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
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
|
/* BEGIN_HEADER */
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "string.h"
/* Modes for ctr_drbg_validate */
enum reseed_mode
{
RESEED_NEVER, /* never reseed */
RESEED_FIRST, /* instantiate, reseed, generate, generate */
RESEED_SECOND, /* instantiate, generate, reseed, generate */
RESEED_ALWAYS /* prediction resistance, no explicit reseed */
};
static size_t test_offset_idx = 0;
static size_t test_max_idx = 0;
static int mbedtls_test_entropy_func( void *data, unsigned char *buf, size_t len )
{
const unsigned char *p = (unsigned char *) data;
if( test_offset_idx + len > test_max_idx )
return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
memcpy( buf, p + test_offset_idx, len );
test_offset_idx += len;
return( 0 );
}
static void ctr_drbg_validate_internal( int reseed_mode, data_t * nonce,
int entropy_len_arg, data_t * entropy,
data_t * reseed,
data_t * add1, data_t * add2,
data_t * result )
{
mbedtls_ctr_drbg_context ctx;
unsigned char buf[64];
size_t entropy_chunk_len = (size_t) entropy_len_arg;
TEST_ASSERT( entropy_chunk_len <= sizeof( buf ) );
test_offset_idx = 0;
mbedtls_ctr_drbg_init( &ctx );
test_max_idx = entropy->len;
/* CTR_DRBG_Instantiate(entropy[:entropy->len], nonce, perso, <ignored>)
* where nonce||perso = nonce[nonce->len] */
mbedtls_ctr_drbg_set_entropy_len( &ctx, entropy_chunk_len );
mbedtls_ctr_drbg_set_nonce_len( &ctx, 0 );
TEST_ASSERT( mbedtls_ctr_drbg_seed(
&ctx,
mbedtls_test_entropy_func, entropy->x,
nonce->x, nonce->len ) == 0 );
if( reseed_mode == RESEED_ALWAYS )
mbedtls_ctr_drbg_set_prediction_resistance(
&ctx,
MBEDTLS_CTR_DRBG_PR_ON );
if( reseed_mode == RESEED_FIRST )
{
/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
* reseed[:reseed->len]) */
TEST_ASSERT( mbedtls_ctr_drbg_reseed(
&ctx,
reseed->x, reseed->len ) == 0 );
}
/* CTR_DRBG_Generate(result->len * 8 bits, add1[:add1->len]) -> buf */
/* Then reseed if prediction resistance is enabled. */
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
&ctx,
buf, result->len,
add1->x, add1->len ) == 0 );
if( reseed_mode == RESEED_SECOND )
{
/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
* reseed[:reseed->len]) */
TEST_ASSERT( mbedtls_ctr_drbg_reseed(
&ctx,
reseed->x, reseed->len ) == 0 );
}
/* CTR_DRBG_Generate(result->len * 8 bits, add2->x[:add2->len]) -> buf */
/* Then reseed if prediction resistance is enabled. */
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
&ctx,
buf, result->len,
add2->x, add2->len ) == 0 );
TEST_ASSERT( memcmp( buf, result->x, result->len ) == 0 );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_HEADER */
/* BEGIN_DEPENDENCIES
* depends_on:MBEDTLS_CTR_DRBG_C
* END_DEPENDENCIES
*/
/* BEGIN_CASE */
void ctr_drbg_special_behaviours( )
{
mbedtls_ctr_drbg_context ctx;
unsigned char output[512];
unsigned char additional[512];
mbedtls_ctr_drbg_init( &ctx );
memset( output, 0, sizeof( output ) );
memset( additional, 0, sizeof( additional ) );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
output, MBEDTLS_CTR_DRBG_MAX_REQUEST + 1,
additional, 16 ) ==
MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
output, 16,
additional, MBEDTLS_CTR_DRBG_MAX_INPUT + 1 ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + 1 ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
mbedtls_ctr_drbg_set_entropy_len( &ctx, ~0 );
TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_no_reseed( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add2,
data_t * result_string )
{
data_t empty = { 0, 0 };
ctr_drbg_validate_internal( RESEED_NEVER, add_init,
entropy->len, entropy,
&empty, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_pr( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add2,
data_t * result_string )
{
data_t empty = { 0, 0 };
ctr_drbg_validate_internal( RESEED_ALWAYS, add_init,
entropy->len / 3, entropy,
&empty, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_reseed_between( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add_reseed,
data_t * add2, data_t * result_string )
{
ctr_drbg_validate_internal( RESEED_SECOND, add_init,
entropy->len / 2, entropy,
add_reseed, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_reseed_first( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add_reseed,
data_t * add2, data_t * result_string )
{
ctr_drbg_validate_internal( RESEED_FIRST, add_init,
entropy->len / 2, entropy,
add_reseed, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_entropy_strength( int expected_bit_strength )
{
unsigned char entropy[/*initial entropy*/ MBEDTLS_CTR_DRBG_ENTROPY_LEN +
/*nonce*/ MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN +
/*reseed*/ MBEDTLS_CTR_DRBG_ENTROPY_LEN];
mbedtls_ctr_drbg_context ctx;
size_t last_idx;
size_t byte_strength = expected_bit_strength / 8;
mbedtls_ctr_drbg_init( &ctx );
test_offset_idx = 0;
test_max_idx = sizeof( entropy );
memset( entropy, 0, sizeof( entropy ) );
/* The initial seeding must grab at least byte_strength bytes of entropy
* for the entropy input and byte_strength/2 bytes for a nonce. */
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx,
mbedtls_test_entropy_func, entropy,
NULL, 0 ) == 0 );
TEST_ASSERT( test_offset_idx >= ( byte_strength * 3 + 1 ) / 2 );
last_idx = test_offset_idx;
/* A reseed must grab at least byte_strength bytes of entropy. */
TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) == 0 );
TEST_ASSERT( test_offset_idx - last_idx >= byte_strength );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_entropy_usage( int entropy_nonce_len )
{
unsigned char out[16];
unsigned char add[16];
unsigned char entropy[1024];
mbedtls_ctr_drbg_context ctx;
size_t i, reps = 10;
size_t expected_idx = 0;
mbedtls_ctr_drbg_init( &ctx );
test_offset_idx = 0;
test_max_idx = sizeof( entropy );
memset( entropy, 0, sizeof( entropy ) );
memset( out, 0, sizeof( out ) );
memset( add, 0, sizeof( add ) );
if( entropy_nonce_len >= 0 )
TEST_ASSERT( mbedtls_ctr_drbg_set_nonce_len( &ctx, entropy_nonce_len ) == 0 );
/* Init must use entropy */
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_entropy_func, entropy, NULL, 0 ) == 0 );
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
if( entropy_nonce_len >= 0 )
expected_idx += entropy_nonce_len;
else
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN;
TEST_EQUAL( test_offset_idx, expected_idx );
/* By default, PR is off and reseed_interval is large,
* so the next few calls should not use entropy */
for( i = 0; i < reps; i++ )
{
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) - 4,
add, sizeof( add ) ) == 0 );
}
TEST_EQUAL( test_offset_idx, expected_idx );
/* While at it, make sure we didn't write past the requested length */
TEST_ASSERT( out[sizeof( out ) - 4] == 0 );
TEST_ASSERT( out[sizeof( out ) - 3] == 0 );
TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
/* Set reseed_interval to the number of calls done,
* so the next call should reseed */
mbedtls_ctr_drbg_set_reseed_interval( &ctx, 2 * reps );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
TEST_EQUAL( test_offset_idx, expected_idx );
/* The new few calls should not reseed */
for( i = 0; i < reps / 2; i++ )
{
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) ,
add, sizeof( add ) ) == 0 );
}
TEST_EQUAL( test_offset_idx, expected_idx );
/* Call update with too much data (sizeof entropy > MAX(_SEED)_INPUT).
* Make sure it's detected as an error and doesn't cause memory
* corruption. */
TEST_ASSERT( mbedtls_ctr_drbg_update_ret(
&ctx, entropy, sizeof( entropy ) ) != 0 );
/* Now enable PR, so the next few calls should all reseed */
mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
TEST_EQUAL( test_offset_idx, expected_idx );
/* Finally, check setting entropy_len */
mbedtls_ctr_drbg_set_entropy_len( &ctx, 42 );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_idx += 42;
TEST_EQUAL( test_offset_idx, expected_idx );
mbedtls_ctr_drbg_set_entropy_len( &ctx, 13 );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_idx += 13;
TEST_EQUAL( test_offset_idx, expected_idx );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
void ctr_drbg_seed_file( char * path, int ret )
{
mbedtls_ctr_drbg_context ctx;
mbedtls_ctr_drbg_init( &ctx );
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_rnd_std_rand,
NULL, NULL, 0 ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_write_seed_file( &ctx, path ) == ret );
TEST_ASSERT( mbedtls_ctr_drbg_update_seed_file( &ctx, path ) == ret );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
void ctr_drbg_selftest( )
{
TEST_ASSERT( mbedtls_ctr_drbg_self_test( 1 ) == 0 );
}
/* END_CASE */
|