/* Copyright 2023 Google LLC

Licensed under the Apache License, Version 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

      http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

*/

#include <string.h>

#include "krb5.h"

#include "gssapi.h"

extern int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)

{

    OM_uint32 maj_stat, min_stat;

    gss_ctx_id_t ctx = GSS_C_NO_CONTEXT;

    gss_name_t client_name = GSS_C_NO_NAME;

    gss_cred_id_t deleg_cred = GSS_C_NO_CREDENTIAL;

    /* Each fuzz input contains multiple tokens preceded by a length field.

     * Process them in turn with gss_accept_sec_context while

     * GSS_S_CONTINUE_NEEDED is set

     */

    do {

        unsigned short token_length;

        gss_buffer_desc input_token, output_token = GSS_C_EMPTY_BUFFER;

        if (Size < sizeof(token_length))

            break;

        token_length = *(unsigned short *)Data;

        Data += sizeof(token_length);

        Size -= sizeof(token_length);

        if (token_length == 0 || token_length > Size)

            break;

        input_token.length = token_length;

        input_token.value = malloc(token_length);

        memcpy(input_token.value, Data, token_length);

        Data += token_length;

        Size -= token_length;

        maj_stat = gss_accept_sec_context(

            &min_stat,

            &ctx,

            GSS_C_NO_CREDENTIAL, /* server_creds */

            &input_token,

            GSS_C_NO_CHANNEL_BINDINGS, /* input_bindings */

            &client_name,

            NULL, /* mech_type */

            &output_token,

            NULL, /* ret_flags */

            NULL, /* time */

            &deleg_cred

        );

        gss_release_buffer(&min_stat, &output_token);

        gss_release_buffer(&min_stat, &input_token);

        if (GSS_ERROR(maj_stat)) {

            if (ctx != GSS_C_NO_CONTEXT)

                gss_delete_sec_context(&min_stat, &ctx, GSS_C_NO_BUFFER);

            break;

        }

    } while(maj_stat & GSS_S_CONTINUE_NEEDED);

    gss_release_name(&min_stat, &client_name);

    gss_release_cred(&min_stat, &deleg_cred);

    return 0;

}