/*
* ks_attribute.c
* --------------
* Keystore attribute API. This is internal within libhal.
*
* 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.
*/
#include <string.h>
#include "hal.h"
#include "hal_internal.h"
/*
* Read and write attribute headers (type and length). We could do
* this with a structure type and casts, but that has portability
* issues, and doing it this way just isn't expensive enough to worry about.
*/
const size_t hal_ks_attribute_header_size = 6;
static inline hal_error_t read_header(const uint8_t * const bytes, const size_t bytes_len,
uint32_t *attribute_type, size_t *attribute_len)
{
if (bytes == NULL || bytes_len < hal_ks_attribute_header_size ||
attribute_type == NULL || attribute_len == NULL)
return HAL_ERROR_BAD_ARGUMENTS;
*attribute_type = ((bytes[0] << 24) |
(bytes[1] << 16) |
(bytes[2] << 8) |
(bytes[3] << 0));
*attribute_len = ((bytes[4] << 8) |
(bytes[5] << 0));
return HAL_OK;
}
static inline hal_error_t write_header(uint8_t *bytes, const size_t bytes_len,
const uint32_t attribute_type, const size_t attribute_len)
{
if (bytes == NULL || bytes_len < hal_ks_attribute_header_size)
return HAL_ERROR_BAD_ARGUMENTS;
bytes[0] = (attribute_type >> 24) & 0xFF;
bytes[1] = (attribute_type >> 16) & 0xFF;
bytes[2] = (attribute_type >> 8) & 0xFF;
bytes[3] = (attribute_type >> 0) & 0xFF;
bytes[4] = (attribute_len >> 8) & 0xFF;
bytes[5] = (attribute_len >> 0) & 0xFF;
return HAL_OK;
}
hal_error_t hal_ks_attribute_scan(const uint8_t * const bytes, const size_t bytes_len,
hal_pkey_attribute_t *attributes, const unsigned attributes_len,
size_t *total_len)
{
if (bytes == NULL)
return HAL_ERROR_BAD_ARGUMENTS;
const uint8_t *b = bytes;
const uint8_t * const end = bytes + bytes_len;
for (unsigned i = 0; i < attributes_len; i++) {
uint32_t type;
size_t length;
hal_error_t err = read_header(b, end - b, &type, &length);
if (err != HAL_OK)
return err;
if (b + hal_ks_attribute_header_size + length > end)
return HAL_ERROR_BAD_ATTRIBUTE_LENGTH;
b += hal_ks_attribute_header_size;
if (attributes != NULL) {
attributes[i].type = type;
attributes[i].length = length;
attributes[i].value = b;
}
b += length;
}
if (total_len != NULL)
*total_len = b - bytes;
return HAL_OK;
}
hal_error_t hal_ks_attribute_delete(uint8_t *bytes, const size_t bytes_len,
hal_pkey_attribute_t *attributes, unsigned *attributes_len,
size_t *total_len,
const uint32_t type)
{
if (bytes == NULL || attributes == NULL || attributes_len == NULL || total_len == NULL)
return HAL_ERROR_BAD_ARGUMENTS;
/*
* Search for attribute by type. Note that there can be only one
* attribute of any given type.
*/
unsigned i = 0;
while (i < *attributes_len && attributes[i].type != type)
i++;
/* If not found, great, it's already deleted from the key. */
if (i == *attributes_len)
return HAL_OK;
const size_t delete_length = hal_ks_attribute_header_size + attributes[i].length;
const size_t delete_offset = (uint8_t*) attributes[i].value - hal_ks_attribute_header_size - bytes;
if (delete_offset + delete_length > *total_len)
return HAL_ERROR_IMPOSSIBLE;
memmove(bytes + delete_offset,
bytes + delete_offset + delete_length,
*total_len - delete_length - delete_offset);
return hal_ks_attribute_scan(bytes, bytes_len, attributes, --*attributes_len, total_len);
}
hal_error_t hal_ks_attribute_insert(uint8_t *bytes, const size_t bytes_len,
hal_pkey_attribute_t *attributes, unsigned *attributes_len,
size_t *total_len,
const uint32_t type,
const uint8_t * const value, const size_t value_len)
{
if (bytes == NULL || attributes == NULL || attributes_len == NULL ||
total_len == NULL || value == NULL)
return HAL_ERROR_BAD_ARGUMENTS;
/* Delete the existing attribute value (if present), then write the new value. */
hal_error_t err
= hal_ks_attribute_delete(bytes, bytes_len, attributes, attributes_len, total_len, type);
if (err != HAL_OK)
return err;
if (*total_len + hal_ks_attribute_header_size + value_len > bytes_len)
return HAL_ERROR_RESULT_TOO_LONG;
uint8_t *b = bytes + *total_len;
if ((err = write_header(b, bytes_len - *total_len, type, value_len)) != HAL_OK)
return err;
memcpy(b + hal_ks_attribute_header_size, value, value_len);
return hal_ks_attribute_scan(bytes, bytes_len, attributes, ++*attributes_len, total_len);
}
/*
* Local variables:
* indent-tabs-mode: nil
* End:
*/
