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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 */
/** */
/** Transport Layer Security (TLS) - PHASH function */
/** */
/**************************************************************************/
/**************************************************************************/
#include "nx_crypto_phash.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_phash PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function implements phash for the crypto module. */
/* */
/* INPUT */
/* */
/* phash phash control block */
/* output Pointer to output buffer */
/* desired_length Number of bytes to return */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* Application */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), improved */
/* buffer length verification, */
/* verified memcpy use cases, */
/* and updated constants, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_phash(NX_CRYPTO_PHASH *phash, UCHAR *output, UINT desired_length)
{
UINT offset; /* point to the memory for the coming hmac data */
UINT hash_size; /* the length of hmac output */
UINT output_len; /* desired output length of hmac */
UINT status;
/* A(i) */
UCHAR *temp_A;
UINT temp_A_size;
/* secret */
UCHAR *secret;
UINT secret_len;
/* seed */
UCHAR *seed;
UINT seed_len;
/* metadata */
UCHAR *metadata;
UINT metadata_size;
/* hmac output size */
UCHAR *hmac_output;
UINT hmac_output_size;
UINT A_len; /* the length of current A(i) */
UINT remaining_len, i; /* remaining length of data to be generated. */
VOID *handler = NX_CRYPTO_NULL;
NX_CRYPTO_METHOD *hash_method = phash -> nx_crypto_hmac_method;
NX_CRYPTO_STATE_CHECK
/* Validate pointers. */
if (hash_method == NX_CRYPTO_NULL
|| hash_method -> nx_crypto_operation == NX_CRYPTO_NULL
|| hash_method -> nx_crypto_cleanup == NX_CRYPTO_NULL
|| output == NX_CRYPTO_NULL)
{
return(NX_CRYPTO_INVALID_PARAMETER);
}
/* Initialize temporary variables. */
secret = phash -> nx_crypto_phash_secret;
secret_len = phash -> nx_crypto_phash_secret_length;
seed = phash -> nx_crypto_phash_seed;
seed_len = phash -> nx_crypto_phash_seed_length;
temp_A = phash -> nx_crypto_phash_temp_A;
temp_A_size = phash -> nx_crypto_phash_temp_A_size;
hash_size = hash_method -> nx_crypto_ICV_size_in_bits >> 3;
metadata = phash -> nx_crypto_hmac_metadata;
metadata_size = phash -> nx_crypto_hmac_metadata_size;
hmac_output = phash -> nx_crypto_hmac_output;
hmac_output_size = phash -> nx_crypto_hmac_output_size;
if (hash_size > hmac_output_size)
{
return(NX_CRYPTO_INVALID_PARAMETER);
}
if (seed_len > temp_A_size)
{
return(NX_CRYPTO_SIZE_ERROR);
}
/* Assign the seed as A(0). */
NX_CRYPTO_MEMSET(temp_A, 0, temp_A_size);
NX_CRYPTO_MEMCPY(temp_A, seed, seed_len); /* Use case of memcpy is verified. */
A_len = phash -> nx_crypto_phash_seed_length;
remaining_len = desired_length;
for (offset = 0; offset < desired_length; offset += hash_size)
{
/* Calculate A(i) */
if (hash_method -> nx_crypto_init)
{
status = hash_method -> nx_crypto_init(hash_method,
secret,
(NX_CRYPTO_KEY_SIZE)(secret_len << 3),
&handler,
metadata,
metadata_size);
if(status != NX_CRYPTO_SUCCESS)
{
return(status);
}
}
status = hash_method -> nx_crypto_operation(NX_CRYPTO_AUTHENTICATE,
handler,
hash_method,
secret,
(NX_CRYPTO_KEY_SIZE)(secret_len << 3),
temp_A,
A_len,
NX_CRYPTO_NULL,
temp_A,
temp_A_size,
metadata,
metadata_size,
NX_CRYPTO_NULL,
NX_CRYPTO_NULL);
if(status != NX_CRYPTO_SUCCESS)
{
return(status);
}
/* Updated the length of A(i) */
A_len = hash_size;
if ((A_len + seed_len) > temp_A_size)
{
return(NX_CRYPTO_SIZE_ERROR);
}
/* Concatenate A[i] and seed to feed into digest. */
NX_CRYPTO_MEMCPY(&temp_A[A_len], seed, seed_len); /* Use case of memcpy is verified. */
/* Output block is the size of the digest unless the remaining
desired length is smaller than the digest length. */
if (remaining_len < hash_size)
{
output_len = remaining_len;
}
else
{
output_len = hash_size;
}
/* Calculate p-hash block, store in output. */
status = hash_method -> nx_crypto_operation(NX_CRYPTO_AUTHENTICATE,
handler,
hash_method,
secret,
(NX_CRYPTO_KEY_SIZE)(secret_len << 3),
temp_A,
A_len + seed_len,
NX_CRYPTO_NULL,
hmac_output,
output_len,
metadata,
metadata_size,
NX_CRYPTO_NULL,
NX_CRYPTO_NULL);
if(status != NX_CRYPTO_SUCCESS)
{
return(status);
}
/* Append the hmac result to the output. */
for (i = 0; i < output_len; i++)
{
output[offset + i] ^= hmac_output[i];
}
/* Adjust our remaining length by the number of bytes written. */
remaining_len -= hash_size;
status = hash_method -> nx_crypto_cleanup(metadata);
if(status != NX_CRYPTO_SUCCESS)
{
return(status);
}
}
return(NX_CRYPTO_SUCCESS);
}