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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 Secure Component */
/** */
/** Transport Layer Security (TLS) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SECURE_SOURCE_CODE
#include "nx_secure_tls.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_1_3_client_handshake PORTABLE C */
/* 6.1.4 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function runs the TLS Client mode state machine for TLSv1.3. */
/* It processes an incoming handshake record and takes appropriate */
/* action to advance the TLS Client handshake. The TLSv1.3 handshake */
/* state machine differs fairly significantly from the earlier TLS */
/* versions so we have split the 1.3 handshake into its own function. */
/* */
/* INPUT */
/* */
/* tls_session TLS control block */
/* packet_buffer Pointer into record buffer */
/* data_length Length of packet buffer */
/* wait_option Controls timeout actions */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_tls_allocate_handshake_packet */
/* Allocate TLS packet */
/* _nx_secure_tls_generate_keys Generate session keys */
/* _nx_secure_tls_generate_premaster_secret */
/* Generate premaster secret */
/* _nx_secure_tls_handshake_hash_update Update Finished hash */
/* _nx_secure_tls_map_error_to_alert Map internal error to alert */
/* _nx_secure_tls_packet_allocate Allocate internal TLS packet */
/* _nx_secure_tls_process_certificate_request */
/* Process certificate request */
/* _nx_secure_tls_process_finished Process Finished message */
/* _nx_secure_tls_process_handshake_header */
/* Process handshake header */
/* _nx_secure_tls_process_remote_certificate */
/* Process server certificate */
/* _nx_secure_tls_process_server_key_exchange */
/* Process ServerKeyExchange */
/* _nx_secure_tls_process_serverhello Process ServerHello */
/* _nx_secure_tls_remote_certificate_free_all */
/* Free all remote certificates */
/* _nx_secure_tls_send_alert Send TLS alert */
/* _nx_secure_tls_send_certificate Send TLS certificate */
/* _nx_secure_tls_send_certificate_verify */
/* Send certificate verify */
/* _nx_secure_tls_send_changecipherspec Send ChangeCipherSpec */
/* _nx_secure_tls_send_client_key_exchange */
/* Send ClientKeyExchange */
/* _nx_secure_tls_send_clienthello Send ClientHello */
/* _nx_secure_tls_send_finished Send Finished message */
/* _nx_secure_tls_send_handshake_record Send TLS handshake record */
/* _nx_secure_tls_send_record Send TLS records */
/* _nx_secure_tls_session_keys_set Set session keys */
/* nx_secure_tls_packet_release Release packet */
/* [nx_secure_tls_session_renegotiation_callback] */
/* Renegotiation callback */
/* tx_mutex_get Get protection mutex */
/* tx_mutex_put Put protection mutex */
/* */
/* CALLED BY */
/* */
/* _nx_secure_tls_process_record Process TLS record data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* released packet securely, */
/* fixed certificate buffer */
/* allocation, */
/* resulting in version 6.1 */
/* 12-31-2020 Timothy Stapko Modified comment(s), */
/* improved buffer length */
/* verification, */
/* resulting in version 6.1.3 */
/* 02-02-2021 Timothy Stapko Modified comment(s), added */
/* support for fragmented TLS */
/* Handshake messages, */
/* resulting in version 6.1.4 */
/* */
/**************************************************************************/
/* State transition table for TLS 1.3 Client. *
Current state Processing Function Valid next states (SendAlert is a next state for all others)
------------------------------------------------------------------------------------------------
ClientHelloSent process_clienthello ServerHelloReceived
ServerHelloReceived process_serverhello EncryptedExtensionsReceived
EncryptedExtensionsReceived process_server_extensions CertificateRequestRx, CertificateRx,
CertificateVerifyRx, FinishedRx
CertificateRequestRx process_cert_request CertificateRx, FinishedRx,
CertificateRx process_certificate CertificateVerifyRx, FinishedRx
CertificateVerifyRx process_certificate_verify FinishedRx
FinishedRx process_finished SendCert, SendCertVerify, SendFinished
SendCert send_certificate SendCertVerify
SendCertVerify send_certificate_verify SendFinished
SendFinished send_finished ApplicationData
*/
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
/* Defined in nx_secure_tls_send_serverhello.c */
extern const UCHAR _nx_secure_tls_1_2_random[8];
extern const UCHAR _nx_secure_tls_1_1_random[8];
UINT _nx_secure_tls_1_3_client_handshake(NX_SECURE_TLS_SESSION *tls_session, UCHAR *packet_buffer,
UINT data_length, ULONG wait_option)
{
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
UINT status;
USHORT message_type = NX_SECURE_TLS_INVALID_MESSAGE;
UINT header_bytes;
UINT message_length;
UINT packet_buffer_length = data_length;
UCHAR *packet_start;
NX_PACKET *send_packet = NX_NULL;
NX_PACKET_POOL *packet_pool;
UINT error_number;
UINT alert_number;
UINT alert_level;
const NX_CRYPTO_METHOD
*method_ptr = NX_NULL;
const UCHAR *server_random;
/* Basic state machine for handshake:
* 1. We have received a handshake message, now process the header.
* 2. Then process the message itself and populate the TLS socket structure.
* 3. Follow up with whatever actions are needed.
*/
/* TLS 1.3 handshake state machine (TLS 1.3 RFC draft 28):
Key ^ ClientHello
Exch | + key_share*
| + signature_algorithms*
| + psk_key_exchange_modes*
v + pre_shared_key* -------->
ServerHello ^ Key
+ key_share* | Exch
+ pre_shared_key* v
{EncryptedExtensions} ^ Server
{CertificateRequest*} v Params
{Certificate*} ^
{CertificateVerify*} | Auth
{Finished} v
<-------- [Application Data*]
^ {Certificate*}
Auth | {CertificateVerify*}
v {Finished} -------->
[Application Data] <-------> [Application Data]
+ Indicates noteworthy extensions sent in the
previously noted message.
* Indicates optional or situation-dependent
messages/extensions that are not always sent.
{} Indicates messages protected using keys
derived from a [sender]_handshake_traffic_secret.
[] Indicates messages protected using keys
derived from [sender]_application_traffic_secret_N
Figure 1: Message flow for full TLS Handshake
- Key Exchange: Establish shared keying material and select the
cryptographic parameters. Everything after this phase is
encrypted.
- Server Parameters: Establish other handshake parameters (whether
the client is authenticated, application layer protocol support,
etc.).
- Authentication: Authenticate the server (and optionally the
client) and provide key confirmation and handshake integrity.
*/
/* Loop through multiple messages in a single record. This can happen if the remote host
packs multiple handshake messages into a single TLS record. */
while (data_length > 0)
{
/* Save a pointer to the actual packet data (before we do fragment reassembly, etc. below)
* so we can hash it. */
packet_start = packet_buffer;
header_bytes = data_length;
/* First, process the handshake message to get our state and any data therein. */
status = _nx_secure_tls_process_handshake_header(packet_buffer, &message_type, &header_bytes, &message_length);
if (status != NX_SECURE_TLS_SUCCESS)
{
return(status);
}
/* Check for fragmented message. */
if((message_length + header_bytes) > data_length)
{
/* Incomplete message! A single message is fragmented across several records. We need to obtain the next fragment. */
tls_session -> nx_secure_tls_handshake_record_expected_length = message_length + header_bytes;
tls_session -> nx_secure_tls_handshake_record_fragment_state = NX_SECURE_TLS_HANDSHAKE_RECEIVED_FRAGMENT;
return(NX_SECURE_TLS_HANDSHAKE_FRAGMENT_RECEIVED);
}
/* Advance the buffer pointer past the handshake header. */
packet_buffer += header_bytes;
/* Allocate a packet for all send operations. */
packet_pool = tls_session -> nx_secure_tls_packet_pool;
/* Hash this handshake message. We do not hash HelloRequest messages.
Hashes include the handshake layer header but not the record layer header. */
if (tls_session->nx_secure_tls_local_session_active && message_type != NX_SECURE_TLS_HELLO_REQUEST && message_type != NX_SECURE_TLS_HELLO_VERIFY_REQUEST
&& message_type != NX_SECURE_TLS_FINISHED)
{
_nx_secure_tls_handshake_hash_update(tls_session, packet_start, message_length + header_bytes);
}
/* Reduce total length by the size of this message. */
data_length -= (message_length + header_bytes);
/* Process the message itself information from the header. */
status = NX_SECURE_TLS_HANDSHAKE_FAILURE;
switch (message_type)
{
case NX_SECURE_TLS_SERVER_HELLO:
/* Server has responded to our ClientHello. */
status = _nx_secure_tls_process_serverhello(tls_session, packet_buffer, message_length);
/* RFC 8446 4.1.3:
TLS 1.3 clients receiving a ServerHello indicating TLS 1.2 or below MUST check that
the last 8 bytes are not equal to either of these values. */
if ((status == NX_SUCCESS) && (tls_session -> nx_secure_tls_1_3 == NX_FALSE))
{
if (tls_session -> nx_secure_tls_protocol_version == NX_SECURE_TLS_VERSION_TLS_1_2)
{
server_random = _nx_secure_tls_1_2_random;
}
else
{
server_random = _nx_secure_tls_1_1_random;
}
if (NX_SECURE_MEMCMP(&(tls_session -> nx_secure_tls_key_material.nx_secure_tls_server_random[24]),
server_random, 8) == 0)
{
status = NX_SECURE_TLS_UNKNOWN_TLS_VERSION;
}
else
{
/* Server negotiates a version of TLS prior to TLS 1.3. */
return(NX_SUCCESS);
}
}
/* In TLS 1.3, we generate keys now because all further messages will be encrypted (see state machine below). */
break;
case NX_SECURE_TLS_ENCRYPTED_EXTENSIONS:
/* RFC 8446, section 4.3.1, page 59.
* The server MUST send this message immediately after the ServerHello message. */
if (tls_session -> nx_secure_tls_client_state != NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO)
{
break;
}
status = _nx_secure_tls_process_encrypted_extensions(tls_session, packet_buffer, message_length);
break;
case NX_SECURE_TLS_CERTIFICATE_MSG:
/* Server has sent its certificate message. */
status = _nx_secure_tls_process_remote_certificate(tls_session, packet_buffer, message_length, packet_buffer_length);
if (status == NX_SUCCESS)
{
/* Save the transcript hash up to the certificate for the CertificateVerify (next message to send). */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_CERTIFICATE, NX_TRUE);
}
else if (status == NX_SECURE_TLS_EMPTY_REMOTE_CERTIFICATE_RECEIVED)
{
/* If server supplies an empty Certificate message, the client MUST abort the handshake with a "decode_error" alert. */
status = NX_SECURE_TLS_INCORRECT_MESSAGE_LENGTH;
}
break;
case NX_SECURE_TLS_CERTIFICATE_REQUEST:
/* RFC 8446, section 4.3.2, page 59.
* If sent, MUST follow EncryptedExtensions. */
if (tls_session -> nx_secure_tls_client_state != NX_SECURE_TLS_CLIENT_STATE_ENCRYPTED_EXTENSIONS)
{
break;
}
/* Server has requested we provide a client certificate. */
status = _nx_secure_tls_process_certificate_request(tls_session, packet_buffer, message_length);
break;
case NX_SECURE_TLS_FINISHED:
/* Save the transcript hash to this point for processing Finished. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_SERVER_FINISHED, NX_TRUE);
if (status != NX_SUCCESS)
{
break;
}
/* Final handshake message from the server, process it (verify the server handshake hash). */
status = _nx_secure_tls_process_finished(tls_session, packet_buffer, message_length);
if (status != NX_SUCCESS)
{
break;
}
/* Update the transcript hash with the Finished. */
_nx_secure_tls_handshake_hash_update(tls_session, packet_start, message_length + header_bytes);
/* For client, cleanup hash handler after received the finished message from server. */
method_ptr = tls_session -> nx_secure_tls_crypto_table -> nx_secure_tls_handshake_hash_sha256_method;
if (method_ptr -> nx_crypto_cleanup != NX_NULL)
{
status = method_ptr -> nx_crypto_cleanup(tls_session -> nx_secure_tls_handshake_hash.nx_secure_tls_handshake_hash_sha256_metadata);
}
break;
case NX_SECURE_TLS_CERTIFICATE_VERIFY:
/* Handle server-sent certificate verify. */
status = _nx_secure_tls_process_certificate_verify(tls_session, packet_buffer, message_length);
break;
case NX_SECURE_TLS_NEW_SESSION_TICKET:
/* TLS 1.3 post-handshake message. */
status = NX_SUCCESS;
break;
/* case NX_SECURE_TLS_SERVER_KEY_EXCHANGE: // TLS 1.2 and earlier ONLY!
case NX_SECURE_TLS_SERVER_HELLO_DONE: // TLS 1.2 and earlier ONLY!
case NX_SECURE_TLS_HELLO_REQUEST: // TLS 1.2 and earlier ONLY!
case NX_SECURE_TLS_HELLO_VERIFY_REQUEST: // DTLS ONLY!
case NX_SECURE_TLS_CLIENT_KEY_EXCHANGE:
case NX_SECURE_TLS_CLIENT_HELLO:
case NX_SECURE_TLS_INVALID_MESSAGE:
case NX_SECURE_TLS_CERTIFICATE_URL:
case NX_SECURE_TLS_CERTIFICATE_STATUS:
*/
default:
/* The message received was not a valid TLS server handshake message, send alert and return. */
break;
}
/* Check for errors in processing messages. */
if (status != NX_SECURE_TLS_SUCCESS)
{
/* Get our alert number and level from our status. */
error_number = status;
_nx_secure_tls_map_error_to_alert(error_number, &alert_number, &alert_level);
/* Release the protection before suspending on nx_packet_allocate. */
tx_mutex_put(&_nx_secure_tls_protection);
status = _nx_secure_tls_packet_allocate(tls_session, packet_pool, &send_packet, wait_option);
/* Get the protection after nx_packet_allocate. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status == NX_SUCCESS)
{
_nx_secure_tls_send_alert(tls_session, send_packet, (UCHAR)alert_number, (UCHAR)alert_level);
status = _nx_secure_tls_send_record(tls_session, send_packet, NX_SECURE_TLS_ALERT, wait_option);
if (status != NX_SUCCESS)
{
nx_secure_tls_packet_release(send_packet);
}
}
return(error_number);
}
/* Now take any actions based on state set in the message processing. */
switch (tls_session -> nx_secure_tls_client_state)
{
case NX_SECURE_TLS_CLIENT_STATE_IDLE:
case NX_SECURE_TLS_CLIENT_STATE_RENEGOTIATING:
/* Client isn't doing anything right now. */
break;
case NX_SECURE_TLS_CLIENT_STATE_ERROR:
case NX_SECURE_TLS_CLIENT_STATE_ALERT_SENT:
/* This means an error was encountered at some point in processing a valid message. At this point
the alert was sent, so just return a status indicating as much. */
return(NX_SECURE_TLS_HANDSHAKE_FAILURE);
break;
case NX_SECURE_TLS_CLIENT_STATE_HELLO_RETRY:
if(tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length > 0)
{
/* We have some cached messages from earlier in the handshake that we need to process. Generally
this will just be the ClientHello in TLS 1.3. */
status = _nx_secure_tls_handshake_hash_update(tls_session, tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache,
tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length);
if(status != NX_SUCCESS)
{
break;
}
/* Indicate that all cached messages have been hashed. */
tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length = 0;
}
/* Update the transcript hash with the ServerHelloRetry. */
_nx_secure_tls_handshake_hash_update(tls_session, packet_start, message_length + header_bytes);
/* Allocate a handshake packet so we can send the ClientHello. */
status = _nx_secure_tls_allocate_handshake_packet(tls_session, tls_session -> nx_secure_tls_packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
return(status);
}
/* Populate our packet with clienthello data. */
status = _nx_secure_tls_send_clienthello(tls_session, send_packet);
if (status == NX_SUCCESS)
{
/* To avoid a hash update on the second ClientHello packet switch to idle state (pre-handshake). */
tls_session -> nx_secure_tls_client_state = NX_SECURE_TLS_CLIENT_STATE_IDLE;
/* Send the ClientHello. */
status = _nx_secure_tls_send_handshake_record(tls_session, send_packet, NX_SECURE_TLS_CLIENT_HELLO, wait_option);
/* This state is used to avoid processing a second HelloRetryRequest packet if one is sent in error. */
tls_session -> nx_secure_tls_client_state = NX_SECURE_TLS_CLIENT_STATE_HELLO_RETRY;
}
/* If anything after the allocate fails, we need to release our packet. */
if (status != NX_SUCCESS)
{
/* Release the protection. */
nx_secure_tls_packet_release(send_packet);
return(status);
}
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO:
/* We processed a serverhello above. In TLS 1.3, it is time to generate keys and switch on encryption for the handshake. */
if(tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length > 0)
{
/* We have some cached messages from earlier in the handshake that we need to process. Generally
this will just be the ClientHello in TLS 1.3. */
status = _nx_secure_tls_handshake_hash_update(tls_session, tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache,
tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length);
if(status != NX_SUCCESS)
{
break;
}
/* Indicate that all cached messages have been hashed. */
tls_session->nx_secure_tls_key_material.nx_secure_tls_handshake_cache_length = 0;
/* Save the transcript hash for ClientHello - ServerHello was processed so we now have a ciphersuite and know what
out hash method is. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_CLIENTHELLO, NX_TRUE);
if(status != NX_SUCCESS)
{
break;
}
}
/* Update the transcript hash with the ServerHello. */
_nx_secure_tls_handshake_hash_update(tls_session, packet_start, message_length + header_bytes);
/* Save the transcript hash to this point for key generation - ServerHello was processed so use it. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_SERVERHELLO, NX_TRUE);
if(status != NX_SUCCESS)
{
break;
}
/* Generate TLS 1.3 keys and secrets for the handshake. */
status = _nx_secure_tls_1_3_generate_handshake_keys(tls_session);
if(status != NX_SUCCESS)
{
break;
}
/* Now turn on encryption. */
tls_session -> nx_secure_tls_local_session_active = 1;
tls_session -> nx_secure_tls_remote_session_active = 1;
break;
case NX_SECURE_TLS_CLIENT_STATE_ENCRYPTED_EXTENSIONS:
/* Processed an encrypted extensions message above. */
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVER_CERTIFICATE:
/* Processed a server certificate above. Here, we extract the public key and do any verification
we want - the TLS implementation will verify certificate authenticity by checking the issuer
signature, but any other verification will be done by the caller via a callback. */
break;
case NX_SECURE_TLS_CLIENT_STATE_CERTIFICATE_REQUEST:
/* Set flag to send CertificateVerify once we have received ServerHelloDone. */
tls_session -> nx_secure_tls_client_certificate_requested = 1;
break;
case NX_SECURE_TLS_CLIENT_STATE_HANDSHAKE_FINISHED:
/* We received a Finished, meaning we now have all the information we need to generate
our session key material. First check if the server requested our client certificate. */
/* Save the transcript hash to this point for key generation - Server Finished was processed so save it. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_SERVER_FINISHED, NX_TRUE);
if(status != NX_SUCCESS)
{
break;
}
/* Check for certificate request. */
if (tls_session -> nx_secure_tls_client_certificate_requested)
{
/* The server has requested a client certificate. Provide that certificate to the server here. */
status = _nx_secure_tls_allocate_handshake_packet(tls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
status = _nx_secure_tls_send_certificate(tls_session, send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
status = _nx_secure_tls_send_handshake_record(tls_session, send_packet, NX_SECURE_TLS_CERTIFICATE_MSG, wait_option);
if (status != NX_SUCCESS)
{
break;
}
/* Save the transcript hash up to the certificate for the CertificateVerify (next message to send). */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_CERTIFICATE, NX_TRUE);
if (status != NX_SUCCESS)
{
break;
}
}
/* After sending ClientKeyExchange, we need to send a CertificateVerify message if the
server has requested a certificate. If no certificate is available, this flag will
be cleared after the empty certificate message is sent. */
if (tls_session -> nx_secure_tls_client_certificate_requested)
{
/* We can now clear the flag since this is the last specific certificate message sent. */
tls_session -> nx_secure_tls_client_certificate_requested = 0;
/* Allocate packet for CertificateVerify. */
status = _nx_secure_tls_allocate_handshake_packet(tls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
status = _nx_secure_tls_send_certificate_verify(tls_session, send_packet);
if (status != NX_SUCCESS)
{
break;
}
status = _nx_secure_tls_send_handshake_record(tls_session, send_packet, NX_SECURE_TLS_CERTIFICATE_VERIFY, wait_option);
if (status != NX_SUCCESS)
{
break;
}
}
/* We processed a server finished message, completing the handshake. Verify all is good and if so,
continue to the encrypted session. */
/* Generate TLS 1.3 keys and secrets for the application data session. */
status = _nx_secure_tls_1_3_generate_session_keys(tls_session);
if(status != NX_SUCCESS)
{
break;
}
/* Now switch to the session keys for our remote session since we have processed the Finished from the server. */
status = _nx_secure_tls_1_3_session_keys_set(tls_session, NX_SECURE_TLS_KEY_SET_REMOTE);
if(status != NX_SUCCESS)
{
break;
}
/* Save the transcript hash to this point for generating Finished. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_SERVER_FINISHED, NX_TRUE);
if(status != NX_SUCCESS)
{
break;
}
/* We can now send our finished message, which will be encrypted using the chosen ciphersuite. */
status = _nx_secure_tls_allocate_handshake_packet(tls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
/* Generate and send the finished message, which completes the handshake. */
_nx_secure_tls_send_finished(tls_session, send_packet);
status = _nx_secure_tls_send_handshake_record(tls_session, send_packet, NX_SECURE_TLS_FINISHED, wait_option);
/* Save the transcript hash to this point for key generation - Client Finished was just sent so save it. */
status = _nx_secure_tls_1_3_transcript_hash_save(tls_session, NX_SECURE_TLS_TRANSCRIPT_IDX_CLIENT_FINISHED, NX_TRUE);
if(status != NX_SUCCESS)
{
break;
}
/* Now switch to the session keys for our local session since we have sent the Finished method. */
status = _nx_secure_tls_1_3_session_keys_set(tls_session, NX_SECURE_TLS_KEY_SET_LOCAL);
if(status != NX_SUCCESS)
{
break;
}
/* Generate TLS 1.3 keys and secrets for the post-handshake (e.g. session resumption PSK). */
status = _nx_secure_tls_1_3_generate_session_keys(tls_session);
if(status != NX_SUCCESS)
{
break;
}
break;
/* Cases not handled in TLS 1.3 (for reference):
case NX_SECURE_TLS_CLIENT_STATE_HELLO_REQUEST: // TLS 1.3: No HelloRequest message!
case NX_SECURE_TLS_CLIENT_STATE_HELLO_VERIFY: // DTLS ONLY!
case NX_SECURE_TLS_CLIENT_STATE_SERVER_KEY_EXCHANGE: // TLS 1.3: No ServerKeyExchange message!
case NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO_DONE: // TLS 1.3: No ServerHelloDone message!
*/
default:
status = NX_SECURE_TLS_INVALID_STATE;
}
/* If we have an error at this point, we have experienced a problem in sending
handshake messages, which is some type of internal issue. Send an alert
back to the remote host indicating the error. */
if (status != NX_SUCCESS)
{
/* Get our alert number and level from our status. */
error_number = status;
_nx_secure_tls_map_error_to_alert(error_number, &alert_number, &alert_level);
/* Release the protection before suspending on nx_packet_allocate. */
tx_mutex_put(&_nx_secure_tls_protection);
status = _nx_secure_tls_packet_allocate(tls_session, packet_pool, &send_packet, wait_option);
/* Get the protection after nx_packet_allocate. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status == NX_SUCCESS)
{
_nx_secure_tls_send_alert(tls_session, send_packet, (UCHAR)alert_number, (UCHAR)alert_level);
status = _nx_secure_tls_send_record(tls_session, send_packet, NX_SECURE_TLS_ALERT, wait_option);
if (status != NX_SUCCESS)
{
nx_secure_tls_packet_release(send_packet);
}
}
return(error_number);
}
/* Advance the buffer pointer past the message. */
packet_buffer += message_length;
} /* End while. */
return(NX_SUCCESS);
#else /* TLS Client disabled. */
/* We don't use the parameters since this is an error case. */
NX_PARAMETER_NOT_USED(packet_buffer);
NX_PARAMETER_NOT_USED(wait_option);
NX_PARAMETER_NOT_USED(data_length);
/* If TLS Client is disabled and we are in the client state machine, something is wrong... */
tls_session -> nx_secure_tls_server_state = NX_SECURE_TLS_SERVER_STATE_ERROR;
return(NX_SECURE_TLS_INVALID_STATE);
#endif
}
#endif
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