reactos/dll/3rdparty/mbedtls/havege.c

   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
  40 #include <string.h>
  41
  42 /* Implementation that should never be optimized out by the compiler */
  43 static void mbedtls_zeroize( void *v, size_t n ) {
  44     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
  45 }
  46
  47 /* ------------------------------------------------------------------------
  48  * On average, one iteration accesses two 8-word blocks in the havege WALK
  49  * table, and generates 16 words in the RES array.
  50  *
  51  * The data read in the WALK table is updated and permuted after each use.
  52  * The result of the hardware clock counter read is used  for this update.
  53  *
  54  * 25 conditional tests are present.  The conditional tests are grouped in
  55  * two nested  groups of 12 conditional tests and 1 test that controls the
  56  * permutation; on average, there should be 6 tests executed and 3 of them
  57  * should be mispredicted.
  58  * ------------------------------------------------------------------------
  59  */
  60
  61 #define SWAP(X,Y) { int *T = X; X = Y; Y = T; }
  62
  63 #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
  64 #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
  65
  66 #define TST1_LEAVE U1++; }
  67 #define TST2_LEAVE U2++; }
  68
  69 #define ONE_ITERATION                                   \
  70                                                         \
  71     PTEST = PT1 >> 20;                                  \
  72                                                         \
  73     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  74     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  75     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  76                                                         \
  77     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  78     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  79     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  80                                                         \
  81     PTX = (PT1 >> 18) & 7;                              \
  82     PT1 &= 0x1FFF;                                      \
  83     PT2 &= 0x1FFF;                                      \
  84     CLK = (int) mbedtls_timing_hardclock();                            \
  85                                                         \
  86     i = 0;                                              \
  87     A = &WALK[PT1    ]; RES[i++] ^= *A;                 \
  88     B = &WALK[PT2    ]; RES[i++] ^= *B;                 \
  89     C = &WALK[PT1 ^ 1]; RES[i++] ^= *C;                 \
  90     D = &WALK[PT2 ^ 4]; RES[i++] ^= *D;                 \
  91                                                         \
  92     IN = (*A >> (1)) ^ (*A << (31)) ^ CLK;              \
  93     *A = (*B >> (2)) ^ (*B << (30)) ^ CLK;              \
  94     *B = IN ^ U1;                                       \
  95     *C = (*C >> (3)) ^ (*C << (29)) ^ CLK;              \
  96     *D = (*D >> (4)) ^ (*D << (28)) ^ CLK;              \
  97                                                         \
  98     A = &WALK[PT1 ^ 2]; RES[i++] ^= *A;                 \
  99     B = &WALK[PT2 ^ 2]; RES[i++] ^= *B;                 \
 100     C = &WALK[PT1 ^ 3]; RES[i++] ^= *C;                 \
 101     D = &WALK[PT2 ^ 6]; RES[i++] ^= *D;                 \
 102                                                         \
 103     if( PTEST & 1 ) SWAP( A, C );                       \
 104                                                         \
 105     IN = (*A >> (5)) ^ (*A << (27)) ^ CLK;              \
 106     *A = (*B >> (6)) ^ (*B << (26)) ^ CLK;              \
 107     *B = IN; CLK = (int) mbedtls_timing_hardclock();                   \
 108     *C = (*C >> (7)) ^ (*C << (25)) ^ CLK;              \
 109     *D = (*D >> (8)) ^ (*D << (24)) ^ CLK;              \
 110                                                         \
 111     A = &WALK[PT1 ^ 4];                                 \
 112     B = &WALK[PT2 ^ 1];                                 \
 113                                                         \
 114     PTEST = PT2 >> 1;                                   \
 115                                                         \
 116     PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]);   \
 117     PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8);  \
 118     PTY = (PT2 >> 10) & 7;                              \
 119                                                         \
 120     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 121     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 122     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 123                                                         \
 124     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 125     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 126     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 127                                                         \
 128     C = &WALK[PT1 ^ 5];                                 \
 129     D = &WALK[PT2 ^ 5];                                 \
 130                                                         \
 131     RES[i++] ^= *A;                                     \
 132     RES[i++] ^= *B;                                     \
 133     RES[i++] ^= *C;                                     \
 134     RES[i++] ^= *D;                                     \
 135                                                         \
 136     IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK;             \
 137     *A = (*B >> (10)) ^ (*B << (22)) ^ CLK;             \
 138     *B = IN ^ U2;                                       \
 139     *C = (*C >> (11)) ^ (*C << (21)) ^ CLK;             \
 140     *D = (*D >> (12)) ^ (*D << (20)) ^ CLK;             \
 141                                                         \
 142     A = &WALK[PT1 ^ 6]; RES[i++] ^= *A;                 \
 143     B = &WALK[PT2 ^ 3]; RES[i++] ^= *B;                 \
 144     C = &WALK[PT1 ^ 7]; RES[i++] ^= *C;                 \
 145     D = &WALK[PT2 ^ 7]; RES[i++] ^= *D;                 \
 146                                                         \
 147     IN = (*A >> (13)) ^ (*A << (19)) ^ CLK;             \
 148     *A = (*B >> (14)) ^ (*B << (18)) ^ CLK;             \
 149     *B = IN;                                            \
 150     *C = (*C >> (15)) ^ (*C << (17)) ^ CLK;             \
 151     *D = (*D >> (16)) ^ (*D << (16)) ^ CLK;             \
 152                                                         \
 153     PT1 = ( RES[( i - 8 ) ^ PTX] ^                      \
 154             WALK[PT1 ^ PTX ^ 7] ) & (~1);               \
 155     PT1 ^= (PT2 ^ 0x10) & 0x10;                         \
 156                                                         \
 157     for( n++, i = 0; i < 16; i++ )                      \
 158         hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i];
 159
 160 /*
 161  * Entropy gathering function
 162  */
 163 static void havege_fill( mbedtls_havege_state *hs )
 164 {
 165     int i, n = 0;
 166     int  U1,  U2, *A, *B, *C, *D;
 167     int PT1, PT2, *WALK, RES[16];
 168     int PTX, PTY, CLK, PTEST, IN;
 169
 170     WALK = hs->WALK;
 171     PT1  = hs->PT1;
 172     PT2  = hs->PT2;
 173
 174     PTX  = U1 = 0;
 175     PTY  = U2 = 0;
 176
 177     memset( RES, 0, sizeof( RES ) );
 178
 179     while( n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4 )
 180     {
 181         ONE_ITERATION
 182         ONE_ITERATION
 183         ONE_ITERATION
 184         ONE_ITERATION
 185     }
 186
 187     hs->PT1 = PT1;
 188     hs->PT2 = PT2;
 189
 190     hs->offset[0] = 0;
 191     hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2;
 192 }
 193
 194 /*
 195  * HAVEGE initialization
 196  */
 197 void mbedtls_havege_init( mbedtls_havege_state *hs )
 198 {
 199     memset( hs, 0, sizeof( mbedtls_havege_state ) );
 200
 201     havege_fill( hs );
 202 }
 203
 204 void mbedtls_havege_free( mbedtls_havege_state *hs )
 205 {
 206     if( hs == NULL )
 207         return;
 208
 209     mbedtls_zeroize( hs, sizeof( mbedtls_havege_state ) );
 210 }
 211
 212 /*
 213  * HAVEGE rand function
 214  */
 215 int mbedtls_havege_random( void *p_rng, unsigned char *buf, size_t len )
 216 {
 217     int val;
 218     size_t use_len;
 219     mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng;
 220     unsigned char *p = buf;
 221
 222     while( len > 0 )
 223     {
 224         use_len = len;
 225         if( use_len > sizeof(int) )
 226             use_len = sizeof(int);
 227
 228         if( hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE )
 229             havege_fill( hs );
 230
 231         val  = hs->pool[hs->offset[0]++];
 232         val ^= hs->pool[hs->offset[1]++];
 233
 234         memcpy( p, &val, use_len );
 235
 236         len -= use_len;
 237         p += use_len;
 238     }
 239
 240     return( 0 );
 241 }
 242
 243 #endif /* MBEDTLS_HAVEGE_C */