/* Copyright (C) 2007-2022 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 Pablo Rincon <pablo.rincon.crespo@gmail.com>

 *

 * Implements support for http_header keyword.

 */

#include "suricata-common.h"

#include "threads.h"

#include "decode.h"

#include "detect.h"

#include "detect-parse.h"

#include "detect-engine.h"

#include "detect-engine-mpm.h"

#include "detect-engine-state.h"

#include "detect-engine-prefilter.h"

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

#include "detect-content.h"

#include "detect-pcre.h"

#include "util-debug.h"

#include "util-print.h"

#include "util-memcmp.h"

#include "util-profiling.h"

#include "util-validate.h"

#include "app-layer.h"

#include "app-layer-parser.h"

#include "app-layer-htp.h"

#include "detect-http-header.h"

#include "detect-http-header-common.h"

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

#ifdef UNITTESTS

static void DetectHttpHeaderRegisterTests(void);

#endif

static int g_http_header_buffer_id = 0;

static int g_keyword_thread_id = 0;

static int g_http2_thread_id = 0;

#define BUFFER_SIZE_STEP    1024

static HttpHeaderThreadDataConfig g_td_config = { BUFFER_SIZE_STEP };

static uint8_t *GetBufferForTX(

        htp_tx_t *tx, DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, uint32_t *buffer_len)

{

    *buffer_len = 0;

    HttpHeaderThreadData *hdr_td = NULL;

    HttpHeaderBuffer *buf =

            HttpHeaderGetBufferSpace(det_ctx, f, flags, g_keyword_thread_id, &hdr_td);

    if (unlikely(buf == NULL)) {

        return NULL;

    }

    htp_table_t *headers;

    if (flags & STREAM_TOSERVER) {

        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, tx, flags) <=

                HTP_REQUEST_HEADERS)

            return NULL;

        headers = tx->request_headers;

    } else {

        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, tx, flags) <=

                HTP_RESPONSE_HEADERS)

            return NULL;

        headers = tx->response_headers;

    }

    if (headers == NULL)

        return NULL;

    size_t i = 0;

    size_t no_of_headers = htp_table_size(headers);

    for (; i < no_of_headers; i++) {

        htp_header_t *h = htp_table_get_index(headers, i, NULL);

        size_t size1 = bstr_size(h->name);

        size_t size2 = bstr_size(h->value);

        if (flags & STREAM_TOSERVER) {

            if (size1 == 6 &&

                SCMemcmpLowercase("cookie", bstr_ptr(h->name), 6) == 0) {

                continue;

            }

        } else {

            if (size1 == 10 &&

                SCMemcmpLowercase("set-cookie", bstr_ptr(h->name), 10) == 0) {

                continue;

            }

        }

        size_t size = size1 + size2 + 4;

#if 0

        if (i + 1 == no_of_headers)

            size += 2;

#endif

        if (size + buf->len > buf->size) {

            if (HttpHeaderExpandBuffer(hdr_td, buf, size) != 0) {

                return NULL;

            }

        }

        memcpy(buf->buffer + buf->len, bstr_ptr(h->name), bstr_size(h->name));

        buf->len += bstr_size(h->name);

        buf->buffer[buf->len++] = ':';

        buf->buffer[buf->len++] = ' ';

        memcpy(buf->buffer + buf->len, bstr_ptr(h->value), bstr_size(h->value));

        buf->len += bstr_size(h->value);

        buf->buffer[buf->len++] = '\r';

        buf->buffer[buf->len++] = '\n';

#if 0 // looks like this breaks existing rules

        if (i + 1 == no_of_headers) {

            buf->buffer[buf->len++] = '\r';

            buf->buffer[buf->len++] = '\n';

        }

#endif

    }

    *buffer_len = buf->len;

    return buf->buffer;

}

static InspectionBuffer *GetBuffer2ForTX(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) {

        uint32_t b_len = 0;

        const uint8_t *b = NULL;

        void *thread_buf = DetectThreadCtxGetGlobalKeywordThreadCtx(det_ctx, g_http2_thread_id);

        if (thread_buf == NULL)

            return NULL;

        if (SCHttp2TxGetHeaders(txv, flow_flags, &b, &b_len, thread_buf) != 1)

            return NULL;

        if (b == NULL || b_len == 0)

            return NULL;

        InspectionBufferSetup(det_ctx, list_id, buffer, b, b_len);

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

/** \internal

 *  \brief custom inspect function to utilize the cached headers

 */

static uint8_t DetectEngineInspectBufferHttpHeader(DetectEngineCtx *de_ctx,

        DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine,

        const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)

{

    SCEnter();

    const int list_id = engine->sm_list;

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        SCLogDebug("setting up inspect buffer %d", list_id);

        /* if prefilter didn't already run, we need to consider transformations */

        const DetectEngineTransforms *transforms = NULL;

        if (!engine->mpm) {

            transforms = engine->v2.transforms;

        }

        uint32_t rawdata_len = 0;

        uint8_t *rawdata = GetBufferForTX(txv, det_ctx, f, flags, &rawdata_len);

        if (rawdata_len == 0) {

            SCLogDebug("no data");

            goto end;

        }

        /* setup buffer and apply transforms */

        InspectionBufferSetup(det_ctx, list_id, buffer, rawdata, rawdata_len);

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    const uint32_t data_len = buffer->inspect_len;

    const uint8_t *data = buffer->inspect;

    const uint64_t offset = buffer->inspect_offset;

    det_ctx->discontinue_matching = 0;

    det_ctx->buffer_offset = 0;

    det_ctx->inspection_recursion_counter = 0;

    /* Inspect all the uricontents fetched on each

     * transaction at the app layer */

    int r = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd,

            NULL, f, (uint8_t *)data, data_len, offset,

            DETECT_CI_FLAGS_SINGLE, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);

    SCLogDebug("r = %d", r);

    if (r == 1) {

        return DETECT_ENGINE_INSPECT_SIG_MATCH;

    }

end:

    if (flags & STREAM_TOSERVER) {

        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, txv, flags) >

                HTP_REQUEST_HEADERS)

            return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;

    } else {

        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, txv, flags) >

                HTP_RESPONSE_HEADERS)

            return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;

    }

    return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

}

typedef struct PrefilterMpmHttpHeaderCtx {

    int list_id;

    const MpmCtx *mpm_ctx;

    const DetectEngineTransforms *transforms;

} PrefilterMpmHttpHeaderCtx;

/** \brief Generic Mpm prefilter callback

 *

 *  \param det_ctx detection engine thread ctx

 *  \param p packet to inspect

 *  \param f flow to inspect

 *  \param txv tx to inspect

 *  \param pectx inspection context

 */

static void PrefilterMpmHttpHeader(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,

        Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags)

{

    SCEnter();

    const PrefilterMpmHttpHeaderCtx *ctx = pectx;

    const MpmCtx *mpm_ctx = ctx->mpm_ctx;

    SCLogDebug("running on list %d", ctx->list_id);

    const int list_id = ctx->list_id;

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        uint32_t rawdata_len = 0;

        uint8_t *rawdata = GetBufferForTX(txv, det_ctx, f, flags, &rawdata_len);

        if (rawdata_len == 0)

            return;

        /* setup buffer and apply transforms */

        InspectionBufferSetup(det_ctx, list_id, buffer, rawdata, rawdata_len);

        InspectionBufferApplyTransforms(buffer, ctx->transforms);

    }

    const uint32_t data_len = buffer->inspect_len;

    const uint8_t *data = buffer->inspect;

    SCLogDebug("mpm'ing buffer:");

    //PrintRawDataFp(stdout, data, data_len);

    if (data != NULL && data_len >= mpm_ctx->minlen) {

        (void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx,

                &det_ctx->mtcu, &det_ctx->pmq, data, data_len);

        PREFILTER_PROFILING_ADD_BYTES(det_ctx, data_len);

    }

}

static void PrefilterMpmHttpTrailer(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,

        Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags)

{

    SCEnter();

    htp_tx_t *tx = txv;

    const HtpTxUserData *htud = (const HtpTxUserData *)htp_tx_get_user_data(tx);

    /* if the request wasn't flagged as having a trailer, we skip */

    if (htud && (

            ((flags & STREAM_TOSERVER) && !htud->request_has_trailers) ||

            ((flags & STREAM_TOCLIENT) && !htud->response_has_trailers))) {

        SCReturn;

    }

    PrefilterMpmHttpHeader(det_ctx, pectx, p, f, txv, idx, _txd, flags);

    SCReturn;

}

static void PrefilterMpmHttpHeaderFree(void *ptr)

{

    SCFree(ptr);

}

static int PrefilterMpmHttpHeaderRequestRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,

        MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)

{

    SCEnter();

    /* header */

    PrefilterMpmHttpHeaderCtx *pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    int r = PrefilterAppendTxEngine(de_ctx, sgh, PrefilterMpmHttpHeader,

            mpm_reg->app_v2.alproto, HTP_REQUEST_HEADERS,

            pectx, PrefilterMpmHttpHeaderFree, mpm_reg->pname);

    if (r != 0) {

        SCFree(pectx);

        return r;

    }

    /* trailer */

    pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    r = PrefilterAppendTxEngine(de_ctx, sgh, PrefilterMpmHttpTrailer,

            mpm_reg->app_v2.alproto, HTP_REQUEST_TRAILER,

            pectx, PrefilterMpmHttpHeaderFree, mpm_reg->pname);

    if (r != 0) {

        SCFree(pectx);

    }

    return r;

}

static int PrefilterMpmHttpHeaderResponseRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,

        MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)

{

    SCEnter();

    /* header */

    PrefilterMpmHttpHeaderCtx *pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    int r = PrefilterAppendTxEngine(de_ctx, sgh, PrefilterMpmHttpHeader,

            mpm_reg->app_v2.alproto, HTP_RESPONSE_HEADERS,

            pectx, PrefilterMpmHttpHeaderFree, mpm_reg->pname);

    if (r != 0) {

        SCFree(pectx);

        return r;

    }

    /* trailer */

    pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    r = PrefilterAppendTxEngine(de_ctx, sgh, PrefilterMpmHttpTrailer,

            mpm_reg->app_v2.alproto, HTP_RESPONSE_TRAILER,

            pectx, PrefilterMpmHttpHeaderFree, mpm_reg->pname);

    if (r != 0) {

        SCFree(pectx);

    }

    return r;

}

/**

 * \brief The setup function for the http_header keyword for a signature.

 *

 * \param de_ctx Pointer to the detection engine context.

 * \param s      Pointer to signature for the current Signature being parsed

 *               from the rules.

 * \param m      Pointer to the head of the SigMatchs for the current rule

 *               being parsed.

 * \param arg    Pointer to the string holding the keyword value.

 *

 * \retval  0 On success.

 * \retval -1 On failure.

 */

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

{

    return DetectEngineContentModifierBufferSetup(

            de_ctx, s, arg, DETECT_AL_HTTP_HEADER, g_http_header_buffer_id, ALPROTO_HTTP1);

}

/**

 * \brief this function setup the http.header 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 DetectHttpHeaderSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

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

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)

        return -1;

    return 0;

}

/**

 * \brief Registers the keyword handlers for the "http_header" keyword.

 */

void DetectHttpHeaderRegister(void)

{

    /* http_header content modifier */

    sigmatch_table[DETECT_AL_HTTP_HEADER].name = "http_header";

    sigmatch_table[DETECT_AL_HTTP_HEADER].desc = "content modifier to match only on the HTTP header-buffer";

    sigmatch_table[DETECT_AL_HTTP_HEADER].url = "/rules/http-keywords.html#http-header-and-http-raw-header";

    sigmatch_table[DETECT_AL_HTTP_HEADER].Setup = DetectHttpHeaderSetup;

#ifdef UNITTESTS

    sigmatch_table[DETECT_AL_HTTP_HEADER].RegisterTests = DetectHttpHeaderRegisterTests;

#endif

    sigmatch_table[DETECT_AL_HTTP_HEADER].flags |= SIGMATCH_NOOPT ;

    sigmatch_table[DETECT_AL_HTTP_HEADER].flags |= SIGMATCH_INFO_CONTENT_MODIFIER;

    sigmatch_table[DETECT_AL_HTTP_HEADER].alternative = DETECT_HTTP_HEADER;

    /* http.header sticky buffer */

    sigmatch_table[DETECT_HTTP_HEADER].name = "http.header";

    sigmatch_table[DETECT_HTTP_HEADER].desc = "sticky buffer to match on the normalized HTTP header-buffer";

    sigmatch_table[DETECT_HTTP_HEADER].url = "/rules/http-keywords.html#http-header-and-http-raw-header";

    sigmatch_table[DETECT_HTTP_HEADER].Setup = DetectHttpHeaderSetupSticky;

    sigmatch_table[DETECT_HTTP_HEADER].flags |= SIGMATCH_NOOPT;

    sigmatch_table[DETECT_HTTP_HEADER].flags |= SIGMATCH_INFO_STICKY_BUFFER;

    DetectAppLayerInspectEngineRegister2("http_header", ALPROTO_HTTP1, SIG_FLAG_TOSERVER,

            HTP_REQUEST_HEADERS, DetectEngineInspectBufferHttpHeader, NULL);

    DetectAppLayerMpmRegister2("http_header", SIG_FLAG_TOSERVER, 2,

            PrefilterMpmHttpHeaderRequestRegister, NULL, ALPROTO_HTTP1,

            0); /* not used, registered twice: HEADERS/TRAILER */

    DetectAppLayerInspectEngineRegister2("http_header", ALPROTO_HTTP1, SIG_FLAG_TOCLIENT,

            HTP_RESPONSE_HEADERS, DetectEngineInspectBufferHttpHeader, NULL);

    DetectAppLayerMpmRegister2("http_header", SIG_FLAG_TOCLIENT, 2,

            PrefilterMpmHttpHeaderResponseRegister, NULL, ALPROTO_HTTP1,

            0); /* not used, registered twice: HEADERS/TRAILER */

    DetectAppLayerInspectEngineRegister2("http_header", ALPROTO_HTTP2, SIG_FLAG_TOSERVER,

            HTTP2StateOpen, DetectEngineInspectBufferGeneric, GetBuffer2ForTX);

    DetectAppLayerMpmRegister2("http_header", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetBuffer2ForTX, ALPROTO_HTTP2, HTTP2StateOpen);

    DetectAppLayerInspectEngineRegister2("http_header", ALPROTO_HTTP2, SIG_FLAG_TOCLIENT,

            HTTP2StateDataServer, DetectEngineInspectBufferGeneric, GetBuffer2ForTX);

    DetectAppLayerMpmRegister2("http_header", SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,

            GetBuffer2ForTX, ALPROTO_HTTP2, HTTP2StateDataServer);

    DetectBufferTypeSetDescriptionByName("http_header",

            "http headers");

    g_http_header_buffer_id = DetectBufferTypeGetByName("http_header");

    g_keyword_thread_id = DetectRegisterThreadCtxGlobalFuncs("http_header",

            HttpHeaderThreadDataInit, &g_td_config, HttpHeaderThreadDataFree);

    g_http2_thread_id = DetectRegisterThreadCtxGlobalFuncs(

            "http2.header", SCHttp2ThreadBufDataInit, NULL, SCHttp2ThreadBufDataFree);

}

static int g_http_request_header_buffer_id = 0;

static int g_http_response_header_buffer_id = 0;

static int g_request_header_thread_id = 0;

static int g_response_header_thread_id = 0;

static int g_h2_request_header_thread_id = 0;

static int g_h2_response_header_thread_id = 0;

static InspectionBuffer *GetHttp2HeaderData(DetectEngineThreadCtx *det_ctx, const uint8_t flags,

        const DetectEngineTransforms *transforms, Flow *_f, const struct MpmListIdDataArgs *cbdata,

        int list_id)

{

    SCEnter();

    InspectionBuffer *buffer =

            InspectionBufferMultipleForListGet(det_ctx, list_id, cbdata->local_id);

    if (buffer == NULL)

        return NULL;

    if (buffer->initialized)

        return buffer;

    uint32_t b_len = 0;

    const uint8_t *b = NULL;

    int kw_thread_id;

    if (flags & STREAM_TOSERVER) {

        kw_thread_id = g_h2_request_header_thread_id;

    } else {

        kw_thread_id = g_h2_response_header_thread_id;

    }

    void *hdr_td = DetectThreadCtxGetGlobalKeywordThreadCtx(det_ctx, kw_thread_id);

    if (unlikely(hdr_td == NULL)) {

        return NULL;

    }

    if (SCHttp2TxGetHeader(hdr_td, cbdata->txv, flags, cbdata->local_id, &b, &b_len) != 1) {

        InspectionBufferSetupMultiEmpty(buffer);

        return NULL;

    }

    if (b == NULL || b_len == 0) {

        InspectionBufferSetupMultiEmpty(buffer);

        return NULL;

    }

    InspectionBufferSetupMulti(buffer, transforms, b, b_len);

    SCReturnPtr(buffer, "InspectionBuffer");

}

static void PrefilterTxHttp2Header(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,

        Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags)

{

    SCEnter();

    const PrefilterMpmListId *ctx = (const PrefilterMpmListId *)pectx;

    const MpmCtx *mpm_ctx = ctx->mpm_ctx;

    const int list_id = ctx->list_id;

    uint32_t local_id = 0;

    while (1) {

        // loop until we get a NULL

        struct MpmListIdDataArgs cbdata = { local_id, txv };

        InspectionBuffer *buffer =

                GetHttp2HeaderData(det_ctx, flags, ctx->transforms, f, &cbdata, list_id);

        if (buffer == NULL)

            break;

        if (buffer->inspect_len >= mpm_ctx->minlen) {

            (void)mpm_table[mpm_ctx->mpm_type].Search(

                    mpm_ctx, &det_ctx->mtcu, &det_ctx->pmq, buffer->inspect, buffer->inspect_len);

            PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len);

        }

        local_id++;

    }

}

static uint8_t DetectEngineInspectHttp2Header(DetectEngineCtx *de_ctx,

        DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine,

        const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)

{

    uint32_t local_id = 0;

    const DetectEngineTransforms *transforms = NULL;

    if (!engine->mpm) {

        transforms = engine->v2.transforms;

    }

    while (1) {

        struct MpmListIdDataArgs cbdata = {

            local_id,

            txv,

        };

        InspectionBuffer *buffer =

                GetHttp2HeaderData(det_ctx, flags, transforms, f, &cbdata, engine->sm_list);

        if (buffer == NULL || buffer->inspect == NULL)

            break;

        det_ctx->buffer_offset = 0;

        det_ctx->discontinue_matching = 0;

        det_ctx->inspection_recursion_counter = 0;

        const int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, NULL, f,

                (uint8_t *)buffer->inspect, buffer->inspect_len, buffer->inspect_offset,

                DETECT_CI_FLAGS_SINGLE, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);

        if (match == 1) {

            return DETECT_ENGINE_INSPECT_SIG_MATCH;

        }

        local_id++;

    }

    return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

}

static int PrefilterMpmHttp2HeaderRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,

        MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)

{

    PrefilterMpmListId *pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxHttp2Header, mpm_reg->app_v2.alproto,

            mpm_reg->app_v2.tx_min_progress, pectx, PrefilterMpmHttpHeaderFree, mpm_reg->name);

}

typedef struct HttpMultiBufItem {

    uint8_t *buffer;

    size_t len;

} HttpMultiBufItem;

typedef struct HttpMultiBufHeaderThreadData {

    // array of items, being defined as a buffer with its length just above

    HttpMultiBufItem *items;

    // capacity of items (size of allocation)

    size_t cap;

    // length of items (number in use)

    size_t len;

} HttpMultiBufHeaderThreadData;

static void *HttpMultiBufHeaderThreadDataInit(void *data)

{

    HttpMultiBufHeaderThreadData *td = SCCalloc(1, sizeof(*td));

    /* This return value check to satisfy our Cocci malloc checks. */

    if (td == NULL) {

        SCLogError("failed to allocate %" PRIuMAX " bytes: %s", (uintmax_t)sizeof(*td),

                strerror(errno));

        return NULL;

    }

    return td;

}

static void HttpMultiBufHeaderThreadDataFree(void *data)

{

    HttpMultiBufHeaderThreadData *td = data;

    for (size_t i = 0; i < td->cap; i++) {

        SCFree(td->items[i].buffer);

    }

    SCFree(td->items);

    SCFree(td);

}

static InspectionBuffer *GetHttp1HeaderData(DetectEngineThreadCtx *det_ctx, const uint8_t flags,

        const DetectEngineTransforms *transforms, Flow *f, const struct MpmListIdDataArgs *cbdata,

        int list_id)

{

    SCEnter();

    InspectionBuffer *buffer =

            InspectionBufferMultipleForListGet(det_ctx, list_id, cbdata->local_id);

    if (buffer == NULL)

        return NULL;

    if (buffer->initialized)

        return buffer;

    int kw_thread_id;

    if (flags & STREAM_TOSERVER) {

        kw_thread_id = g_request_header_thread_id;

    } else {

        kw_thread_id = g_response_header_thread_id;

    }

    HttpMultiBufHeaderThreadData *hdr_td =

            DetectThreadCtxGetGlobalKeywordThreadCtx(det_ctx, kw_thread_id);

    if (unlikely(hdr_td == NULL)) {

        return NULL;

    }

    htp_tx_t *tx = (htp_tx_t *)cbdata->txv;

    htp_table_t *headers;

    if (flags & STREAM_TOSERVER) {

        headers = tx->request_headers;

    } else {

        headers = tx->response_headers;

    }

    size_t no_of_headers = htp_table_size(headers);

    if (cbdata->local_id == 0) {

        // We initialize a big buffer on first item

        // Then, we will just use parts of it

        hdr_td->len = 0;

        if (hdr_td->cap < no_of_headers) {

            void *new_buffer = SCRealloc(hdr_td->items, no_of_headers * sizeof(HttpMultiBufItem));

            if (unlikely(new_buffer == NULL)) {

                return NULL;

            }

            hdr_td->items = new_buffer;

            // zeroes the new part of the items

            memset(hdr_td->items + hdr_td->cap, 0,

                    (no_of_headers - hdr_td->cap) * sizeof(HttpMultiBufItem));

            hdr_td->cap = no_of_headers;

        }

        for (size_t i = 0; i < no_of_headers; i++) {

            htp_header_t *h = htp_table_get_index(headers, i, NULL);

            size_t size1 = bstr_size(h->name);

            size_t size2 = bstr_size(h->value);

            size_t size = size1 + size2 + 2;

            if (hdr_td->items[i].len < size) {

                // Use realloc, as this pointer is not freed until HttpMultiBufHeaderThreadDataFree

                void *tmp = SCRealloc(hdr_td->items[i].buffer, size);

                if (unlikely(tmp == NULL)) {

                    return NULL;

                }

                hdr_td->items[i].buffer = tmp;

            }

            memcpy(hdr_td->items[i].buffer, bstr_ptr(h->name), size1);

            hdr_td->items[i].buffer[size1] = ':';

            hdr_td->items[i].buffer[size1 + 1] = ' ';

            memcpy(hdr_td->items[i].buffer + size1 + 2, bstr_ptr(h->value), size2);

            hdr_td->items[i].len = size;

        }

        hdr_td->len = no_of_headers;

    }

    // cbdata->local_id is the index of the requested header buffer

    // hdr_td->len is the number of header buffers

    if (cbdata->local_id < hdr_td->len) {

        // we have one valid header buffer

        InspectionBufferSetupMulti(buffer, transforms, hdr_td->items[cbdata->local_id].buffer,

                hdr_td->items[cbdata->local_id].len);

        SCReturnPtr(buffer, "InspectionBuffer");

    } // else there are no more header buffer to get

    InspectionBufferSetupMultiEmpty(buffer);

    return NULL;

}

static void PrefilterTxHttp1Header(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,

        Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags)

{

    SCEnter();

    const PrefilterMpmListId *ctx = (const PrefilterMpmListId *)pectx;

    const MpmCtx *mpm_ctx = ctx->mpm_ctx;

    const int list_id = ctx->list_id;

    uint32_t local_id = 0;

    while (1) {

        // loop until we get a NULL

        struct MpmListIdDataArgs cbdata = { local_id, txv };

        InspectionBuffer *buffer =

                GetHttp1HeaderData(det_ctx, flags, ctx->transforms, f, &cbdata, list_id);

        if (buffer == NULL)

            break;

        if (buffer->inspect_len >= mpm_ctx->minlen) {

            (void)mpm_table[mpm_ctx->mpm_type].Search(

                    mpm_ctx, &det_ctx->mtcu, &det_ctx->pmq, buffer->inspect, buffer->inspect_len);

            PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len);

        }

        local_id++;

    }

}

static int PrefilterMpmHttp1HeaderRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,

        MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)

{

    PrefilterMpmListId *pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxHttp1Header, mpm_reg->app_v2.alproto,

            mpm_reg->app_v2.tx_min_progress, pectx, PrefilterMpmHttpHeaderFree, mpm_reg->name);

}

static uint8_t DetectEngineInspectHttp1Header(DetectEngineCtx *de_ctx,

        DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine,

        const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)

{

    uint32_t local_id = 0;

    const DetectEngineTransforms *transforms = NULL;

    if (!engine->mpm) {

        transforms = engine->v2.transforms;

    }

    while (1) {

        struct MpmListIdDataArgs cbdata = {

            local_id,

            txv,

        };

        InspectionBuffer *buffer =

                GetHttp1HeaderData(det_ctx, flags, transforms, f, &cbdata, engine->sm_list);

        if (buffer == NULL || buffer->inspect == NULL)

            break;

        det_ctx->buffer_offset = 0;

        det_ctx->discontinue_matching = 0;

        det_ctx->inspection_recursion_counter = 0;

        const int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, NULL, f,

                (uint8_t *)buffer->inspect, buffer->inspect_len, buffer->inspect_offset,

                DETECT_CI_FLAGS_SINGLE, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);

        if (match == 1) {

            return DETECT_ENGINE_INSPECT_SIG_MATCH;

        }

        local_id++;

    }

    return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

}

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

{

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

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) != 0)

        return -1;

    return 0;

}

void DetectHttpRequestHeaderRegister(void)

{

    sigmatch_table[DETECT_HTTP_REQUEST_HEADER].name = "http.request_header";

    sigmatch_table[DETECT_HTTP_REQUEST_HEADER].desc =

            "sticky buffer to match on only one HTTP header name and value";

    sigmatch_table[DETECT_HTTP_REQUEST_HEADER].url = "/rules/http-keywords.html#request_header";

    sigmatch_table[DETECT_HTTP_REQUEST_HEADER].Setup = DetectHTTPRequestHeaderSetup;

    sigmatch_table[DETECT_HTTP_REQUEST_HEADER].flags |=

            SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;

    DetectAppLayerMpmRegister2("http_request_header", SIG_FLAG_TOSERVER, 2,

            PrefilterMpmHttp2HeaderRegister, NULL, ALPROTO_HTTP2, HTTP2StateOpen);

    DetectAppLayerInspectEngineRegister2("http_request_header", ALPROTO_HTTP2, SIG_FLAG_TOSERVER,

            HTTP2StateOpen, DetectEngineInspectHttp2Header, NULL);

    DetectAppLayerMpmRegister2("http_request_header", SIG_FLAG_TOSERVER, 2,

            PrefilterMpmHttp1HeaderRegister, NULL, ALPROTO_HTTP1, HTP_REQUEST_HEADERS);

    DetectAppLayerInspectEngineRegister2("http_request_header", ALPROTO_HTTP1, SIG_FLAG_TOSERVER,

            HTP_REQUEST_HEADERS, DetectEngineInspectHttp1Header, NULL);

    DetectBufferTypeSetDescriptionByName("http_request_header", "HTTP header name and value");

    g_http_request_header_buffer_id = DetectBufferTypeGetByName("http_request_header");

    DetectBufferTypeSupportsMultiInstance("http_request_header");

    g_request_header_thread_id = DetectRegisterThreadCtxGlobalFuncs("http_request_header",

            HttpMultiBufHeaderThreadDataInit, NULL, HttpMultiBufHeaderThreadDataFree);

    g_h2_request_header_thread_id = DetectRegisterThreadCtxGlobalFuncs("http2_request_header",

            SCHttp2ThreadMultiBufDataInit, NULL, SCHttp2ThreadMultiBufDataFree);

}

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

{

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

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) != 0)

        return -1;

    return 0;

}

void DetectHttpResponseHeaderRegister(void)

{

    sigmatch_table[DETECT_HTTP_RESPONSE_HEADER].name = "http.response_header";

    sigmatch_table[DETECT_HTTP_RESPONSE_HEADER].desc =

            "sticky buffer to match on only one HTTP header name and value";

    sigmatch_table[DETECT_HTTP_RESPONSE_HEADER].url = "/rules/http2-keywords.html#response_header";

    sigmatch_table[DETECT_HTTP_RESPONSE_HEADER].Setup = DetectHTTPResponseHeaderSetup;

    sigmatch_table[DETECT_HTTP_RESPONSE_HEADER].flags |=

            SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;

    DetectAppLayerMpmRegister2("http_response_header", SIG_FLAG_TOCLIENT, 2,

            PrefilterMpmHttp2HeaderRegister, NULL, ALPROTO_HTTP2, HTTP2StateOpen);

    DetectAppLayerInspectEngineRegister2("http_response_header", ALPROTO_HTTP2, SIG_FLAG_TOCLIENT,

            HTTP2StateOpen, DetectEngineInspectHttp2Header, NULL);

    DetectAppLayerMpmRegister2("http_response_header", SIG_FLAG_TOCLIENT, 2,

            PrefilterMpmHttp1HeaderRegister, NULL, ALPROTO_HTTP1, HTP_RESPONSE_HEADERS);

    DetectAppLayerInspectEngineRegister2("http_response_header", ALPROTO_HTTP1, SIG_FLAG_TOCLIENT,

            HTP_RESPONSE_HEADERS, DetectEngineInspectHttp1Header, NULL);

    DetectBufferTypeSetDescriptionByName("http_response_header", "HTTP header name and value");

    g_http_response_header_buffer_id = DetectBufferTypeGetByName("http_response_header");

    DetectBufferTypeSupportsMultiInstance("http_response_header");

    g_response_header_thread_id = DetectRegisterThreadCtxGlobalFuncs("http_response_header",

            HttpMultiBufHeaderThreadDataInit, NULL, HttpMultiBufHeaderThreadDataFree);

    g_h2_response_header_thread_id = DetectRegisterThreadCtxGlobalFuncs("http2_response_header",

            SCHttp2ThreadMultiBufDataInit, NULL, SCHttp2ThreadMultiBufDataFree);

}

/************************************Unittests*********************************/

#ifdef UNITTESTS

#include "tests/detect-http-header.c"

#endif

/**

 * @}

 */