Outline ![]()
Files ![]()
loading...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
/**************************************************************************/
/* */
/* 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_send_certificate PORTABLE C */
/* 6.1.6 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function populates an NX_PACKET with the TLS Certificate */
/* message, which contains the identity certificate for this device. */
/* */
/* INPUT */
/* */
/* tls_session TLS control block */
/* send_packet Packet to be filled */
/* wait_option Controls timeout actions */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_distinguished_name_compare */
/* Compare distinguished name */
/* _nx_secure_x509_local_device_certificate_get */
/* Get local certificate to send */
/* nx_packet_data_append Append data to packet */
/* tx_mutex_get Get protection mutex */
/* tx_mutex_put Put protection mutex */
/* */
/* CALLED BY */
/* */
/* _nx_secure_dtls_client_handshake DTLS client state machine */
/* _nx_secure_dtls_server_handshake DTLS server state machine */
/* _nx_secure_tls_client_handshake TLS client state machine */
/* _nx_secure_tls_server_handshake TLS server state machine */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* 04-02-2021 Timothy Stapko Modified comment(s), */
/* updated X.509 return value, */
/* resulting in version 6.1.6 */
/* */
/**************************************************************************/
UINT _nx_secure_tls_send_certificate(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
ULONG wait_option)
{
UINT length;
UINT total_length;
UCHAR length_buffer[3];
UINT status = NX_SECURE_TLS_SUCCESS;
NX_SECURE_X509_CERT *cert;
INT compare_result = 0;
UCHAR *record_start;
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
UINT extensions_length;
#endif
/* Structure:
* | 3 | <Total Length> |
* | Total length | 3 | <Cert[0] Length> | 3 + <Cert[x] Len> |
* | | Cert[0] Length | Certificate[0] | More certs... |
*/
/* TLS 1.3 Structure:
* | 1 | <Ctx Len> | 3 | <Total Length> |
* | Ctx Len | Context | Total length | 3 | <Cert[x] Length> | 2 | <ExtLen> |
* | | Cert[x] Length | Certificate[x] | ExtLen | Extensions |
*/
/* See if the local certificate has been overridden. If so, use that instead. */
if (tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate != NX_NULL)
{
cert = tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate;
}
else
{
/* Get reference to local device certificate. NX_NULL is passed for name to get default entry. */
status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
NX_NULL, &cert);
}
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
/* See if this is a TLS client sending a certificate in response to a certificate request from
the remote server. */
if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_CLIENT &&
(status == NX_SECURE_X509_CERTIFICATE_NOT_FOUND))
{
/* If this is a TLS client, as per the RFC we can have no certificate assigned in which
case our response to the server that has requested our certificate will contain
an empty certificate field. */
cert = NX_NULL;
/* Clear the requested flag so no further certificate-specific messages are sent. */
tls_session -> nx_secure_tls_client_certificate_requested = NX_FALSE;
}
else
#endif
{
if (status)
{
/* Translate some X.509 return values into TLS return values. */
if (status == NX_SECURE_X509_CERTIFICATE_NOT_FOUND)
{
return(NX_SECURE_TLS_CERTIFICATE_NOT_FOUND);
}
/* No certificate found, error! */
return(status);
}
}
if (((ULONG)(send_packet -> nx_packet_data_end) - (ULONG)(send_packet -> nx_packet_append_ptr)) < 3u)
{
/* Packet buffer is too small to hold random and ID. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
/* In TLS 1.3, the context length is the first field, followed by the context itself (if necessary). */
if(tls_session->nx_secure_tls_1_3)
{
send_packet -> nx_packet_append_ptr[0] = 0;
send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 1;
send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(1);
}
#endif
/* Save a reference to the start of our record. */
record_start = send_packet -> nx_packet_append_ptr;
/* Pointer to where we are going to place the next certificate. */
/* The first 3 bytes hold the total length field. Therefore
certificate data starts from offset 3.*/
send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 3;
send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(3);
/* Total length is the length of all certificates and is the first 3 bytes of the message. */
total_length = 0;
while (status == NX_SUCCESS)
{
/* Place certificate data into the packet buffer with the appropriate length.
NOTE: We need to use the RAW data of the certificate when sending, not the parsed certificate! */
length = cert -> nx_secure_x509_certificate_raw_data_length;
/* Total length is increased by the length of the certificate plus the 3 bytes for
the certificate length parameter. */
total_length += (length + 3);
/* Put the length of this certificate into the buffer. */
length_buffer[0] = (UCHAR)((length & 0xFF0000) >> 16);
length_buffer[1] = (UCHAR)((length & 0xFF00) >> 8);
length_buffer[2] = (UCHAR)(length & 0xFF);
/* Release the protection before suspending on nx_packet_data_append. */
tx_mutex_put(&_nx_secure_tls_protection);
/* Put the length into the buffer. */
status = nx_packet_data_append(send_packet, length_buffer, 3,
tls_session -> nx_secure_tls_packet_pool, wait_option);
/* Get the protection after nx_packet_data_append. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status != NX_SUCCESS)
{
return(status);
}
/* Release the protection before suspending on nx_packet_data_append. */
tx_mutex_put(&_nx_secure_tls_protection);
/* Put the certificate data into the buffer. */
status = nx_packet_data_append(send_packet, cert -> nx_secure_x509_certificate_raw_data, length,
tls_session -> nx_secure_tls_packet_pool, wait_option);
/* Get the protection after nx_packet_data_append. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
/* Check for TLS 1.3 extensions following each certificate. */
if(tls_session->nx_secure_tls_1_3)
{
extensions_length = 0;
/* Add extension length to packet. */
send_packet -> nx_packet_append_ptr[0] = (UCHAR)((extensions_length & 0xFF00) >> 8);
send_packet -> nx_packet_append_ptr[1] = (UCHAR)(extensions_length & 0x00FF);
/* Adjust pointer and length in packet according to extensions sent. */
send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 2;
send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(2);
total_length += 2;
}
#endif
if (status != NX_SUCCESS)
{
return(status);
}
/* Get certificate issuer - if it exists in the store, send it, otherwise we are done. */
status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
&cert -> nx_secure_x509_issuer, &cert);
/* If certificate was not found, don't try to dereference. */
if (status == NX_SUCCESS)
{
/* Prevent infinite loop if certificate is self-signed. */
compare_result = _nx_secure_x509_distinguished_name_compare(&cert -> nx_secure_x509_distinguished_name,
&cert -> nx_secure_x509_issuer, NX_SECURE_X509_NAME_ALL_FIELDS);
if (compare_result == 0)
{
break;
}
}
/* If an issuer certificate was not found, that is OK - this should actually be the common case
* as any certificate that is not self-signed should not have its root CA certificate on the
* same device.
*/
}
/* Put the total length of all certificates into the buffer. */
record_start[0] = (UCHAR)((total_length & 0xFF0000) >> 16);
record_start[1] = (UCHAR)((total_length & 0xFF00) >> 8);
record_start[2] = (UCHAR)(total_length & 0xFF);
return(NX_SUCCESS);
}