diff --git a/rust/src/dns/dns.rs b/rust/src/dns/dns.rs index 382c76ae59b5..0fb702b1de93 100644 --- a/rust/src/dns/dns.rs +++ b/rust/src/dns/dns.rs @@ -881,6 +881,24 @@ pub unsafe extern "C" fn rs_dns_tx_get_query_name( return 0; } +/// Get the DNS response answer name and index i. +#[no_mangle] +pub unsafe extern "C" fn SCDnsTxGetAnswerName( + tx: &mut DNSTransaction, i: u32, buf: *mut *const u8, len: *mut u32, +) -> bool { + let index = i as usize; + if let Some(response) = &tx.response { + if let Some(name) = response.answers.get(index).map(|answer| &answer.name) { + if !name.is_empty() { + *buf = name.as_ptr(); + *len = name.len() as u32; + return true; + } + } + } + false +} + /// Get the DNS transaction ID of a transaction. // /// extern uint16_t rs_dns_tx_get_tx_id(RSDNSTransaction *); diff --git a/src/Makefile.am b/src/Makefile.am index 48a5ce850ce2..0114389a2062 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -121,6 +121,7 @@ noinst_HEADERS = \ detect-detection-filter.h \ detect-distance.h \ detect-dnp3.h \ + detect-dns-answer-name.h \ detect-dns-opcode.h \ detect-dns-query.h \ detect-dsize.h \ @@ -732,6 +733,7 @@ libsuricata_c_a_SOURCES = \ detect-detection-filter.c \ detect-distance.c \ detect-dnp3.c \ + detect-dns-answer-name.c \ detect-dns-opcode.c \ detect-dns-query.c \ detect-dsize.c \ diff --git a/src/detect-dns-answer-name.c b/src/detect-dns-answer-name.c new file mode 100644 index 000000000000..063725a04452 --- /dev/null +++ b/src/detect-dns-answer-name.c @@ -0,0 +1,173 @@ +/* Copyright (C) 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. + */ + +/** + * \file + * + * Detect keyword for DNS answer rdata: dns.response.answer.rdata + */ + +#include "detect.h" +#include "detect-parse.h" +#include "detect-engine.h" +#include "detect-engine-prefilter.h" +#include "detect-engine-content-inspection.h" +#include "detect-dns-answer-name.h" +#include "util-profiling.h" +#include "rust.h" + +static int DetectSetup(DetectEngineCtx *, Signature *, const char *); +static uint8_t DetectEngineInspectCb(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const struct DetectEngineAppInspectionEngine_ *engine, const Signature *s, Flow *f, + uint8_t flags, void *alstate, void *txv, uint64_t tx_id); +static int PrefilterMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, + const DetectBufferMpmRegistry *mpm_reg, int list_id); + +static int dns_response_answer_name_id = 0; + +void DetectDnsResponseAnswerNameRegister(void) +{ + static const char *keyword = "dns.response.answer.name"; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].name = keyword; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].desc = "DNS answer name sticky buffer"; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].url = "/rules/TODOTODOTODO"; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].Setup = DetectSetup; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].flags |= SIGMATCH_NOOPT; + sigmatch_table[DETECT_AL_DNS_RESPONSE_ANSWER_NAME].flags |= SIGMATCH_INFO_STICKY_BUFFER; + + DetectAppLayerInspectEngineRegister( + keyword, ALPROTO_DNS, SIG_FLAG_TOCLIENT, 0, DetectEngineInspectCb, NULL); + DetectAppLayerMpmRegister( + keyword, SIG_FLAG_TOCLIENT, 2, PrefilterMpmRegister, NULL, ALPROTO_DNS, 1); + + DetectBufferTypeSetDescriptionByName(keyword, "dns response answer name"); + DetectBufferTypeSupportsMultiInstance(keyword); + + dns_response_answer_name_id = DetectBufferTypeGetByName(keyword); +} + +static int DetectSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (DetectBufferSetActiveList(de_ctx, s, dns_response_answer_name_id) < 0) { + return -1; + } + if (DetectSignatureSetAppProto(s, ALPROTO_DNS) < 0) { + return -1; + } + + return 0; +} + +static InspectionBuffer *GetBuffer(DetectEngineThreadCtx *det_ctx, + const DetectEngineTransforms *transforms, void *txv, uint32_t index, int list_id) +{ + InspectionBuffer *buffer = InspectionBufferMultipleForListGet(det_ctx, list_id, index); + if (buffer == NULL) { + return NULL; + } + if (buffer->initialized) { + return buffer; + } + + const uint8_t *data = NULL; + uint32_t data_len = 0; + + if (!SCDnsTxGetAnswerName(txv, index, &data, &data_len)) { + InspectionBufferSetupMultiEmpty(buffer); + return NULL; + } + InspectionBufferSetupMulti(buffer, transforms, data, data_len); + return buffer; +} + +static uint8_t DetectEngineInspectCb(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const struct DetectEngineAppInspectionEngine_ *engine, const Signature *s, Flow *f, + uint8_t flags, void *alstate, void *txv, uint64_t tx_id) +{ + const DetectEngineTransforms *transforms = NULL; + if (!engine->mpm) { + transforms = engine->v2.transforms; + } + + for (uint32_t i = 0;; i++) { + InspectionBuffer *buffer = GetBuffer(det_ctx, transforms, txv, i, engine->sm_list); + if (buffer == NULL || buffer->inspect == NULL) { + break; + } + + det_ctx->buffer_offset = 0; + det_ctx->discontinue_matching = 0; + det_ctx->inspection_recursion_counter = 0; + + const int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, NULL, f, + (uint8_t *)buffer->inspect, buffer->inspect_len, buffer->inspect_offset, + DETECT_CI_FLAGS_SINGLE, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE); + if (match == 1) { + return DETECT_ENGINE_INSPECT_SIG_MATCH; + } + } + + return DETECT_ENGINE_INSPECT_SIG_NO_MATCH; +} + +typedef struct PrefilterMpm { + int list_id; + const MpmCtx *mpm_ctx; + const DetectEngineTransforms *transforms; +} PrefilterMpm; + +static void PrefilterTx(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p, Flow *f, + void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags) +{ + SCEnter(); + + const PrefilterMpm *ctx = (const PrefilterMpm *)pectx; + const MpmCtx *mpm_ctx = ctx->mpm_ctx; + const int list_id = ctx->list_id; + + for (uint32_t i = 0;; i++) { + InspectionBuffer *buffer = GetBuffer(det_ctx, ctx->transforms, txv, i, list_id); + if (buffer == NULL) { + break; + } + + if (buffer->inspect_len >= mpm_ctx->minlen) { + (void)mpm_table[mpm_ctx->mpm_type].Search( + mpm_ctx, &det_ctx->mtcu, &det_ctx->pmq, buffer->inspect, buffer->inspect_len); + PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len); + } + } +} + +static void PrefilterMpmFree(void *ptr) +{ + SCFree(ptr); +} + +static int PrefilterMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, + const DetectBufferMpmRegistry *mpm_reg, int list_id) +{ + PrefilterMpm *pectx = SCCalloc(1, sizeof(*pectx)); + if (pectx == NULL) + return -1; + pectx->list_id = list_id; + pectx->mpm_ctx = mpm_ctx; + pectx->transforms = &mpm_reg->transforms; + + return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTx, mpm_reg->app_v2.alproto, + mpm_reg->app_v2.tx_min_progress, pectx, PrefilterMpmFree, mpm_reg->pname); +} diff --git a/src/detect-dns-answer-name.h b/src/detect-dns-answer-name.h new file mode 100644 index 000000000000..bd26b82eb75e --- /dev/null +++ b/src/detect-dns-answer-name.h @@ -0,0 +1,29 @@ +/* Copyright (C) 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. + */ + +/** + * \file + * + * \author FirstName LastName + */ + +#ifndef __DETECT_DNS_ANSWER_RDATA_H__ +#define __DETECT_DNS_ANSWER_RDATA_H__ + +void DetectDnsResponseAnswerNameRegister(void); + +#endif /* __DETECT_DNS_ANSWER_RDATA_H__ */ diff --git a/src/detect-engine-register.c b/src/detect-engine-register.c index df6e4a738ffc..6f9c43614a38 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -47,6 +47,7 @@ #include "detect-engine-dcepayload.h" #include "detect-dns-opcode.h" #include "detect-dns-query.h" +#include "detect-dns-answer-name.h" #include "detect-tls-sni.h" #include "detect-tls-certs.h" #include "detect-tls-cert-fingerprint.h" @@ -511,6 +512,7 @@ void SigTableSetup(void) DetectDnsQueryRegister(); DetectDnsOpcodeRegister(); + DetectDnsResponseAnswerNameRegister(); DetectModbusRegister(); DetectCipServiceRegister(); DetectEnipCommandRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index 7d6c457ef9b0..1ee5f948ce8e 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -223,6 +223,7 @@ enum DetectKeywordId { DETECT_AL_DNS_QUERY, DETECT_AL_DNS_OPCODE, + DETECT_AL_DNS_RESPONSE_ANSWER_NAME, DETECT_AL_TLS_SNI, DETECT_AL_TLS_CERTS, DETECT_AL_TLS_CERT_ISSUER,