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/*
* Copyright (C) 2014 ANSSI
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* \author David DIALLO <diallo@et.esiea.fr>
*
* Implements the Modbus function and access keywords
* You can specify a:
* - concrete function like Modbus:
* function 8, subfunction 4 (diagnostic: Force Listen Only Mode)
* - data (in primary table) register access (r/w) like Modbus:
* access read coils, address 1000 (.i.e Read coils: at address 1000)
* - write data value at specific address Modbus:
* access write, address 1500<>2000, value >2000 (Write multiple coils/register:
* at address between 1500 and 2000 value greater than 2000)
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-modbus.h"
#include "util-debug.h"
#include "util-byte.h"
#include "stream-tcp.h"
#include "rust.h"
static int g_modbus_buffer_id = 0;
/** \internal
*
* \brief this function will free memory associated with DetectModbus
*
* \param ptr pointer to DetectModbus
*/
static void DetectModbusFree(DetectEngineCtx *de_ctx, void *ptr) {
SCEnter();
if (ptr != NULL) {
rs_modbus_free(ptr);
}
SCReturn;
}
/** \internal
*
* \brief this function is used to add the parsed "id" option into the current signature
*
* \param de_ctx Pointer to the Detection Engine Context
* \param s Pointer to the Current Signature
* \param str Pointer to the user provided "id" option
*
* \retval 0 on Success or -1 on Failure
*/
static int DetectModbusSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
SCEnter();
DetectModbusRust *modbus = NULL;
SigMatch *sm = NULL;
if (DetectSignatureSetAppProto(s, ALPROTO_MODBUS) != 0)
return -1;
if ((modbus = rs_modbus_parse(str)) == NULL) {
SCLogError("invalid modbus option");
goto error;
}
/* Okay so far so good, lets get this into a SigMatch and put it in the Signature. */
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_AL_MODBUS;
sm->ctx = (void *) modbus;
SigMatchAppendSMToList(s, sm, g_modbus_buffer_id);
SCReturnInt(0);
error:
if (modbus != NULL)
DetectModbusFree(de_ctx, modbus);
if (sm != NULL)
SCFree(sm);
SCReturnInt(-1);
}
static int DetectModbusMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, void *state,
void *txv, const Signature *s, const SigMatchCtx *ctx)
{
return rs_modbus_inspect(txv, (void *)ctx);
}
/**
* \brief Registration function for Modbus keyword
*/
void DetectModbusRegister(void)
{
sigmatch_table[DETECT_AL_MODBUS].name = "modbus";
sigmatch_table[DETECT_AL_MODBUS].desc = "match on various properties of Modbus requests";
sigmatch_table[DETECT_AL_MODBUS].url = "/rules/modbus-keyword.html#modbus-keyword";
sigmatch_table[DETECT_AL_MODBUS].Match = NULL;
sigmatch_table[DETECT_AL_MODBUS].Setup = DetectModbusSetup;
sigmatch_table[DETECT_AL_MODBUS].Free = DetectModbusFree;
sigmatch_table[DETECT_AL_MODBUS].AppLayerTxMatch = DetectModbusMatch;
DetectAppLayerInspectEngineRegister2(
"modbus", ALPROTO_MODBUS, SIG_FLAG_TOSERVER, 0, DetectEngineInspectGenericList, NULL);
g_modbus_buffer_id = DetectBufferTypeGetByName("modbus");
}
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