/* BEGIN_HEADER */

#include <mbedtls/constant_time.h>
#include <mbedtls/md.h>
#include <constant_time_internal.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.
     */
    mbedtls_md_context_t ctx, ref_ctx;
    const mbedtls_md_info_t *md_info;
    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_MD_MAX_SIZE];
    unsigned char *data = NULL;
    unsigned char *out = NULL;
    unsigned char rec_num = 0;

    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;

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

    /* 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));

    /*
     * 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));
            TEST_EQUAL(0, mbedtls_ct_hmac(&ctx, add_data, sizeof(add_data),
                                          data, in_len,
                                          min_in_len, max_in_len,
                                          out));
            TEST_CF_PUBLIC(&in_len, sizeof(in_len));
            TEST_CF_PUBLIC(out, out_len);

            /* 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);
        }

        mbedtls_free(data);
        data = NULL;
    }

exit:
    mbedtls_md_free(&ref_ctx);
    mbedtls_md_free(&ctx);

    mbedtls_free(data);
    mbedtls_free(out);
}
/* END_CASE */
