/* Copyright (C) 2020 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

/**

 * \file

 *

 * \author Sascha Steinbiss <sascha@steinbiss.name>

 */

#include "suricata-common.h"

#include "conf.h"

#include "detect.h"

#include "detect-parse.h"

#include "detect-engine.h"

#include "detect-engine-content-inspection.h"

#include "detect-mqtt-connack-sessionpresent.h"

#include "util-unittest.h"

#include "rust.h"

#define PARSE_REGEX "^true|false|yes|no$"

static DetectParseRegex parse_regex;

static int mqtt_connack_session_present_id = 0;

static int DetectMQTTConnackSessionPresentMatch(DetectEngineThreadCtx *det_ctx,

                               Flow *f, uint8_t flags, void *state,

                               void *txv, const Signature *s,

                               const SigMatchCtx *ctx);

static int DetectMQTTConnackSessionPresentSetup (DetectEngineCtx *, Signature *, const char *);

void MQTTConnackSessionPresentRegisterTests(void);

void DetectMQTTConnackSessionPresentFree(DetectEngineCtx *de_ctx, void *);

/**

 * \brief Registration function for mqtt.connack.session_present: keyword

 */

void DetectMQTTConnackSessionPresentRegister (void)

{

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].name = "mqtt.connack.session_present";

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].desc = "match MQTT CONNACK session present flag";

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].url = "/rules/mqtt-keywords.html#mqtt-connack-session-present";

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].AppLayerTxMatch = DetectMQTTConnackSessionPresentMatch;

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].Setup = DetectMQTTConnackSessionPresentSetup;

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].Free  = DetectMQTTConnackSessionPresentFree;

#ifdef UNITTESTS

    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].RegisterTests = MQTTConnackSessionPresentRegisterTests;

#endif

    DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);

    DetectAppLayerInspectEngineRegister2("mqtt.connack.session_present", ALPROTO_MQTT,

            SIG_FLAG_TOCLIENT, 1, DetectEngineInspectGenericList, NULL);

    mqtt_connack_session_present_id = DetectBufferTypeGetByName("mqtt.connack.session_present");

}

/**

 * \internal

 * \brief Function to match session_present flag of an MQTT CONNACK message

 *

 * \param det_ctx Pointer to the pattern matcher thread.

 * \param f       Pointer to the current flow.

 * \param flags   Flags.

 * \param state   App layer state.

 * \param txv     Pointer to the transaction.

 * \param s       Pointer to the Signature.

 * \param ctx     Pointer to the sigmatch that we will cast into DetectMQTTConnackSessionPresentData.

 *

 * \retval 0 no match.

 * \retval 1 match.

 */

static int DetectMQTTConnackSessionPresentMatch(DetectEngineThreadCtx *det_ctx,

                               Flow *f, uint8_t flags, void *state,

                               void *txv, const Signature *s,

                               const SigMatchCtx *ctx)

{

    const bool *de = (const bool *)ctx;

    bool value = false;

    if (!de)

        return 0;

    if (rs_mqtt_tx_get_connack_sessionpresent(txv, &value) ==0 ) {

        return 0;

    }

    if (value != *de) {

        return 0;

    }

    return 1;

}

/**

 * \internal

 * \brief This function is used to parse options passed via mqtt.connack.session_present: keyword

 *

 * \param rawstr Pointer to the user provided options

 *

 * \retval de pointer to DetectMQTTConnackSessionPresentData on success

 * \retval NULL on failure

 */

static bool *DetectMQTTConnackSessionPresentParse(const char *rawstr)

{

    bool *de = NULL;

    de = SCMalloc(sizeof(bool));

    if (unlikely(de == NULL))

        return NULL;

    *de = false;

    if (strcmp(rawstr, "yes") == 0) {

        *de = true;

    } else if (strcmp(rawstr, "true") == 0) {

        *de = true;

    } else if (strcmp(rawstr, "no") == 0) {

        *de = false;

    } else if (strcmp(rawstr, "false") == 0) {

        *de = false;

    } else {

        SCLogError("invalid session_present flag definition: %s", rawstr);

        goto error;

    }

    return de;

error:

    /* de can't be NULL here */

    SCFree(de);

    return NULL;

}

/**

 * \internal

 * \brief this function is used to add the parsed type query into the current signature

 *

 * \param de_ctx pointer to the Detection Engine Context

 * \param s pointer to the Current Signature

 * \param rawstr pointer to the user provided options

 *

 * \retval 0 on Success

 * \retval -1 on Failure

 */

static int DetectMQTTConnackSessionPresentSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)

{

    bool *de = NULL;

    SigMatch *sm = NULL;

    if (DetectSignatureSetAppProto(s, ALPROTO_MQTT) < 0)

        return -1;

    de = DetectMQTTConnackSessionPresentParse(rawstr);

    if (de == NULL)

        goto error;

    sm = SigMatchAlloc();

    if (sm == NULL)

        goto error;

    sm->type = DETECT_AL_MQTT_CONNACK_SESSION_PRESENT;

    sm->ctx = (SigMatchCtx *)de;

    SigMatchAppendSMToList(s, sm, mqtt_connack_session_present_id);

    return 0;

error:

    if (de != NULL)

        SCFree(de);

    if (sm != NULL)

        SCFree(sm);

    return -1;

}

/**

 * \internal

 * \brief this function will free memory associated with DetectMQTTConnackSessionPresentData

 *

 * \param de pointer to DetectMQTTConnackSessionPresentData

 */

void DetectMQTTConnackSessionPresentFree(DetectEngineCtx *de_ctx, void *de_ptr)

{

    if (de_ptr != NULL)

        SCFree(de_ptr);

}

/*

 * ONLY TESTS BELOW THIS COMMENT

 */

#ifdef UNITTESTS

/**

 * \test MQTTConnackSessionPresentTestParse01 is a test for a valid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTConnackSessionPresentTestParse01 (void)

{

    bool *de = NULL;

    de = DetectMQTTConnackSessionPresentParse("yes");

    FAIL_IF_NULL(de);

    DetectMQTTConnackSessionPresentFree(NULL, de);

    de = DetectMQTTConnackSessionPresentParse("true");

    FAIL_IF_NULL(de);

    DetectMQTTConnackSessionPresentFree(NULL, de);

    de = DetectMQTTConnackSessionPresentParse("false");

    FAIL_IF_NULL(de);

    DetectMQTTConnackSessionPresentFree(NULL, de);

    de = DetectMQTTConnackSessionPresentParse("no");

    FAIL_IF_NULL(de);

    DetectMQTTConnackSessionPresentFree(NULL, de);

    PASS;

}

/**

 * \test MQTTConnackSessionPresentTestParse02 is a test for an invalid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTConnackSessionPresentTestParse02 (void)

{

    bool *de = NULL;

    de = DetectMQTTConnackSessionPresentParse("nix");

    if (de) {

        DetectMQTTConnackSessionPresentFree(NULL, de);

        FAIL;

    }

    PASS;

}

/**

 * \test MQTTConnackSessionPresentTestParse03 is a test for an invalid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTConnackSessionPresentTestParse03 (void)

{

    bool *de = NULL;

    de = DetectMQTTConnackSessionPresentParse("");

    if (de) {

        DetectMQTTConnackSessionPresentFree(NULL, de);

        FAIL;

    }

    PASS;

}

/**

 * \test MQTTConnackSessionPresentTestParse04 is a test for an invalid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTConnackSessionPresentTestParse04 (void)

{

    bool *de = NULL;

    de = DetectMQTTConnackSessionPresentParse(",");

    if (de) {

        DetectMQTTConnackSessionPresentFree(NULL, de);

        FAIL;

    }

    PASS;

}

#endif /* UNITTESTS */

/**

 * \brief this function registers unit tests for MQTTConnackSessionPresent

 */

void MQTTConnackSessionPresentRegisterTests(void)

{

#ifdef UNITTESTS

    UtRegisterTest("MQTTConnackSessionPresentTestParse01", MQTTConnackSessionPresentTestParse01);

    UtRegisterTest("MQTTConnackSessionPresentTestParse02", MQTTConnackSessionPresentTestParse02);

    UtRegisterTest("MQTTConnackSessionPresentTestParse03", MQTTConnackSessionPresentTestParse03);

    UtRegisterTest("MQTTConnackSessionPresentTestParse04", MQTTConnackSessionPresentTestParse04);

#endif /* UNITTESTS */

}