suricata/src/detect-http-protocol.c

/* Copyright (C) 2007-2017 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 Victor Julien <victor@inliniac.net>
 *
 * Implements support http_protocol sticky buffer
 */

#include "suricata-common.h"
#include "threads.h"
#include "decode.h"

#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-buffer.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 "detect-http-header-common.h"
#include "detect-http-protocol.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 "util-print.h"

#include "app-layer.h"
#include "app-layer-parser.h"

#include "app-layer-htp.h"
#include "detect-http-header.h"
#include "stream-tcp.h"

#define KEYWORD_NAME "http.protocol"
#define KEYWORD_NAME_LEGACY "http_protocol"
#define KEYWORD_DOC "http-keywords.html#http-protocol"
#define BUFFER_NAME "http_protocol"
#define BUFFER_DESC "http protocol"
static int g_buffer_id = 0;

static int DetectHttpProtocolSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
{
    if (SCDetectBufferSetActiveList(de_ctx, s, g_buffer_id) < 0)
        return -1;

    if (SCDetectSignatureSetAppProto(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) {
        const bstr *str = NULL;
        htp_tx_t *tx = (htp_tx_t *)txv;

        if (flow_flags & STREAM_TOSERVER)
            str = htp_tx_request_protocol(tx);
        else if (flow_flags & STREAM_TOCLIENT)
            str = htp_tx_response_protocol(tx);

        if (str == NULL) {
            SCLogDebug("HTTP protocol not set");
            return NULL;
        }

        uint32_t data_len = (uint32_t)bstr_size(str);
        uint8_t *data = bstr_ptr(str);
        if (data == NULL || data_len == 0) {
            SCLogDebug("HTTP protocol not present");
            return NULL;
        }

        InspectionBufferSetupAndApplyTransforms(
                det_ctx, list_id, buffer, data, data_len, 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) {
        InspectionBufferSetupAndApplyTransforms(
                det_ctx, list_id, buffer, (const uint8_t *)"HTTP/2", strlen("HTTP/2"), transforms);
    }

    return buffer;
}

static bool DetectHttpProtocolValidateCallback(
        const Signature *s, const char **sigerror, const DetectBufferType *dbt)
{
    for (uint32_t x = 0; x < s->init_data->buffer_index; x++) {
        if (s->init_data->buffers[x].id != (uint32_t)dbt->id)
            continue;
        const SigMatch *sm = s->init_data->buffers[x].head;
        for (; sm != NULL; sm = sm->next) {
            if (sm->type != DETECT_CONTENT)
                continue;
            const DetectContentData *cd = (DetectContentData *)sm->ctx;
            for (size_t i = 0; i < cd->content_len; ++i) {
                if (cd->content[i] == ' ') {
                    *sigerror = "Invalid http.protocol string containing a space";
                    SCLogWarning("rule %u: %s", s->id, *sigerror);
                    return false;
                }
            }
        }
    }
    return true;
}

/**
 * \brief Registers the keyword handlers for the "http.protocol" keyword.
 */
void DetectHttpProtocolRegister(void)
{
    sigmatch_table[DETECT_HTTP_PROTOCOL].name = KEYWORD_NAME;
    sigmatch_table[DETECT_HTTP_PROTOCOL].alias = KEYWORD_NAME_LEGACY;
    sigmatch_table[DETECT_HTTP_PROTOCOL].desc = BUFFER_NAME " sticky buffer";
    sigmatch_table[DETECT_HTTP_PROTOCOL].url = "/rules/" KEYWORD_DOC;
    sigmatch_table[DETECT_HTTP_PROTOCOL].Setup = DetectHttpProtocolSetup;
    sigmatch_table[DETECT_HTTP_PROTOCOL].flags |= SIGMATCH_INFO_STICKY_BUFFER | SIGMATCH_NOOPT;

    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,
            GetData, ALPROTO_HTTP1, HTP_REQUEST_PROGRESS_LINE);
    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,
            GetData, ALPROTO_HTTP1, HTP_RESPONSE_PROGRESS_LINE);
    DetectAppLayerInspectEngineRegister(BUFFER_NAME, ALPROTO_HTTP1, SIG_FLAG_TOSERVER,
            HTP_REQUEST_PROGRESS_LINE, DetectEngineInspectBufferGeneric, GetData);
    DetectAppLayerInspectEngineRegister(BUFFER_NAME, ALPROTO_HTTP1, SIG_FLAG_TOCLIENT,
            HTP_RESPONSE_PROGRESS_LINE, DetectEngineInspectBufferGeneric, GetData);

    DetectAppLayerInspectEngineRegister(BUFFER_NAME, ALPROTO_HTTP2, SIG_FLAG_TOSERVER,
            HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);
    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,
            GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);
    DetectAppLayerInspectEngineRegister(BUFFER_NAME, ALPROTO_HTTP2, SIG_FLAG_TOCLIENT,
            HTTP2StateDataServer, DetectEngineInspectBufferGeneric, GetData2);
    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,
            GetData2, ALPROTO_HTTP2, HTTP2StateDataServer);

    DetectBufferTypeSetDescriptionByName(BUFFER_NAME,
            BUFFER_DESC);
    DetectBufferTypeRegisterValidateCallback(BUFFER_NAME, DetectHttpProtocolValidateCallback);

    g_buffer_id = DetectBufferTypeGetByName(BUFFER_NAME);
}