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93 lines
3.1 KiB
C
93 lines
3.1 KiB
C
/* Copyright (C) 2023 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* Detect keyword for DNS answer name: dns.answer.name
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*/
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#include "detect.h"
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#include "detect-parse.h"
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#include "detect-engine.h"
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#include "detect-engine-prefilter.h"
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#include "detect-engine-content-inspection.h"
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#include "detect-dns-answer-name.h"
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#include "util-profiling.h"
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#include "rust.h"
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static int detect_buffer_id = 0;
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static int DetectSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
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{
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if (DetectBufferSetActiveList(de_ctx, s, detect_buffer_id) < 0) {
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return -1;
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}
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if (DetectSignatureSetAppProto(s, ALPROTO_DNS) < 0) {
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return -1;
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}
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return 0;
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}
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static InspectionBuffer *GetBuffer(DetectEngineThreadCtx *det_ctx,
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const DetectEngineTransforms *transforms, Flow *f, uint8_t flags, void *txv, int list_id,
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uint32_t index)
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{
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InspectionBuffer *buffer = InspectionBufferMultipleForListGet(det_ctx, list_id, index);
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if (buffer == NULL) {
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return NULL;
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}
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if (buffer->initialized) {
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return buffer;
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}
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bool to_client = (flags & STREAM_TOSERVER) == 0;
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const uint8_t *data = NULL;
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uint32_t data_len = 0;
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if (!SCDnsTxGetAnswerName(txv, to_client, index, &data, &data_len)) {
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InspectionBufferSetupMultiEmpty(buffer);
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return NULL;
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}
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InspectionBufferSetupMulti(buffer, transforms, data, data_len);
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buffer->flags = DETECT_CI_FLAGS_SINGLE;
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return buffer;
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}
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void DetectDnsAnswerNameRegister(void)
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{
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static const char *keyword = "dns.answer.name";
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sigmatch_table[DETECT_DNS_ANSWER_NAME].name = keyword;
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sigmatch_table[DETECT_DNS_ANSWER_NAME].desc = "DNS answer name sticky buffer";
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sigmatch_table[DETECT_DNS_ANSWER_NAME].url = "/rules/dns-keywords.html#dns-answer-name";
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sigmatch_table[DETECT_DNS_ANSWER_NAME].Setup = DetectSetup;
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sigmatch_table[DETECT_DNS_ANSWER_NAME].flags |= SIGMATCH_NOOPT;
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sigmatch_table[DETECT_DNS_ANSWER_NAME].flags |= SIGMATCH_INFO_STICKY_BUFFER;
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/* Register in the TO_SERVER direction, even though this is not
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normal, it could be provided as part of a request. */
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DetectAppLayerMultiRegister(keyword, ALPROTO_DNS, SIG_FLAG_TOSERVER, 0, GetBuffer, 2, 1);
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/* Register in the TO_CLIENT direction. */
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DetectAppLayerMultiRegister(keyword, ALPROTO_DNS, SIG_FLAG_TOCLIENT, 0, GetBuffer, 2, 1);
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DetectBufferTypeSetDescriptionByName(keyword, "dns answer name");
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DetectBufferTypeSupportsMultiInstance(keyword);
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detect_buffer_id = DetectBufferTypeGetByName(keyword);
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}
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