/* Copyright (C) 2007-2019 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 Anoop Saldanha <anoopsaldanha@gmail.com>

 *

 * Implements support for the http_host 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-prefilter.h"

#include "detect-content.h"

#include "detect-pcre.h"

#include "flow.h"

#include "flow-var.h"

#include "flow-util.h"

#include "util-debug.h"

#include "util-unittest.h"

#include "util-unittest-helper.h"

#include "util-spm.h"

#include "app-layer.h"

#include "app-layer-parser.h"

#include "app-layer-htp.h"

#include "stream-tcp.h"

#include "detect-http-host.h"

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

#ifdef UNITTESTS

static void DetectHttpHHRegisterTests(void);

#endif

static bool DetectHttpHostValidateCallback(const Signature *s, const char **sigerror);

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

static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms,

        Flow *_f, const uint8_t _flow_flags,

        void *txv, const int list_id);

static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,

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

        const int list_id);

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

static int g_http_raw_host_buffer_id = 0;

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

static InspectionBuffer *GetRawData(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *_f,

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

static InspectionBuffer *GetRawData2(DetectEngineThreadCtx *det_ctx,

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

        const int list_id);

static int g_http_host_buffer_id = 0;

/**

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

 */

void DetectHttpHHRegister(void)

{

    /* http_host content modifier */

    sigmatch_table[DETECT_AL_HTTP_HOST].name = "http_host";

    sigmatch_table[DETECT_AL_HTTP_HOST].desc = "content modifier to match on the HTTP hostname";

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

    sigmatch_table[DETECT_AL_HTTP_HOST].Setup = DetectHttpHHSetup;

#ifdef UNITTESTS

    sigmatch_table[DETECT_AL_HTTP_HOST].RegisterTests = DetectHttpHHRegisterTests;

#endif

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

    sigmatch_table[DETECT_AL_HTTP_HOST].alternative = DETECT_HTTP_HOST;

    /* http.host sticky buffer */

    sigmatch_table[DETECT_HTTP_HOST].name = "http.host";

    sigmatch_table[DETECT_HTTP_HOST].desc = "sticky buffer to match on the HTTP Host buffer";

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

    sigmatch_table[DETECT_HTTP_HOST].Setup = DetectHttpHostSetup;

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

    DetectAppLayerInspectEngineRegister2("http_host", ALPROTO_HTTP1, SIG_FLAG_TOSERVER,

            HTP_REQUEST_HEADERS, DetectEngineInspectBufferGeneric, GetData);

    DetectAppLayerMpmRegister2("http_host", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetData, ALPROTO_HTTP1, HTP_REQUEST_HEADERS);

    DetectAppLayerInspectEngineRegister2("http_host", ALPROTO_HTTP2, SIG_FLAG_TOSERVER,

            HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);

    DetectAppLayerMpmRegister2("http_host", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);

    DetectBufferTypeRegisterValidateCallback("http_host",

            DetectHttpHostValidateCallback);

    DetectBufferTypeSetDescriptionByName("http_host",

            "http host");

    g_http_host_buffer_id = DetectBufferTypeGetByName("http_host");

    /* http_raw_host content modifier */

    sigmatch_table[DETECT_AL_HTTP_RAW_HOST].name = "http_raw_host";

    sigmatch_table[DETECT_AL_HTTP_RAW_HOST].desc = "content modifier to match on the HTTP host header or the raw hostname from the HTTP uri";

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

    sigmatch_table[DETECT_AL_HTTP_RAW_HOST].Setup = DetectHttpHRHSetup;

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

    sigmatch_table[DETECT_AL_HTTP_RAW_HOST].alternative = DETECT_HTTP_HOST_RAW;

    /* http.host sticky buffer */

    sigmatch_table[DETECT_HTTP_HOST_RAW].name = "http.host.raw";

    sigmatch_table[DETECT_HTTP_HOST_RAW].desc = "sticky buffer to match on the HTTP host header or the raw hostname from the HTTP uri";

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

    sigmatch_table[DETECT_HTTP_HOST_RAW].Setup = DetectHttpHostRawSetupSticky;

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

    DetectAppLayerInspectEngineRegister2("http_raw_host", ALPROTO_HTTP1, SIG_FLAG_TOSERVER,

            HTP_REQUEST_HEADERS, DetectEngineInspectBufferGeneric, GetRawData);

    DetectAppLayerMpmRegister2("http_raw_host", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetRawData, ALPROTO_HTTP1, HTP_REQUEST_HEADERS);

    DetectAppLayerInspectEngineRegister2("http_raw_host", ALPROTO_HTTP2, SIG_FLAG_TOSERVER,

            HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetRawData2);

    DetectAppLayerMpmRegister2("http_raw_host", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetRawData2, ALPROTO_HTTP2, HTTP2StateDataClient);

    DetectBufferTypeSetDescriptionByName("http_raw_host",

            "http raw host header");

    g_http_raw_host_buffer_id = DetectBufferTypeGetByName("http_raw_host");

}

/**

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

 *

 * \param de_ctx Pointer to the detection engine context.

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

 *               parsed from the rules.

 * \param m      Pointer to the head of the SigMatch 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 DetectHttpHHSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)

{

    return DetectEngineContentModifierBufferSetup(

            de_ctx, s, arg, DETECT_AL_HTTP_HOST, g_http_host_buffer_id, ALPROTO_HTTP1);

}

static bool DetectHttpHostValidateCallback(const Signature *s, const char **sigerror)

{

    for (uint32_t x = 0; x < s->init_data->buffer_index; x++) {

        if (s->init_data->buffers[x].id != (uint32_t)g_http_host_buffer_id)

            continue;

        const SigMatch *sm = s->init_data->buffers[x].head;

        for (; sm != NULL; sm = sm->next) {

            if (sm->type == DETECT_CONTENT) {

                DetectContentData *cd = (DetectContentData *)sm->ctx;

                if (cd->flags & DETECT_CONTENT_NOCASE) {

                    *sigerror = "http.host keyword "

                                "specified along with \"nocase\". "

                                "The hostname buffer is normalized "

                                "to lowercase, specifying "

                                "nocase is redundant.";

                    SCLogWarning("rule %u: %s", s->id, *sigerror);

                    return false;

                } else {

                    uint32_t u;

                    for (u = 0; u < cd->content_len; u++) {

                        if (isupper(cd->content[u]))

                            break;

                    }

                    if (u != cd->content_len) {

                        *sigerror = "A pattern with "

                                    "uppercase characters detected for http.host. "

                                    "The hostname buffer is normalized to lowercase, "

                                    "please specify a lowercase pattern.";

                        SCLogWarning("rule %u: %s", s->id, *sigerror);

                        return false;

                    }

                }

            }

        }

    }

    return true;

}

/**

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

{

    if (DetectBufferSetActiveList(de_ctx, s, g_http_host_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)

{

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        htp_tx_t *tx = (htp_tx_t *)txv;

        if (tx->request_hostname == NULL)

            return NULL;

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

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

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

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

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) {

        uint32_t b_len = 0;

        const uint8_t *b = NULL;

        if (rs_http2_tx_get_host_norm(txv, &b, &b_len) != 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;

}

static InspectionBuffer *GetRawData2(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;

        if (rs_http2_tx_get_host(txv, &b, &b_len) != 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;

}

/**

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

 *

 * \param de_ctx Pointer to the detection engine context.

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

 *               parsed from the rules.

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

 *               being parsed.

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

 *

 * \retval  0 On success

 * \retval -1 On failure

 */

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

{

    return DetectEngineContentModifierBufferSetup(

            de_ctx, s, arg, DETECT_AL_HTTP_RAW_HOST, g_http_raw_host_buffer_id, ALPROTO_HTTP1);

}

/**

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

{

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

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)

        return -1;

    return 0;

}

static InspectionBuffer *GetRawData(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) {

        htp_tx_t *tx = (htp_tx_t *)txv;

        const uint8_t *data = NULL;

        uint32_t data_len = 0;

        if (tx->parsed_uri == NULL || tx->parsed_uri->hostname == NULL) {

            if (tx->request_headers == NULL)

                return NULL;

            htp_header_t *h = (htp_header_t *)htp_table_get_c(tx->request_headers,

                    "Host");

            if (h == NULL || h->value == NULL)

                return NULL;

            data = (const uint8_t *)bstr_ptr(h->value);

            data_len = bstr_len(h->value);

        } else {

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

            data_len = bstr_len(tx->parsed_uri->hostname);

        }

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

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

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

#ifdef UNITTESTS

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

#endif /* UNITTESTS */

/**

 * @}

 */