mbedtls/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 */