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/*
* ks_mmap.c
* ---------
* Keystore implementation over POSIX mmap().
*
* Authors: Rob Austein
* Copyright (c) 2015, 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.
*/
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <string.h>
#include <sys/errno.h>
#include <unistd.h>
#include "hal.h"
#include "hal_internal.h"
#ifndef HAL_KS_MMAP_FILE
#define HAL_KS_MMAP_FILE ".cryptech_hal_keystore"
#endif
#ifndef MAP_FILE
#define MAP_FILE 0
#endif
/*
* Storing the KEK in with the keys it's protecting is a bad idea, but we have no better
* place to put it (real protection requires dedicated hardware, which we don't have here).
*/
#define KEKBUF_LEN (bitsToBytes(256))
static hal_ks_keydb_t *db;
static uint8_t *kekbuf;
const hal_ks_keydb_t *hal_ks_get_keydb(void)
{
if (db != NULL)
return db;
const char * const env = getenv("CRYPTECH_KEYSTORE");
const char * const home = getenv("HOME");
const char * const base = HAL_KS_MMAP_FILE;
const long pagemask = sysconf(_SC_PAGESIZE) - 1;
const size_t len = (sizeof(hal_ks_keydb_t) + KEKBUF_LEN + pagemask) & ~pagemask;
char fn_[strlen(base) + (home == NULL ? 0 : strlen(home)) + 2];
const char *fn = fn_;
int fd;
if (pagemask < 0)
return NULL;
if (env != NULL)
fn = env;
else if (home == NULL)
fn = base;
else
strcat(strcat(strcpy(fn_, home), "/"), base);
if ((fd = open(fn, O_RDWR | O_CREAT | O_EXCL, 0600)) >= 0) {
uint8_t zeros[len];
memset(zeros, 0, sizeof(zeros));
(void) write(fd, zeros, sizeof(zeros));
}
else if (errno == EEXIST) {
fd = open(fn, O_RDWR | O_CREAT, 0600);
}
if (fd >= 0 && (db = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0)) != NULL)
kekbuf = (uint8_t *) (db + 1);
(void) close(fd);
return db;
}
hal_error_t hal_ks_set_keydb(const hal_ks_key_t * const key,
const int loc,
const int updating)
{
if (key == NULL || loc < 0 || loc >= sizeof(db->keys)/sizeof(*db->keys) || (!key->in_use != !updating))
return HAL_ERROR_BAD_ARGUMENTS;
db->keys[loc] = *key;
db->keys[loc].in_use = 1;
return HAL_OK;
}
hal_error_t hal_ks_del_keydb(const int loc)
{
if (loc < 0 || loc >= sizeof(db->keys)/sizeof(*db->keys))
return HAL_ERROR_BAD_ARGUMENTS;
db->keys[loc].in_use = 0;
memset(&db->keys[loc], 0, sizeof(db->keys[loc]));
return HAL_OK;
}
hal_error_t hal_set_pin(const hal_user_t user,
const hal_ks_pin_t * const pin)
{
if (pin == NULL)
return HAL_ERROR_BAD_ARGUMENTS;
hal_ks_pin_t *p = NULL;
switch (user) {
case HAL_USER_WHEEL: p = &db->wheel_pin; break;
case HAL_USER_SO: p = &db->so_pin; break;
case HAL_USER_NORMAL: p = &db->user_pin; break;
default: return HAL_ERROR_BAD_ARGUMENTS;
}
*p = *pin;
return HAL_OK;
}
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;
if (kekbuf == NULL)
return HAL_ERROR_IMPOSSIBLE;
hal_error_t err;
const size_t len = ((kek_max < bitsToBytes(192)) ? bitsToBytes(128) :
(kek_max < bitsToBytes(256)) ? bitsToBytes(192) :
bitsToBytes(256));
uint8_t t = 0;
for (int i = 0; i < KEKBUF_LEN; i++)
t |= kekbuf[i];
if (t == 0 && (err = hal_rpc_get_random(kekbuf, sizeof(KEKBUF_LEN))) != HAL_OK)
return err;
memcpy(kek, kekbuf, len);
*kek_len = len;
return HAL_OK;
}
/*
* Local variables:
* indent-tabs-mode: nil
* End:
*/
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