/*

 * Copyright 2019 Andreas Schneider <asn@cryptomilk.org>

 *

 * 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 <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <signal.h>

#include <stdbool.h>

#define LIBSSH_STATIC 1

#include <libssh/libssh.h>

#include <libssh/callbacks.h>

static int auth_callback(const char *prompt,

                         char *buf,

                         size_t len,

                         int echo,

                         int verify,

                         void *userdata)

{

    (void)prompt;   /* unused */

    (void)echo;     /* unused */

    (void)verify;   /* unused */

    (void)userdata; /* unused */

    snprintf(buf, len, "secret");

    return 0;

}

struct ssh_callbacks_struct cb = {

    .userdata = NULL,

    .auth_function = auth_callback,

};

static void select_loop(ssh_session session, ssh_channel channel)

{

    ssh_connector connector_in, connector_out, connector_err;

    ssh_event event = ssh_event_new();

    /* stdin */

    connector_in = ssh_connector_new(session);

    ssh_connector_set_out_channel(connector_in, channel, SSH_CONNECTOR_STDINOUT);

    ssh_connector_set_in_fd(connector_in, 0);

    ssh_event_add_connector(event, connector_in);

    /* stdout */

    connector_out = ssh_connector_new(session);

    ssh_connector_set_out_fd(connector_out, 1);

    ssh_connector_set_in_channel(connector_out, channel, SSH_CONNECTOR_STDINOUT);

    ssh_event_add_connector(event, connector_out);

    /* stderr */

    connector_err = ssh_connector_new(session);

    ssh_connector_set_out_fd(connector_err, 2);

    ssh_connector_set_in_channel(connector_err, channel, SSH_CONNECTOR_STDERR);

    ssh_event_add_connector(event, connector_err);

    while (ssh_channel_is_open(channel)) {

        ssh_event_dopoll(event, 60000);

    }

    ssh_event_remove_connector(event, connector_in);

    ssh_event_remove_connector(event, connector_out);

    ssh_event_remove_connector(event, connector_err);

    ssh_connector_free(connector_in);

    ssh_connector_free(connector_out);

    ssh_connector_free(connector_err);

    ssh_event_free(event);

}

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)

{

    ssh_session session = NULL;

    ssh_channel channel = NULL;

    const char *env = NULL;

    int socket_fds[2] = {-1, -1};

    ssize_t nwritten;

    bool no = false;

    int rc;

    long timeout = 1; /* use short timeout to avoid timeouts during fuzzing */

    /* This is the maximum that can be handled by the socket buffer before the

     * other side will read some data. Other option would be feeding the socket

     * from different thread which would not mind if it would be blocked, but I

     * believe all the important inputs should fit into this size */

    if (size > 219264) {

        return -1;

    }

    /* Set up the socket to send data */

    rc = socketpair(AF_UNIX, SOCK_STREAM, 0, socket_fds);

    assert(rc == 0);

    nwritten = send(socket_fds[1], data, size, 0);

    assert((size_t)nwritten == size);

    rc = shutdown(socket_fds[1], SHUT_WR);

    assert(rc == 0);

    ssh_init();

    session = ssh_new();

    assert(session != NULL);

    env = getenv("LIBSSH_VERBOSITY");

    if (env != NULL && strlen(env) > 0) {

        ssh_options_set(session, SSH_OPTIONS_LOG_VERBOSITY_STR, env);

    }

    rc = ssh_options_set(session, SSH_OPTIONS_FD, &socket_fds[0]);

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_HOST, "127.0.0.1");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_USER, "alice");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_CIPHERS_C_S, "none");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_CIPHERS_S_C, "none");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_HMAC_C_S, "none");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_HMAC_S_C, "none");

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_PROCESS_CONFIG, &no);

    assert(rc == 0);

    rc = ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &timeout);

    assert(rc == 0);

    ssh_callbacks_init(&cb);

    ssh_set_callbacks(session, &cb);

    rc = ssh_connect(session);

    if (rc != SSH_OK) {

        goto out;

    }

    rc = ssh_userauth_none(session, NULL);

    if (rc != SSH_OK) {

        goto out;

    }

    channel = ssh_channel_new(session);

    if (channel == NULL) {

        goto out;

    }

    rc = ssh_channel_open_session(channel);

    if (rc != SSH_OK) {

        goto out;

    }

    rc = ssh_channel_request_exec(channel, "ls");

    if (rc != SSH_OK) {

        goto out;

    }

    select_loop(session, channel);

out:

    ssh_channel_free(channel);

    ssh_disconnect(session);

    ssh_free(session);

    ssh_finalize();

    close(socket_fds[0]);

    close(socket_fds[1]);

    return 0;

}