1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** NetX Secure Component */
16 /** */
17 /** Transport Layer Security (TLS) */
18 /** */
19 /**************************************************************************/
20 /**************************************************************************/
21
22 #define NX_SECURE_SOURCE_CODE
23
24 #include "nx_secure_tls.h"
25
26 /**************************************************************************/
27 /* */
28 /* FUNCTION RELEASE */
29 /* */
30 /* _nx_secure_tls_send_certificate PORTABLE C */
31 /* 6.3.0 */
32 /* AUTHOR */
33 /* */
34 /* Timothy Stapko, Microsoft Corporation */
35 /* */
36 /* DESCRIPTION */
37 /* */
38 /* This function populates an NX_PACKET with the TLS Certificate */
39 /* message, which contains the identity certificate for this device. */
40 /* */
41 /* INPUT */
42 /* */
43 /* tls_session TLS control block */
44 /* send_packet Packet to be filled */
45 /* wait_option Controls timeout actions */
46 /* */
47 /* OUTPUT */
48 /* */
49 /* status Completion status */
50 /* */
51 /* CALLS */
52 /* */
53 /* _nx_secure_x509_distinguished_name_compare */
54 /* Compare distinguished name */
55 /* _nx_secure_x509_local_device_certificate_get */
56 /* Get local certificate to send */
57 /* nx_packet_data_append Append data to packet */
58 /* tx_mutex_get Get protection mutex */
59 /* tx_mutex_put Put protection mutex */
60 /* */
61 /* CALLED BY */
62 /* */
63 /* _nx_secure_dtls_client_handshake DTLS client state machine */
64 /* _nx_secure_dtls_server_handshake DTLS server state machine */
65 /* _nx_secure_tls_client_handshake TLS client state machine */
66 /* _nx_secure_tls_server_handshake TLS server state machine */
67 /* */
68 /* RELEASE HISTORY */
69 /* */
70 /* DATE NAME DESCRIPTION */
71 /* */
72 /* 05-19-2020 Timothy Stapko Initial Version 6.0 */
73 /* 09-30-2020 Timothy Stapko Modified comment(s), */
74 /* resulting in version 6.1 */
75 /* 04-02-2021 Timothy Stapko Modified comment(s), */
76 /* updated X.509 return value, */
77 /* resulting in version 6.1.6 */
78 /* 04-25-2022 Zhen Kong Modified comment(s), removed */
79 /* unreachable error code, */
80 /* resulting in version 6.1.11 */
81 /* 03-08-2023 Yanwu Cai Modified comment(s), */
82 /* fixed compiler errors when */
83 /* x509 is disabled, */
84 /* resulting in version 6.2.1 */
85 /* 10-31-2023 Yanwu Cai Modified comment(s), */
86 /* fixed packet buffer overrun,*/
87 /* resulting in version 6.3.0 */
88 /* */
89 /**************************************************************************/
_nx_secure_tls_send_certificate(NX_SECURE_TLS_SESSION * tls_session,NX_PACKET * send_packet,ULONG wait_option)90 UINT _nx_secure_tls_send_certificate(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
91 ULONG wait_option)
92 {
93 #ifndef NX_SECURE_DISABLE_X509
94 UINT length;
95 UINT total_length;
96 UCHAR length_buffer[3];
97 UINT status = NX_SECURE_TLS_SUCCESS;
98 NX_SECURE_X509_CERT *cert;
99 INT compare_result = 0;
100 UCHAR *record_start;
101 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
102 USHORT extensions_length;
103 #endif
104
105
106 /* Structure:
107 * | 3 | <Total Length> |
108 * | Total length | 3 | <Cert[0] Length> | 3 + <Cert[x] Len> |
109 * | | Cert[0] Length | Certificate[0] | More certs... |
110 */
111
112 /* TLS 1.3 Structure:
113 * | 1 | <Ctx Len> | 3 | <Total Length> |
114 * | Ctx Len | Context | Total length | 3 | <Cert[x] Length> | 2 | <ExtLen> |
115 * | | Cert[x] Length | Certificate[x] | ExtLen | Extensions |
116 */
117
118 /* See if the local certificate has been overridden. If so, use that instead. */
119 if (tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate != NX_NULL)
120 {
121 cert = tls_session -> nx_secure_tls_credentials.nx_secure_tls_active_certificate;
122 }
123 else
124 {
125 /* Get reference to local device certificate. NX_NULL is passed for name to get default entry. */
126 status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
127 NX_NULL, &cert);
128 }
129
130 #ifndef NX_SECURE_TLS_CLIENT_DISABLED
131 /* See if this is a TLS client sending a certificate in response to a certificate request from
132 the remote server. */
133 if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_CLIENT &&
134 (status == NX_SECURE_X509_CERTIFICATE_NOT_FOUND))
135 {
136 /* If this is a TLS client, as per the RFC we can have no certificate assigned in which
137 case our response to the server that has requested our certificate will contain
138 an empty certificate field. */
139 cert = NX_NULL;
140
141 /* Clear the requested flag so no further certificate-specific messages are sent. */
142 tls_session -> nx_secure_tls_client_certificate_requested = NX_FALSE;
143 }
144 else
145 #endif
146 {
147 if (status)
148 {
149
150 /* _nx_secure_x509_local_device_certificate_get can only return
151 NX_SECURE_X509_CERTIFICATE_NOT_FOUND in this case. */
152 return(NX_SECURE_TLS_CERTIFICATE_NOT_FOUND);
153 }
154 }
155
156 if (((ULONG)(send_packet -> nx_packet_data_end) - (ULONG)(send_packet -> nx_packet_append_ptr)) < 3u)
157 {
158
159 /* Packet buffer is too small to hold random and ID. */
160 return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
161 }
162
163 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
164 /* In TLS 1.3, the context length is the first field, followed by the context itself (if necessary). */
165 if(tls_session->nx_secure_tls_1_3)
166 {
167 send_packet -> nx_packet_append_ptr[0] = 0;
168 send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 1;
169 send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(1);
170 }
171 #endif
172
173 /* Save a reference to the start of our record. */
174 record_start = send_packet -> nx_packet_append_ptr;
175
176 /* Pointer to where we are going to place the next certificate. */
177 /* The first 3 bytes hold the total length field. Therefore
178 certificate data starts from offset 3.*/
179 send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + 3;
180 send_packet -> nx_packet_length = send_packet -> nx_packet_length + (USHORT)(3);
181
182 /* Total length is the length of all certificates and is the first 3 bytes of the message. */
183 total_length = 0;
184
185 while (status == NX_SUCCESS)
186 {
187 /* Place certificate data into the packet buffer with the appropriate length.
188 NOTE: We need to use the RAW data of the certificate when sending, not the parsed certificate! */
189 length = cert -> nx_secure_x509_certificate_raw_data_length;
190
191 /* Total length is increased by the length of the certificate plus the 3 bytes for
192 the certificate length parameter. */
193 total_length += (length + 3);
194
195 /* Put the length of this certificate into the buffer. */
196 length_buffer[0] = (UCHAR)((length & 0xFF0000) >> 16);
197 length_buffer[1] = (UCHAR)((length & 0xFF00) >> 8);
198 length_buffer[2] = (UCHAR)(length & 0xFF);
199
200 /* Release the protection before suspending on nx_packet_data_append. */
201 tx_mutex_put(&_nx_secure_tls_protection);
202
203 /* Put the length into the buffer. */
204 status = nx_packet_data_append(send_packet, length_buffer, 3,
205 tls_session -> nx_secure_tls_packet_pool, wait_option);
206
207 /* Get the protection after nx_packet_data_append. */
208 tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
209
210 if (status != NX_SUCCESS)
211 {
212 return(status);
213 }
214
215 /* Release the protection before suspending on nx_packet_data_append. */
216 tx_mutex_put(&_nx_secure_tls_protection);
217
218 /* Put the certificate data into the buffer. */
219 status = nx_packet_data_append(send_packet, cert -> nx_secure_x509_certificate_raw_data, length,
220 tls_session -> nx_secure_tls_packet_pool, wait_option);
221
222 /* Get the protection after nx_packet_data_append. */
223 tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
224
225 #if (NX_SECURE_TLS_TLS_1_3_ENABLED)
226 /* Check for TLS 1.3 extensions following each certificate. */
227 if (tls_session -> nx_secure_tls_1_3)
228 {
229 extensions_length = 0;
230 NX_CHANGE_USHORT_ENDIAN(extensions_length);
231
232 /* Add extension length to packet. */
233 status = nx_packet_data_append(send_packet, &extensions_length,
234 sizeof(extensions_length),
235 tls_session -> nx_secure_tls_packet_pool,
236 wait_option);
237 if (status != NX_SUCCESS)
238 {
239 return(status);
240 }
241
242 total_length += 2;
243 }
244 #endif
245
246
247 if (status != NX_SUCCESS)
248 {
249 return(status);
250 }
251
252 /* Get certificate issuer - if it exists in the store, send it, otherwise we are done. */
253 status = _nx_secure_x509_local_device_certificate_get(&tls_session -> nx_secure_tls_credentials.nx_secure_tls_certificate_store,
254 &cert -> nx_secure_x509_issuer, &cert);
255
256 /* If certificate was not found, don't try to dereference. */
257 if (status == NX_SUCCESS)
258 {
259 /* Prevent infinite loop if certificate is self-signed. */
260 compare_result = _nx_secure_x509_distinguished_name_compare(&cert -> nx_secure_x509_distinguished_name,
261 &cert -> nx_secure_x509_issuer, NX_SECURE_X509_NAME_ALL_FIELDS);
262 if (compare_result == 0)
263 {
264 break;
265 }
266 }
267
268 /* If an issuer certificate was not found, that is OK - this should actually be the common case
269 * as any certificate that is not self-signed should not have its root CA certificate on the
270 * same device.
271 */
272 }
273
274 /* Put the total length of all certificates into the buffer. */
275 record_start[0] = (UCHAR)((total_length & 0xFF0000) >> 16);
276 record_start[1] = (UCHAR)((total_length & 0xFF00) >> 8);
277 record_start[2] = (UCHAR)(total_length & 0xFF);
278
279 return(NX_SUCCESS);
280 #else
281 NX_PARAMETER_NOT_USED(tls_session);
282 NX_PARAMETER_NOT_USED(send_packet);
283 NX_PARAMETER_NOT_USED(wait_option);
284
285 return(NX_NOT_SUPPORTED);
286 #endif
287 }
288
