summaryrefslogtreecommitdiffhomepage
path: root/libs/px5g/src/library/havege.c
blob: 266299d3bbbf414728085228f4f36ea986fa8150 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/*
 *  HAVEGE: HArdware Volatile Entropy Gathering and Expansion
 *
 *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
 *
 *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *  
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *  The HAVEGE RNG was designed by Andre Seznec in 2002.
 *
 *  http://www.irisa.fr/caps/projects/hipsor/publi.php
 *
 *  Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
 */

#include <string.h>
#include <time.h>

#include "polarssl/config.h"

#if defined(POLARSSL_HAVEGE_C)

#include "polarssl/havege.h"
#include "polarssl/timing.h"

/* ------------------------------------------------------------------------
 * On average, one iteration accesses two 8-word blocks in the havege WALK
 * table, and generates 16 words in the RES array.
 *
 * The data read in the WALK table is updated and permuted after each use.
 * The result of the hardware clock counter read is used  for this update.
 *
 * 25 conditional tests are present.  The conditional tests are grouped in
 * two nested  groups of 12 conditional tests and 1 test that controls the
 * permutation; on average, there should be 6 tests executed and 3 of them
 * should be mispredicted.
 * ------------------------------------------------------------------------
 */

#define SWAP(X,Y) { int *T = X; X = Y; Y = T; }

#define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
#define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;

#define TST1_LEAVE U1++; }
#define TST2_LEAVE U2++; }

#define ONE_ITERATION                                   \
                                                        \
    PTEST = PT1 >> 20;                                  \
                                                        \
    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
                                                        \
    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
                                                        \
    PTX = (PT1 >> 18) & 7;                              \
    PT1 &= 0x1FFF;                                      \
    PT2 &= 0x1FFF;                                      \
    CLK = (int) hardclock();                            \
                                                        \
    i = 0;                                              \
    A = &WALK[PT1    ]; RES[i++] ^= *A;                 \
    B = &WALK[PT2    ]; RES[i++] ^= *B;                 \
    C = &WALK[PT1 ^ 1]; RES[i++] ^= *C;                 \
    D = &WALK[PT2 ^ 4]; RES[i++] ^= *D;                 \
                                                        \
    IN = (*A >> (1)) ^ (*A << (31)) ^ CLK;              \
    *A = (*B >> (2)) ^ (*B << (30)) ^ CLK;              \
    *B = IN ^ U1;                                       \
    *C = (*C >> (3)) ^ (*C << (29)) ^ CLK;              \
    *D = (*D >> (4)) ^ (*D << (28)) ^ CLK;              \
                                                        \
    A = &WALK[PT1 ^ 2]; RES[i++] ^= *A;                 \
    B = &WALK[PT2 ^ 2]; RES[i++] ^= *B;                 \
    C = &WALK[PT1 ^ 3]; RES[i++] ^= *C;                 \
    D = &WALK[PT2 ^ 6]; RES[i++] ^= *D;                 \
                                                        \
    if( PTEST & 1 ) SWAP( A, C );                       \
                                                        \
    IN = (*A >> (5)) ^ (*A << (27)) ^ CLK;              \
    *A = (*B >> (6)) ^ (*B << (26)) ^ CLK;              \
    *B = IN; CLK = (int) hardclock();                   \
    *C = (*C >> (7)) ^ (*C << (25)) ^ CLK;              \
    *D = (*D >> (8)) ^ (*D << (24)) ^ CLK;              \
                                                        \
    A = &WALK[PT1 ^ 4];                                 \
    B = &WALK[PT2 ^ 1];                                 \
                                                        \
    PTEST = PT2 >> 1;                                   \
                                                        \
    PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]);   \
    PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8);  \
    PTY = (PT2 >> 10) & 7;                              \
                                                        \
    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
                                                        \
    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
                                                        \
    C = &WALK[PT1 ^ 5];                                 \
    D = &WALK[PT2 ^ 5];                                 \
                                                        \
    RES[i++] ^= *A;                                     \
    RES[i++] ^= *B;                                     \
    RES[i++] ^= *C;                                     \
    RES[i++] ^= *D;                                     \
                                                        \
    IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK;             \
    *A = (*B >> (10)) ^ (*B << (22)) ^ CLK;             \
    *B = IN ^ U2;                                       \
    *C = (*C >> (11)) ^ (*C << (21)) ^ CLK;             \
    *D = (*D >> (12)) ^ (*D << (20)) ^ CLK;             \
                                                        \
    A = &WALK[PT1 ^ 6]; RES[i++] ^= *A;                 \
    B = &WALK[PT2 ^ 3]; RES[i++] ^= *B;                 \
    C = &WALK[PT1 ^ 7]; RES[i++] ^= *C;                 \
    D = &WALK[PT2 ^ 7]; RES[i++] ^= *D;                 \
                                                        \
    IN = (*A >> (13)) ^ (*A << (19)) ^ CLK;             \
    *A = (*B >> (14)) ^ (*B << (18)) ^ CLK;             \
    *B = IN;                                            \
    *C = (*C >> (15)) ^ (*C << (17)) ^ CLK;             \
    *D = (*D >> (16)) ^ (*D << (16)) ^ CLK;             \
                                                        \
    PT1 = ( RES[(i - 8) ^ PTX] ^                        \
            WALK[PT1 ^ PTX ^ 7] ) & (~1);               \
    PT1 ^= (PT2 ^ 0x10) & 0x10;                         \
                                                        \
    for( n++, i = 0; i < 16; i++ )                      \
        hs->pool[n % COLLECT_SIZE] ^= RES[i];

/*
 * Entropy gathering function
 */
static void havege_fill( havege_state *hs )
{
    int i, n = 0;
    int  U1,  U2, *A, *B, *C, *D;
    int PT1, PT2, *WALK, RES[16];
    int PTX, PTY, CLK, PTEST, IN;

    WALK = hs->WALK;
    PT1  = hs->PT1;
    PT2  = hs->PT2;

    PTX  = U1 = 0;
    PTY  = U2 = 0;

    memset( RES, 0, sizeof( RES ) );

    while( n < COLLECT_SIZE * 4 )
    {
        ONE_ITERATION
        ONE_ITERATION
        ONE_ITERATION
        ONE_ITERATION
    }

    hs->PT1 = PT1;
    hs->PT2 = PT2;

    hs->offset[0] = 0;
    hs->offset[1] = COLLECT_SIZE / 2;
}

/*
 * HAVEGE initialization
 */
void havege_init( havege_state *hs )
{
    memset( hs, 0, sizeof( havege_state ) );

    havege_fill( hs );
}

/*
 * HAVEGE rand function
 */
int havege_rand( void *p_rng )
{
    int ret;
    havege_state *hs = (havege_state *) p_rng;

    if( hs->offset[1] >= COLLECT_SIZE )
        havege_fill( hs );

    ret  = hs->pool[hs->offset[0]++];
    ret ^= hs->pool[hs->offset[1]++];

    return( ret );
}

#if defined(POLARSSL_RAND_TEST)

#include <stdio.h>

int main( int argc, char *argv[] )
{
    FILE *f;
    time_t t;
    int i, j, k;
    havege_state hs;
    unsigned char buf[1024];

    if( argc < 2 )
    {
        fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
        return( 1 );
    }

    if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
    {
        printf( "failed to open '%s' for writing.\n", argv[0] );
        return( 1 );
    }

    havege_init( &hs );

    t = time( NULL );

    for( i = 0, k = 32768; i < k; i++ )
    {
        for( j = 0; j < sizeof( buf ); j++ )
            buf[j] = havege_rand( &hs );

        fwrite( buf, sizeof( buf ), 1, f );

        printf( "Generating 32Mb of data in file '%s'... %04.1f" \
                "%% done\r", argv[1], (100 * (float) (i + 1)) / k );
        fflush( stdout );
    }

    if( t == time( NULL ) )
        t--;

    fclose( f );
    return( 0 );
}

#endif

#endif