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/* Copyright (C) 2015-2020 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.
*/
/**
* \file
*
* \author Pierre Chifflier <chifflier@wzdftpd.net>
*/
#include "suricata-common.h"
#include "conf.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-content-inspection.h"
#include "detect-snmp-version.h"
#include "detect-engine-uint.h"
#include "app-layer-parser.h"
#include "rust.h"
static int DetectSNMPVersionSetup (DetectEngineCtx *, Signature *s, const char *str);
static void DetectSNMPVersionFree(DetectEngineCtx *, void *);
#ifdef UNITTESTS
static void DetectSNMPVersionRegisterTests(void);
#endif
static int g_snmp_version_buffer_id = 0;
static int DetectSNMPVersionMatch (DetectEngineThreadCtx *, Flow *,
uint8_t, void *, void *, const Signature *,
const SigMatchCtx *);
/**
* \brief Registration function for snmp.procedure keyword.
*/
void DetectSNMPVersionRegister (void)
{
sigmatch_table[DETECT_AL_SNMP_VERSION].name = "snmp.version";
sigmatch_table[DETECT_AL_SNMP_VERSION].desc = "match SNMP version";
sigmatch_table[DETECT_AL_SNMP_VERSION].url = "/rules/snmp-keywords.html#snmp-version";
sigmatch_table[DETECT_AL_SNMP_VERSION].Match = NULL;
sigmatch_table[DETECT_AL_SNMP_VERSION].AppLayerTxMatch = DetectSNMPVersionMatch;
sigmatch_table[DETECT_AL_SNMP_VERSION].Setup = DetectSNMPVersionSetup;
sigmatch_table[DETECT_AL_SNMP_VERSION].Free = DetectSNMPVersionFree;
#ifdef UNITTESTS
sigmatch_table[DETECT_AL_SNMP_VERSION].RegisterTests = DetectSNMPVersionRegisterTests;
#endif
DetectAppLayerInspectEngineRegister2("snmp.version", ALPROTO_SNMP, SIG_FLAG_TOSERVER, 0,
DetectEngineInspectGenericList, NULL);
DetectAppLayerInspectEngineRegister2("snmp.version", ALPROTO_SNMP, SIG_FLAG_TOCLIENT, 0,
DetectEngineInspectGenericList, NULL);
g_snmp_version_buffer_id = DetectBufferTypeGetByName("snmp.version");
}
/**
* \internal
* \brief Function to match version of a TX
*
* \param t Pointer to thread vars.
* \param det_ctx Pointer to the pattern matcher thread.
* \param f Pointer to the current flow.
* \param flags Flags.
* \param state App layer state.
* \param s Pointer to the Signature.
* \param m Pointer to the sigmatch that we will cast into
* DetectU32Data.
*
* \retval 0 no match.
* \retval 1 match.
*/
static int DetectSNMPVersionMatch (DetectEngineThreadCtx *det_ctx,
Flow *f, uint8_t flags, void *state,
void *txv, const Signature *s,
const SigMatchCtx *ctx)
{
SCEnter();
const DetectU32Data *dd = (const DetectU32Data *)ctx;
uint32_t version;
rs_snmp_tx_get_version(txv, &version);
SCLogDebug("version %u mode %u ref_version %d", version, dd->mode, dd->arg1);
if (DetectU32Match(version, dd))
SCReturnInt(1);
SCReturnInt(0);
}
/**
* \internal
* \brief Function to parse options passed via snmp.version keywords.
*
* \param rawstr Pointer to the user provided options.
*
* \retval dd pointer to DetectU32Data on success.
* \retval NULL on failure.
*/
static DetectU32Data *DetectSNMPVersionParse(const char *rawstr)
{
return DetectU32Parse(rawstr);
}
/**
* \brief Function to add the parsed snmp version field into the current signature.
*
* \param de_ctx Pointer to the Detection Engine Context.
* \param s Pointer to the Current Signature.
* \param rawstr Pointer to the user provided flags options.
* \param type Defines if this is notBefore or notAfter.
*
* \retval 0 on Success.
* \retval -1 on Failure.
*/
static int DetectSNMPVersionSetup (DetectEngineCtx *de_ctx, Signature *s,
const char *rawstr)
{
DetectU32Data *dd = NULL;
SigMatch *sm = NULL;
if (DetectSignatureSetAppProto(s, ALPROTO_SNMP) != 0)
return -1;
dd = DetectSNMPVersionParse(rawstr);
if (dd == NULL) {
SCLogError("Parsing \'%s\' failed", rawstr);
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_SNMP_VERSION;
sm->ctx = (void *)dd;
SCLogDebug("snmp.version %d", dd->arg1);
SigMatchAppendSMToList(s, sm, g_snmp_version_buffer_id);
return 0;
error:
DetectSNMPVersionFree(de_ctx, dd);
return -1;
}
/**
* \internal
* \brief Function to free memory associated with DetectU32Data.
*
* \param de_ptr Pointer to DetectU32Data.
*/
static void DetectSNMPVersionFree(DetectEngineCtx *de_ctx, void *ptr)
{
rs_detect_u32_free(ptr);
}
#ifdef UNITTESTS
#include "tests/detect-snmp-version.c"
#endif /* UNITTESTS */
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