source: azure_iot_hub_mbedtls/trunk/mbedtls-2.16.1/library/havege.c@ 398

Last change on this file since 398 was 398, checked in by coas-nagasima, 5 years ago

mbedTLS版Azure IoT Hub接続サンプルのソースコードを追加
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1/**
2 * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21/*
22 * The HAVEGE RNG was designed by Andre Seznec in 2002.
23 *
24 * http://www.irisa.fr/caps/projects/hipsor/publi.php
25 *
26 * Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
27 */
28
29#if !defined(MBEDTLS_CONFIG_FILE)
30#include "mbedtls/config.h"
31#else
32#include MBEDTLS_CONFIG_FILE
33#endif
34
35#if defined(MBEDTLS_HAVEGE_C)
36
37#include "mbedtls/havege.h"
38#include "mbedtls/timing.h"
39#include "mbedtls/platform_util.h"
40
41#include <string.h>
42
43/* ------------------------------------------------------------------------
44 * On average, one iteration accesses two 8-word blocks in the havege WALK
45 * table, and generates 16 words in the RES array.
46 *
47 * The data read in the WALK table is updated and permuted after each use.
48 * The result of the hardware clock counter read is used for this update.
49 *
50 * 25 conditional tests are present. The conditional tests are grouped in
51 * two nested groups of 12 conditional tests and 1 test that controls the
52 * permutation; on average, there should be 6 tests executed and 3 of them
53 * should be mispredicted.
54 * ------------------------------------------------------------------------
55 */
56
57#define SWAP(X,Y) { int *T = X; X = Y; Y = T; }
58
59#define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
60#define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
61
62#define TST1_LEAVE U1++; }
63#define TST2_LEAVE U2++; }
64
65#define ONE_ITERATION \
66 \
67 PTEST = PT1 >> 20; \
68 \
69 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
70 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
71 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
72 \
73 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
74 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
75 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
76 \
77 PTX = (PT1 >> 18) & 7; \
78 PT1 &= 0x1FFF; \
79 PT2 &= 0x1FFF; \
80 CLK = (int) mbedtls_timing_hardclock(); \
81 \
82 i = 0; \
83 A = &WALK[PT1 ]; RES[i++] ^= *A; \
84 B = &WALK[PT2 ]; RES[i++] ^= *B; \
85 C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \
86 D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \
87 \
88 IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \
89 *A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \
90 *B = IN ^ U1; \
91 *C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \
92 *D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \
93 \
94 A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \
95 B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \
96 C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \
97 D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \
98 \
99 if( PTEST & 1 ) SWAP( A, C ); \
100 \
101 IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \
102 *A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \
103 *B = IN; CLK = (int) mbedtls_timing_hardclock(); \
104 *C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \
105 *D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \
106 \
107 A = &WALK[PT1 ^ 4]; \
108 B = &WALK[PT2 ^ 1]; \
109 \
110 PTEST = PT2 >> 1; \
111 \
112 PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \
113 PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \
114 PTY = (PT2 >> 10) & 7; \
115 \
116 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
117 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
118 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
119 \
120 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
121 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
122 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
123 \
124 C = &WALK[PT1 ^ 5]; \
125 D = &WALK[PT2 ^ 5]; \
126 \
127 RES[i++] ^= *A; \
128 RES[i++] ^= *B; \
129 RES[i++] ^= *C; \
130 RES[i++] ^= *D; \
131 \
132 IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \
133 *A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \
134 *B = IN ^ U2; \
135 *C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \
136 *D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \
137 \
138 A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \
139 B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \
140 C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \
141 D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \
142 \
143 IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \
144 *A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \
145 *B = IN; \
146 *C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \
147 *D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \
148 \
149 PT1 = ( RES[( i - 8 ) ^ PTX] ^ \
150 WALK[PT1 ^ PTX ^ 7] ) & (~1); \
151 PT1 ^= (PT2 ^ 0x10) & 0x10; \
152 \
153 for( n++, i = 0; i < 16; i++ ) \
154 hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i];
155
156/*
157 * Entropy gathering function
158 */
159static void havege_fill( mbedtls_havege_state *hs )
160{
161 int i, n = 0;
162 int U1, U2, *A, *B, *C, *D;
163 int PT1, PT2, *WALK, RES[16];
164 int PTX, PTY, CLK, PTEST, IN;
165
166 WALK = hs->WALK;
167 PT1 = hs->PT1;
168 PT2 = hs->PT2;
169
170 PTX = U1 = 0;
171 PTY = U2 = 0;
172
173 (void)PTX;
174
175 memset( RES, 0, sizeof( RES ) );
176
177 while( n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4 )
178 {
179 ONE_ITERATION
180 ONE_ITERATION
181 ONE_ITERATION
182 ONE_ITERATION
183 }
184
185 hs->PT1 = PT1;
186 hs->PT2 = PT2;
187
188 hs->offset[0] = 0;
189 hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2;
190}
191
192/*
193 * HAVEGE initialization
194 */
195void mbedtls_havege_init( mbedtls_havege_state *hs )
196{
197 memset( hs, 0, sizeof( mbedtls_havege_state ) );
198
199 havege_fill( hs );
200}
201
202void mbedtls_havege_free( mbedtls_havege_state *hs )
203{
204 if( hs == NULL )
205 return;
206
207 mbedtls_platform_zeroize( hs, sizeof( mbedtls_havege_state ) );
208}
209
210/*
211 * HAVEGE rand function
212 */
213int mbedtls_havege_random( void *p_rng, unsigned char *buf, size_t len )
214{
215 int val;
216 size_t use_len;
217 mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng;
218 unsigned char *p = buf;
219
220 while( len > 0 )
221 {
222 use_len = len;
223 if( use_len > sizeof(int) )
224 use_len = sizeof(int);
225
226 if( hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE )
227 havege_fill( hs );
228
229 val = hs->pool[hs->offset[0]++];
230 val ^= hs->pool[hs->offset[1]++];
231
232 memcpy( p, &val, use_len );
233
234 len -= use_len;
235 p += use_len;
236 }
237
238 return( 0 );
239}
240
241#endif /* MBEDTLS_HAVEGE_C */
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