From b1782b2a245dcee27ff66c319d14bb14bbcc0973 Mon Sep 17 00:00:00 2001 From: Jason Ish Date: Tue, 14 Nov 2023 17:01:49 -0600 Subject: [PATCH] wip: dns.query.name --- rust/src/dns/dns.rs | 25 +++++ src/Makefile.am | 2 + src/detect-dns-query-name.c | 182 +++++++++++++++++++++++++++++++++++ src/detect-dns-query-name.h | 23 +++++ src/detect-engine-register.h | 1 + 5 files changed, 233 insertions(+) create mode 100644 src/detect-dns-query-name.c create mode 100644 src/detect-dns-query-name.h diff --git a/rust/src/dns/dns.rs b/rust/src/dns/dns.rs index 0fb702b1de93..00b75c7fb7d4 100644 --- a/rust/src/dns/dns.rs +++ b/rust/src/dns/dns.rs @@ -881,6 +881,31 @@ pub unsafe extern "C" fn rs_dns_tx_get_query_name( return 0; } +/// Get the DNS query name at index i. +#[no_mangle] +pub unsafe extern "C" fn SCDnsTxGetQueryName( + tx: &mut DNSTransaction, to_client: bool, i: u32, buf: *mut *const u8, len: *mut u32, +) -> bool { + let queries = if to_client { + tx.response.as_ref().map(|response| &response.queries) + } else { + tx.request.as_ref().map(|request| &request.queries) + }; + let index = i as usize; + + if let Some(queries) = queries { + if let Some(query) = queries.get(index) { + if !query.name.is_empty() { + *buf = query.name.as_ptr(); + *len = query.name.len() as u32; + return true; + } + } + } + + false +} + /// Get the DNS response answer name and index i. #[no_mangle] pub unsafe extern "C" fn SCDnsTxGetAnswerName( diff --git a/src/Makefile.am b/src/Makefile.am index 0114389a2062..5edcab784958 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -124,6 +124,7 @@ noinst_HEADERS = \ detect-dns-answer-name.h \ detect-dns-opcode.h \ detect-dns-query.h \ + detect-dns-query-name.h \ detect-dsize.h \ detect-engine-address.h \ detect-engine-address-ipv4.h \ @@ -736,6 +737,7 @@ libsuricata_c_a_SOURCES = \ detect-dns-answer-name.c \ detect-dns-opcode.c \ detect-dns-query.c \ + detect-dns-query-name.c \ detect-dsize.c \ detect-engine-address.c \ detect-engine-address-ipv4.c \ diff --git a/src/detect-dns-query-name.c b/src/detect-dns-query-name.c new file mode 100644 index 000000000000..c5f0153bbac8 --- /dev/null +++ b/src/detect-dns-query-name.c @@ -0,0 +1,182 @@ +/* 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 query names: dns.query.name + */ + +#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-query-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_query_name_id = 0; + +void DetectDnsQueryNameRegister(void) +{ + static const char *keyword = "dns.query.name"; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].name = keyword; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].desc = "DNS query name sticky buffer"; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].url = "/rules/TODOTODOTODO"; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].Setup = DetectSetup; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].flags |= SIGMATCH_NOOPT; + sigmatch_table[DETECT_AL_DNS_QUERY_NAME].flags |= SIGMATCH_INFO_STICKY_BUFFER; + + /* Register in both directions as the query is usually echoed back + in the response. */ + DetectAppLayerInspectEngineRegister( + keyword, ALPROTO_DNS, SIG_FLAG_TOSERVER, 0, DetectEngineInspectCb, NULL); + DetectAppLayerMpmRegister( + keyword, SIG_FLAG_TOSERVER, 2, PrefilterMpmRegister, NULL, ALPROTO_DNS, 1); + + DetectAppLayerInspectEngineRegister( + keyword, ALPROTO_DNS, SIG_FLAG_TOCLIENT, 0, DetectEngineInspectCb, NULL); + DetectAppLayerMpmRegister( + keyword, SIG_FLAG_TOCLIENT, 2, PrefilterMpmRegister, NULL, ALPROTO_DNS, 1); + + DetectBufferTypeSetDescriptionByName(keyword, "dns query name"); + DetectBufferTypeSupportsMultiInstance(keyword); + + dns_query_name_id = DetectBufferTypeGetByName(keyword); +} + +static int DetectSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (DetectBufferSetActiveList(de_ctx, s, dns_query_name_id) < 0) { + return -1; + } + if (DetectSignatureSetAppProto(s, ALPROTO_DNS) < 0) { + return -1; + } + + return 0; +} + +static InspectionBuffer *GetBuffer(DetectEngineThreadCtx *det_ctx, const uint8_t flags, + 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; + } + + bool to_client = (flags & STREAM_TOSERVER) == 0; + const uint8_t *data = NULL; + uint32_t data_len = 0; + + if (!SCDnsTxGetQueryName(txv, to_client, 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, flags, 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, flags, 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-query-name.h b/src/detect-dns-query-name.h new file mode 100644 index 000000000000..b1d7db99e8c5 --- /dev/null +++ b/src/detect-dns-query-name.h @@ -0,0 +1,23 @@ +/* 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. + */ + +#ifndef __DETECT_DNS_QUERY_NAME_H__ +#define __DETECT_DNS_QUERY_NAME_H__ + +void DetectDnsQueryNameRegister(void); + +#endif /* __DETECT_DNS_QUERY_NAME_H__ */ diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index 781695c44a87..854cf760d588 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -224,6 +224,7 @@ enum DetectKeywordId { DETECT_AL_DNS_QUERY, DETECT_AL_DNS_OPCODE, DETECT_AL_DNS_ANSWER_NAME, + DETECT_AL_DNS_QUERY_NAME, DETECT_AL_TLS_SNI, DETECT_AL_TLS_CERTS, DETECT_AL_TLS_CERT_ISSUER,