Marco Zecchini / Mbed OS Example_RTOS

Rtos API example

mbed-os/features/mbedtls/src/havege.c@0:9fca2b23d0ba, 2019-02-23 (annotated)

Committer:
marcozecchini
Date:
Sat Feb 23 12:13:36 2019 +0000
Revision:
0:9fca2b23d0ba
final commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
marcozecchini 0:9fca2b23d0ba 1 /**
marcozecchini 0:9fca2b23d0ba 2 * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
marcozecchini 0:9fca2b23d0ba 3 *
marcozecchini 0:9fca2b23d0ba 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
marcozecchini 0:9fca2b23d0ba 5 * SPDX-License-Identifier: Apache-2.0
marcozecchini 0:9fca2b23d0ba 6 *
marcozecchini 0:9fca2b23d0ba 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
marcozecchini 0:9fca2b23d0ba 8 * not use this file except in compliance with the License.
marcozecchini 0:9fca2b23d0ba 9 * You may obtain a copy of the License at
marcozecchini 0:9fca2b23d0ba 10 *
marcozecchini 0:9fca2b23d0ba 11 * http://www.apache.org/licenses/LICENSE-2.0
marcozecchini 0:9fca2b23d0ba 12 *
marcozecchini 0:9fca2b23d0ba 13 * Unless required by applicable law or agreed to in writing, software
marcozecchini 0:9fca2b23d0ba 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
marcozecchini 0:9fca2b23d0ba 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
marcozecchini 0:9fca2b23d0ba 16 * See the License for the specific language governing permissions and
marcozecchini 0:9fca2b23d0ba 17 * limitations under the License.
marcozecchini 0:9fca2b23d0ba 18 *
marcozecchini 0:9fca2b23d0ba 19 * This file is part of mbed TLS (https://tls.mbed.org)
marcozecchini 0:9fca2b23d0ba 20 */
marcozecchini 0:9fca2b23d0ba 21 /*
marcozecchini 0:9fca2b23d0ba 22 * The HAVEGE RNG was designed by Andre Seznec in 2002.
marcozecchini 0:9fca2b23d0ba 23 *
marcozecchini 0:9fca2b23d0ba 24 * http://www.irisa.fr/caps/projects/hipsor/publi.php
marcozecchini 0:9fca2b23d0ba 25 *
marcozecchini 0:9fca2b23d0ba 26 * Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
marcozecchini 0:9fca2b23d0ba 27 */
marcozecchini 0:9fca2b23d0ba 28
marcozecchini 0:9fca2b23d0ba 29 #if !defined(MBEDTLS_CONFIG_FILE)
marcozecchini 0:9fca2b23d0ba 30 #include "mbedtls/config.h"
marcozecchini 0:9fca2b23d0ba 31 #else
marcozecchini 0:9fca2b23d0ba 32 #include MBEDTLS_CONFIG_FILE
marcozecchini 0:9fca2b23d0ba 33 #endif
marcozecchini 0:9fca2b23d0ba 34
marcozecchini 0:9fca2b23d0ba 35 #if defined(MBEDTLS_HAVEGE_C)
marcozecchini 0:9fca2b23d0ba 36
marcozecchini 0:9fca2b23d0ba 37 #include "mbedtls/havege.h"
marcozecchini 0:9fca2b23d0ba 38 #include "mbedtls/timing.h"
marcozecchini 0:9fca2b23d0ba 39
marcozecchini 0:9fca2b23d0ba 40 #include <string.h>
marcozecchini 0:9fca2b23d0ba 41
marcozecchini 0:9fca2b23d0ba 42 /* Implementation that should never be optimized out by the compiler */
marcozecchini 0:9fca2b23d0ba 43 static void mbedtls_zeroize( void *v, size_t n ) {
marcozecchini 0:9fca2b23d0ba 44 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
marcozecchini 0:9fca2b23d0ba 45 }
marcozecchini 0:9fca2b23d0ba 46
marcozecchini 0:9fca2b23d0ba 47 /* ------------------------------------------------------------------------
marcozecchini 0:9fca2b23d0ba 48 * On average, one iteration accesses two 8-word blocks in the havege WALK
marcozecchini 0:9fca2b23d0ba 49 * table, and generates 16 words in the RES array.
marcozecchini 0:9fca2b23d0ba 50 *
marcozecchini 0:9fca2b23d0ba 51 * The data read in the WALK table is updated and permuted after each use.
marcozecchini 0:9fca2b23d0ba 52 * The result of the hardware clock counter read is used for this update.
marcozecchini 0:9fca2b23d0ba 53 *
marcozecchini 0:9fca2b23d0ba 54 * 25 conditional tests are present. The conditional tests are grouped in
marcozecchini 0:9fca2b23d0ba 55 * two nested groups of 12 conditional tests and 1 test that controls the
marcozecchini 0:9fca2b23d0ba 56 * permutation; on average, there should be 6 tests executed and 3 of them
marcozecchini 0:9fca2b23d0ba 57 * should be mispredicted.
marcozecchini 0:9fca2b23d0ba 58 * ------------------------------------------------------------------------
marcozecchini 0:9fca2b23d0ba 59 */
marcozecchini 0:9fca2b23d0ba 60
marcozecchini 0:9fca2b23d0ba 61 #define SWAP(X,Y) { int *T = X; X = Y; Y = T; }
marcozecchini 0:9fca2b23d0ba 62
marcozecchini 0:9fca2b23d0ba 63 #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
marcozecchini 0:9fca2b23d0ba 64 #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
marcozecchini 0:9fca2b23d0ba 65
marcozecchini 0:9fca2b23d0ba 66 #define TST1_LEAVE U1++; }
marcozecchini 0:9fca2b23d0ba 67 #define TST2_LEAVE U2++; }
marcozecchini 0:9fca2b23d0ba 68
marcozecchini 0:9fca2b23d0ba 69 #define ONE_ITERATION \
marcozecchini 0:9fca2b23d0ba 70 \
marcozecchini 0:9fca2b23d0ba 71 PTEST = PT1 >> 20; \
marcozecchini 0:9fca2b23d0ba 72 \
marcozecchini 0:9fca2b23d0ba 73 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
marcozecchini 0:9fca2b23d0ba 74 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
marcozecchini 0:9fca2b23d0ba 75 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
marcozecchini 0:9fca2b23d0ba 76 \
marcozecchini 0:9fca2b23d0ba 77 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
marcozecchini 0:9fca2b23d0ba 78 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
marcozecchini 0:9fca2b23d0ba 79 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
marcozecchini 0:9fca2b23d0ba 80 \
marcozecchini 0:9fca2b23d0ba 81 PTX = (PT1 >> 18) & 7; \
marcozecchini 0:9fca2b23d0ba 82 PT1 &= 0x1FFF; \
marcozecchini 0:9fca2b23d0ba 83 PT2 &= 0x1FFF; \
marcozecchini 0:9fca2b23d0ba 84 CLK = (int) mbedtls_timing_hardclock(); \
marcozecchini 0:9fca2b23d0ba 85 \
marcozecchini 0:9fca2b23d0ba 86 i = 0; \
marcozecchini 0:9fca2b23d0ba 87 A = &WALK[PT1 ]; RES[i++] ^= *A; \
marcozecchini 0:9fca2b23d0ba 88 B = &WALK[PT2 ]; RES[i++] ^= *B; \
marcozecchini 0:9fca2b23d0ba 89 C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \
marcozecchini 0:9fca2b23d0ba 90 D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \
marcozecchini 0:9fca2b23d0ba 91 \
marcozecchini 0:9fca2b23d0ba 92 IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 93 *A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 94 *B = IN ^ U1; \
marcozecchini 0:9fca2b23d0ba 95 *C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 96 *D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 97 \
marcozecchini 0:9fca2b23d0ba 98 A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \
marcozecchini 0:9fca2b23d0ba 99 B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \
marcozecchini 0:9fca2b23d0ba 100 C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \
marcozecchini 0:9fca2b23d0ba 101 D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \
marcozecchini 0:9fca2b23d0ba 102 \
marcozecchini 0:9fca2b23d0ba 103 if( PTEST & 1 ) SWAP( A, C ); \
marcozecchini 0:9fca2b23d0ba 104 \
marcozecchini 0:9fca2b23d0ba 105 IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 106 *A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 107 *B = IN; CLK = (int) mbedtls_timing_hardclock(); \
marcozecchini 0:9fca2b23d0ba 108 *C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 109 *D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 110 \
marcozecchini 0:9fca2b23d0ba 111 A = &WALK[PT1 ^ 4]; \
marcozecchini 0:9fca2b23d0ba 112 B = &WALK[PT2 ^ 1]; \
marcozecchini 0:9fca2b23d0ba 113 \
marcozecchini 0:9fca2b23d0ba 114 PTEST = PT2 >> 1; \
marcozecchini 0:9fca2b23d0ba 115 \
marcozecchini 0:9fca2b23d0ba 116 PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \
marcozecchini 0:9fca2b23d0ba 117 PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \
marcozecchini 0:9fca2b23d0ba 118 PTY = (PT2 >> 10) & 7; \
marcozecchini 0:9fca2b23d0ba 119 \
marcozecchini 0:9fca2b23d0ba 120 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
marcozecchini 0:9fca2b23d0ba 121 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
marcozecchini 0:9fca2b23d0ba 122 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
marcozecchini 0:9fca2b23d0ba 123 \
marcozecchini 0:9fca2b23d0ba 124 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
marcozecchini 0:9fca2b23d0ba 125 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
marcozecchini 0:9fca2b23d0ba 126 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
marcozecchini 0:9fca2b23d0ba 127 \
marcozecchini 0:9fca2b23d0ba 128 C = &WALK[PT1 ^ 5]; \
marcozecchini 0:9fca2b23d0ba 129 D = &WALK[PT2 ^ 5]; \
marcozecchini 0:9fca2b23d0ba 130 \
marcozecchini 0:9fca2b23d0ba 131 RES[i++] ^= *A; \
marcozecchini 0:9fca2b23d0ba 132 RES[i++] ^= *B; \
marcozecchini 0:9fca2b23d0ba 133 RES[i++] ^= *C; \
marcozecchini 0:9fca2b23d0ba 134 RES[i++] ^= *D; \
marcozecchini 0:9fca2b23d0ba 135 \
marcozecchini 0:9fca2b23d0ba 136 IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 137 *A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 138 *B = IN ^ U2; \
marcozecchini 0:9fca2b23d0ba 139 *C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 140 *D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 141 \
marcozecchini 0:9fca2b23d0ba 142 A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \
marcozecchini 0:9fca2b23d0ba 143 B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \
marcozecchini 0:9fca2b23d0ba 144 C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \
marcozecchini 0:9fca2b23d0ba 145 D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \
marcozecchini 0:9fca2b23d0ba 146 \
marcozecchini 0:9fca2b23d0ba 147 IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 148 *A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 149 *B = IN; \
marcozecchini 0:9fca2b23d0ba 150 *C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 151 *D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \
marcozecchini 0:9fca2b23d0ba 152 \
marcozecchini 0:9fca2b23d0ba 153 PT1 = ( RES[( i - 8 ) ^ PTX] ^ \
marcozecchini 0:9fca2b23d0ba 154 WALK[PT1 ^ PTX ^ 7] ) & (~1); \
marcozecchini 0:9fca2b23d0ba 155 PT1 ^= (PT2 ^ 0x10) & 0x10; \
marcozecchini 0:9fca2b23d0ba 156 \
marcozecchini 0:9fca2b23d0ba 157 for( n++, i = 0; i < 16; i++ ) \
marcozecchini 0:9fca2b23d0ba 158 hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i];
marcozecchini 0:9fca2b23d0ba 159
marcozecchini 0:9fca2b23d0ba 160 /*
marcozecchini 0:9fca2b23d0ba 161 * Entropy gathering function
marcozecchini 0:9fca2b23d0ba 162 */
marcozecchini 0:9fca2b23d0ba 163 static void havege_fill( mbedtls_havege_state *hs )
marcozecchini 0:9fca2b23d0ba 164 {
marcozecchini 0:9fca2b23d0ba 165 int i, n = 0;
marcozecchini 0:9fca2b23d0ba 166 int U1, U2, *A, *B, *C, *D;
marcozecchini 0:9fca2b23d0ba 167 int PT1, PT2, *WALK, RES[16];
marcozecchini 0:9fca2b23d0ba 168 int PTX, PTY, CLK, PTEST, IN;
marcozecchini 0:9fca2b23d0ba 169
marcozecchini 0:9fca2b23d0ba 170 WALK = hs->WALK;
marcozecchini 0:9fca2b23d0ba 171 PT1 = hs->PT1;
marcozecchini 0:9fca2b23d0ba 172 PT2 = hs->PT2;
marcozecchini 0:9fca2b23d0ba 173
marcozecchini 0:9fca2b23d0ba 174 PTX = U1 = 0;
marcozecchini 0:9fca2b23d0ba 175 PTY = U2 = 0;
marcozecchini 0:9fca2b23d0ba 176
marcozecchini 0:9fca2b23d0ba 177 (void)PTX;
marcozecchini 0:9fca2b23d0ba 178
marcozecchini 0:9fca2b23d0ba 179 memset( RES, 0, sizeof( RES ) );
marcozecchini 0:9fca2b23d0ba 180
marcozecchini 0:9fca2b23d0ba 181 while( n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4 )
marcozecchini 0:9fca2b23d0ba 182 {
marcozecchini 0:9fca2b23d0ba 183 ONE_ITERATION
marcozecchini 0:9fca2b23d0ba 184 ONE_ITERATION
marcozecchini 0:9fca2b23d0ba 185 ONE_ITERATION
marcozecchini 0:9fca2b23d0ba 186 ONE_ITERATION
marcozecchini 0:9fca2b23d0ba 187 }
marcozecchini 0:9fca2b23d0ba 188
marcozecchini 0:9fca2b23d0ba 189 hs->PT1 = PT1;
marcozecchini 0:9fca2b23d0ba 190 hs->PT2 = PT2;
marcozecchini 0:9fca2b23d0ba 191
marcozecchini 0:9fca2b23d0ba 192 hs->offset[0] = 0;
marcozecchini 0:9fca2b23d0ba 193 hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2;
marcozecchini 0:9fca2b23d0ba 194 }
marcozecchini 0:9fca2b23d0ba 195
marcozecchini 0:9fca2b23d0ba 196 /*
marcozecchini 0:9fca2b23d0ba 197 * HAVEGE initialization
marcozecchini 0:9fca2b23d0ba 198 */
marcozecchini 0:9fca2b23d0ba 199 void mbedtls_havege_init( mbedtls_havege_state *hs )
marcozecchini 0:9fca2b23d0ba 200 {
marcozecchini 0:9fca2b23d0ba 201 memset( hs, 0, sizeof( mbedtls_havege_state ) );
marcozecchini 0:9fca2b23d0ba 202
marcozecchini 0:9fca2b23d0ba 203 havege_fill( hs );
marcozecchini 0:9fca2b23d0ba 204 }
marcozecchini 0:9fca2b23d0ba 205
marcozecchini 0:9fca2b23d0ba 206 void mbedtls_havege_free( mbedtls_havege_state *hs )
marcozecchini 0:9fca2b23d0ba 207 {
marcozecchini 0:9fca2b23d0ba 208 if( hs == NULL )
marcozecchini 0:9fca2b23d0ba 209 return;
marcozecchini 0:9fca2b23d0ba 210
marcozecchini 0:9fca2b23d0ba 211 mbedtls_zeroize( hs, sizeof( mbedtls_havege_state ) );
marcozecchini 0:9fca2b23d0ba 212 }
marcozecchini 0:9fca2b23d0ba 213
marcozecchini 0:9fca2b23d0ba 214 /*
marcozecchini 0:9fca2b23d0ba 215 * HAVEGE rand function
marcozecchini 0:9fca2b23d0ba 216 */
marcozecchini 0:9fca2b23d0ba 217 int mbedtls_havege_random( void *p_rng, unsigned char *buf, size_t len )
marcozecchini 0:9fca2b23d0ba 218 {
marcozecchini 0:9fca2b23d0ba 219 int val;
marcozecchini 0:9fca2b23d0ba 220 size_t use_len;
marcozecchini 0:9fca2b23d0ba 221 mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng;
marcozecchini 0:9fca2b23d0ba 222 unsigned char *p = buf;
marcozecchini 0:9fca2b23d0ba 223
marcozecchini 0:9fca2b23d0ba 224 while( len > 0 )
marcozecchini 0:9fca2b23d0ba 225 {
marcozecchini 0:9fca2b23d0ba 226 use_len = len;
marcozecchini 0:9fca2b23d0ba 227 if( use_len > sizeof(int) )
marcozecchini 0:9fca2b23d0ba 228 use_len = sizeof(int);
marcozecchini 0:9fca2b23d0ba 229
marcozecchini 0:9fca2b23d0ba 230 if( hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE )
marcozecchini 0:9fca2b23d0ba 231 havege_fill( hs );
marcozecchini 0:9fca2b23d0ba 232
marcozecchini 0:9fca2b23d0ba 233 val = hs->pool[hs->offset[0]++];
marcozecchini 0:9fca2b23d0ba 234 val ^= hs->pool[hs->offset[1]++];
marcozecchini 0:9fca2b23d0ba 235
marcozecchini 0:9fca2b23d0ba 236 memcpy( p, &val, use_len );
marcozecchini 0:9fca2b23d0ba 237
marcozecchini 0:9fca2b23d0ba 238 len -= use_len;
marcozecchini 0:9fca2b23d0ba 239 p += use_len;
marcozecchini 0:9fca2b23d0ba 240 }
marcozecchini 0:9fca2b23d0ba 241
marcozecchini 0:9fca2b23d0ba 242 return( 0 );
marcozecchini 0:9fca2b23d0ba 243 }
marcozecchini 0:9fca2b23d0ba 244
marcozecchini 0:9fca2b23d0ba 245 #endif /* MBEDTLS_HAVEGE_C */