/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <open62541/server_config_default.h>

#include "ua_server_internal.h"

#include "testing_networklayers.h"

#include <stdint.h>

#include <stdarg.h>

#include <string.h>

/* Feed fuzzed service payloads through a fully configured SecurityPolicy None

 * channel. The fixed symmetric envelope gets mutations through channel and

 * token validation to the request type and service decoders. */

static void *

removeServerComponent(void *application, UA_ServerComponent *sc) {

    UA_assert(sc->state == UA_LIFECYCLESTATE_STOPPED);

    sc->clear(sc);

    UA_free(sc);

    return NULL;

}

static void

silentLog(void *context, UA_LogLevel level, UA_LogCategory category,

          const char *message, va_list args) {

    (void)context;

    (void)level;

    (void)category;

    (void)message;

    (void)args;

}

static UA_Logger silentLogger = {silentLog, NULL, NULL};

struct FuzzServer {

    UA_Server *server;

    UA_ServerComponent *bpm;

    UA_ConnectionManager *cm;

    UA_SecurityPolicy *nonePolicy;

    void *listenerContext;

    uintptr_t nextConnectionId;

    FuzzServer()

        : server(NULL), bpm(NULL), cm(NULL), nonePolicy(NULL), listenerContext(NULL),

          nextConnectionId(2) {

        UA_ServerConfig config;

        memset(&config, 0, sizeof(config));

        config.logging = &silentLogger;

        if(UA_ServerConfig_setDefault(&config) != UA_STATUSCODE_GOOD) {

            UA_ServerConfig_clear(&config);

            return;

        }

        config.allowEmptyVariables = UA_RULEHANDLING_ACCEPT;

        config.securityPolicyNoneDiscoveryOnly = false;

        server = UA_Server_newWithConfig(&config);

        if(!server)

            return;

        ZIP_ITER(UA_ServerComponentTree, &server->serverComponents,

                 removeServerComponent, server);

        ZIP_INIT(&server->serverComponents);

        bpm = UA_BinaryProtocolManager_new(server);

        if(!bpm)

            return;

        addServerComponent(server, bpm, NULL);

        for(size_t i = 0; i < server->config.securityPoliciesSize; i++) {

            if(UA_String_equal(&server->config.securityPolicies[i].policyUri,

                               &UA_SECURITY_POLICY_NONE_URI)) {

                nonePolicy = &server->config.securityPolicies[i];

                break;

            }

        }

        cm = TestConnectionManager_new("tcp", NULL);

        if(!cm)

            return;

        /* Keep the server socket and protocol manager for the fuzz process. */

        serverNetworkCallback(cm, 1, bpm, &listenerContext,

                              UA_CONNECTIONSTATE_ESTABLISHED,

                              &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

    }

    ~FuzzServer() {

        UA_NodeId_clear(&unsafe_fuzz_authenticationToken);

        if(listenerContext)

            serverNetworkCallback(cm, 1, bpm, &listenerContext,

                                  UA_CONNECTIONSTATE_CLOSING,

                                  &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

        if(server)

            UA_Server_delete(server);

        if(cm)

            cm->eventSource.free(&cm->eventSource);

    }

    uintptr_t

    getConnectionId() {

        uintptr_t connectionId = nextConnectionId++;

        if(nextConnectionId <= 1)

            nextConnectionId = 2;

        return connectionId;

    }

};

static FuzzServer &

getFuzzServer(void) {

    static FuzzServer fuzzServer;

    return fuzzServer;

}

static void

clearSessions(UA_Server *server) {

    lockServer(server);

    session_list_entry *entry;

    while((entry = LIST_FIRST(&server->sessions)))

        UA_Session_remove(server, &entry->session, UA_SHUTDOWNREASON_CLOSE);

    unlockServer(server);

    /* Session memory is released with delayed callbacks. */

    UA_Server_run_iterate(server, false);

    UA_Server_run_iterate(server, false);

}

static void

writeUInt32(UA_Byte *buf, size_t *offset, UA_UInt32 value) {

    buf[(*offset)++] = (UA_Byte)value;

    buf[(*offset)++] = (UA_Byte)(value >> 8);

    buf[(*offset)++] = (UA_Byte)(value >> 16);

    buf[(*offset)++] = (UA_Byte)(value >> 24);

}

static UA_ByteString

makeMSG(const UA_SecureChannel *channel, const uint8_t *payload,

        size_t payloadSize) {

    const size_t headerSize = 8 + 4 + 4 + 8;

    UA_ByteString message = UA_BYTESTRING_NULL;

    if(payloadSize > UA_UINT32_MAX - headerSize)

        return message;

    const size_t messageSize = headerSize + payloadSize;

    if(UA_ByteString_allocBuffer(&message, messageSize) != UA_STATUSCODE_GOOD)

        return message;

    size_t offset = 0;

    memcpy(&message.data[offset], "MSGF", 4);

    offset += 4;

    writeUInt32(message.data, &offset, (UA_UInt32)messageSize);

    writeUInt32(message.data, &offset, channel->securityToken.channelId);

    writeUInt32(message.data, &offset, channel->securityToken.tokenId);

    writeUInt32(message.data, &offset, 1); /* SequenceNumber */

    writeUInt32(message.data, &offset, 1); /* RequestId */

    if(payloadSize > 0)

        memcpy(&message.data[offset], payload, payloadSize);

    return message;

}

extern "C" int

LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

    UA_NodeId_clear(&unsafe_fuzz_authenticationToken);

    /* Generated corpus entries contain complete MSG chunks plus an optional

     * four-byte memory-limit trailer. Extract their service payload. */

    if(size >= 24 && memcmp(data, "MSG", 3) == 0) {

        UA_UInt32 declaredSize = (UA_UInt32)data[4] |

            ((UA_UInt32)data[5] << 8) | ((UA_UInt32)data[6] << 16) |

            ((UA_UInt32)data[7] << 24);

        if(declaredSize >= 24 && declaredSize <= size) {

            data += 24;

            size = declaredSize - 24;

        }

    }

    FuzzServer &fuzzServer = getFuzzServer();

    if(!fuzzServer.bpm || !fuzzServer.nonePolicy ||

       !fuzzServer.listenerContext)

        return 0;

    /* Create only disposable channel and session state for this iteration. */

    uintptr_t connectionId = fuzzServer.getConnectionId();

    void *connectionContext = fuzzServer.listenerContext;

    serverNetworkCallback(fuzzServer.cm, connectionId,

                          fuzzServer.bpm, &connectionContext,

                          UA_CONNECTIONSTATE_ESTABLISHED,

                          &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

    UA_SecureChannel *channel = (UA_SecureChannel*)connectionContext;

    /* Configure an open SecurityPolicy None channel with a current token. */

    UA_ByteString noCertificate = UA_BYTESTRING_NULL;

    if(!channel ||

       UA_SecureChannel_setSecurityPolicy(channel, fuzzServer.nonePolicy,

                                          &noCertificate) !=

           UA_STATUSCODE_GOOD) {

        if(connectionContext)

            serverNetworkCallback(fuzzServer.cm, connectionId,

                                  fuzzServer.bpm, &connectionContext,

                                  UA_CONNECTIONSTATE_CLOSING,

                                  &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

        return 0;

    }

    channel->securityMode = UA_MESSAGESECURITYMODE_NONE;

    channel->securityToken.tokenId = 1;

    channel->securityToken.createdAt = UA_DateTime_nowMonotonic();

    channel->securityToken.revisedLifetime = 600000;

    channel->state = UA_SECURECHANNELSTATE_OPEN;

    /* Attach an activated session. The fuzz-only request-token rewrite in

     * processRequest makes decoded requests select this session. */

    UA_CreateSessionRequest createRequest;

    UA_CreateSessionRequest_init(&createRequest);

    createRequest.requestedSessionTimeout = 600000;

    UA_Session *session = NULL;

    lockServer(fuzzServer.server);

    UA_StatusCode res =

        UA_Session_create(fuzzServer.server, channel, &createRequest, &session);

    if(res == UA_STATUSCODE_GOOD) {

        UA_NodeId_clear(&session->authenticationToken);

        session->authenticationToken = UA_NODEID_NUMERIC(1, 1);

        session->activated = true;

        UA_NodeId_copy(&session->authenticationToken,

                       &unsafe_fuzz_authenticationToken);

    }

    unlockServer(fuzzServer.server);

    if(res != UA_STATUSCODE_GOOD) {

        serverNetworkCallback(fuzzServer.cm, connectionId,

                              fuzzServer.bpm, &connectionContext,

                              UA_CONNECTIONSTATE_CLOSING,

                              &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

        clearSessions(fuzzServer.server);

        return 0;

    }

    UA_ByteString msg = makeMSG(channel, data, size);

    if(msg.data) {

        serverNetworkCallback(fuzzServer.cm, connectionId,

                              fuzzServer.bpm, &connectionContext,

                              UA_CONNECTIONSTATE_ESTABLISHED,

                              &UA_KEYVALUEMAP_NULL, msg);

        UA_ByteString_clear(&msg);

    }

    UA_NodeId_clear(&unsafe_fuzz_authenticationToken);

    serverNetworkCallback(fuzzServer.cm, connectionId,

                          fuzzServer.bpm, &connectionContext,

                          UA_CONNECTIONSTATE_CLOSING,

                          &UA_KEYVALUEMAP_NULL, UA_BYTESTRING_NULL);

    clearSessions(fuzzServer.server);

    return 0;

}