/*
* xdr.c
* -----
* Serialization/deserialization routines, using XDR (RFC 4506) encoding.
* These functions are not part of the public libhal API.
*
* Copyright (c) 2016-2018, 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 <stdio.h>
#include <stdint.h>
#include <string.h> /* memcpy, memset */
#include "hal.h"
#include "hal_internal.h" /* htonl/ntohl */
#include "xdr_internal.h"
/* encode/decode_int. This covers int, unsigned int, enum, and bool types,
* which are all encoded as 32-bit big-endian fields. Signed integers are
* defined to use two's complement, but that's universal these days, yes?
*/
hal_error_t hal_xdr_encode_int(uint8_t ** const outbuf, const uint8_t * const limit, const uint32_t value)
{
/* arg checks */
hal_assert(outbuf != NULL && *outbuf != NULL && limit != NULL && limit >= *outbuf);
/* buffer overflow check */
if ((size_t)(limit - *outbuf) < sizeof(value))
return HAL_ERROR_XDR_BUFFER_OVERFLOW;
**(uint32_t **)outbuf = htonl(value);
*outbuf += sizeof(value);
return HAL_OK;
}
/* decode an integer value without advancing the input pointer */
hal_error_t hal_xdr_decode_int_peek(const uint8_t ** const inbuf, const uint8_t * const limit, uint32_t *value)
{
/* arg checks */
hal_assert(inbuf != NULL && *inbuf != NULL && limit != NULL && limit >= *inbuf && value != NULL);
/* buffer overflow check */
if ((size_t)(limit - *inbuf) < sizeof(*value))
return HAL_ERROR_XDR_BUFFER_OVERFLOW;
*value = ntohl(**(uint32_t **)inbuf);
return HAL_OK;
}
/* decode an integer value the regular way */
hal_error_t hal_xdr_decode_int(const uint8_t ** const inbuf, const uint8_t * const limit, uint32_t *value)
{
hal_error_t err;
if ((err = hal_xdr_decode_int_peek(inbuf, limit, value)) == HAL_OK)
*inbuf += sizeof(*value);
return err;
}
/* encode/decode_fixed_opaque. This covers fixed-length string and opaque types.
* The data is padded to a multiple of 4 bytes as necessary.
*/
hal_error_t hal_xdr_encode_fixed_opaque(uint8_t ** const outbuf, const uint8_t * const limit, const uint8_t * const value, const size_t len)
{
/* arg checks */
hal_assert(outbuf != NULL && *outbuf != NULL && limit != NULL && limit >= *outbuf && (value != NULL || len == 0));
/* buffer overflow check */
/* We need to explicitly check (len > 0xfffffffc) because padding will
* round it up to 0.
*/
if ((len > 0xfffffffc) || ((size_t)(limit - *outbuf) < ((len + 3) & ~3)))
return HAL_ERROR_XDR_BUFFER_OVERFLOW;
/* write the data */
memcpy(*outbuf, value, len);
*outbuf += len;
/* pad if necessary */
for (size_t i = len; (i & 3) != 0; ++i)
*((*outbuf)++) = 0;
return HAL_OK;
}
hal_error_t hal_xdr_decode_fixed_opaque_ptr(const uint8_t ** const inbuf, const uint8_t * const limit, const uint8_t ** const value, const size_t len)
{
/* arg checks */
hal_assert(inbuf != NULL && *inbuf != NULL && limit != NULL && limit >= *inbuf && value != NULL);
/* buffer overflow check */
if ((size_t)(limit - *inbuf) < len)
return HAL_ERROR_XDR_BUFFER_OVERFLOW;
/* return a pointer to the data */
*value = *inbuf;
/* update the buffer pointer, skipping any padding bytes */
*inbuf += ((len + 3) & ~3);
return HAL_OK;
}
hal_error_t hal_xdr_decode_fixed_opaque(const uint8_t ** const inbuf, const uint8_t * const limit, uint8_t * const value, const size_t len)
{
const uint8_t *p;
hal_error_t err;
/* get and advance the input data pointer */
if ((err = hal_xdr_decode_fixed_opaque_ptr(inbuf, limit, &p, len)) == HAL_OK)
/* read the data */
memcpy(value, p, len);
return err;
}
/* encode/decode_variable_opaque. This covers variable-length string and opaque types.
* The data is preceded by a 4-byte length word (encoded as above), and padded
* to a multiple of 4 bytes as necessary.
*/
hal_error_t hal_xdr_encode_variable_opaque(uint8_t ** const outbuf, const uint8_t * const limit, const uint8_t * const value, const size_t len)
{
hal_error_t err;
/* encode length */
if ((err = hal_xdr_encode_int(outbuf, limit, (uint32_t)len)) == HAL_OK) {
/* encode data */
if ((err = hal_xdr_encode_fixed_opaque(outbuf, limit, value, len)) != HAL_OK)
/* undo write of length */
*outbuf -= 4;
}
return err;
}
/* This version returns a pointer to the data in the input buffer.
* It is used in the rpc server.
*/
hal_error_t hal_xdr_decode_variable_opaque_ptr(const uint8_t ** const inbuf, const uint8_t * const limit, const uint8_t ** const value, size_t * const len)
{
hal_error_t err;
uint32_t xdr_len;
/* arg checks */
hal_assert(len != NULL);
/* read length */
if ((err = hal_xdr_decode_int(inbuf, limit, &xdr_len)) == HAL_OK) {
/* get the data pointer */
if ((err = hal_xdr_decode_fixed_opaque_ptr(inbuf, limit, value, xdr_len)) == HAL_OK)
*len = xdr_len;
else
/* undo read of length */
*inbuf -= 4;
}
return err;
}
/* This version copies the data to the user-supplied buffer.
* It is used in the rpc client.
*/
hal_error_t hal_xdr_decode_variable_opaque(const uint8_t ** const inbuf, const uint8_t * const limit, uint8_t * const value, size_t * const len)
{
hal_error_t err;
size_t xdr_len;
const uint8_t *p;
/* read data pointer and length */
if ((err = hal_xdr_decode_variable_opaque_ptr(inbuf, limit, &p, &xdr_len)) == HAL_OK) {
/* user buffer overflow check */
if (*len < xdr_len)
return HAL_ERROR_XDR_BUFFER_OVERFLOW;
/* read the data */
memcpy(value, p, xdr_len);
*len = xdr_len;
}
return err;
}
