1 /*
2 chronyd/chronyc - Programs for keeping computer clocks accurate.
3
4 **********************************************************************
5 * Copyright (C) Miroslav Lichvar 2019
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of version 2 of the GNU General Public License as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 *
20 **********************************************************************
21
22 =======================================================================
23
24 Support for AES128 and AES256 CMAC in Nettle.
25
26 */
27
28 #include "config.h"
29
30 #include "sysincl.h"
31
32 #include <nettle/cmac.h>
33
34 #include "cmac.h"
35 #include "memory.h"
36
37 struct CMC_Instance_Record {
38 int key_length;
39 union {
40 struct cmac_aes128_ctx aes128;
41 struct cmac_aes256_ctx aes256;
42 } context;
43 };
44
45 /* ================================================== */
46
47 int
CMC_GetKeyLength(CMC_Algorithm algorithm)48 CMC_GetKeyLength(CMC_Algorithm algorithm)
49 {
50 if (algorithm == CMC_AES128)
51 return AES128_KEY_SIZE;
52 else if (algorithm == CMC_AES256)
53 return AES256_KEY_SIZE;
54 return 0;
55 }
56
57 /* ================================================== */
58
59 CMC_Instance
CMC_CreateInstance(CMC_Algorithm algorithm,const unsigned char * key,int length)60 CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key, int length)
61 {
62 CMC_Instance inst;
63
64 if (length <= 0 || length != CMC_GetKeyLength(algorithm))
65 return NULL;
66
67 inst = MallocNew(struct CMC_Instance_Record);
68 inst->key_length = length;
69
70 switch (length) {
71 case AES128_KEY_SIZE:
72 cmac_aes128_set_key(&inst->context.aes128, key);
73 break;
74 case AES256_KEY_SIZE:
75 cmac_aes256_set_key(&inst->context.aes256, key);
76 break;
77 default:
78 assert(0);
79 }
80
81 return inst;
82 }
83
84 /* ================================================== */
85
86 int
CMC_Hash(CMC_Instance inst,const void * in,int in_len,unsigned char * out,int out_len)87 CMC_Hash(CMC_Instance inst, const void *in, int in_len, unsigned char *out, int out_len)
88 {
89 if (in_len < 0 || out_len < 0)
90 return 0;
91
92 if (out_len > CMAC128_DIGEST_SIZE)
93 out_len = CMAC128_DIGEST_SIZE;
94
95 switch (inst->key_length) {
96 case AES128_KEY_SIZE:
97 cmac_aes128_update(&inst->context.aes128, in_len, in);
98 cmac_aes128_digest(&inst->context.aes128, out_len, out);
99 break;
100 case AES256_KEY_SIZE:
101 cmac_aes256_update(&inst->context.aes256, in_len, in);
102 cmac_aes256_digest(&inst->context.aes256, out_len, out);
103 break;
104 default:
105 assert(0);
106 }
107
108 return out_len;
109 }
110
111 /* ================================================== */
112
113 void
CMC_DestroyInstance(CMC_Instance inst)114 CMC_DestroyInstance(CMC_Instance inst)
115 {
116 Free(inst);
117 }
118