Level: BOR off
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// Bit 1 OPTSTRT: Option start: ignored by flash_program_option_bytes
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// Bit 0 OPTLOCK: Option lock: ignored by flash_program_option_bytes
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flash_program_option_bytes(0x0FFCCCEC);
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flash_lock_option_bytes();
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#endif
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}
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// Remove write-protection on all flash sectors.
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//
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// This is an undocumented feature/bug of STM32F205/F405 microcontrollers,
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// where flash controller reads its write protection bits from FLASH_OPTCR
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// register not from OPTION_BYTES, rendering write protection useless.
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// This behaviour is fixed in future designs of flash controller used for
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// example in STM32F427, where the protection bits are read correctly
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// from OPTION_BYTES and not form FLASH_OPCTR register.
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//
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// Read protection is unaffected and always stays locked to the desired value.
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void memory_write_unlock(void) {
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flash_unlock_option_bytes();
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flash_program_option_bytes(0x0FFFCCEC);
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flash_lock_option_bytes();
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}
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int memory_bootloader_hash(uint8_t *hash) {
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sha256_Raw(FLASH_PTR(FLASH_BOOT_START), FLASH_BOOT_LEN, hash);
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sha256_Raw(hash, 32, hash);
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return 32;
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}
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