119 lines
5.1 KiB
C
119 lines
5.1 KiB
C
/************************************************************************************//**
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* \file seednkey.c
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* \brief XCP Seed and Key shared library source file.
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* \ingroup SeedNKey
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* \internal
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*----------------------------------------------------------------------------------------
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* C O P Y R I G H T
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*----------------------------------------------------------------------------------------
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* Copyright (c) 2017 by Feaser http://www.feaser.com All rights reserved
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*
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*----------------------------------------------------------------------------------------
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* L I C E N S E
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*----------------------------------------------------------------------------------------
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* This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You have received a copy of the GNU General Public License along with OpenBLT. It
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* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
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*
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* \endinternal
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include <assert.h> /* for assertions */
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#include <stddef.h> /* for NULL declaration */
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#include "seednkey.h" /* XCP seed and key */
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/************************************************************************************//**
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** \brief Computes the key for the requested resource.
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** \param resource resource for which the unlock key is requested
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** \param seedLen length of the seed
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** \param seedPtr pointer to the seed data
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** \param keyLenPtr pointer where to store the key length
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** \param keyPtr pointer where to store the key data
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** \return XCP_RESULT_OK on success, otherwise XCP_RESULT_ERROR.
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**
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****************************************************************************************/
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LIBOPENBLT_EXPORT uint32_t XCP_ComputeKeyFromSeed(uint8_t resource, uint8_t seedLen,
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uint8_t const * seedPtr,
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uint8_t * keyLenPtr,
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uint8_t * keyPtr)
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{
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uint32_t result = XCP_RESULT_ERROR;
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uint8_t idx;
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/* Check parameters. */
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assert(seedLen > 0);
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assert(seedPtr != NULL);
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assert(keyLenPtr != NULL);
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assert(keyPtr != NULL);
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/* Only continue if the parameters are valid. */
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if ( (seedLen > 0) && (seedPtr != NULL) && (keyLenPtr != NULL) &&
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(keyPtr != NULL) ) /*lint !e774 */
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{
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/* This example implementation of the key algorithm for PGM simply decrements the value
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* of each seed byte by 1. This coincides with the default implementation of the hook-
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* function XcpVerifyKeyHook() in the OpenBLT demo bootloaders.
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*/
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if (resource == XCP_RESOURCE_PGM)
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{
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/* Compute the key. */
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for (idx = 0; idx < seedLen; idx++)
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{
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keyPtr[idx] = seedPtr[idx] - 1;
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}
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/* Set the key length. */
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*keyLenPtr = seedLen;
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/* Update the result value. */
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result = XCP_RESULT_OK;
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}
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}
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/* Give the result back to the caller. */
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return result;
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} /*** end of XCP_ComputeKeyFromSeed ***/
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/************************************************************************************//**
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** \brief Obtains a bitmask of the resources for which an key algorithm is available.
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** \param resourcePtr pointer where to store the supported resources for the key
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** computation.
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** \return XCP_RESULT_OK on success, otherwise XCP_RESULT_ERROR.
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**
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****************************************************************************************/
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LIBOPENBLT_EXPORT uint32_t XCP_GetAvailablePrivileges(uint8_t * resourcePtr)
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{
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uint32_t result = XCP_RESULT_ERROR;
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/* Check parameters. */
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assert(resourcePtr != NULL);
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/* Only continue if the parameter is valid. */
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if (resourcePtr != NULL) /*lint !e774 */
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{
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/* This example implementation supports a key computation algorithm for the PGM
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* resource.
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*/
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*resourcePtr = XCP_RESOURCE_PGM;
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/* Update the result value. */
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result = XCP_RESULT_OK;
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}
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/* Give the result back to the caller. */
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return result;
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} /*** end of XCP_GetAvailablePrivileges ***/
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/*********************************** end of seednkey.c *********************************/
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