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/* Copyright (C) 2015-2019 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.
*/
/**
* \file
*
* \author Pierre Chifflier <chifflier@wzdftpd.net>
*
* Set up of the "snmp.community" keyword to allow content
* inspections on the decoded snmp community.
*/
#include "suricata-common.h"
#include "conf.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-snmp-community.h"
#include "app-layer-parser.h"
#include "rust.h"
static int DetectSNMPCommunitySetup(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);
#ifdef UNITTESTS
static void DetectSNMPCommunityRegisterTests(void);
#endif
static int g_snmp_rust_id = 0;
void DetectSNMPCommunityRegister(void)
{
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].name = "snmp.community";
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].desc =
"SNMP content modifier to match on the SNMP community";
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].Setup =
DetectSNMPCommunitySetup;
#ifdef UNITTESTS
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].RegisterTests = DetectSNMPCommunityRegisterTests;
#endif
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].url = "/rules/snmp-keywords.html#snmp-community";
sigmatch_table[DETECT_AL_SNMP_COMMUNITY].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER;
/* register inspect engines */
DetectAppLayerInspectEngineRegister2("snmp.community",
ALPROTO_SNMP, SIG_FLAG_TOSERVER, 0,
DetectEngineInspectBufferGeneric, GetData);
DetectAppLayerMpmRegister2("snmp.community", SIG_FLAG_TOSERVER, 2,
PrefilterGenericMpmRegister, GetData, ALPROTO_SNMP, 0);
DetectAppLayerInspectEngineRegister2("snmp.community",
ALPROTO_SNMP, SIG_FLAG_TOCLIENT, 0,
DetectEngineInspectBufferGeneric, GetData);
DetectAppLayerMpmRegister2("snmp.community", SIG_FLAG_TOCLIENT, 2,
PrefilterGenericMpmRegister, GetData, ALPROTO_SNMP, 0);
DetectBufferTypeSetDescriptionByName("snmp.community", "SNMP Community identifier");
g_snmp_rust_id = DetectBufferTypeGetByName("snmp.community");
}
static int DetectSNMPCommunitySetup(DetectEngineCtx *de_ctx, Signature *s,
const char *str)
{
if (DetectBufferSetActiveList(de_ctx, s, g_snmp_rust_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_SNMP) != 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) {
uint32_t data_len = 0;
const uint8_t *data = NULL;
rs_snmp_tx_get_community(txv, &data, &data_len);
if (data == NULL || data_len == 0) {
return NULL;
}
InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
#ifdef UNITTESTS
#include "tests/detect-snmp-community.c"
#endif /* UNITTESTS */
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