path: root/ks_mmap.c

/*
 * 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

static hal_ks_keydb_t *db;

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) + 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);

  (void) close(fd);

  return db;
}

hal_error_t hal_ks_set_keydb(const hal_ks_key_t * const key,
                             const int loc)
{
  if (key == NULL || loc < 0 || loc >= sizeof(db->keys)/sizeof(*db->keys) || key->in_use)
    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;
}

/*
 * Local variables:
 * indent-tabs-mode: nil
 * End:
 */