/* * This file is part of the Trezor project, https://trezor.io/ * * Copyright (c) SatoshiLabs * * 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, either version 3 of the License, or * (at your option) any later version. * * 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, see <http://www.gnu.org/licenses/>. */ #include <string.h> #include "common.h" #include "flash_area.h" #include "memzero.h" #include "norcow.h" #include "storage_utils.h" // NRC2 = 4e524332 #define NORCOW_MAGIC ((uint32_t)0x3243524e) // NRCW = 4e524357 #define NORCOW_MAGIC_V0 ((uint32_t)0x5743524e) #define NORCOW_MAGIC_LEN sizeof(uint32_t) #define NORCOW_VERSION_LEN sizeof(uint32_t) // The offset from the beginning of the sector where stored items start. #define NORCOW_STORAGE_START \ FLASH_ALIGN(NORCOW_HEADER_LEN + NORCOW_MAGIC_LEN + NORCOW_VERSION_LEN) // The key value which is used to indicate that the entry is not set. #define NORCOW_KEY_FREE (0xFFFF) // The key value which is used to indicate that the entry has been deleted. #define NORCOW_KEY_DELETED (0x0000) #define NORCOW_KEY_LEN 2 #define NORCOW_LEN_LEN 2 // The index of the active reading sector and writing sector. These should be // equal except when storage version upgrade or compaction is in progress. static uint8_t norcow_active_sector = 0; static uint8_t norcow_write_sector = 0; // The norcow version of the reading sector. static uint32_t norcow_active_version = 0; // The offset of the first free item in the writing sector. static uint32_t norcow_free_offset = 0; // Tracks how much data was already flashed in update_bytes function static uint16_t norcow_write_buffer_flashed = 0; static const void *norcow_ptr(uint8_t sector, uint32_t offset, uint32_t size); static secbool find_item(uint8_t sector, uint16_t key, const void **val, uint16_t *len); #ifdef FLASH_BIT_ACCESS #include "norcow_bitwise.h" #else #include "norcow_blockwise.h" #endif /* * Returns pointer to sector, starting with offset * Fails when there is not enough space for data of given size */ static const void *norcow_ptr(uint8_t sector, uint32_t offset, uint32_t size) { ensure(sectrue * (sector <= NORCOW_SECTOR_COUNT), "invalid sector"); return flash_area_get_address(&STORAGE_AREAS[sector], offset, size); } /* * Erases sector (and sets a magic) */ static void erase_sector(uint8_t sector, secbool set_magic) { #if NORCOW_HEADER_LEN > 0 // Backup the sector header. uint32_t header_backup[NORCOW_HEADER_LEN / sizeof(uint32_t)] = {0}; const void *sector_start = norcow_ptr(sector, 0, NORCOW_HEADER_LEN); memcpy(header_backup, sector_start, sizeof(header_backup)); #endif ensure(flash_area_erase(&STORAGE_AREAS[sector], NULL), "erase failed"); #if NORCOW_HEADER_LEN > 0 // Copy the sector header back. ensure(flash_unlock_write(), NULL); for (uint32_t i = 0; i < NORCOW_HEADER_LEN / sizeof(uint32_t); ++i) { ensure(flash_write_word(norcow_sectors[sector], i * sizeof(uint32_t), header_backup[i]), NULL); } ensure(flash_lock_write(), NULL); #endif if (sectrue == set_magic) { ensure(flash_unlock_write(), NULL); #if FLASH_BLOCK_WORDS == 1 flash_block_t block_magic = {NORCOW_MAGIC}; ensure(flash_area_write_block(&STORAGE_AREAS[sector], NORCOW_HEADER_LEN, block_magic), NULL); flash_block_t block_version = {~NORCOW_VERSION}; ensure(flash_area_write_block(&STORAGE_AREAS[sector], NORCOW_HEADER_LEN + NORCOW_MAGIC_LEN, block_version), "set version failed"); #else flash_block_t block = {NORCOW_MAGIC, ~NORCOW_VERSION}; ensure(flash_area_write_block(&STORAGE_AREAS[sector], NORCOW_HEADER_LEN, block), "set magic and version failed"); #endif ensure(flash_lock_write(), NULL); } } /* * Finds the offset from the beginning of the sector where stored items start. */ static secbool find_start_offset(uint8_t sector, uint32_t *offset, uint32_t *version) { const uint32_t *magic = norcow_ptr(sector, NORCOW_HEADER_LEN, NORCOW_MAGIC_LEN + NORCOW_VERSION_LEN); if (magic == NULL) { return secfalse; } if (*magic == NORCOW_MAGIC) { *offset = NORCOW_STORAGE_START; *version = ~(magic[1]); } else if (*magic == NORCOW_MAGIC_V0) { *offset = NORCOW_HEADER_LEN + NORCOW_MAGIC_LEN; *version = 0; } else { return secfalse; } return sectrue; } /* * Finds item in given sector */ static secbool find_item(uint8_t sector, uint16_t key, const void **val, uint16_t *len) { *val = NULL; *len = 0; uint32_t offset = 0; uint32_t version = 0; if (sectrue != find_start_offset(sector, &offset, &version)) { return secfalse; } for (;;) { uint16_t k = 0, l = 0; const void *v = NULL; uint32_t pos = 0; if (sectrue != read_item(sector, offset, &k, &v, &l, &pos)) { break; } if (key == k) { *val = v; *len = l; } offset = pos; } return sectrue * (*val != NULL); } /* * Finds first unused offset in given sector */ static uint32_t find_free_offset(uint8_t sector) { uint32_t offset = 0; uint32_t version = 0; if (sectrue != find_start_offset(sector, &offset, &version)) { return secfalse; } for (;;) { uint16_t key = 0, len = 0; const void *val = NULL; uint32_t pos = 0; if (sectrue != read_item(sector, offset, &key, &val, &len, &pos)) { break; } offset = pos; } return offset; } /* * Compacts active sector and sets new active sector */ static void compact(void) { uint32_t offsetr = 0; uint32_t version = 0; if (sectrue != find_start_offset(norcow_active_sector, &offsetr, &version)) { return; } norcow_write_sector = (norcow_active_sector + 1) % NORCOW_SECTOR_COUNT; erase_sector(norcow_write_sector, sectrue); uint32_t offsetw = NORCOW_STORAGE_START; for (;;) { // read item uint16_t k = 0, l = 0; const void *v = NULL; uint32_t posr = 0; secbool r = read_item(norcow_active_sector, offsetr, &k, &v, &l, &posr); if (sectrue != r) { break; } offsetr = posr; // skip deleted items if (k == NORCOW_KEY_DELETED) { continue; } // copy the item uint32_t posw = 0; ensure(write_item(norcow_write_sector, offsetw, k, v, l, &posw), "compaction write failed"); offsetw = posw; } erase_sector(norcow_active_sector, secfalse); norcow_active_sector = norcow_write_sector; norcow_active_version = NORCOW_VERSION; norcow_free_offset = find_free_offset(norcow_write_sector); } /* * Initializes storage */ void norcow_init(uint32_t *norcow_version) { secbool found = secfalse; *norcow_version = 0; norcow_active_sector = 0; // detect active sector - starts with magic and has highest version for (uint8_t i = 0; i < NORCOW_SECTOR_COUNT; i++) { uint32_t offset = 0; if (sectrue == find_start_offset(i, &offset, &norcow_active_version) && norcow_active_version >= *norcow_version) { found = sectrue; norcow_active_sector = i; *norcow_version = norcow_active_version; } } // If no active sectors found or version downgrade, then erase. if (sectrue != found || *norcow_version > NORCOW_VERSION) { norcow_wipe(); *norcow_version = NORCOW_VERSION; } else if (*norcow_version < NORCOW_VERSION) { // Prepare write sector for storage upgrade. norcow_write_sector = (norcow_active_sector + 1) % NORCOW_SECTOR_COUNT; erase_sector(norcow_write_sector, sectrue); norcow_free_offset = find_free_offset(norcow_write_sector); } else { norcow_write_sector = norcow_active_sector; norcow_free_offset = find_free_offset(norcow_write_sector); } } /* * Wipe the storage */ void norcow_wipe(void) { // Erase the active sector first, because it contains sensitive data. erase_sector(norcow_active_sector, sectrue); for (uint8_t i = 0; i < NORCOW_SECTOR_COUNT; i++) { if (i != norcow_active_sector) { erase_sector(i, secfalse); } } norcow_active_version = NORCOW_VERSION; norcow_write_sector = norcow_active_sector; norcow_free_offset = NORCOW_STORAGE_START; } /* * Looks for the given key, returns status of the operation */ secbool norcow_get(uint16_t key, const void **val, uint16_t *len) { return find_item(norcow_active_sector, key, val, len); } /* * Reads the next entry in the storage starting at offset. Returns secfalse if * there is none. */ secbool norcow_get_next(uint32_t *offset, uint16_t *key, const void **val, uint16_t *len) { if (*offset == 0) { uint32_t version = 0; if (sectrue != find_start_offset(norcow_active_sector, offset, &version)) { return secfalse; } } for (;;) { uint32_t pos = 0; secbool ret = read_item(norcow_active_sector, *offset, key, val, len, &pos); if (sectrue != ret) { break; } *offset = pos; // Skip deleted items. if (*key == NORCOW_KEY_DELETED) { continue; } if (norcow_active_version == 0) { // Check whether the item is the latest instance. uint32_t offsetr = *offset; for (;;) { uint16_t k = 0; uint16_t l = 0; const void *v = NULL; ret = read_item(norcow_active_sector, offsetr, &k, &v, &l, &offsetr); if (sectrue != ret) { // There is no newer instance of the item. return sectrue; } if (*key == k) { // There exists a newer instance of the item. break; } } } else { return sectrue; } } return secfalse; } /* * Sets the given key, returns status of the operation. If NULL is passed * as val, then norcow_set allocates a new key of size len. The value should * then be written using norcow_update_bytes(). */ secbool norcow_set(uint16_t key, const void *val, uint16_t len) { secbool found = secfalse; return norcow_set_ex(key, val, len, &found); } secbool norcow_set_ex(uint16_t key, const void *val, uint16_t len, secbool *found) { // Key 0xffff is used as a marker to indicate that the entry is not set. if (key == NORCOW_KEY_FREE) { return secfalse; } const flash_area_t *area = &STORAGE_AREAS[norcow_write_sector]; const void *ptr = NULL; uint16_t len_old = 0; *found = find_item(norcow_write_sector, key, &ptr, &len_old); uint32_t val_offset = 0; if (sectrue == *found) { val_offset = (const uint8_t *)ptr - (const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE); // Try to update the entry if it already exists. if (sectrue == flash_area_write_bytes(area, val_offset, len_old, val, len)) { return sectrue; } } // Delete the old item. if (sectrue == *found) { norcow_delete_item(area, len_old, val_offset); } // Check whether there is enough free space and compact if full. if (norcow_free_offset + FLASH_ALIGN(NORCOW_MAX_PREFIX_LEN + len) > NORCOW_SECTOR_SIZE) { compact(); } // Write new item. uint32_t pos = 0; if (sectrue != write_item(norcow_write_sector, norcow_free_offset, key, val, len, &pos)) { return secfalse; } norcow_free_offset = pos; return sectrue; } /* * Deletes the given key, returns status of the operation. */ secbool norcow_delete(uint16_t key) { // Key 0xffff is used as a marker to indicate that the entry is not set. if (key == NORCOW_KEY_FREE) { return secfalse; } const flash_area_t *area = &STORAGE_AREAS[norcow_write_sector]; const void *ptr = NULL; uint16_t len = 0; if (sectrue != find_item(norcow_write_sector, key, &ptr, &len)) { return secfalse; } uint32_t val_offset = (const uint8_t *)ptr - (const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE); norcow_delete_item(area, len, val_offset); return sectrue; } secbool norcow_set_counter(uint16_t key, uint32_t count) { // The count is stored as a 32-bit integer followed by a tail of "1" bits, // which is used as a tally. uint32_t value[1 + COUNTER_TAIL_WORDS] = {0}; value[0] = count; memset(&value[1], 0xff, sizeof(value) - sizeof(value[0])); return norcow_set(key, value, sizeof(value)); } /* * Complete storage version upgrade */ secbool norcow_upgrade_finish(void) { erase_sector(norcow_active_sector, secfalse); norcow_active_sector = norcow_write_sector; norcow_active_version = NORCOW_VERSION; return sectrue; }