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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_generate_server_key_exchange PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Yanwu Cai, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function generates a ServerKeyExchange message, which is used */
/* when the chosen ciphersuite requires additional information for key */
/* generation, such as when using Diffie-Hellman ciphers. */
/* */
/* INPUT */
/* */
/* ciphersuite Selected cipher suite */
/* protocol_version Selected TLS version */
/* tls_1_3 Whether TLS 1.3 is chosen */
/* tls_crypto_table TLS crypto methods */
/* tls_handshake_hash Metadata for handshake hash */
/* tls_key_material TLS key material */
/* tls_credentials TLS credentials */
/* data_buffer Pointer to output buffer */
/* buffer_length Length of data buffer */
/* output_size Size of data written to buffer*/
/* public_cipher_metadata Metadata for public cipher */
/* public_cipher_metadata_size Size of public cipher metadata*/
/* public_auth_metadata Metadata for public auth */
/* public_auth_metadata_size Size of public auth metadata */
/* tls_ecc_curves ECC curves */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_tls_ecc_generate_keys Generate keys for ECC exchange*/
/* [nx_crypto_init] Initialize Crypto Method */
/* [nx_crypto_operation] Crypto operation */
/* */
/* CALLED BY */
/* */
/* _nx_secure_tls_send_server_key_exchange */
/* Send ServerKeyExchange */
/* */
/**************************************************************************/
UINT _nx_secure_generate_server_key_exchange(const NX_SECURE_TLS_CIPHERSUITE_INFO *ciphersuite, USHORT protocol_version, UCHAR tls_1_3,
NX_SECURE_TLS_CRYPTO *tls_crypto_table, NX_SECURE_TLS_HANDSHAKE_HASH *tls_handshake_hash,
NX_SECURE_TLS_KEY_MATERIAL *tls_key_material, NX_SECURE_TLS_CREDENTIALS *tls_credentials,
UCHAR *data_buffer, ULONG buffer_length, ULONG *output_size,
VOID *public_cipher_metadata, ULONG public_cipher_metadata_size,
VOID *public_auth_metadata, ULONG public_auth_metadata_size, VOID *tls_ecc_curves)
{
UINT length;
#if defined(NX_SECURE_ENABLE_ECJPAKE_CIPHERSUITE) || defined(NX_SECURE_ENABLE_ECC_CIPHERSUITE)
UINT status;
#endif /* defined(NX_SECURE_ENABLE_ECJPAKE_CIPHERSUITE) || defined(NX_SECURE_ENABLE_ECC_CIPHERSUITE) */
#ifdef NX_SECURE_ENABLE_PSK_CIPHERSUITES
USHORT identity_length;
UCHAR *identity;
#endif
#if defined(NX_SECURE_ENABLE_ECJPAKE_CIPHERSUITE)
VOID *handler = NX_NULL;
USHORT named_curve;
NX_CRYPTO_METHOD *crypto_method;
NX_CRYPTO_EXTENDED_OUTPUT extended_output;
#endif /* defined(NX_SECURE_ENABLE_ECJPAKE_CIPHERSUITE) */
#ifdef NX_SECURE_ENABLE_ECC_CIPHERSUITE
NX_SECURE_TLS_ECDHE_HANDSHAKE_DATA *ecdhe_data;
#endif
/* Build up the server key exchange message. Structure:
* | 2 | <key data length> |
* | Key data length | Key data (opaque) |
*/
#ifndef NX_SECURE_ENABLE_ECC_CIPHERSUITE
NX_PARAMETER_NOT_USED(ciphersuite);
NX_PARAMETER_NOT_USED(protocol_version);
NX_PARAMETER_NOT_USED(tls_1_3);
NX_PARAMETER_NOT_USED(tls_crypto_table);
NX_PARAMETER_NOT_USED(tls_handshake_hash);
NX_PARAMETER_NOT_USED(tls_key_material);
NX_PARAMETER_NOT_USED(tls_credentials);
NX_PARAMETER_NOT_USED(data_buffer);
NX_PARAMETER_NOT_USED(buffer_length);
NX_PARAMETER_NOT_USED(public_cipher_metadata);
NX_PARAMETER_NOT_USED(public_cipher_metadata_size);
NX_PARAMETER_NOT_USED(public_auth_metadata);
NX_PARAMETER_NOT_USED(public_auth_metadata_size);
NX_PARAMETER_NOT_USED(tls_ecc_curves);
#endif
length = 0;
/* In the future, any Diffie-Hellman-based ciphersuites will populate this message with key
data. RSA ciphersuites do not use this message. */
#ifdef NX_SECURE_ENABLE_PSK_CIPHERSUITES
/* Check for PSK ciphersuites. */
if (ciphersuite -> nx_secure_tls_public_auth -> nx_crypto_algorithm == NX_CRYPTO_KEY_EXCHANGE_PSK)
{
/* If PSK is being used, the server sends an identity value to the client so
the client can respond with the appropriate PSK. */
/* Get identity hint and length. */
identity = tls_credentials -> nx_secure_tls_psk_store[0].nx_secure_tls_psk_id_hint;
identity_length = (USHORT)tls_credentials -> nx_secure_tls_psk_store[0].nx_secure_tls_psk_id_hint_size;
if ((identity_length + 2u) > buffer_length)
{
/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* Use identity hint length for key data length. */
data_buffer[length] = (UCHAR)((identity_length & 0xFF00) >> 8);
data_buffer[length + 1] = (UCHAR)(identity_length & 0x00FF);
length = (USHORT)(length + 2);
/* Extract the identity hint and put it into the packet buffer. */
NX_SECURE_MEMCPY(&data_buffer[length], identity, identity_length); /* Use case of memcpy is verified. */
/* Advance our total length. */
length = (USHORT)(length + identity_length);
}
#endif
#ifdef NX_SECURE_ENABLE_ECJPAKE_CIPHERSUITE
/* Check for ECJ-PAKE ciphersuites. */
if (ciphersuite -> nx_secure_tls_public_auth -> nx_crypto_algorithm == NX_CRYPTO_KEY_EXCHANGE_ECJPAKE)
{
if (buffer_length < 3)
{
/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* ECCurveType: named_curve (3). */
data_buffer[length] = NX_CRYPTO_EC_CURVE_TYPE_NAMED_CURVE;
length += 1;
/* NamedCurve: secp256r1 (23) */
named_curve = (USHORT)NX_CRYPTO_EC_SECP256R1;
data_buffer[length] = (UCHAR)((named_curve >> 8) & 0xFF);
data_buffer[length + 1] = (UCHAR)(named_curve & 0xFF);
length += 2;
extended_output.nx_crypto_extended_output_data = &data_buffer[length];
extended_output.nx_crypto_extended_output_length_in_byte = buffer_length - length;
extended_output.nx_crypto_extended_output_actual_size = 0;
crypto_method = (NX_CRYPTO_METHOD*)ciphersuite -> nx_secure_tls_public_auth;
status = crypto_method -> nx_crypto_operation(NX_CRYPTO_ECJPAKE_SERVER_KEY_EXCHANGE_GENERATE,
handler,
crypto_method,
NX_NULL, 0,
NX_NULL, 0, NX_NULL,
(UCHAR *)&extended_output,
sizeof(extended_output),
public_auth_metadata,
public_auth_metadata_size,
NX_NULL, NX_NULL);
if (status)
{
return(status);
}
length += extended_output.nx_crypto_extended_output_actual_size;
}
#endif
#ifdef NX_SECURE_ENABLE_ECC_CIPHERSUITE
/* Check for ECDHE ciphersuites. */
if (ciphersuite -> nx_secure_tls_public_cipher -> nx_crypto_algorithm == NX_CRYPTO_KEY_EXCHANGE_ECDHE)
{
ecdhe_data = (NX_SECURE_TLS_ECDHE_HANDSHAKE_DATA *)tls_key_material -> nx_secure_tls_new_key_material_data;
length = buffer_length;
status = _nx_secure_tls_ecc_generate_keys(ciphersuite, protocol_version, tls_1_3,
tls_crypto_table, tls_handshake_hash, (NX_SECURE_TLS_ECC *)tls_ecc_curves,
tls_key_material, tls_credentials, ecdhe_data -> nx_secure_tls_ecdhe_named_curve, NX_TRUE,
data_buffer, &length, ecdhe_data, public_cipher_metadata, public_cipher_metadata_size,
public_auth_metadata, public_auth_metadata_size);
if (status != NX_SUCCESS)
{
return(status);
}
}
#endif /* NX_SECURE_ENABLE_ECC_CIPHERSUITE */
/* Finally, we let the caller know the length . */
*output_size = length;
return(NX_SECURE_TLS_SUCCESS);
}
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