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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"
#ifdef NX_SECURE_ENABLE_DTLS
#include "nx_secure_dtls.h"
#endif /* NX_SECURE_ENABLE_DTLS */
/* This table is used to determine the legacy TLS versions currently enabled and supported. */
static const NX_SECURE_TLS_VERSIONS nx_secure_tls_supported_versions[] =
{
{NX_SECURE_TLS_VERSION_SSL_3_0, NX_SECURE_TLS_SSL_3_0_ENABLED}, /* SSLv3 */
{NX_SECURE_TLS_VERSION_TLS_1_0, NX_SECURE_TLS_TLS_1_0_ENABLED}, /* TLS 1.0 */
{NX_SECURE_TLS_VERSION_TLS_1_1, NX_SECURE_TLS_TLS_1_1_ENABLED}, /* TLS 1.1 */
{NX_SECURE_TLS_VERSION_TLS_1_2, NX_SECURE_TLS_TLS_1_2_ENABLED}, /* TLS 1.2 */
/* This array contains legacy versions only so TLS 1.3 is not included. */
};
#ifdef NX_SECURE_ENABLE_DTLS
/* This table is used to determine the DTLS versions currently enabled and supported. */
static const NX_SECURE_TLS_VERSIONS nx_secure_dtls_supported_versions[] =
{
{NX_SECURE_DTLS_VERSION_1_0, NX_SECURE_TLS_TLS_1_1_ENABLED}, /* DTLS 1.0 */
{NX_SECURE_DTLS_VERSION_1_2, NX_SECURE_TLS_TLS_1_2_ENABLED}, /* DTLS 1.2 */
};
#endif /* NX_SECURE_ENABLE_DTLS */
/* Supported version list for TLS and DTLS. */
NX_SECURE_VERSIONS_LIST nx_secure_supported_versions_list[] =
{
{nx_secure_tls_supported_versions, sizeof(nx_secure_tls_supported_versions) / sizeof(NX_SECURE_TLS_VERSIONS)},
#ifdef NX_SECURE_ENABLE_DTLS
{nx_secure_dtls_supported_versions, sizeof(nx_secure_dtls_supported_versions) / sizeof(NX_SECURE_TLS_VERSIONS)},
#endif /* NX_SECURE_ENABLE_DTLS */
};
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_check_protocol_version PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function checks the protocol version in received TLS/DTLS */
/* headers against the established TLS/DTLS session version. */
/* */
/* The function also uses a compile-time constant table to see if the */
/* version provided in the initial Hello messages is currently */
/* supported and enabled in the TLS/DTLS stack. If the version is not */
/* recognized or not supported, an error is returned. */
/* */
/* INPUT */
/* */
/* tls_session TLS session */
/* protocol_version Received TLS version */
/* id TLS or DTLS */
/* */
/* OUTPUT */
/* */
/* status Enabled status of version */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_secure_dtls_process_header Process record header */
/* _nx_secure_tls_process_clienthello Process ClientHello */
/* _nx_secure_tls_process_header Process record header */
/* _nx_secure_tls_process_serverhello Process ServerHello */
/* */
/**************************************************************************/
UINT _nx_secure_tls_check_protocol_version(NX_SECURE_TLS_SESSION *tls_session,
USHORT protocol_version, UINT id)
{
UINT i;
/* See if this is an established TLS session with a negotiated TLS version. */
if (tls_session -> nx_secure_tls_protocol_version != 0)
{
/* If the session already has a protocol version, it means the version was already
* determined, and if we get a different version in a received record, we have a problem. */
if (tls_session -> nx_secure_tls_protocol_version == protocol_version)
{
/* Version is good, return success. */
return(NX_SUCCESS);
}
#if !defined(NX_SECURE_TLS_DISABLE_PROTOCOL_VERSION_DOWNGRADE) && !defined(NX_SECURE_TLS_CLIENT_DISABLED)
if ((tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_SERVER) ||
(tls_session -> nx_secure_tls_client_state != NX_SECURE_TLS_CLIENT_STATE_IDLE))
#endif /* !defined(NX_SECURE_TLS_DISABLE_PROTOCOL_VERSION_DOWNGRADE) && !defined(NX_SECURE_TLS_CLIENT_DISABLED) */
{
/* We have an established session, but the incoming version does not match! This is
a fatal error. */
return(NX_SECURE_TLS_PROTOCOL_VERSION_CHANGED);
}
}
/* See if the application has overridden the protocol version. */
if (tls_session -> nx_secure_tls_protocol_version_override != 0)
{
/* If the override is euqal to the supplied version, we're all good. */
if (tls_session -> nx_secure_tls_protocol_version_override == protocol_version)
{
return(NX_SUCCESS);
}
/* Supplied version doesn't match the override, allow the stack to re-negotiate
to the selected version by returning "unsupported version" even if we do support
the supplied version. */
return(NX_SECURE_TLS_UNSUPPORTED_TLS_VERSION);
}
/* Loop through the supported versions to see if the passed-in version is one that is enabled. */
for (i = 0; i < nx_secure_supported_versions_list[id].nx_secure_versions_list_count; ++i)
{
if (protocol_version == nx_secure_supported_versions_list[id].nx_secure_versions_list[i].nx_secure_tls_protocol_version)
{
/* We have a match. See if it is supported. */
if (nx_secure_supported_versions_list[id].nx_secure_versions_list[i].nx_secure_tls_is_supported)
{
/* Supported version. Return success. */
return(NX_SUCCESS);
}
else
{
/* Recognized the version, but it is not enabled or supported. */
return(NX_SECURE_TLS_UNSUPPORTED_TLS_VERSION);
}
}
}
/* This error indicates an incorrect TLS record or possible attack. */
return(NX_SECURE_TLS_UNKNOWN_TLS_VERSION);
}
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