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suricata/src/detect-dns-query.c

142 lines
4.3 KiB
C

/* Copyright (C) 2013-2023 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 dnslayer
*
* @{
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*/
#include "suricata-common.h"
#include "threads.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-build.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-content.h"
#include "detect-pcre.h"
#include "flow.h"
#include "flow-util.h"
#include "flow-var.h"
#include "util-debug.h"
#include "util-spm.h"
#include "util-print.h"
#include "stream-tcp.h"
#include "app-layer.h"
#include "app-layer-parser.h"
#include "detect-dns-query.h"
#include "util-profiling.h"
#include "rust.h"
static int DetectDnsQuerySetup(DetectEngineCtx *, Signature *, const char *);
static int g_dns_query_buffer_id = 0;
static InspectionBuffer *DnsQueryGetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *f, const uint8_t flags, void *txv,
int list_id, uint32_t local_id)
{
SCEnter();
InspectionBuffer *buffer = InspectionBufferMultipleForListGet(det_ctx, list_id, local_id);
if (buffer == NULL)
return NULL;
if (buffer->initialized)
return buffer;
const uint8_t *data;
uint32_t data_len;
if (SCDnsTxGetQueryName(txv, false, local_id, &data, &data_len) == 0) {
InspectionBufferSetupMultiEmpty(buffer);
return NULL;
}
InspectionBufferSetupMulti(det_ctx, buffer, transforms, data, data_len);
buffer->flags = DETECT_CI_FLAGS_SINGLE;
SCReturnPtr(buffer, "InspectionBuffer");
}
/**
* \brief Registration function for keyword: dns_query
*/
void DetectDnsQueryRegister (void)
{
sigmatch_table[DETECT_DNS_QUERY].name = "dns.query";
sigmatch_table[DETECT_DNS_QUERY].alias = "dns_query";
sigmatch_table[DETECT_DNS_QUERY].desc = "sticky buffer to match DNS query-buffer";
sigmatch_table[DETECT_DNS_QUERY].url = "/rules/dns-keywords.html#dns-query";
sigmatch_table[DETECT_DNS_QUERY].Setup = DetectDnsQuerySetup;
sigmatch_table[DETECT_DNS_QUERY].flags |= SIGMATCH_NOOPT;
sigmatch_table[DETECT_DNS_QUERY].flags |= SIGMATCH_INFO_STICKY_BUFFER;
DetectAppLayerMultiRegister(
"dns_query", ALPROTO_DNS, SIG_FLAG_TOSERVER, 1, DnsQueryGetData, 2, 1);
DetectBufferTypeSetDescriptionByName("dns_query",
"dns request query");
DetectBufferTypeSupportsMultiInstance("dns_query");
g_dns_query_buffer_id = DetectBufferTypeGetByName("dns_query");
/* register these generic engines from here for now */
DetectAppLayerInspectEngineRegister(
"dns_request", ALPROTO_DNS, SIG_FLAG_TOSERVER, 1, DetectEngineInspectGenericList, NULL);
DetectAppLayerInspectEngineRegister("dns_response", ALPROTO_DNS, SIG_FLAG_TOCLIENT, 1,
DetectEngineInspectGenericList, NULL);
DetectBufferTypeSetDescriptionByName("dns_request",
"dns requests");
DetectBufferTypeSetDescriptionByName("dns_response", "dns responses");
}
/**
* \brief setup the dns_query sticky buffer 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
* \retval -1 On failure
*/
static int DetectDnsQuerySetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
if (DetectBufferSetActiveList(de_ctx, s, g_dns_query_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_DNS) < 0)
return -1;
return 0;
}