1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** NetX Secure Component */
17 /** */
18 /** Transport Layer Security (TLS) */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 #define NX_SECURE_SOURCE_CODE
24
25 #include "nx_secure_tls.h"
26
27 /**************************************************************************/
28 /* */
29 /* FUNCTION RELEASE */
30 /* */
31 /* _nx_secure_tls_send_certificate PORTABLE C */
32 /* 6.3.0 */
33 /* AUTHOR */
34 /* */
35 /* Timothy Stapko, Microsoft Corporation */
36 /* */
37 /* DESCRIPTION */
38 /* */
39 /* This function populates an NX_PACKET with the TLS Certificate */
40 /* message, which contains the identity certificate for this device. */
41 /* */
42 /* INPUT */
43 /* */
44 /* tls_session TLS control block */
45 /* send_packet Packet to be filled */
46 /* wait_option Controls timeout actions */
47 /* */
48 /* OUTPUT */
49 /* */
50 /* status Completion status */
51 /* */
52 /* CALLS */
53 /* */
54 /* _nx_secure_x509_distinguished_name_compare */
55 /* Compare distinguished name */
56 /* _nx_secure_x509_local_device_certificate_get */
57 /* Get local certificate to send */
58 /* nx_packet_data_append Append data to packet */
59 /* tx_mutex_get Get protection mutex */
60 /* tx_mutex_put Put protection mutex */
61 /* */
62 /* CALLED BY */
63 /* */
64 /* _nx_secure_dtls_client_handshake DTLS client state machine */
65 /* _nx_secure_dtls_server_handshake DTLS server state machine */
66 /* _nx_secure_tls_client_handshake TLS client state machine */
67 /* _nx_secure_tls_server_handshake TLS server state machine */
68 /* */
69 /* RELEASE HISTORY */
70 /* */
71 /* DATE NAME DESCRIPTION */
72 /* */
73 /* 05-19-2020 Timothy Stapko Initial Version 6.0 */
74 /* 09-30-2020 Timothy Stapko Modified comment(s), */
75 /* resulting in version 6.1 */
76 /* 04-02-2021 Timothy Stapko Modified comment(s), */
77 /* updated X.509 return value, */
78 /* resulting in version 6.1.6 */
79 /* 04-25-2022 Zhen Kong Modified comment(s), removed */
80 /* unreachable error code, */
81 /* resulting in version 6.1.11 */
82 /* 03-08-2023 Yanwu Cai Modified comment(s), */
83 /* fixed compiler errors when */
84 /* x509 is disabled, */
85 /* resulting in version 6.2.1 */
86 /* 10-31-2023 Yanwu Cai Modified comment(s), */
87 /* fixed packet buffer overrun,*/
88 /* resulting in version 6.3.0 */
89 /* */
90 /**************************************************************************/
_nx_secure_tls_send_certificate(NX_SECURE_TLS_SESSION * tls_session,NX_PACKET * send_packet,ULONG wait_option)91 UINT _nx_secure_tls_send_certificate(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
92 ULONG wait_option)
93 {
94 #ifndef NX_SECURE_DISABLE_X509
95 UINT length;
96 UINT total_length;
97 UCHAR length_buffer[3];
98 UINT status = NX_SECURE_TLS_SUCCESS;
99 NX_SECURE_X509_CERT *cert;
100 INT compare_result = 0;
101 UCHAR *record_start;
102 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
103 USHORT extensions_length;
104 #endif
105
106
107 /* Structure:
108 * | 3 | <Total Length> |
109 * | Total length | 3 | <Cert[0] Length> | 3 + <Cert[x] Len> |
110 * | | Cert[0] Length | Certificate[0] | More certs... |
111 */
112
113 /* TLS 1.3 Structure:
114 * | 1 | <Ctx Len> | 3 | <Total Length> |
115 * | Ctx Len | Context | Total length | 3 | <Cert[x] Length> | 2 | <ExtLen> |
116 * | | Cert[x] Length | Certificate[x] | ExtLen | Extensions |
117 */
118
119 /* See if the local certificate has been overridden. If so, use that instead. */
120 if (tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate != NX_NULL)
121 {
122 cert = tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate;
123 }
124 else
125 {
126 /* Get reference to local device certificate. NX_NULL is passed for name to get default entry. */
127 status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
128 NX_NULL, &cert);
129 }
130
131 #ifndef NX_SECURE_TLS_CLIENT_DISABLED
132 /* See if this is a TLS client sending a certificate in response to a certificate request from
133 the remote server. */
134 if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_CLIENT &&
135 (status == NX_SECURE_X509_CERTIFICATE_NOT_FOUND))
136 {
137 /* If this is a TLS client, as per the RFC we can have no certificate assigned in which
138 case our response to the server that has requested our certificate will contain
139 an empty certificate field. */
140 cert = NX_NULL;
141
142 /* Clear the requested flag so no further certificate-specific messages are sent. */
143 tls_session -> nx_secure_tls_client_certificate_requested = NX_FALSE;
144 }
145 else
146 #endif
147 {
148 if (status)
149 {
150
151 /* _nx_secure_x509_local_device_certificate_get can only return
152 NX_SECURE_X509_CERTIFICATE_NOT_FOUND in this case. */
153 return(NX_SECURE_TLS_CERTIFICATE_NOT_FOUND);
154 }
155 }
156
157 if (((ULONG)(send_packet -> nx_packet_data_end) - (ULONG)(send_packet -> nx_packet_append_ptr)) < 3u)
158 {
159
160 /* Packet buffer is too small to hold random and ID. */
161 return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
162 }
163
164 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
165 /* In TLS 1.3, the context length is the first field, followed by the context itself (if necessary). */
166 if(tls_session->nx_secure_tls_1_3)
167 {
168 send_packet -> nx_packet_append_ptr[0] = 0;
169 send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 1;
170 send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(1);
171 }
172 #endif
173
174 /* Save a reference to the start of our record. */
175 record_start = send_packet -> nx_packet_append_ptr;
176
177 /* Pointer to where we are going to place the next certificate. */
178 /* The first 3 bytes hold the total length field. Therefore
179 certificate data starts from offset 3.*/
180 send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 3;
181 send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(3);
182
183 /* Total length is the length of all certificates and is the first 3 bytes of the message. */
184 total_length = 0;
185
186 while (status == NX_SUCCESS)
187 {
188 /* Place certificate data into the packet buffer with the appropriate length.
189 NOTE: We need to use the RAW data of the certificate when sending, not the parsed certificate! */
190 length = cert -> nx_secure_x509_certificate_raw_data_length;
191
192 /* Total length is increased by the length of the certificate plus the 3 bytes for
193 the certificate length parameter. */
194 total_length += (length + 3);
195
196 /* Put the length of this certificate into the buffer. */
197 length_buffer[0] = (UCHAR)((length & 0xFF0000) >> 16);
198 length_buffer[1] = (UCHAR)((length & 0xFF00) >> 8);
199 length_buffer[2] = (UCHAR)(length & 0xFF);
200
201 /* Release the protection before suspending on nx_packet_data_append. */
202 tx_mutex_put(&_nx_secure_tls_protection);
203
204 /* Put the length into the buffer. */
205 status = nx_packet_data_append(send_packet, length_buffer, 3,
206 tls_session -> nx_secure_tls_packet_pool, wait_option);
207
208 /* Get the protection after nx_packet_data_append. */
209 tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
210
211 if (status != NX_SUCCESS)
212 {
213 return(status);
214 }
215
216 /* Release the protection before suspending on nx_packet_data_append. */
217 tx_mutex_put(&_nx_secure_tls_protection);
218
219 /* Put the certificate data into the buffer. */
220 status = nx_packet_data_append(send_packet, cert -> nx_secure_x509_certificate_raw_data, length,
221 tls_session -> nx_secure_tls_packet_pool, wait_option);
222
223 /* Get the protection after nx_packet_data_append. */
224 tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
225
226 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
227 /* Check for TLS 1.3 extensions following each certificate. */
228 if (tls_session -> nx_secure_tls_1_3)
229 {
230 extensions_length = 0;
231 NX_CHANGE_USHORT_ENDIAN(extensions_length);
232
233 /* Add extension length to packet. */
234 status = nx_packet_data_append(send_packet, &extensions_length,
235 sizeof(extensions_length),
236 tls_session -> nx_secure_tls_packet_pool,
237 wait_option);
238 if (status != NX_SUCCESS)
239 {
240 return(status);
241 }
242
243 total_length += 2;
244 }
245 #endif
246
247
248 if (status != NX_SUCCESS)
249 {
250 return(status);
251 }
252
253 /* Get certificate issuer - if it exists in the store, send it, otherwise we are done. */
254 status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
255 &cert -> nx_secure_x509_issuer, &cert);
256
257 /* If certificate was not found, don't try to dereference. */
258 if (status == NX_SUCCESS)
259 {
260 /* Prevent infinite loop if certificate is self-signed. */
261 compare_result = _nx_secure_x509_distinguished_name_compare(&cert -> nx_secure_x509_distinguished_name,
262 &cert -> nx_secure_x509_issuer, NX_SECURE_X509_NAME_ALL_FIELDS);
263 if (compare_result == 0)
264 {
265 break;
266 }
267 }
268
269 /* If an issuer certificate was not found, that is OK - this should actually be the common case
270 * as any certificate that is not self-signed should not have its root CA certificate on the
271 * same device.
272 */
273 }
274
275 /* Put the total length of all certificates into the buffer. */
276 record_start[0] = (UCHAR)((total_length & 0xFF0000) >> 16);
277 record_start[1] = (UCHAR)((total_length & 0xFF00) >> 8);
278 record_start[2] = (UCHAR)(total_length & 0xFF);
279
280 return(NX_SUCCESS);
281 #else
282 NX_PARAMETER_NOT_USED(tls_session);
283 NX_PARAMETER_NOT_USED(send_packet);
284 NX_PARAMETER_NOT_USED(wait_option);
285
286 return(NX_NOT_SUPPORTED);
287 #endif
288 }
289
