/*

 * Copyright 2026 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 * https://www.openssl.org/source/license.html

 * or in the file LICENSE in the source distribution.

 */

#include <limits.h>

#include <openssl/ech.h>

#include <openssl/err.h>

#include <openssl/bio.h>

#include <openssl/crypto.h>

#include <openssl/e_os2.h>

#include <openssl/byteorder.h>

#include "fuzzer.h"

static void parse_one(const uint8_t *buf, int len)

{

    OSSL_ECHSTORE *es;

    BIO *in;

    es = OSSL_ECHSTORE_new(NULL, NULL);

    if (es == NULL)

        return;

    in = BIO_new_mem_buf(buf, len);

    if (in == NULL) {

        OSSL_ECHSTORE_free(es);

        return;

    }

    OSSL_ECHSTORE_read_echconfiglist(es, in);

    OSSL_ECHSTORE_free(es);

    BIO_free(in);

}

int FuzzerInitialize(int *argc, char ***argv)

{

    return 1;

}

int FuzzerTestOneInput(const uint8_t *buf, size_t len)

{

    uint8_t *fixed_buf = NULL;

    int bio_len;

    uint16_t outer_len, inner_len;

    if (len > INT_MAX)

        return 0;

    bio_len = (int)len;

    /* Target raw without any fixup */

    parse_one(buf, bio_len);

    /*

     * ech_decode_and_flatten has a strict size check:

     * OSSL_ECH_MIN_ECHCONFIG_LEN = 32

     * OSSL_ECH_MAX_ECHCONFIG_LEN = 1500

     */

    if (len < OSSL_ECH_MIN_ECHCONFIG_LEN || len >= OSSL_ECH_MAX_ECHCONFIG_LEN)

        goto end;

    outer_len = (uint16_t)(len - 2);

    inner_len = (uint16_t)(len - 6);

    fixed_buf = OPENSSL_memdup(buf, len);

    if (fixed_buf == NULL)

        goto end;

    /* Fix up to pass initial checks*/

    OPENSSL_store_u16_be(fixed_buf, outer_len);

    OPENSSL_store_u16_be(fixed_buf + 2, OSSL_ECH_RFC9849_VERSION);

    OPENSSL_store_u16_be(fixed_buf + 4, inner_len);

    parse_one(fixed_buf, bio_len);

end:

    OPENSSL_free(fixed_buf);

    ERR_clear_error();

    return 0;

}

void FuzzerCleanup(void)

{

}