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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Crypto Component */
/** */
/** CBC Mode */
/** */
/**************************************************************************/
/**************************************************************************/
#include "nx_crypto_cbc.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_cbc_xor PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs XOR operation on the output buffer. */
/* */
/* INPUT */
/* */
/* plaintext Pointer to input plantext */
/* key Value to be xor'ed */
/* ciphertext Output buffer */
/* block_size Block size */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_cbc_encrypt Perform CBC mode encryption */
/* _nx_crypto_cbc_decrypt Perform CBC mode decryption */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 09-30-2020 Timothy Stapko Initial Version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_cbc_xor(UCHAR *plaintext, UCHAR *key, UCHAR *ciphertext, UCHAR block_size)
{
UINT i;
for (i = 0; i < block_size; i++)
{
ciphertext[i] = plaintext[i] ^ key[i];
}
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_cbc_encrypt PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs CBC mode encryption. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* cbc_metadata Pointer to CBC metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to clear text input */
/* output Pointer to encrypted output */
/* The size of the output */
/* buffer must be at least */
/* the size of input message. */
/* length Length of the input message. */
/* block_size Block size */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_crypto_cbc_xor Perform CBC XOR operation */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_cbc_operation Handle AES encrypt or decrypt */
/* _nx_crypto_method_des_operation Handle DES encrypt or decrypt */
/* _nx_crypto_method_3des_operation Handle 3DES encrypt or decrypt*/
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* and updated constants, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_cbc_encrypt(VOID *crypto_metadata, NX_CRYPTO_CBC *cbc_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length, UCHAR block_size)
{
UCHAR *last_cipher;
UINT i;
if (block_size == 0)
{
return(NX_CRYPTO_INVALID_PARAMETER);
}
/* Determine if data length is multiple of block size. */
if (length % block_size)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Determine if block size is larger than the size of save_input. */
if (block_size > sizeof(cbc_metadata -> nx_crypto_cbc_last_block))
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Pick up last cipher. */
last_cipher = cbc_metadata -> nx_crypto_cbc_last_block;
for (i = 0; i < length; i += block_size)
{
/* XOR. */
_nx_crypto_cbc_xor(&input[i], last_cipher, output, block_size);
/* Encrypt the block. */
crypto_function(crypto_metadata, output, output, block_size);
/* Remember the previous encrypt block result. */
last_cipher = output;
output += block_size;
}
/* Store the last cipher for next round. */
NX_CRYPTO_MEMCPY(cbc_metadata -> nx_crypto_cbc_last_block, last_cipher, block_size); /* Use case of memcpy is verified. */
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_cbc_decrypt PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs CBC mode decryption. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* cbc_metadata Pointer to CBC metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to clear text input */
/* output Pointer to encrypted output */
/* The size of the output */
/* buffer must be at least */
/* the size of input message. */
/* length Length of the input message. */
/* block_size Block size */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_crypto_cbc_xor Perform CBC XOR operation */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_cbc_operation Handle AES encrypt or decrypt */
/* _nx_crypto_method_des_operation Handle DES encrypt or decrypt */
/* _nx_crypto_method_3des_operation Handle 3DES encrypt or decrypt*/
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* and updated constants, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_cbc_decrypt(VOID *crypto_metadata, NX_CRYPTO_CBC *cbc_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length, UCHAR block_size)
{
UCHAR *last_cipher;
UCHAR save_input[16];
UINT i;
if (block_size == 0)
{
return(NX_CRYPTO_INVALID_PARAMETER);
}
/* Determine if data length is multiple of block size. */
if (length % block_size)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Determine if block size is larger than the size of save_input. */
if (block_size > sizeof(cbc_metadata -> nx_crypto_cbc_last_block))
{
return(NX_CRYPTO_PTR_ERROR);
}
last_cipher = cbc_metadata -> nx_crypto_cbc_last_block;
for (i = 0; i < length; i += block_size)
{
/* If input == output, the xor clobbers the input buffer so we need to save off our last ciphertext
before doing the xor. */
NX_CRYPTO_MEMCPY(save_input, &input[i], block_size); /* Use case of memcpy is verified. */
/* Decrypt the block. */
crypto_function(crypto_metadata, &input[i], &output[i], block_size);
/* XOR. */
_nx_crypto_cbc_xor(&output[i], last_cipher, &output[i], block_size);
NX_CRYPTO_MEMCPY(last_cipher, save_input, block_size); /* Use case of memcpy is verified. */
}
#ifdef NX_SECURE_KEY_CLEAR
NX_CRYPTO_MEMSET(save_input, 0, sizeof(save_input));
#endif /* NX_SECURE_KEY_CLEAR */
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_cbc_encrypt_init PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs CBC mode initialization. */
/* */
/* INPUT */
/* */
/* cbc_metadata Pointer to CBC metadata */
/* iv Pointer to Initial Vector */
/* iv_len Length of Initial Vector */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_cbc_operation Handle AES encrypt or decrypt */
/* _nx_crypto_method_des_operation Handle DES encrypt or decrypt */
/* _nx_crypto_method_3des_operation Handle 3DES encrypt or decrypt*/
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_cbc_encrypt_init(NX_CRYPTO_CBC *cbc_metadata, UCHAR *iv, UINT iv_len)
{
/* Determine if IV size is larger than the size of save_input. */
if (iv_len > sizeof(cbc_metadata -> nx_crypto_cbc_last_block))
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Copy IV to last cipher. */
NX_CRYPTO_MEMCPY(cbc_metadata -> nx_crypto_cbc_last_block, iv, iv_len); /* Use case of memcpy is verified. */
return(NX_CRYPTO_SUCCESS);
}
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