/* * This file is part of the Trezor project, https://trezor.io/ * * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com> * * This library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This library 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, see <http://www.gnu.org/licenses/>. */ #include "memory.h" #include <libopencm3/stm32/flash.h> #include <stdint.h> #include "sha2.h" #define FLASH_OPTION_BYTES_1 (*(const uint64_t *)0x1FFFC000) #define FLASH_OPTION_BYTES_2 (*(const uint64_t *)0x1FFFC008) void memory_protect(void) { #if MEMORY_PROTECT // Reference STM32F205 Flash programming manual revision 5 // http://www.st.com/resource/en/programming_manual/cd00233952.pdf Section 2.6 // Option bytes // set RDP level 2 WRP for sectors 0 and // 1 flash option control register matches if (((FLASH_OPTION_BYTES_1 & 0xFFEC) == 0xCCEC) && ((FLASH_OPTION_BYTES_2 & 0xFFF) == 0xFFC) && (FLASH_OPTCR == 0x0FFCCCED)) { return; // already set up correctly - bail out } flash_unlock(); for (int i = FLASH_STORAGE_SECTOR_FIRST; i <= FLASH_STORAGE_SECTOR_LAST; i++) { flash_erase_sector(i, FLASH_CR_PROGRAM_X32); } flash_lock(); flash_unlock_option_bytes(); // Section 2.8.6 Flash option control register (FLASH_OPTCR) // Bits 31:28 Reserved, must be kept cleared. // Bits 27:16 nWRP: Not write protect: write protect bootloader code in // flash main memory sectors 0 and 1 (Section 2.3; table 2) Bits 15:8 RDP: // Read protect: level 2 chip read protection active Bits 7:5 USER: User // option bytes: no reset on standby, no reset on stop, software watchdog // Bit 4 Reserved, must be kept cleared. // Bits 3:2 BOR_LEV: BOR reset Level: BOR off // Bit 1 OPTSTRT: Option start: ignored by flash_program_option_bytes // Bit 0 OPTLOCK: Option lock: ignored by flash_program_option_bytes flash_program_option_bytes(0x0FFCCCEC); flash_lock_option_bytes(); #endif } // Remove write-protection on all flash sectors. // // This is an undocumented feature/bug of STM32F205/F405 microcontrollers, // where flash controller reads its write protection bits from FLASH_OPTCR // register not from OPTION_BYTES, rendering write protection useless. // This behaviour is fixed in future designs of flash controller used for // example in STM32F427, where the protection bits are read correctly // from OPTION_BYTES and not form FLASH_OPCTR register. // // Read protection is unaffected and always stays locked to the desired value. void memory_write_unlock(void) { flash_unlock_option_bytes(); flash_program_option_bytes(0x0FFFCCEC); flash_lock_option_bytes(); } int memory_bootloader_hash(uint8_t *hash) { sha256_Raw(FLASH_PTR(FLASH_BOOT_START), FLASH_BOOT_LEN, hash); sha256_Raw(hash, 32, hash); return 32; }