/*
* masterkey.c
* -----------
* Masterkey set/get functions.
*
* Copyright (c) 2016, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define HAL_OK CMIS_HAL_OK
#include "stm-init.h"
#include "stm-keystore.h"
#undef HAL_OK
#define HAL_OK LIBHAL_OK
#include "hal.h"
#include "masterkey.h"
#undef HAL_OK
#include <string.h>
static int volatile_init = 0, flash_init = 0;
static const hal_core_t *core = NULL;
#define MKM_VOLATILE_STATUS_ADDRESS 0
#define SCLK_DIV 0x20
#define MKM_FLASH_STATUS_ADDRESS (KEYSTORE_SECTOR_SIZE * (KEYSTORE_NUM_SECTORS - 1))
#define MKM_FLASH_STATUS_IN_USE 0x0000ffff
#define KEK_LENGTH (256 / 8)
hal_error_t masterkey_volatile_init()
{
hal_error_t err;
uint32_t status;
if (! volatile_init) {
if ((core = hal_core_find(MKMIF_NAME, NULL)) == NULL) {
return HAL_ERROR_CORE_NOT_FOUND;
}
err =
hal_mkmif_set_clockspeed(core, SCLK_DIV) ||
hal_mkmif_init(core) ||
hal_mkmif_read_word(core, MKM_VOLATILE_STATUS_ADDRESS, &status);
if (err != LIBHAL_OK) return err;
if (status != HSM_MASTERKEY_SET &&
status != HSM_MASTERKEY_NOT_SET) {
if ((err = hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, HSM_MASTERKEY_NOT_SET)) != LIBHAL_OK) {
return err;
}
}
volatile_init = 1;
}
return LIBHAL_OK;
}
masterkey_status_t masterkey_volatile_read(uint8_t *buf, size_t len)
{
hal_error_t err;
uint32_t status;
err =
masterkey_volatile_init() ||
hal_mkmif_read_word(core, MKM_VOLATILE_STATUS_ADDRESS, &status);
if (err != LIBHAL_OK) return HSM_MASTERKEY_FAIL;
if (buf != NULL && status == HSM_MASTERKEY_SET) {
if ((err = hal_mkmif_read(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, len)) == LIBHAL_OK) {
return HSM_MASTERKEY_SET;
}
}
if (status == HSM_MASTERKEY_SET || status == HSM_MASTERKEY_NOT_SET) {
return (masterkey_status_t) status;
}
return HSM_MASTERKEY_FAIL;
}
masterkey_status_t masterkey_volatile_write(uint8_t *buf, size_t len)
{
hal_error_t err;
if (len != KEK_LENGTH) return HSM_MASTERKEY_FAIL;
if (! buf) return HSM_MASTERKEY_FAIL;
err =
masterkey_volatile_init() ||
hal_mkmif_write(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, len) ||
hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, HSM_MASTERKEY_SET);
if (err != LIBHAL_OK) return HSM_MASTERKEY_FAIL;
return HSM_MASTERKEY_OK;
}
masterkey_status_t masterkey_volatile_erase(size_t len)
{
uint8_t buf[KEK_LENGTH] = {0};
hal_error_t err;
if (len != KEK_LENGTH) return HSM_MASTERKEY_FAIL;
err =
masterkey_volatile_init() ||
hal_mkmif_write(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, sizeof(buf)) ||
hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, HSM_MASTERKEY_NOT_SET);
if (err != LIBHAL_OK) return HSM_MASTERKEY_FAIL;
return HSM_MASTERKEY_OK;
}
/* Storing the master key in flash is a pretty Bad Idea, but since the Alpha board
* doesn't have a battery mounted (only pin headers for attaching one), it might
* help in non-production use where one doesn't have tamper protection anyways.
*
* For production use on the Alpha, one option is to have the Master Key on paper
* and enter it into volatile RAM after each power on.
*/
hal_error_t masterkey_flash_init()
{
if (! flash_init) {
if (! keystore_check_id()) return HAL_ERROR_IO_UNEXPECTED;
flash_init = 1;
}
return LIBHAL_OK;
}
masterkey_status_t masterkey_flash_read(uint8_t *buf, size_t len)
{
uint8_t page[KEYSTORE_PAGE_SIZE];
uint32_t *status = (uint32_t *) page;
if (len > sizeof(page) - 4) return HSM_MASTERKEY_FAIL;
if (masterkey_flash_init() != LIBHAL_OK) return HSM_MASTERKEY_FAIL;
if (! keystore_read_data(MKM_FLASH_STATUS_ADDRESS, page, sizeof(page))) {
memset(page, 0, sizeof(page));
return HSM_MASTERKEY_FAIL;
}
if (buf != NULL && len) memcpy(buf, page + 4, len);
memset(page + 4, 0, sizeof(page) - 4);
if (*status == MKM_FLASH_STATUS_IN_USE) return HSM_MASTERKEY_SET;
if (*status == 0x0 || *status == 0xffffffff) return HSM_MASTERKEY_NOT_SET;
return HSM_MASTERKEY_FAIL;
}
masterkey_status_t masterkey_flash_write(uint8_t *buf, size_t len)
{
uint8_t page[KEYSTORE_PAGE_SIZE] = {0xff};
uint32_t *status = (uint32_t *) page;
int res;
if (len > sizeof(page) - 4) return HSM_MASTERKEY_FAIL;
if (buf == NULL) return HSM_MASTERKEY_FAIL;
if (masterkey_flash_init() != LIBHAL_OK) return HSM_MASTERKEY_FAIL;
*status = MKM_FLASH_STATUS_IN_USE;
memcpy(page + 4, buf, len);
res = keystore_write_data(MKM_FLASH_STATUS_ADDRESS, page, sizeof(page));
memset(page, 0, sizeof(page));
if (res != 1) {
return HSM_MASTERKEY_FAIL;
}
return HSM_MASTERKEY_OK;
}
masterkey_status_t masterkey_flash_erase(size_t len)
{
if (len > KEYSTORE_PAGE_SIZE - 4) return HSM_MASTERKEY_FAIL;
if (keystore_erase_sectors(MKM_FLASH_STATUS_ADDRESS / KEYSTORE_SECTOR_SIZE,
MKM_FLASH_STATUS_ADDRESS / KEYSTORE_SECTOR_SIZE) != 1) {
return HSM_MASTERKEY_FAIL;
}
return HSM_MASTERKEY_OK;
}
