6aceb51e43
mbedtls_ctr_drbg_set_reseed_interval() and mbedtls_hmac_drbg_set_reseed_interval() can now be called before their seed functions and the reseed_interval value will persist. Previously it would be overwritten with the default value. *_drbg_reseed_interval is now set in init() and free(). mbedtls_ctr_drbg_free() and mbedtls_hmac_drbg_free() now reset the drbg context to the state immediately after init(). Tests: - Added test to check that DRBG reseeds when reseed_counter reaches reseed_interval, if reseed_interval set before seed and reseed_interval is less than MBEDTLS_CTR_DRBG_RESEED_INTERVAL. Signed-off-by: gacquroff <gavina352@gmail.com>
339 lines
12 KiB
Plaintext
339 lines
12 KiB
Plaintext
/* BEGIN_HEADER */
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "string.h"
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/* Modes for ctr_drbg_validate */
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enum reseed_mode
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{
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RESEED_NEVER, /* never reseed */
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RESEED_FIRST, /* instantiate, reseed, generate, generate */
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RESEED_SECOND, /* instantiate, generate, reseed, generate */
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RESEED_ALWAYS /* prediction resistance, no explicit reseed */
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};
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static size_t test_offset_idx = 0;
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static size_t test_max_idx = 0;
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static int mbedtls_test_entropy_func( void *data, unsigned char *buf, size_t len )
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{
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const unsigned char *p = (unsigned char *) data;
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if( test_offset_idx + len > test_max_idx )
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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memcpy( buf, p + test_offset_idx, len );
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test_offset_idx += len;
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return( 0 );
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}
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static void ctr_drbg_validate_internal( int reseed_mode, data_t * nonce,
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int entropy_len_arg, data_t * entropy,
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data_t * reseed,
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data_t * add1, data_t * add2,
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data_t * result )
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{
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mbedtls_ctr_drbg_context ctx;
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unsigned char buf[64];
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size_t entropy_chunk_len = (size_t) entropy_len_arg;
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TEST_ASSERT( entropy_chunk_len <= sizeof( buf ) );
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test_offset_idx = 0;
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mbedtls_ctr_drbg_init( &ctx );
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test_max_idx = entropy->len;
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/* CTR_DRBG_Instantiate(entropy[:entropy->len], nonce, perso, <ignored>)
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* where nonce||perso = nonce[nonce->len] */
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mbedtls_ctr_drbg_set_entropy_len( &ctx, entropy_chunk_len );
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mbedtls_ctr_drbg_set_nonce_len( &ctx, 0 );
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TEST_ASSERT( mbedtls_ctr_drbg_seed(
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&ctx,
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mbedtls_test_entropy_func, entropy->x,
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nonce->x, nonce->len ) == 0 );
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if( reseed_mode == RESEED_ALWAYS )
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mbedtls_ctr_drbg_set_prediction_resistance(
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&ctx,
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MBEDTLS_CTR_DRBG_PR_ON );
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if( reseed_mode == RESEED_FIRST )
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{
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/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
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* reseed[:reseed->len]) */
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TEST_ASSERT( mbedtls_ctr_drbg_reseed(
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&ctx,
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reseed->x, reseed->len ) == 0 );
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}
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/* CTR_DRBG_Generate(result->len * 8 bits, add1[:add1->len]) -> buf */
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/* Then reseed if prediction resistance is enabled. */
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
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&ctx,
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buf, result->len,
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add1->x, add1->len ) == 0 );
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if( reseed_mode == RESEED_SECOND )
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{
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/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
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* reseed[:reseed->len]) */
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TEST_ASSERT( mbedtls_ctr_drbg_reseed(
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&ctx,
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reseed->x, reseed->len ) == 0 );
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}
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/* CTR_DRBG_Generate(result->len * 8 bits, add2->x[:add2->len]) -> buf */
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/* Then reseed if prediction resistance is enabled. */
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
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&ctx,
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buf, result->len,
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add2->x, add2->len ) == 0 );
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TEST_ASSERT( memcmp( buf, result->x, result->len ) == 0 );
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exit:
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mbedtls_ctr_drbg_free( &ctx );
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}
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/* END_HEADER */
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/* BEGIN_DEPENDENCIES
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* depends_on:MBEDTLS_CTR_DRBG_C
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* END_DEPENDENCIES
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*/
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/* BEGIN_CASE */
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void ctr_drbg_special_behaviours( )
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{
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mbedtls_ctr_drbg_context ctx;
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unsigned char output[512];
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unsigned char additional[512];
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mbedtls_ctr_drbg_init( &ctx );
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memset( output, 0, sizeof( output ) );
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memset( additional, 0, sizeof( additional ) );
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
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output, MBEDTLS_CTR_DRBG_MAX_REQUEST + 1,
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additional, 16 ) ==
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MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
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output, 16,
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additional, MBEDTLS_CTR_DRBG_MAX_INPUT + 1 ) ==
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MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
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TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
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MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + 1 ) ==
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MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
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mbedtls_ctr_drbg_set_entropy_len( &ctx, ~0 );
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TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
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MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) ==
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MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
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exit:
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mbedtls_ctr_drbg_free( &ctx );
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_validate_no_reseed( data_t * add_init, data_t * entropy,
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data_t * add1, data_t * add2,
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data_t * result_string )
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{
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data_t empty = { 0, 0 };
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ctr_drbg_validate_internal( RESEED_NEVER, add_init,
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entropy->len, entropy,
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&empty, add1, add2,
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result_string );
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goto exit; // goto is needed to avoid warning ( no test assertions in func)
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_validate_pr( data_t * add_init, data_t * entropy,
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data_t * add1, data_t * add2,
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data_t * result_string )
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{
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data_t empty = { 0, 0 };
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ctr_drbg_validate_internal( RESEED_ALWAYS, add_init,
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entropy->len / 3, entropy,
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&empty, add1, add2,
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result_string );
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goto exit; // goto is needed to avoid warning ( no test assertions in func)
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_validate_reseed_between( data_t * add_init, data_t * entropy,
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data_t * add1, data_t * add_reseed,
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data_t * add2, data_t * result_string )
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{
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ctr_drbg_validate_internal( RESEED_SECOND, add_init,
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entropy->len / 2, entropy,
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add_reseed, add1, add2,
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result_string );
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goto exit; // goto is needed to avoid warning ( no test assertions in func)
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_validate_reseed_first( data_t * add_init, data_t * entropy,
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data_t * add1, data_t * add_reseed,
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data_t * add2, data_t * result_string )
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{
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ctr_drbg_validate_internal( RESEED_FIRST, add_init,
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entropy->len / 2, entropy,
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add_reseed, add1, add2,
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result_string );
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goto exit; // goto is needed to avoid warning ( no test assertions in func)
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_entropy_strength( int expected_bit_strength )
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{
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unsigned char entropy[/*initial entropy*/ MBEDTLS_CTR_DRBG_ENTROPY_LEN +
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/*nonce*/ MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN +
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/*reseed*/ MBEDTLS_CTR_DRBG_ENTROPY_LEN];
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mbedtls_ctr_drbg_context ctx;
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size_t last_idx;
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size_t byte_strength = expected_bit_strength / 8;
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mbedtls_ctr_drbg_init( &ctx );
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test_offset_idx = 0;
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test_max_idx = sizeof( entropy );
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memset( entropy, 0, sizeof( entropy ) );
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/* The initial seeding must grab at least byte_strength bytes of entropy
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* for the entropy input and byte_strength/2 bytes for a nonce. */
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TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx,
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mbedtls_test_entropy_func, entropy,
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NULL, 0 ) == 0 );
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TEST_ASSERT( test_offset_idx >= ( byte_strength * 3 + 1 ) / 2 );
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last_idx = test_offset_idx;
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/* A reseed must grab at least byte_strength bytes of entropy. */
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TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) == 0 );
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TEST_ASSERT( test_offset_idx - last_idx >= byte_strength );
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exit:
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mbedtls_ctr_drbg_free( &ctx );
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}
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/* END_CASE */
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/* BEGIN_CASE */
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void ctr_drbg_entropy_usage( int entropy_nonce_len )
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{
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unsigned char out[16];
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unsigned char add[16];
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unsigned char entropy[1024];
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mbedtls_ctr_drbg_context ctx;
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size_t i, reps = 10;
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size_t expected_idx = 0;
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mbedtls_ctr_drbg_init( &ctx );
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test_offset_idx = 0;
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test_max_idx = sizeof( entropy );
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memset( entropy, 0, sizeof( entropy ) );
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memset( out, 0, sizeof( out ) );
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memset( add, 0, sizeof( add ) );
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if( entropy_nonce_len >= 0 )
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TEST_ASSERT( mbedtls_ctr_drbg_set_nonce_len( &ctx, entropy_nonce_len ) == 0 );
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/* Set reseed interval before seed */
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mbedtls_ctr_drbg_set_reseed_interval( &ctx, 2 * reps );
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/* Init must use entropy */
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TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_entropy_func, entropy, NULL, 0 ) == 0 );
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expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
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if( entropy_nonce_len >= 0 )
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expected_idx += entropy_nonce_len;
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else
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expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN;
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TEST_EQUAL( test_offset_idx, expected_idx );
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/* By default, PR is off, and reseed interval was set to
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* 2 * reps so the next few calls should not use entropy */
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for( i = 0; i < reps; i++ )
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{
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) - 4,
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add, sizeof( add ) ) == 0 );
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}
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TEST_EQUAL( test_offset_idx, expected_idx );
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/* While at it, make sure we didn't write past the requested length */
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TEST_ASSERT( out[sizeof( out ) - 4] == 0 );
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TEST_ASSERT( out[sizeof( out ) - 3] == 0 );
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TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
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TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
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/* There have been 2 * reps calls to random. The next call should reseed */
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
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expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
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TEST_EQUAL( test_offset_idx, expected_idx );
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/* Set reseed interval after seed */
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mbedtls_ctr_drbg_set_reseed_interval( &ctx, 4 * reps + 1 );
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/* The next few calls should not reseed */
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for( i = 0; i < (2 * reps); i++ )
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{
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
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TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) ,
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add, sizeof( add ) ) == 0 );
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}
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TEST_EQUAL( test_offset_idx, expected_idx );
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/* Call update with too much data (sizeof entropy > MAX(_SEED)_INPUT).
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* Make sure it's detected as an error and doesn't cause memory
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* corruption. */
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TEST_ASSERT( mbedtls_ctr_drbg_update_ret(
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&ctx, entropy, sizeof( entropy ) ) != 0 );
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/* Now enable PR, so the next few calls should all reseed */
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mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
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expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
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TEST_EQUAL( test_offset_idx, expected_idx );
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/* Finally, check setting entropy_len */
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mbedtls_ctr_drbg_set_entropy_len( &ctx, 42 );
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
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expected_idx += 42;
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TEST_EQUAL( test_offset_idx, expected_idx );
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mbedtls_ctr_drbg_set_entropy_len( &ctx, 13 );
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TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
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expected_idx += 13;
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TEST_EQUAL( test_offset_idx, expected_idx );
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exit:
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mbedtls_ctr_drbg_free( &ctx );
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}
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/* END_CASE */
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/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
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void ctr_drbg_seed_file( char * path, int ret )
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{
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mbedtls_ctr_drbg_context ctx;
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mbedtls_ctr_drbg_init( &ctx );
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TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_rnd_std_rand,
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NULL, NULL, 0 ) == 0 );
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TEST_ASSERT( mbedtls_ctr_drbg_write_seed_file( &ctx, path ) == ret );
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TEST_ASSERT( mbedtls_ctr_drbg_update_seed_file( &ctx, path ) == ret );
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exit:
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mbedtls_ctr_drbg_free( &ctx );
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}
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/* END_CASE */
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/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
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void ctr_drbg_selftest( )
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{
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TEST_ASSERT( mbedtls_ctr_drbg_self_test( 1 ) == 0 );
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}
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/* END_CASE */
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