Cleanup prior to rewriting ks_flash.c.

Whack masterkey code to meet libhal coding standards, such as they
are.

Started layout of new ks_flash data structures but no changes to
functions or flash usage yet.

MKM initialization from flash placed under compile-time conditional
with warning because it's a dangerous kludge that should go away.

Started getting rid of obsolete keystore code; ks_mmap.c kept for now,
until I get around to merging the useful bits into ks_volatile.

1 files changed, 320 insertions, 0 deletions

diff --git a/mkm.c b/mkm.c
new file mode 100644
index 0000000..b8dc3c5
--- /dev/null
+++ b/mkm.c
@@ -0,0 +1,320 @@
+/*
+ * mkm.c
+ * -----
+ * Master Key Memory 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 "hal_internal.h"
+#undef HAL_OK
+
+#include <string.h>
+
+
+static int volatile_init = 0, flash_init = 0;
+static 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
+
+
+static hal_error_t hal_mkm_volatile_init(void)
+{
+  if (volatile_init)
+    return LIBHAL_OK;
+
+  hal_error_t err;
+  uint32_t status;
+
+  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 hal_mkm_volatile_read(uint8_t *buf, const size_t len)
+{
+  hal_error_t err;
+  uint32_t status;
+
+  if (len && len != KEK_LENGTH)
+    return HAL_ERROR_MASTERKEY_BAD_LENGTH;
+
+  if ((err = hal_mkm_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)
+      memset(buf, 0x0, len);
+    else if ((err = hal_mkmif_read(core, MKM_VOLATILE_STATUS_ADDRESS + 4, buf, len)) != LIBHAL_OK)
+      return err;
+  }
+
+  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 hal_mkm_volatile_write(const uint8_t * const buf, const size_t len)
+{
+  hal_error_t err;
+
+  if (len != KEK_LENGTH)
+    return HAL_ERROR_MASTERKEY_BAD_LENGTH;
+
+  if (buf == NULL)
+    return HAL_ERROR_MASTERKEY_FAIL;
+
+  if ((err = hal_mkm_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 hal_mkm_volatile_erase(const 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 = hal_mkm_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;
+}
+
+#if HAL_MKM_FLASH_BACKUP_KLUDGE
+
+static hal_error_t hal_mkm_flash_init(void)
+{
+  if (flash_init)
+    return LIBHAL_OK;
+
+  if (!keystore_check_id())
+    return HAL_ERROR_IO_UNEXPECTED;
+
+  flash_init = 1;
+  return LIBHAL_OK;
+}
+
+hal_error_t hal_mkm_flash_read(uint8_t *buf, const 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 = hal_mkm_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 hal_mkm_flash_write(const uint8_t * const buf, const 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 (hal_mkm_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 hal_mkm_flash_erase(const 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;
+}
+
+#endif /* HAL_MKM_FLASH_BACKUP_KLUDGE */
+
+
+hal_error_t hal_mkm_get_kek(uint8_t *kek,
+			    size_t *kek_len,
+			    const size_t kek_max)
+{
+  if (kek == NULL || kek_len == NULL || kek_max < bitsToBytes(128))
+    return HAL_ERROR_BAD_ARGUMENTS;
+
+  const size_t len = ((kek_max < bitsToBytes(192)) ? bitsToBytes(128) :
+                      (kek_max < bitsToBytes(256)) ? bitsToBytes(192) :
+                      bitsToBytes(256));
+
+  hal_error_t err = hal_mkm_volatile_read(kek, len);
+
+  if (err == LIBHAL_OK) {
+    *kek_len = len;
+    return LIBHAL_OK;
+  }
+
+#if HAL_MKM_FLASH_BACKUP_KLUDGE
+
+  if (hal_mkm_flash_read(kek, len) == LIBHAL_OK) {
+    *kek_len = len;
+    return LIBHAL_OK;
+  }
+
+#endif
+
+  /*
+   * Both keystores returned an error, probably HAL_ERROR_MASTERKEY_NOT_SET.
+   * I could try to be clever and compare the errors, but really the volatile
+   * keystore is the important one (you shouldn't store the master key in
+   * flash), so return that error.
+   */
+  return err;
+}
+
+/*
+ * "Any programmer who fails to comply with the standard naming, formatting,
+ *  or commenting conventions should be shot.  If it so happens that it is
+ *  inconvenient to shoot him, then he is to be politely requested to recode
+ *  his program in adherence to the above standard."
+ *                      -- Michael Spier, Digital Equipment Corporation
+ *
+ * Local variables:
+ * indent-tabs-mode: nil
+ * End:
+ */