package/px5g/src/library/havege.c

   1 /*
   2  *  HAVEGE: HArdware Volatile Entropy Gathering and Expansion
   3  *
   4  *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
   5  *
   6  *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
   7  *
   8  *  All rights reserved.
   9  *
  10  *  Redistribution and use in source and binary forms, with or without
  11  *  modification, are permitted provided that the following conditions
  12  *  are met:
  13  *
  14  *    * Redistributions of source code must retain the above copyright
  15  *      notice, this list of conditions and the following disclaimer.
  16  *    * Redistributions in binary form must reproduce the above copyright
  17  *      notice, this list of conditions and the following disclaimer in the
  18  *      documentation and/or other materials provided with the distribution.
  19  *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
  20  *      may be used to endorse or promote products derived from this software
  21  *      without specific prior written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  26  *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35 /*
  36  *  The HAVEGE RNG was designed by Andre Seznec in 2002.
  37  *
  38  *  http://www.irisa.fr/caps/projects/hipsor/publi.php
  39  *
  40  *  Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
  41  */
  42
  43 #include <string.h>
  44 #include <time.h>
  45
  46 #include "polarssl/config.h"
  47
  48 #if defined(POLARSSL_HAVEGE_C)
  49
  50 #include "polarssl/havege.h"
  51 #include "polarssl/timing.h"
  52
  53 /* ------------------------------------------------------------------------
  54  * On average, one iteration accesses two 8-word blocks in the havege WALK
  55  * table, and generates 16 words in the RES array.
  56  *
  57  * The data read in the WALK table is updated and permuted after each use.
  58  * The result of the hardware clock counter read is used  for this update.
  59  *
  60  * 25 conditional tests are present.  The conditional tests are grouped in
  61  * two nested  groups of 12 conditional tests and 1 test that controls the
  62  * permutation; on average, there should be 6 tests executed and 3 of them
  63  * should be mispredicted.
  64  * ------------------------------------------------------------------------
  65  */
  66
  67 #define SWAP(X,Y) { int *T = X; X = Y; Y = T; }
  68
  69 #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
  70 #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
  71
  72 #define TST1_LEAVE U1++; }
  73 #define TST2_LEAVE U2++; }
  74
  75 #define ONE_ITERATION                                   \
  76                                                         \
  77     PTEST = PT1 >> 20;                                  \
  78                                                         \
  79     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  80     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  81     TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
  82                                                         \
  83     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  84     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  85     TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
  86                                                         \
  87     PTX = (PT1 >> 18) & 7;                              \
  88     PT1 &= 0x1FFF;                                      \
  89     PT2 &= 0x1FFF;                                      \
  90     CLK = (int) hardclock();                            \
  91                                                         \
  92     i = 0;                                              \
  93     A = &WALK[PT1    ]; RES[i++] ^= *A;                 \
  94     B = &WALK[PT2    ]; RES[i++] ^= *B;                 \
  95     C = &WALK[PT1 ^ 1]; RES[i++] ^= *C;                 \
  96     D = &WALK[PT2 ^ 4]; RES[i++] ^= *D;                 \
  97                                                         \
  98     IN = (*A >> (1)) ^ (*A << (31)) ^ CLK;              \
  99     *A = (*B >> (2)) ^ (*B << (30)) ^ CLK;              \
 100     *B = IN ^ U1;                                       \
 101     *C = (*C >> (3)) ^ (*C << (29)) ^ CLK;              \
 102     *D = (*D >> (4)) ^ (*D << (28)) ^ CLK;              \
 103                                                         \
 104     A = &WALK[PT1 ^ 2]; RES[i++] ^= *A;                 \
 105     B = &WALK[PT2 ^ 2]; RES[i++] ^= *B;                 \
 106     C = &WALK[PT1 ^ 3]; RES[i++] ^= *C;                 \
 107     D = &WALK[PT2 ^ 6]; RES[i++] ^= *D;                 \
 108                                                         \
 109     if( PTEST & 1 ) SWAP( A, C );                       \
 110                                                         \
 111     IN = (*A >> (5)) ^ (*A << (27)) ^ CLK;              \
 112     *A = (*B >> (6)) ^ (*B << (26)) ^ CLK;              \
 113     *B = IN; CLK = (int) hardclock();                   \
 114     *C = (*C >> (7)) ^ (*C << (25)) ^ CLK;              \
 115     *D = (*D >> (8)) ^ (*D << (24)) ^ CLK;              \
 116                                                         \
 117     A = &WALK[PT1 ^ 4];                                 \
 118     B = &WALK[PT2 ^ 1];                                 \
 119                                                         \
 120     PTEST = PT2 >> 1;                                   \
 121                                                         \
 122     PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]);   \
 123     PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8);  \
 124     PTY = (PT2 >> 10) & 7;                              \
 125                                                         \
 126     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 127     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 128     TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
 129                                                         \
 130     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 131     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 132     TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
 133                                                         \
 134     C = &WALK[PT1 ^ 5];                                 \
 135     D = &WALK[PT2 ^ 5];                                 \
 136                                                         \
 137     RES[i++] ^= *A;                                     \
 138     RES[i++] ^= *B;                                     \
 139     RES[i++] ^= *C;                                     \
 140     RES[i++] ^= *D;                                     \
 141                                                         \
 142     IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK;             \
 143     *A = (*B >> (10)) ^ (*B << (22)) ^ CLK;             \
 144     *B = IN ^ U2;                                       \
 145     *C = (*C >> (11)) ^ (*C << (21)) ^ CLK;             \
 146     *D = (*D >> (12)) ^ (*D << (20)) ^ CLK;             \
 147                                                         \
 148     A = &WALK[PT1 ^ 6]; RES[i++] ^= *A;                 \
 149     B = &WALK[PT2 ^ 3]; RES[i++] ^= *B;                 \
 150     C = &WALK[PT1 ^ 7]; RES[i++] ^= *C;                 \
 151     D = &WALK[PT2 ^ 7]; RES[i++] ^= *D;                 \
 152                                                         \
 153     IN = (*A >> (13)) ^ (*A << (19)) ^ CLK;             \
 154     *A = (*B >> (14)) ^ (*B << (18)) ^ CLK;             \
 155     *B = IN;                                            \
 156     *C = (*C >> (15)) ^ (*C << (17)) ^ CLK;             \
 157     *D = (*D >> (16)) ^ (*D << (16)) ^ CLK;             \
 158                                                         \
 159     PT1 = ( RES[(i - 8) ^ PTX] ^                        \
 160             WALK[PT1 ^ PTX ^ 7] ) & (~1);               \
 161     PT1 ^= (PT2 ^ 0x10) & 0x10;                         \
 162                                                         \
 163     for( n++, i = 0; i < 16; i++ )                      \
 164         hs->pool[n % COLLECT_SIZE] ^= RES[i];
 165
 166 /*
 167  * Entropy gathering function
 168  */
 169 static void havege_fill( havege_state *hs )
 170 {
 171     int i, n = 0;
 172     int  U1,  U2, *A, *B, *C, *D;
 173     int PT1, PT2, *WALK, RES[16];
 174     int PTX, PTY, CLK, PTEST, IN;
 175
 176     WALK = hs->WALK;
 177     PT1  = hs->PT1;
 178     PT2  = hs->PT2;
 179
 180     PTX  = U1 = 0;
 181     PTY  = U2 = 0;
 182
 183     memset( RES, 0, sizeof( RES ) );
 184
 185     while( n < COLLECT_SIZE * 4 )
 186     {
 187         ONE_ITERATION
 188         ONE_ITERATION
 189         ONE_ITERATION
 190         ONE_ITERATION
 191     }
 192
 193     hs->PT1 = PT1;
 194     hs->PT2 = PT2;
 195
 196     hs->offset[0] = 0;
 197     hs->offset[1] = COLLECT_SIZE / 2;
 198 }
 199
 200 /*
 201  * HAVEGE initialization
 202  */
 203 void havege_init( havege_state *hs )
 204 {
 205     memset( hs, 0, sizeof( havege_state ) );
 206
 207     havege_fill( hs );
 208 }
 209
 210 /*
 211  * HAVEGE rand function
 212  */
 213 int havege_rand( void *p_rng )
 214 {
 215     int ret;
 216     havege_state *hs = (havege_state *) p_rng;
 217
 218     if( hs->offset[1] >= COLLECT_SIZE )
 219         havege_fill( hs );
 220
 221     ret  = hs->pool[hs->offset[0]++];
 222     ret ^= hs->pool[hs->offset[1]++];
 223
 224     return( ret );
 225 }
 226
 227 #if defined(POLARSSL_RAND_TEST)
 228
 229 #include <stdio.h>
 230
 231 int main( int argc, char *argv[] )
 232 {
 233     FILE *f;
 234     time_t t;
 235     int i, j, k;
 236     havege_state hs;
 237     unsigned char buf[1024];
 238
 239     if( argc < 2 )
 240     {
 241         fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
 242         return( 1 );
 243     }
 244
 245     if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
 246     {
 247         printf( "failed to open '%s' for writing.\n", argv[0] );
 248         return( 1 );
 249     }
 250
 251     havege_init( &hs );
 252
 253     t = time( NULL );
 254
 255     for( i = 0, k = 32768; i < k; i++ )
 256     {
 257         for( j = 0; j < sizeof( buf ); j++ )
 258             buf[j] = havege_rand( &hs );
 259
 260         fwrite( buf, sizeof( buf ), 1, f );
 261
 262         printf( "Generating 32Mb of data in file '%s'... %04.1f" \
 263                 "%% done\r", argv[1], (100 * (float) (i + 1)) / k );
 264         fflush( stdout );
 265     }
 266
 267     if( t == time( NULL ) )
 268         t--;
 269
 270     fclose( f );
 271     return( 0 );
 272 }
 273
 274 #endif
 275
 276 #endif