/*
* 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.
*/
/*
* Code to load the Master key (Key Encryption Key) from either the volatile MKM
* (by asking the FPGA to provide it, using the mkmif) or from the last sector in
* the keystore flash.
*
* 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.
*
* In both volatile memory and flash, the data is stored as a 32 bit status to
* know if the memory is initialized or not, followed by 32 bytes (256 bits) of
* Master Key.
*/
#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 MKM_VOLATILE_SCLK_DIV 0x20
#define MKM_FLASH_STATUS_ADDRESS (KEYSTORE_SECTOR_SIZE * (KEYSTORE_NUM_SECTORS - 1))
#define KEK_LENGTH (256 / 8)
/* Match uninitialized flash for the "not set" value.
* Leave some bits at 1 for the "set" value to allow
* for adding more values later, if needed.
*/
#define MKM_STATUS_NOT_SET 0xffffffff
#define MKM_STATUS_SET 0x0000ffff
#define MKM_STATUS_ERASED 0x00000000
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;
}
if ((err = hal_mkmif_set_clockspeed(core, MKM_VOLATILE_SCLK_DIV)) != LIBHAL_OK ||
(err = hal_mkmif_init(core)) != LIBHAL_OK ||
(err = hal_mkmif_read_word(core, MKM_VOLATILE_STATUS_ADDRESS, &status)) != LIBHAL_OK)
return err;
if (status != MKM_STATUS_SET && status != MKM_STATUS_NOT_SET) {
/* XXX Something is a bit fishy here. If we just write the status word, it reads back wrong sometimes,
* while if we write the full buf too it is consistently right afterwards.
*/
uint8_t buf[KEK_LENGTH] = {0};
if ((err = hal_mkmif_write(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, sizeof(buf))) != LIBHAL_OK ||
(err = hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, MKM_STATUS_NOT_SET)) != LIBHAL_OK)
return err;
}
volatile_init = 1;
}
return LIBHAL_OK;
}
hal_error_t masterkey_volatile_read(uint8_t *buf, size_t len)
{
hal_error_t err;
uint32_t status;
if (len && len != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if ((err = masterkey_volatile_init()) != LIBHAL_OK ||
(err = hal_mkmif_read_word(core, MKM_VOLATILE_STATUS_ADDRESS, &status)) != LIBHAL_OK)
return err;
if (buf != NULL && len) {
/* Don't return the random bytes in the RAM memory in case it isn't initialized.
* Or maybe we should fill the buffer with proper random data in that case... hmm.
*/
if (status == MKM_STATUS_SET) {
if ((err = hal_mkmif_read(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, len)) != LIBHAL_OK) {
return err;
}
} else {
memset(buf, 0x0, len);
}
}
if (status == MKM_STATUS_SET) return LIBHAL_OK;
if (status == MKM_STATUS_NOT_SET) return HAL_ERROR_MASTERKEY_NOT_SET;
return HAL_ERROR_MASTERKEY_FAIL;
}
hal_error_t masterkey_volatile_write(uint8_t *buf, size_t len)
{
hal_error_t err;
if (len != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if (! buf) return HAL_ERROR_MASTERKEY_FAIL;
if ((err = masterkey_volatile_init()) != LIBHAL_OK ||
(err = hal_mkmif_write(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, len)) != LIBHAL_OK ||
(err = hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, MKM_STATUS_SET)) != LIBHAL_OK)
return err;
return LIBHAL_OK;
}
hal_error_t masterkey_volatile_erase(size_t len)
{
uint8_t buf[KEK_LENGTH] = {0};
hal_error_t err;
if (len != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if ((err = masterkey_volatile_init()) != LIBHAL_OK ||
(err = hal_mkmif_write(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, sizeof(buf))) != LIBHAL_OK ||
(err = hal_mkmif_write_word(core, MKM_VOLATILE_STATUS_ADDRESS, MKM_STATUS_NOT_SET)) != LIBHAL_OK)
return err;
return LIBHAL_OK;
}
hal_error_t masterkey_flash_init()
{
if (! flash_init) {
if (! keystore_check_id()) return HAL_ERROR_IO_UNEXPECTED;
flash_init = 1;
}
return LIBHAL_OK;
}
hal_error_t masterkey_flash_read(uint8_t *buf, size_t len)
{
uint8_t page[KEYSTORE_PAGE_SIZE];
uint32_t *status = (uint32_t *) page;
hal_error_t err;
if (len && len != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if ((err = masterkey_flash_init()) != LIBHAL_OK) return err;
if (! keystore_read_data(MKM_FLASH_STATUS_ADDRESS, page, sizeof(page))) {
memset(page, 0, sizeof(page));
return HAL_ERROR_MASTERKEY_FAIL;
}
if (buf != NULL && len) {
/* Don't return what's in the flash memory in case it isn't initialized.
* Or maybe we should fill the buffer with proper random data in that case... hmm.
*/
if (*status == MKM_STATUS_SET) {
memcpy(buf, page + 4, len);
} else {
memset(buf, 0x0, len);
}
}
memset(page + 4, 0, sizeof(page) - 4);
if (*status == MKM_STATUS_SET) return LIBHAL_OK;
if (*status == MKM_STATUS_ERASED || *status == MKM_STATUS_NOT_SET) return HAL_ERROR_MASTERKEY_NOT_SET;
return HAL_ERROR_MASTERKEY_FAIL;
}
hal_error_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 != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if (buf == NULL) return HAL_ERROR_MASTERKEY_FAIL;
if (masterkey_flash_init() != LIBHAL_OK) return HAL_ERROR_MASTERKEY_FAIL;
*status = MKM_STATUS_SET;
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 HAL_ERROR_MASTERKEY_FAIL;
}
return LIBHAL_OK;
}
hal_error_t masterkey_flash_erase(size_t len)
{
if (len != KEK_LENGTH) return HAL_ERROR_MASTERKEY_BAD_LENGTH;
if (keystore_erase_sectors(MKM_FLASH_STATUS_ADDRESS / KEYSTORE_SECTOR_SIZE,
MKM_FLASH_STATUS_ADDRESS / KEYSTORE_SECTOR_SIZE) != 1) {
return HAL_ERROR_MASTERKEY_FAIL;
}
return LIBHAL_OK;
}
