linux-sgx-trts-modified/sdk/tseal/tSeal_util.cpp

/*
 * Copyright (C) 2011-2016 Intel Corporation. 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 Intel Corporation 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
 * OWNER 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,
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 */


#include "sgx_tseal.h"
#ifndef UINT32_MAX
#define UINT32_MAX      0xffffffffU
#endif

uint32_t sgx_calc_sealed_data_size(const uint32_t add_mac_txt_size, const uint32_t txt_encrypt_size) 
{
    if(add_mac_txt_size > UINT32_MAX - txt_encrypt_size)
        return UINT32_MAX;
    uint32_t payload_size = add_mac_txt_size + txt_encrypt_size; //Calculate the payload size

    if(payload_size > UINT32_MAX - sizeof(sgx_sealed_data_t))
        return UINT32_MAX;
    return (uint32_t)(sizeof(sgx_sealed_data_t) + payload_size);
}

uint32_t sgx_get_add_mac_txt_len(const sgx_sealed_data_t* p_sealed_data) 
{
    if(p_sealed_data == NULL)
        return UINT32_MAX;

    uint32_t data_size = p_sealed_data->aes_data.payload_size - p_sealed_data->plain_text_offset;
    if (data_size > p_sealed_data->aes_data.payload_size)
        return UINT32_MAX;
    return data_size;
}

uint32_t sgx_get_encrypt_txt_len(const sgx_sealed_data_t* p_sealed_data) 
{
    return ((p_sealed_data == NULL) ? UINT32_MAX : p_sealed_data->plain_text_offset);
}