From: Hadiqa Alamdar Bukhari Date: Wed, 31 Jan 2024 12:56:33 +0000 (+0500) Subject: dns: add dns.rrtype keyword X-Git-Tag: suricata-8.0.0-beta1~1697 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b81851097658440385db4d406ada423683fd412;p=thirdparty%2Fsuricata.git dns: add dns.rrtype keyword It matches the rrtype field in DNS It's an unsigned integer match valid ranges = [0-65535] Does not support prefilter Supports flow in both directions Feature #6666 --- diff --git a/doc/userguide/rules/dns-keywords.rst b/doc/userguide/rules/dns-keywords.rst index 005164dfd1..bb232e39f0 100644 --- a/doc/userguide/rules/dns-keywords.rst +++ b/doc/userguide/rules/dns-keywords.rst @@ -57,6 +57,31 @@ Match on DNS requests where the **opcode** is not between 7 and 15: dns.opcode:!7-15; +dns.rrtype +---------- + +This keyword matches on the **rrtype** (integer) found in the DNS message. + +dns.rrtype uses an :ref:`unsigned 16-bit integer `. + +Syntax +~~~~~~ + +:: + + dns.rrtype:[!] + +Examples +~~~~~~~~ + +Match on DNS requests and responses with **rrtype** 4:: + + dns.rrtype:4; + +Match on DNS requests and responses where the **rrtype** is NOT 0:: + + dns.rrtype:!0; + dns.query --------- diff --git a/rust/src/dns/detect.rs b/rust/src/dns/detect.rs index 452d4e8380..4e7819513f 100644 --- a/rust/src/dns/detect.rs +++ b/rust/src/dns/detect.rs @@ -1,4 +1,4 @@ -/* Copyright (C) 2019 Open Information Security Foundation +/* Copyright (C) 2019-2024 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 @@ -50,6 +50,32 @@ pub extern "C" fn rs_dns_opcode_match( return 0; } +/// Perform the DNS rrtype match. +/// 1 will be returned on match, otherwise 0 will be returned. +#[no_mangle] +pub extern "C" fn rs_dns_rrtype_match( + tx: &mut DNSTransaction, detect: &mut DetectUintData, flags: u8, +) -> u16 { + if flags & Direction::ToServer as u8 != 0 { + if let Some(request) = &tx.request { + for i in 0..request.queries.len() { + if detect_match_uint(detect, request.queries[i].rrtype) { + return 1; + } + } + } + } else if flags & Direction::ToClient as u8 != 0 { + if let Some(response) = &tx.response { + for i in 0..response.answers.len() { + if detect_match_uint(detect, response.answers[i].rrtype) { + return 1; + } + } + } + } + return 0; +} + #[cfg(test)] mod test { use super::*; @@ -125,4 +151,83 @@ mod test { ((0b0010_0000_0000_0000 >> 11) & 0xf) as u8, )); } + + #[test] + fn parse_rrtype_good() { + assert_eq!( + detect_parse_uint::("1").unwrap().1, + DetectUintData { + mode: DetectUintMode::DetectUintModeEqual, + arg1: 1, + arg2: 0, + } + ); + assert_eq!( + detect_parse_uint::("123").unwrap().1, + DetectUintData { + mode: DetectUintMode::DetectUintModeEqual, + arg1: 123, + arg2: 0, + } + ); + assert_eq!( + detect_parse_uint::("!123").unwrap().1, + DetectUintData { + mode: DetectUintMode::DetectUintModeNe, + arg1: 123, + arg2: 0, + } + ); + assert_eq!( + detect_parse_uint::("7-15").unwrap().1, + DetectUintData { + mode: DetectUintMode::DetectUintModeRange, + arg1: 7, + arg2: 15, + } + ); + assert!(detect_parse_uint::("").is_err()); + assert!(detect_parse_uint::("!").is_err()); + assert!(detect_parse_uint::("! ").is_err()); + assert!(detect_parse_uint::("!asdf").is_err()); + } + + #[test] + fn test_match_rrtype() { + assert!(detect_match_uint( + &DetectUintData { + mode: DetectUintMode::DetectUintModeEqual, + arg1: 0, + arg2: 0, + }, + 0b0000_0000_0000_0000, + )); + + assert!(!detect_match_uint( + &DetectUintData { + mode: DetectUintMode::DetectUintModeNe, + arg1: 0, + arg2: 0, + }, + 0b0000_0000_0000_0000, + )); + + assert!(detect_match_uint( + &DetectUintData { + mode: DetectUintMode::DetectUintModeEqual, + arg1: 4, + arg2: 0, + }, + 4u16, + )); + + assert!(!detect_match_uint( + &DetectUintData { + mode: DetectUintMode::DetectUintModeNe, + arg1: 4, + arg2: 0, + }, + 4u16, + )); + } } diff --git a/src/Makefile.am b/src/Makefile.am index 6619595054..24f1a9781e 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -121,6 +121,7 @@ noinst_HEADERS = \ detect-dnp3.h \ detect-dns-answer-name.h \ detect-dns-opcode.h \ + detect-dns-rrtype.h \ detect-dns-query.h \ detect-dns-query-name.h \ detect-dsize.h \ @@ -741,6 +742,7 @@ libsuricata_c_a_SOURCES = \ detect-dnp3.c \ detect-dns-answer-name.c \ detect-dns-opcode.c \ + detect-dns-rrtype.c \ detect-dns-query.c \ detect-dns-query-name.c \ detect-dsize.c \ diff --git a/src/detect-dns-rrtype.c b/src/detect-dns-rrtype.c new file mode 100644 index 0000000000..6145817635 --- /dev/null +++ b/src/detect-dns-rrtype.c @@ -0,0 +1,85 @@ +/* Copyright (C) 2024 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. + */ + +#include "suricata-common.h" + +#include "detect-parse.h" +#include "detect-engine.h" +#include "detect-dns-rrtype.h" +#include "rust.h" +#include "detect-engine-uint.h" + +static int dns_rrtype_list_id = 0; + +static void DetectDnsRrtypeFree(DetectEngineCtx *, void *ptr); + +static int DetectDnsRrtypeSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + SCEnter(); + + if (DetectSignatureSetAppProto(s, ALPROTO_DNS) != 0) { + SCReturnInt(-1); + } + + void *detect = DetectU16Parse(str); + if (detect == NULL) { + SCLogError("failed to parse dns.rrtype: %s", str); + SCReturnInt(-1); + } + + if (SigMatchAppendSMToList(de_ctx, s, DETECT_AL_DNS_RRTYPE, (SigMatchCtx *)detect, + dns_rrtype_list_id) == NULL) { + DetectDnsRrtypeFree(de_ctx, detect); + SCReturnInt(-1); + } + + SCReturnInt(0); +} + +static void DetectDnsRrtypeFree(DetectEngineCtx *de_ctx, void *ptr) +{ + SCEnter(); + if (ptr != NULL) { + rs_detect_u16_free(ptr); + } + SCReturn; +} + +static int DetectDnsRrtypeMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, void *state, + void *txv, const Signature *s, const SigMatchCtx *ctx) +{ + return rs_dns_rrtype_match(txv, (void *)ctx, flags); +} + +void DetectDnsRrtypeRegister(void) +{ + sigmatch_table[DETECT_AL_DNS_RRTYPE].name = "dns.rrtype"; + sigmatch_table[DETECT_AL_DNS_RRTYPE].desc = "Match the DNS rrtype in message body."; + sigmatch_table[DETECT_AL_DNS_RRTYPE].url = "/rules/dns-keywords.html#dns-rrtype"; + sigmatch_table[DETECT_AL_DNS_RRTYPE].Setup = DetectDnsRrtypeSetup; + sigmatch_table[DETECT_AL_DNS_RRTYPE].Free = DetectDnsRrtypeFree; + sigmatch_table[DETECT_AL_DNS_RRTYPE].Match = NULL; + sigmatch_table[DETECT_AL_DNS_RRTYPE].AppLayerTxMatch = DetectDnsRrtypeMatch; + + DetectAppLayerInspectEngineRegister( + "dns.rrtype", ALPROTO_DNS, SIG_FLAG_TOSERVER, 0, DetectEngineInspectGenericList, NULL); + + DetectAppLayerInspectEngineRegister( + "dns.rrtype", ALPROTO_DNS, SIG_FLAG_TOCLIENT, 0, DetectEngineInspectGenericList, NULL); + + dns_rrtype_list_id = DetectBufferTypeGetByName("dns.rrtype"); +} \ No newline at end of file diff --git a/src/detect-dns-rrtype.h b/src/detect-dns-rrtype.h new file mode 100644 index 0000000000..962364f7e2 --- /dev/null +++ b/src/detect-dns-rrtype.h @@ -0,0 +1,23 @@ +/* Copyright (C) 2024 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_RRTYPE_H__ +#define __DETECT_DNS_RRTYPE_H__ + +void DetectDnsRrtypeRegister(void); + +#endif /* __DETECT_DNS_RRTYPE_H__ */ diff --git a/src/detect-engine-register.c b/src/detect-engine-register.c index 595bffcc57..94fb303987 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -48,6 +48,7 @@ #include "detect-engine-payload.h" #include "detect-engine-dcepayload.h" #include "detect-dns-opcode.h" +#include "detect-dns-rrtype.h" #include "detect-dns-query.h" #include "detect-dns-answer-name.h" #include "detect-dns-query-name.h" @@ -522,6 +523,7 @@ void SigTableSetup(void) DetectDnsQueryRegister(); DetectDnsOpcodeRegister(); + DetectDnsRrtypeRegister(); DetectDnsAnswerNameRegister(); DetectDnsQueryNameRegister(); DetectModbusRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index eff9c0ed25..dc64a4e917 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -230,6 +230,7 @@ enum DetectKeywordId { DETECT_AL_DNS_QUERY, DETECT_AL_DNS_OPCODE, + DETECT_AL_DNS_RRTYPE, DETECT_AL_DNS_ANSWER_NAME, DETECT_AL_DNS_QUERY_NAME, DETECT_AL_TLS_SNI,