tests/suites/test_suite_constant_time_hmac.function

/* BEGIN_HEADER */

#include <mbedtls/constant_time.h>
#include <mbedtls/legacy_or_psa.h>
#include <mbedtls/md.h>
#include <constant_time_internal.h>
#include <hash_info.h>

#include <test/constant_flow.h>
/* END_HEADER */

/* BEGIN_CASE depends_on:MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC:MBEDTLS_TEST_HOOKS */
void ssl_cf_hmac( int hash )
{
    /*
     * Test the function mbedtls_ct_hmac() against a reference
     * implementation.
     */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    mbedtls_svc_key_id_t key = MBEDTLS_SVC_KEY_ID_INIT;
    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
    psa_algorithm_t alg;
    psa_mac_operation_t operation = PSA_MAC_OPERATION_INIT;
#else
    mbedtls_md_context_t ctx, ref_ctx;
    const mbedtls_md_info_t *md_info;
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    size_t out_len, block_size;
    size_t min_in_len, in_len, max_in_len, i;
    /* TLS additional data is 13 bytes (hence the "lucky 13" name) */
    unsigned char add_data[13];
    unsigned char ref_out[MBEDTLS_HASH_MAX_SIZE];
    unsigned char *data = NULL;
    unsigned char *out = NULL;
    unsigned char rec_num = 0;

    USE_PSA_INIT( );

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    alg = PSA_ALG_HMAC( mbedtls_hash_info_psa_from_md( hash ) );

    out_len = PSA_HASH_LENGTH( alg );
    block_size = PSA_HASH_BLOCK_LENGTH( alg );

    /* mbedtls_ct_hmac() requires the key to be exportable */
    psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_EXPORT |
                                          PSA_KEY_USAGE_VERIFY_HASH );
    psa_set_key_algorithm( &attributes, PSA_ALG_HMAC( alg ) );
    psa_set_key_type( &attributes, PSA_KEY_TYPE_HMAC );
#else
    mbedtls_md_init( &ctx );
    mbedtls_md_init( &ref_ctx );

    md_info = mbedtls_md_info_from_type( hash );
    TEST_ASSERT( md_info != NULL );
    out_len = mbedtls_md_get_size( md_info );
    TEST_ASSERT( out_len != 0 );
    block_size = hash == MBEDTLS_MD_SHA384 ? 128 : 64;
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    /* Use allocated out buffer to catch overwrites */
    ASSERT_ALLOC( out, out_len );

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    /* Set up dummy key */
    memset( ref_out, 42, sizeof( ref_out ) );
    TEST_EQUAL( PSA_SUCCESS, psa_import_key( &attributes,
                                             ref_out, out_len,
                                             &key ) );
#else
    /* Set up contexts with the given hash and a dummy key */
    TEST_EQUAL( 0, mbedtls_md_setup( &ctx, md_info, 1 ) );
    TEST_EQUAL( 0, mbedtls_md_setup( &ref_ctx, md_info, 1 ) );
    memset( ref_out, 42, sizeof( ref_out ) );
    TEST_EQUAL( 0, mbedtls_md_hmac_starts( &ctx, ref_out, out_len ) );
    TEST_EQUAL( 0, mbedtls_md_hmac_starts( &ref_ctx, ref_out, out_len ) );
    memset( ref_out, 0, sizeof( ref_out ) );
#endif

    /*
     * Test all possible lengths up to a point. The difference between
     * max_in_len and min_in_len is at most 255, and make sure they both vary
     * by at least one block size.
     */
    for( max_in_len = 0; max_in_len <= 255 + block_size; max_in_len++ )
    {
        mbedtls_test_set_step( max_in_len * 10000 );

        /* Use allocated in buffer to catch overreads */
        ASSERT_ALLOC( data, max_in_len );

        min_in_len = max_in_len > 255 ? max_in_len - 255 : 0;
        for( in_len = min_in_len; in_len <= max_in_len; in_len++ )
        {
            mbedtls_test_set_step( max_in_len * 10000 + in_len );

            /* Set up dummy data and add_data */
            rec_num++;
            memset( add_data, rec_num, sizeof( add_data ) );
            for( i = 0; i < in_len; i++ )
                data[i] = ( i & 0xff ) ^ rec_num;

            /* Get the function's result */
            TEST_CF_SECRET( &in_len, sizeof( in_len ) );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
            TEST_EQUAL( 0, mbedtls_ct_hmac( key, PSA_ALG_HMAC( alg ),
                                            add_data, sizeof( add_data ),
                                            data, in_len,
                                            min_in_len, max_in_len,
                                            out ) );
#else
            TEST_EQUAL( 0, mbedtls_ct_hmac( &ctx, add_data, sizeof( add_data ),
                                            data, in_len,
                                            min_in_len, max_in_len,
                                            out ) );
#endif /* MBEDTLS_USE_PSA_CRYPTO */
            TEST_CF_PUBLIC( &in_len, sizeof( in_len ) );
            TEST_CF_PUBLIC( out, out_len );

#if defined(MBEDTLS_USE_PSA_CRYPTO)
            TEST_EQUAL( PSA_SUCCESS, psa_mac_verify_setup( &operation,
                                                           key, alg ) );
            TEST_EQUAL( PSA_SUCCESS, psa_mac_update( &operation, add_data,
                                                     sizeof( add_data ) ) );
            TEST_EQUAL( PSA_SUCCESS, psa_mac_update( &operation,
                                                     data, in_len ) );
            TEST_EQUAL( PSA_SUCCESS, psa_mac_verify_finish( &operation,
                                                            out, out_len ) );
#else
            /* Compute the reference result */
            TEST_EQUAL( 0, mbedtls_md_hmac_update( &ref_ctx, add_data,
                                                   sizeof( add_data ) ) );
            TEST_EQUAL( 0, mbedtls_md_hmac_update( &ref_ctx, data, in_len ) );
            TEST_EQUAL( 0, mbedtls_md_hmac_finish( &ref_ctx, ref_out ) );
            TEST_EQUAL( 0, mbedtls_md_hmac_reset( &ref_ctx ) );

            /* Compare */
            ASSERT_COMPARE( out, out_len, ref_out, out_len );
#endif /* MBEDTLS_USE_PSA_CRYPTO */
        }

        mbedtls_free( data );
        data = NULL;
    }

exit:
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_mac_abort( &operation );
    psa_destroy_key( key );
#else
    mbedtls_md_free( &ref_ctx );
    mbedtls_md_free( &ctx );
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    mbedtls_free( data );
    mbedtls_free( out );

    USE_PSA_DONE( );
}
/* END_CASE */