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 
25 #include "nx_secure_tls.h"
26 
27 /**************************************************************************/
28 /*                                                                        */
29 /*  FUNCTION                                               RELEASE        */
30 /*                                                                        */
31 /*    _nx_secure_tls_send_client_key_exchange             PORTABLE C      */
32 /*                                                           6.2.0        */
33 /*  AUTHOR                                                                */
34 /*                                                                        */
35 /*    Timothy Stapko, Microsoft Corporation                               */
36 /*                                                                        */
37 /*  DESCRIPTION                                                           */
38 /*                                                                        */
39 /*    This function encrypts the Pre-Master Secret (generated earlier)    */
40 /*    and populates an NX_PACKET with the complete ClientKeyExchange      */
41 /*    message (to be sent by the caller). It also will send ephemeral     */
42 /*    keys for ciphersuites that require them.                            */
43 /*                                                                        */
44 /*  INPUT                                                                 */
45 /*                                                                        */
46 /*    tls_session                           TLS control block             */
47 /*    send_packet                           Outgoing TLS packet           */
48 /*                                                                        */
49 /*  OUTPUT                                                                */
50 /*                                                                        */
51 /*    status                                Completion status             */
52 /*                                                                        */
53 /*  CALLS                                                                 */
54 /*                                                                        */
55 /*    [nx_secure_generate_client_key_exchange]                            */
56 /*                                          Generate ClientKeyExchange    */
57 /*    _nx_secure_tls_remote_certificate_free_all                          */
58 /*                                          Free all remote certificates  */
59 /*                                                                        */
60 /*  CALLED BY                                                             */
61 /*                                                                        */
62 /*    _nx_secure_dtls_client_handshake      DTLS client state machine     */
63 /*    _nx_secure_tls_client_handshake       TLS client state machine      */
64 /*                                                                        */
65 /*  RELEASE HISTORY                                                       */
66 /*                                                                        */
67 /*    DATE              NAME                      DESCRIPTION             */
68 /*                                                                        */
69 /*  05-19-2020     Timothy Stapko           Initial Version 6.0           */
70 /*  09-30-2020     Timothy Stapko           Modified comment(s),          */
71 /*                                            verified memcpy use cases,  */
72 /*                                            resulting in version 6.1    */
73 /*  04-25-2022     Zhen Kong                Modified comment(s), improved */
74 /*                                            internal logic to check data*/
75 /*                                            size and then improved code */
76 /*                                            coverage, resulting in      */
77 /*                                            version 6.1.11              */
78 /*  10-31-2022     Yanwu Cai                Modified comment(s), added    */
79 /*                                            custom secret generation,   */
80 /*                                            resulting in version 6.2.0  */
81 /*                                                                        */
82 /**************************************************************************/
_nx_secure_tls_send_client_key_exchange(NX_SECURE_TLS_SESSION * tls_session,NX_PACKET * send_packet)83 UINT _nx_secure_tls_send_client_key_exchange(NX_SECURE_TLS_SESSION *tls_session,
84                                              NX_PACKET *send_packet)
85 {
86 #if !defined(NX_SECURE_TLS_CLIENT_DISABLED)
87 UINT  status;
88 ULONG data_size = 0;
89 ULONG buffer_length;
90 
91     if (tls_session -> nx_secure_tls_session_ciphersuite == NX_NULL)
92     {
93 
94         /* Likely internal error since at this point ciphersuite negotiation was theoretically completed. */
95         return(NX_SECURE_TLS_UNKNOWN_CIPHERSUITE);
96     }
97 
98     buffer_length = (ULONG)(send_packet -> nx_packet_data_end) - (ULONG)(send_packet -> nx_packet_append_ptr);
99 
100     status = tls_session -> nx_secure_generate_client_key_exchange(tls_session -> nx_secure_tls_session_ciphersuite,
101                                                                    &tls_session -> nx_secure_tls_key_material, &tls_session -> nx_secure_tls_credentials,
102                                                                    send_packet -> nx_packet_append_ptr,
103                                                                    buffer_length,
104                                                                    &data_size, tls_session -> nx_secure_public_cipher_metadata_area,
105                                                                    tls_session -> nx_secure_public_cipher_metadata_size,
106                                                                    tls_session -> nx_secure_public_auth_metadata_area,
107                                                                    tls_session -> nx_secure_public_auth_metadata_size);
108     if (status)
109     {
110         _nx_secure_tls_remote_certificate_free_all(tls_session);
111         return(status);
112     }
113 
114     send_packet -> nx_packet_append_ptr = send_packet -> nx_packet_append_ptr + data_size;
115     send_packet -> nx_packet_length = send_packet -> nx_packet_length + data_size;
116 
117     return(NX_SECURE_TLS_SUCCESS);
118 #else
119     NX_PARAMETER_NOT_USED(tls_session);
120     NX_PARAMETER_NOT_USED(send_packet);
121     return(NX_SECURE_TLS_INVALID_STATE);
122 #endif
123 }
124 
125