nx_secure/src/nx_secure_tls_record_hash_update.c


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/***************************************************************************
 * Copyright (c) 2024 Microsoft Corporation
 * Copyright (c) 2025-present Eclipse ThreadX Contributors
 *
 * This program and the accompanying materials are made available under the
 * terms of the MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 **************************************************************************/


/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** NetX Secure Component                                                 */
/**                                                                       */
/**    Transport Layer Security (TLS)                                     */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

#define NX_SECURE_SOURCE_CODE

#include "nx_secure_tls.h"

/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _nx_secure_tls_record_hash_update                   PORTABLE C      */
/*                                                           6.4.3        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Timothy Stapko, Microsoft Corporation                               */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function updates a previously-initialized MAC hash for a TLS   */
/*    message.                                                            */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    tls_session                           TLS control block             */
/*    data                                  Record payload                */
/*    length                                Length of record payload      */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    status                                Completion status             */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    [nx_crypto_operation]                 Crypto operation              */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    _nx_secure_tls_send_record            Send the TLS record           */
/*                                                                        */
/**************************************************************************/
UINT _nx_secure_tls_record_hash_update(NX_SECURE_TLS_SESSION *tls_session, UCHAR *data, UINT length)
{
UINT                                  status;
const NX_CRYPTO_METHOD               *authentication_method;

    /* We need to generate a Message Authentication Code (MAC) for each record during an "active" TLS session
       (following a ChangeCipherSpec message). The hash algorithm is determined by the ciphersuite, and HMAC
       is used with that hash algorithm to protect the TLS record contents from tampering.

       The MAC is generated as:

       HMAC_hash(MAC_write_secret, seq_num + type + version + length + data);

     */

    if (tls_session -> nx_secure_tls_session_ciphersuite == NX_NULL)
    {

        /* Likely internal error since at this point ciphersuite negotiation was theoretically completed. */
        return(NX_SECURE_TLS_UNKNOWN_CIPHERSUITE);
    }

    /* Get our authentication method from the ciphersuite. */
    authentication_method = tls_session -> nx_secure_tls_session_ciphersuite -> nx_secure_tls_hash;

    /* Assert that we have an authentication mechanism. */
    NX_ASSERT(authentication_method -> nx_crypto_operation != NX_NULL);

    /* Update the hash with the new data. */
    status = authentication_method -> nx_crypto_operation(NX_CRYPTO_HASH_UPDATE,
                                                          tls_session -> nx_secure_hash_mac_handler,
                                                          (NX_CRYPTO_METHOD*)authentication_method,
                                                          NX_NULL,
                                                          0,
                                                          data,
                                                          length,
                                                          NX_NULL,
                                                          NX_NULL,
                                                          0,
                                                          tls_session -> nx_secure_hash_mac_metadata_area,
                                                          tls_session -> nx_secure_hash_mac_metadata_size,
                                                          NX_NULL,
                                                          NX_NULL);

    return(status);
}