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|
/* 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);
}
/* Set reseed interval before seed */
mbedtls_ctr_drbg_set_reseed_interval(&ctx, 2 * reps);
/* 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 was set to
* 2 * reps 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);
/* There have been 2 * reps calls to random. The next call should reseed */
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);
/* Set reseed interval after seed */
mbedtls_ctr_drbg_set_reseed_interval(&ctx, 4 * reps + 1);
/* The next few calls should not reseed */
for (i = 0; i < (2 * reps); 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 */
|
