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trezor-firmware/storage/norcow.c

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/*
* 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.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 NORCOW_WORD_SIZE
#define NORCOW_VERSION_LEN NORCOW_WORD_SIZE
// 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
#ifdef FLASH_BYTE_ACCESS
#define COUNTER_TAIL_WORDS 2
#define NORCOW_WORD_SIZE (sizeof(uint32_t))
#define NORCOW_MAX_PREFIX_LEN (NORCOW_WORD_SIZE)
#define ALIGN(X) ((X) = ((X) + 3) & ~3)
// The offset from the beginning of the sector where stored items start.
#define NORCOW_STORAGE_START \
(NORCOW_HEADER_LEN + NORCOW_MAGIC_LEN + NORCOW_VERSION_LEN)
#else
#define COUNTER_TAIL_WORDS 0
#define NORCOW_WORD_SIZE (4 * sizeof(uint32_t))
// Small items are encoded more efficiently.
#define NORCOW_SMALL_ITEM_SIZE \
(NORCOW_WORD_SIZE - NORCOW_LEN_LEN - NORCOW_KEY_LEN)
// Larger items store first part of data with the same QW as key
#define NORCOW_DELETED_FLAG_LEN 1
#define NORCOW_DATA_OPT_SIZE (NORCOW_WORD_SIZE - NORCOW_DELETED_FLAG_LEN)
#define NORCOW_MAX_PREFIX_LEN (NORCOW_WORD_SIZE + NORCOW_DELETED_FLAG_LEN)
#define ALIGN(X) ((X) = ((X) + 0xF) & ~0xF)
// The offset from the beginning of the sector where stored items start.
#define NORCOW_STORAGE_START (NORCOW_HEADER_LEN + NORCOW_WORD_SIZE)
#endif
// 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;
static uint16_t norcow_write_buffer_flashed = 0;
#ifndef FLASH_BYTE_ACCESS
static uint32_t norcow_write_buffer[4] = {0};
static uint16_t norcow_write_buffer_filled = 0;
static uint16_t norcow_write_buffer_filled_data = 0;
static int32_t norcow_write_buffer_key = -1;
#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);
}
/*
* Writes data to given sector, starting from offset
*/
#ifdef FLASH_BYTE_ACCESS
static secbool norcow_write(uint8_t sector, uint32_t offset, uint16_t key,
const uint8_t *data, uint16_t len) {
if (sector >= NORCOW_SECTOR_COUNT) {
return secfalse;
}
if (offset + NORCOW_MAX_PREFIX_LEN + len > NORCOW_SECTOR_SIZE) {
return secfalse;
}
uint32_t prefix = ((uint32_t)len << 16) | key;
ensure(flash_unlock_write(), NULL);
// write prefix
ensure(flash_area_write_word(&STORAGE_AREAS[sector], offset, prefix), NULL);
offset += NORCOW_MAX_PREFIX_LEN;
if (data != NULL) {
// write data
for (uint16_t i = 0; i < len; i++, offset++) {
ensure(flash_area_write_byte(&STORAGE_AREAS[sector], offset, data[i]),
NULL);
}
} else {
offset += len;
}
// pad with zeroes
for (; offset % NORCOW_WORD_SIZE; offset++) {
ensure(flash_area_write_byte(&STORAGE_AREAS[sector], offset, 0x00), NULL);
}
ensure(flash_lock_write(), NULL);
return sectrue;
}
#else
static secbool norcow_write(uint8_t sector, uint32_t offset, uint16_t key,
const uint8_t *data, uint16_t len) {
if (sector >= NORCOW_SECTOR_COUNT) {
return secfalse;
}
if (len <= NORCOW_SMALL_ITEM_SIZE) {
// the whole item fits into one quadword, let's not waste space
uint16_t len_adjusted = 0x10;
if (offset + len_adjusted > NORCOW_SECTOR_SIZE) {
return secfalse;
}
ensure(flash_unlock_write(), NULL);
uint32_t d[4];
d[0] = len | ((uint32_t)key << 16);
d[1] = 0;
d[2] = 0;
d[3] = 0;
if (len > 0) {
memcpy(&d[1], data, len); // write data
}
ensure(flash_area_write_quadword(&STORAGE_AREAS[sector], offset, d), NULL);
ensure(flash_lock_write(), NULL);
} else {
uint16_t len_adjusted = ((len) + 0xF) & ~0xF;
if (offset + NORCOW_MAX_PREFIX_LEN + len_adjusted > NORCOW_SECTOR_SIZE) {
return secfalse;
}
ensure(flash_unlock_write(), NULL);
uint32_t d[4];
d[0] = len | ((uint32_t)key << 16);
d[1] = 0xFFFFFFFF;
d[2] = 0xFFFFFFFF;
d[3] = 0xFFFFFFFF;
// write len
ensure(flash_area_write_quadword(&STORAGE_AREAS[sector], offset, d), NULL);
offset += NORCOW_WORD_SIZE;
if (data != NULL) {
memset(d, 0, sizeof(d));
d[0] = 0xFE;
if (len >= NORCOW_DATA_OPT_SIZE) {
// write key and first data part
memcpy(&(((uint8_t *)d)[NORCOW_DELETED_FLAG_LEN]), data,
NORCOW_DATA_OPT_SIZE);
ensure(flash_area_write_quadword(&STORAGE_AREAS[sector], offset, d),
NULL);
offset += NORCOW_WORD_SIZE;
data += NORCOW_DATA_OPT_SIZE;
len -= NORCOW_DATA_OPT_SIZE;
} else {
// write key and first data part
memcpy(&(((uint8_t *)d)[NORCOW_DELETED_FLAG_LEN]), data, len);
ensure(flash_area_write_quadword(&STORAGE_AREAS[sector], offset, d),
NULL);
offset += NORCOW_WORD_SIZE;
data += len;
len = 0;
}
while (len > 0) {
memset(d, 0, sizeof(d));
uint16_t data_to_write =
len > NORCOW_WORD_SIZE ? NORCOW_WORD_SIZE : len;
memcpy(d, data, data_to_write);
ensure(flash_area_write_quadword(&STORAGE_AREAS[sector], offset, d),
NULL);
offset += NORCOW_WORD_SIZE;
data += data_to_write;
len -= data_to_write;
}
memset(d, 0, sizeof(norcow_write_buffer));
}
ensure(flash_lock_write(), NULL);
}
return sectrue;
}
#endif
/*
* 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) {
#ifdef FLASH_BYTE_ACCESS
ensure(flash_unlock_write(), NULL);
ensure(flash_area_write_word(&STORAGE_AREAS[sector], NORCOW_HEADER_LEN,
NORCOW_MAGIC),
NULL);
ensure(flash_area_write_word(&STORAGE_AREAS[sector],
NORCOW_HEADER_LEN + NORCOW_MAGIC_LEN,
~NORCOW_VERSION),
"set version failed");
ensure(flash_lock_write(), NULL);
#else
uint32_t d[4];
d[0] = NORCOW_MAGIC;
d[1] = ~NORCOW_VERSION;
d[2] = 0xFFFFFFFF;
d[3] = 0xFFFFFFFF;
ensure(flash_unlock_write(), NULL);
ensure(
flash_area_write_quadword(&STORAGE_AREAS[sector], NORCOW_HEADER_LEN, d),
"set magic and version failed");
ensure(flash_lock_write(), NULL);
#endif
}
}
/*
* Reads one item starting from offset
*/
static secbool read_item(uint8_t sector, uint32_t offset, uint16_t *key,
const void **val, uint16_t *len, uint32_t *pos) {
*pos = offset;
#ifdef FLASH_BYTE_ACCESS
const void *k = norcow_ptr(sector, *pos, NORCOW_KEY_LEN);
if (k == NULL) return secfalse;
*pos += NORCOW_KEY_LEN;
memcpy(key, k, sizeof(uint16_t));
if (*key == NORCOW_KEY_FREE) {
return secfalse;
}
const void *l = norcow_ptr(sector, *pos, NORCOW_LEN_LEN);
if (l == NULL) return secfalse;
*pos += NORCOW_LEN_LEN;
memcpy(len, l, sizeof(uint16_t));
#else
const void *l = norcow_ptr(sector, *pos, NORCOW_LEN_LEN);
if (l == NULL) return secfalse;
memcpy(len, l, sizeof(uint16_t));
if (*len <= NORCOW_SMALL_ITEM_SIZE) {
*pos += NORCOW_LEN_LEN;
const void *k = norcow_ptr(sector, *pos, NORCOW_KEY_LEN);
if (k == NULL) return secfalse;
memcpy(key, k, sizeof(uint16_t));
if (*key == NORCOW_KEY_FREE) {
return secfalse;
}
*pos += NORCOW_KEY_LEN;
} else {
*pos += NORCOW_LEN_LEN;
const void *k = norcow_ptr(sector, *pos, NORCOW_KEY_LEN);
if (k == NULL) return secfalse;
*pos += (NORCOW_KEY_LEN + NORCOW_SMALL_ITEM_SIZE);
const void *flg = norcow_ptr(sector, *pos, NORCOW_DELETED_FLAG_LEN);
if (flg == NULL) return secfalse;
*pos += NORCOW_DELETED_FLAG_LEN;
if (*((const uint8_t *)flg) == 0) {
// Deleted item.
*key = NORCOW_KEY_DELETED;
} else {
memcpy(key, k, sizeof(uint16_t));
if (*key == NORCOW_KEY_FREE) {
return secfalse;
}
}
}
#endif
*val = norcow_ptr(sector, *pos, *len);
if (*val == NULL) return secfalse;
*pos += *len;
ALIGN(*pos);
return sectrue;
}
/*
* Writes one item starting from offset
*/
static secbool write_item(uint8_t sector, uint32_t offset, uint16_t key,
const void *val, uint16_t len, uint32_t *pos) {
#ifndef FLASH_BYTE_ACCESS
if (len <= NORCOW_SMALL_ITEM_SIZE) {
*pos = offset + NORCOW_WORD_SIZE;
} else {
*pos = offset + NORCOW_MAX_PREFIX_LEN + len;
ALIGN(*pos);
}
#else
*pos = offset + NORCOW_MAX_PREFIX_LEN + len;
ALIGN(*pos);
#endif
return norcow_write(sector, offset, key, val, len);
}
/*
* 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];
secbool ret = secfalse;
const void *ptr = NULL;
uint16_t len_old = 0;
*found = find_item(norcow_write_sector, key, &ptr, &len_old);
// Try to update the entry if it already exists.
uint32_t offset = 0;
if (sectrue == *found) {
offset =
(const uint8_t *)ptr -
(const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE);
#ifdef FLASH_BYTE_ACCESS
if (val != NULL && len_old == len) {
ret = sectrue;
ensure(flash_unlock_write(), NULL);
for (uint16_t i = 0; i < len; i++) {
if (sectrue != flash_area_write_byte(area, offset + i,
((const uint8_t *)val)[i])) {
ret = secfalse;
break;
}
}
ensure(flash_lock_write(), NULL);
}
#else
if (val != NULL && len_old == len) {
if (len <= NORCOW_SMALL_ITEM_SIZE) {
secbool updatable = sectrue;
for (uint16_t i = 0; i < len; i++) {
if (((const uint8_t *)val)[i] != ((const uint8_t *)ptr)[i]) {
updatable = secfalse;
break;
}
}
if (updatable == sectrue) {
ret = sectrue;
ensure(flash_unlock_write(), NULL);
uint32_t d[4];
d[0] = len | ((uint32_t)key << 16);
d[1] = 0;
d[2] = 0;
d[3] = 0;
if (len > 0) {
memcpy(&d[1], val, len); // write len
}
ensure(flash_area_write_quadword(area, offset - 4, d), NULL);
ensure(flash_lock_write(), NULL);
}
} else {
secbool updatable = sectrue;
for (uint16_t i = 0; i < len; i++) {
if (((const uint8_t *)val)[i] != ((const uint8_t *)ptr)[i]) {
updatable = secfalse;
break;
}
}
if (updatable == sectrue) {
ret = sectrue;
uint8_t *v = (uint8_t *)val;
int tmp_len = len;
ensure(flash_unlock_write(), NULL);
uint32_t d[4] = {0};
d[0] = 0xFF;
uint16_t data_to_copy =
((size_t)tmp_len > NORCOW_WORD_SIZE ? NORCOW_WORD_SIZE
: (size_t)tmp_len);
memcpy(&(((uint8_t *)norcow_write_buffer)[NORCOW_DELETED_FLAG_LEN]),
v, data_to_copy);
ensure(flash_area_write_quadword(area,
offset - NORCOW_DELETED_FLAG_LEN, d),
NULL);
offset += data_to_copy;
v += data_to_copy;
tmp_len -= data_to_copy;
while (tmp_len > 0) {
data_to_copy =
((size_t)tmp_len > NORCOW_WORD_SIZE ? NORCOW_WORD_SIZE
: (size_t)tmp_len);
memset(d, 0, sizeof(d));
memcpy(d, v, data_to_copy);
ensure(flash_area_write_quadword(area, offset, d), NULL);
offset += data_to_copy;
v += data_to_copy;
tmp_len -= data_to_copy;
}
ensure(flash_lock_write(), NULL);
}
}
}
#endif
}
// If the update was not possible then write the entry as a new item.
if (secfalse == ret) {
// Delete the old item.
if (sectrue == *found) {
ensure(flash_unlock_write(), NULL);
uint32_t end = offset + len_old;
#ifdef FLASH_BYTE_ACCESS
// Update the prefix to indicate that the old item has been deleted.
uint32_t prefix = (uint32_t)len_old << 16;
ensure(
flash_area_write_word(area, offset - NORCOW_MAX_PREFIX_LEN, prefix),
NULL);
#else
if (len_old <= NORCOW_SMALL_ITEM_SIZE) {
// Delete entire content of the quadword.
uint32_t d[4] = {0};
ensure(flash_area_write_quadword(area, offset - 4, d), NULL);
// Move to the next quadword.
offset += NORCOW_WORD_SIZE - NORCOW_LEN_LEN - NORCOW_KEY_LEN;
} else {
// Update the flag to indicate that the old item has been deleted.
// deletes a portion of data too
uint32_t d[4] = {0};
ensure(flash_area_write_quadword(area, offset - NORCOW_DELETED_FLAG_LEN,
d),
NULL);
offset += NORCOW_DATA_OPT_SIZE;
}
#endif
// Delete the old item data.
while (offset < end) {
#ifdef FLASH_BYTE_ACCESS
ensure(flash_area_write_word(area, offset, 0x00000000), NULL);
#else
uint32_t d[4] = {0};
ensure(flash_area_write_quadword(area, offset, d), NULL);
#endif
offset += NORCOW_WORD_SIZE;
}
ensure(flash_lock_write(), NULL);
}
// Check whether there is enough free space and compact if full.
if (norcow_free_offset + NORCOW_MAX_PREFIX_LEN + len > NORCOW_SECTOR_SIZE) {
compact();
}
// Write new item.
uint32_t pos = 0;
ret = write_item(norcow_write_sector, norcow_free_offset, key, val, len,
&pos);
if (sectrue == ret) {
norcow_free_offset = pos;
}
}
return ret;
}
/*
* 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 offset =
(const uint8_t *)ptr -
(const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE);
ensure(flash_unlock_write(), NULL);
uint32_t end = offset + len;
#ifdef FLASH_BYTE_ACCESS
// Update the prefix to indicate that the item has been deleted.
uint32_t prefix = (uint32_t)len << 16;
ensure(flash_area_write_word(area, offset - NORCOW_MAX_PREFIX_LEN, prefix),
NULL);
#else
uint32_t d[4] = {0};
if (len <= NORCOW_SMALL_ITEM_SIZE) {
// Delete entire content of the quadword, setting the length to 0.
ensure(flash_area_write_quadword(
area, offset - NORCOW_LEN_LEN - NORCOW_KEY_LEN, d),
NULL);
// Move to the next quadword.
offset += NORCOW_WORD_SIZE - NORCOW_LEN_LEN - NORCOW_KEY_LEN;
} else {
// Update the flag to indicate that the old item has been deleted.
// deletes a portion of data too
ensure(flash_area_write_quadword(area, offset - NORCOW_DELETED_FLAG_LEN, d),
NULL);
offset += NORCOW_DATA_OPT_SIZE;
}
#endif
// Delete the item data.
while (offset < end) {
#ifdef FLASH_BYTE_ACCESS
ensure(flash_area_write_word(area, offset, 0x00000000), NULL);
#else
ensure(flash_area_write_quadword(area, offset, d), NULL);
#endif
offset += NORCOW_WORD_SIZE;
}
ensure(flash_lock_write(), NULL);
return sectrue;
}
#ifdef FLASH_BYTE_ACCESS
/*
* Update a word in flash at the given pointer. The pointer must point
* into the NORCOW area.
*/
secbool norcow_update_word(uint16_t key, uint16_t offset, uint32_t value) {
const void *ptr = NULL;
uint16_t len = 0;
if (sectrue != find_item(norcow_write_sector, key, &ptr, &len)) {
return secfalse;
}
if ((offset & 3) != 0 || offset >= len) {
return secfalse;
}
uint32_t sector_offset =
(const uint8_t *)ptr -
(const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE) +
offset;
ensure(flash_unlock_write(), NULL);
ensure(flash_area_write_word(&STORAGE_AREAS[norcow_write_sector],
sector_offset, value),
NULL);
ensure(flash_lock_write(), NULL);
return sectrue;
}
#endif
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));
}
secbool norcow_next_counter(uint16_t key, uint32_t *count) {
uint16_t len = 0;
const uint32_t *val_stored = NULL;
if (sectrue != norcow_get(key, (const void **)&val_stored, &len)) {
*count = 0;
return norcow_set_counter(key, 0);
}
if (len < sizeof(uint32_t) || len % sizeof(uint32_t) != 0) {
return secfalse;
}
uint16_t len_words = len / sizeof(uint32_t);
uint16_t i = 1;
while (i < len_words && val_stored[i] == 0) {
++i;
}
*count = val_stored[0] + 1 + 32 * (i - 1);
if (*count < val_stored[0]) {
// Value overflow.
return secfalse;
}
if (i < len_words) {
*count += hamming_weight(~val_stored[i]);
if (*count < val_stored[0]) {
// Value overflow.
return secfalse;
}
#ifdef FLASH_BYTE_ACCESS
return norcow_update_word(key, sizeof(uint32_t) * i, val_stored[i] >> 1);
#else
return norcow_set_counter(key, *count);
#endif
} else {
return norcow_set_counter(key, *count);
}
}
/*
* Update the value of the given key starting at the given offset.
*/
secbool norcow_update_bytes(const uint16_t key, const uint8_t *data,
const uint16_t len) {
const void *ptr = NULL;
uint16_t allocated_len = 0;
if (sectrue != find_item(norcow_write_sector, key, &ptr, &allocated_len)) {
return secfalse;
}
#ifndef FLASH_BYTE_ACCESS
if (allocated_len <= NORCOW_SMALL_ITEM_SIZE) {
// small items are not updated in place
return secfalse;
}
#endif
if (norcow_write_buffer_flashed + len > allocated_len) {
return secfalse;
}
uint32_t sector_offset =
(const uint8_t *)ptr -
(const uint8_t *)norcow_ptr(norcow_write_sector, 0, NORCOW_SECTOR_SIZE);
const flash_area_t *area = &STORAGE_AREAS[norcow_write_sector];
ensure(flash_unlock_write(), NULL);
#ifdef FLASH_BYTE_ACCESS
sector_offset += norcow_write_buffer_flashed;
for (uint16_t i = 0; i < len; i++, sector_offset++) {
ensure(flash_area_write_byte(area, sector_offset, data[i]), NULL);
}
norcow_write_buffer_flashed += len;
if (norcow_write_buffer_flashed >= allocated_len) {
norcow_write_buffer_flashed = 0;
}
#else
if (norcow_write_buffer_key != key && norcow_write_buffer_key != -1) {
// some other update bytes is in process, abort
return secfalse;
}
if (norcow_write_buffer_key == -1) {
memset(norcow_write_buffer, 0, sizeof(norcow_write_buffer));
norcow_write_buffer_key = key;
norcow_write_buffer[0] = 0xFE;
norcow_write_buffer_filled = NORCOW_DELETED_FLAG_LEN;
norcow_write_buffer_filled_data = 0;
norcow_write_buffer_flashed = 0;
}
uint16_t tmp_len = len;
uint16_t flash_offset =
sector_offset - NORCOW_DELETED_FLAG_LEN + norcow_write_buffer_flashed;
while (tmp_len > 0) {
uint16_t buffer_space = NORCOW_WORD_SIZE - norcow_write_buffer_filled;
uint16_t data_to_copy = (tmp_len > buffer_space ? buffer_space : tmp_len);
memcpy(&((uint8_t *)norcow_write_buffer)[norcow_write_buffer_filled], data,
data_to_copy);
data += data_to_copy;
norcow_write_buffer_filled += data_to_copy;
norcow_write_buffer_filled_data += data_to_copy;
tmp_len -= data_to_copy;
if (norcow_write_buffer_filled == NORCOW_WORD_SIZE ||
(norcow_write_buffer_filled_data + norcow_write_buffer_flashed) ==
allocated_len + NORCOW_DELETED_FLAG_LEN) {
ensure(flash_area_write_quadword(area, flash_offset, norcow_write_buffer),
NULL);
ensure(flash_area_write_quadword(area, flash_offset, norcow_write_buffer),
NULL);
flash_offset += NORCOW_WORD_SIZE;
norcow_write_buffer_filled = 0;
norcow_write_buffer_flashed += NORCOW_WORD_SIZE;
memset(norcow_write_buffer, 0, sizeof(norcow_write_buffer));
if ((norcow_write_buffer_flashed) >=
allocated_len + NORCOW_DELETED_FLAG_LEN) {
norcow_write_buffer_key = -1;
norcow_write_buffer_flashed = 0;
}
norcow_write_buffer_filled_data = 0;
}
}
#endif
ensure(flash_lock_write(), NULL);
return sectrue;
}
/*
* 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;
}
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