/* Copyright (C) 2007-2018 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.

 */

/**

 * \ingroup httplayer

 *

 * @{

 */

/**

 * \file

 *

 * \author Gurvinder Singh <gurvindersinghdahiya@gmail.com>

 * \author Anoop Saldanha <anoopsaldanha@gmail.com>

 *

 * Implements the http_stat_msg keyword

 */

#include "suricata-common.h"

#include "threads.h"

#include "decode.h"

#include "detect.h"

#include "detect-parse.h"

#include "detect-engine.h"

#include "detect-content.h"

#include "detect-pcre.h"

#include "detect-engine-mpm.h"

#include "detect-engine-prefilter.h"

#include "flow.h"

#include "flow-var.h"

#include "flow-util.h"

#include "util-debug.h"

#include "util-error.h"

#include "util-unittest.h"

#include "util-unittest-helper.h"

#include "util-spm.h"

#include "util-print.h"

#include "app-layer.h"

#include "app-layer-parser.h"

#include "app-layer-htp.h"

#include "detect-http-stat-msg.h"

#include "stream-tcp-private.h"

#include "stream-tcp.h"

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

#ifdef UNITTESTS

static void DetectHttpStatMsgRegisterTests(void);

#endif

static int g_http_stat_msg_buffer_id = 0;

static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *_f,

        const uint8_t _flow_flags, void *txv, const int list_id);

static int DetectHttpStatMsgSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str);

static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,

        const int list_id)

{

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        InspectionBufferSetup(det_ctx, list_id, buffer, (const uint8_t *)"", 0);

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

/**

 * \brief Registration function for keyword: http_stat_msg

 */

void DetectHttpStatMsgRegister (void)

{

    /* http_stat_msg content modifier */

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].name = "http_stat_msg";

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].desc = "content modifier to match on HTTP stat-msg-buffer";

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].url = "/rules/http-keywords.html#http-stat-msg";

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].Setup = DetectHttpStatMsgSetup;

#ifdef UNITTESTS

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].RegisterTests = DetectHttpStatMsgRegisterTests;

#endif

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_CONTENT_MODIFIER;

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].alternative = DETECT_HTTP_STAT_MSG;

    /* http.stat_msg sticky buffer */

    sigmatch_table[DETECT_HTTP_STAT_MSG].name = "http.stat_msg";

    sigmatch_table[DETECT_HTTP_STAT_MSG].desc = "sticky buffer to match on the HTTP response status message";

    sigmatch_table[DETECT_HTTP_STAT_MSG].url = "/rules/http-keywords.html#http-stat-msg";

    sigmatch_table[DETECT_HTTP_STAT_MSG].Setup = DetectHttpStatMsgSetupSticky;

    sigmatch_table[DETECT_HTTP_STAT_MSG].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER;

    DetectAppLayerInspectEngineRegister2("http_stat_msg", ALPROTO_HTTP1, SIG_FLAG_TOCLIENT,

            HTP_RESPONSE_LINE, DetectEngineInspectBufferGeneric, GetData);

    DetectAppLayerMpmRegister2("http_stat_msg", SIG_FLAG_TOCLIENT, 3, PrefilterGenericMpmRegister,

            GetData, ALPROTO_HTTP1, HTP_RESPONSE_LINE);

    DetectAppLayerInspectEngineRegister2("http_stat_msg", ALPROTO_HTTP2, SIG_FLAG_TOCLIENT,

            HTTP2StateDataServer, DetectEngineInspectBufferGeneric, GetData2);

    DetectAppLayerMpmRegister2("http_stat_msg", SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,

            GetData2, ALPROTO_HTTP2, HTTP2StateDataServer);

    DetectBufferTypeSetDescriptionByName("http_stat_msg",

            "http response status message");

    g_http_stat_msg_buffer_id = DetectBufferTypeGetByName("http_stat_msg");

}

/**

 * \brief this function setups the http_stat_msg modifier keyword used in the rule

 *

 * \param de_ctx   Pointer to the Detection Engine Context

 * \param s        Pointer to the Signature to which the current keyword belongs

 * \param str      Should hold an empty string always

 *

 * \retval  0 On success

 * \retval -1 On failure

 */

static int DetectHttpStatMsgSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)

{

    return DetectEngineContentModifierBufferSetup(

            de_ctx, s, arg, DETECT_AL_HTTP_STAT_MSG, g_http_stat_msg_buffer_id, ALPROTO_HTTP1);

}

/**

 * \brief this function setup the http.stat_msg keyword used in the rule

 *

 * \param de_ctx   Pointer to the Detection Engine Context

 * \param s        Pointer to the Signature to which the current keyword belongs

 * \param str      Should hold an empty string always

 *

 * \retval 0       On success

 */

static int DetectHttpStatMsgSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

    if (DetectBufferSetActiveList(de_ctx, s, g_http_stat_msg_buffer_id) < 0)

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)

        return -1;

    return 0;

}

static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *_f,

        const uint8_t _flow_flags, void *txv, const int list_id)

{

    SCEnter();

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        htp_tx_t *tx = (htp_tx_t *)txv;

        if (tx->response_message == NULL)

            return NULL;

        const uint32_t data_len = bstr_len(tx->response_message);

        const uint8_t *data = bstr_ptr(tx->response_message);

        InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

#ifdef UNITTESTS

#include "tests/detect-http-stat-msg.c"

#endif /* UNITTESTS */

/**

 * @}

 */