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_psk_find PORTABLE C */
32 /* 6.1 */
33 /* AUTHOR */
34 /* */
35 /* Timothy Stapko, Microsoft Corporation */
36 /* */
37 /* DESCRIPTION */
38 /* */
39 /* This function finds a pre-shared key (PSK) in a TLS session for use */
40 /* with a TLS 1.3 PSK extension. The PSK is found using an "identity" */
41 /* that should match a field in the PSK structure in the TLS session. */
42 /* */
43 /* INPUT */
44 /* */
45 /* tls_session Pointer to TLS Session */
46 /* psk_data Pointer to PSK data */
47 /* psk_length Length of PSK data */
48 /* psk_identity PSK identity data */
49 /* identity_length Length of identity data */
50 /* psk_store_index Index of found PSK in store */
51 /* */
52 /* OUTPUT */
53 /* */
54 /* status Completion status */
55 /* */
56 /* CALLS */
57 /* */
58 /* tx_mutex_get Get protection mutex */
59 /* tx_mutex_put Put protection mutex */
60 /* */
61 /* CALLED BY */
62 /* */
63 /* _nx_secure_tls_process_clienthello_psk_extension */
64 /* Process an incoming TLS 1.3 */
65 /* PSK extension */
66 /* */
67 /* RELEASE HISTORY */
68 /* */
69 /* DATE NAME DESCRIPTION */
70 /* */
71 /* 05-19-2020 Timothy Stapko Initial Version 6.0 */
72 /* 09-30-2020 Timothy Stapko Modified comment(s), */
73 /* resulting in version 6.1 */
74 /* */
75 /**************************************************************************/
76 #if (NX_SECURE_TLS_TLS_1_3_ENABLED) && defined(NX_SECURE_ENABLE_PSK_CIPHERSUITES)
_nx_secure_tls_psk_identity_find(NX_SECURE_TLS_SESSION * tls_session,UCHAR ** psk_data,UINT * psk_length,UCHAR * psk_identity,UINT identity_length,UINT * psk_store_index)77 UINT _nx_secure_tls_psk_identity_find(NX_SECURE_TLS_SESSION *tls_session, UCHAR **psk_data, UINT *psk_length,
78 UCHAR *psk_identity, UINT identity_length, UINT *psk_store_index)
79 {
80 UINT psk_list_size;
81 UINT compare_val;
82 UINT i;
83
84 /* Get the protection. */
85 tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
86
87 psk_list_size = tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_count;
88
89 /* Loop through all PSKs, looking for a matching identity string. */
90 for (i = 0; i < psk_list_size; ++i)
91 {
92 /* Save off the PSK and its length. */
93 compare_val = (UINT)NX_SECURE_MEMCMP(tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_id, psk_identity, identity_length);
94
95 /* See if the identity matched, and the length is the same (without the length, we could have a
96 matching prefix which could be a possible attack vector... */
97 if (compare_val == 0 && identity_length == tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_id_size)
98 {
99 /* Found a matching identity, return the associated PSK. */
100 *psk_data = tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_data;
101 *psk_length = tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_data_size;
102
103 if(psk_store_index != NX_NULL)
104 {
105 *psk_store_index = i;
106 }
107
108 /* Release the protection. */
109 tx_mutex_put(&_nx_secure_tls_protection);
110
111 return(NX_SUCCESS);
112 }
113 }
114
115 /* Release the protection. */
116 tx_mutex_put(&_nx_secure_tls_protection);
117
118 return(NX_SECURE_TLS_NO_MATCHING_PSK);
119 }
120 #endif
121
122
