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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_verify_mac PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function verifies the Message Authentication Code (MAC) that */
/* is included in encrypted TLS records. It hashes the incoming */
/* message data and then compares it to the MAC in the received */
/* record. If there is a mismatch, then the record has been corrupted */
/* in transit and represents a possible security breach. */
/* */
/* INPUT */
/* */
/* tls_session TLS control block */
/* header_data TLS record header data */
/* header_length Length of header data */
/* packet_ptr TLS record packet */
/* offset Offset to TLS record in packet*/
/* length Length of payload data */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* [nx_secure_verify_mac] Verify record MAC checksum */
/* */
/* CALLED BY */
/* */
/* _nx_secure_tls_process_record Process TLS record data */
/* */
/**************************************************************************/
UINT _nx_secure_tls_verify_mac(NX_SECURE_TLS_SESSION *tls_session, UCHAR *header_data,
USHORT header_length, NX_PACKET *packet_ptr, ULONG offset, UINT *length)
{
UCHAR *mac_secret;
UINT status;
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);
}
/* Select our proper MAC secret for hashing. */
if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_SERVER)
{
/* If we are a server, we need to use the client's MAC secret. */
mac_secret = tls_session -> nx_secure_tls_key_material.nx_secure_tls_client_write_mac_secret;
}
else
{
/* We are a client, so use the server's MAC secret. */
mac_secret = tls_session -> nx_secure_tls_key_material.nx_secure_tls_server_write_mac_secret;
}
status = tls_session -> nx_secure_verify_mac(tls_session -> nx_secure_tls_session_ciphersuite, mac_secret, tls_session -> nx_secure_tls_remote_sequence_number,
header_data, header_length, packet_ptr, offset, length,
tls_session -> nx_secure_hash_mac_metadata_area, tls_session -> nx_secure_hash_mac_metadata_size);
return(status);
}
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