From: Shivani Bhardwaj Date: Mon, 19 May 2025 06:24:12 +0000 (+0530) Subject: rdp: trigger raw stream inspection X-Git-Tag: suricata-8.0.0-rc1~234 X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=44e098b7b3fe22e3d0e6c44c26740222cc387508;p=thirdparty%2Fsuricata.git rdp: trigger raw stream inspection Internals --------- Suricata's stream engine returns data for inspection to the detection engine from the stream when the chunk size is reached. Bug --- Inspection triggered only in the specified chunk sizes may be too late when it comes to inspection of smaller protocol specific data which could result in delayed inspection, incorrect data logged with a transaction and logs misindicating the pkt that triggered an alert. Fix --- Fix this by making an explicit call from all respective applayer parsers to trigger raw stream inspection which shall make the data available for inspection in the following call of the stream engine. This needs to happen per direction on the completion of an entity like a request or a response. Important notes --------------- 1. The above mentioned behavior with and without this patch is affected internally by the following conditions. - inspection depth - stream depth In these special cases, the inspection window will be affected and Suricata may not consider all the data that could be expected to be inspected. 2. This only applies to applayer protocols running over TCP. 3. The inspection window is only considered up to the ACK'd data. 4. This entire issue is about IDS mode only. RDP parser creates a transaction per request or response. Appropriate calls to trigger raw stream inspection have been added on completion of each request and response. Task 7026 Bug 7004 --- diff --git a/rust/src/rdp/rdp.rs b/rust/src/rdp/rdp.rs index 6ac26e85f2..767f430471 100644 --- a/rust/src/rdp/rdp.rs +++ b/rust/src/rdp/rdp.rs @@ -20,9 +20,10 @@ //! RDP application layer use crate::applayer::{self, *}; -use crate::core::{ALPROTO_UNKNOWN, IPPROTO_TCP}; +use crate::core::{ALPROTO_UNKNOWN, IPPROTO_TCP, sc_app_layer_parser_trigger_raw_stream_inspection}; use crate::flow::Flow; use crate::rdp::parser::*; +use crate::direction::Direction; use nom7::Err; use suricata_sys::sys::AppProto; use std; @@ -162,7 +163,7 @@ impl RdpState { } /// parse buffer captures from client to server - fn parse_ts(&mut self, input: &[u8]) -> AppLayerResult { + fn parse_ts(&mut self, flow: *const Flow, input: &[u8]) -> AppLayerResult { // no need to process input buffer if self.bypass_parsing { return AppLayerResult::ok(); @@ -206,6 +207,9 @@ impl RdpState { let tx = self.new_tx(RdpTransactionItem::X224ConnectionRequest(x224)); self.transactions.push_back(tx); + if !flow.is_null() { + sc_app_layer_parser_trigger_raw_stream_inspection(flow, Direction::ToServer as i32); + } } // X.223 data packet, evaluate what it encapsulates @@ -216,6 +220,9 @@ impl RdpState { let tx = self.new_tx(RdpTransactionItem::McsConnectRequest(mcs)); self.transactions.push_back(tx); + if !flow.is_null() { + sc_app_layer_parser_trigger_raw_stream_inspection(flow, Direction::ToServer as i32); + } } // unknown message in X.223, skip _ => (), @@ -238,7 +245,7 @@ impl RdpState { Err(Err::Failure(_)) | Err(Err::Error(_)) => { if probe_tls_handshake(available) { self.tls_parsing = true; - let r = self.parse_ts(available); + let r = self.parse_ts(flow, available); if r.status == 1 { //adds bytes already consumed to incomplete result let consumed = (input.len() - available.len()) as u32; @@ -256,7 +263,7 @@ impl RdpState { } /// parse buffer captures from server to client - fn parse_tc(&mut self, input: &[u8]) -> AppLayerResult { + fn parse_tc(&mut self, flow: *const Flow, input: &[u8]) -> AppLayerResult { // no need to process input buffer if self.bypass_parsing { return AppLayerResult::ok(); @@ -287,6 +294,9 @@ impl RdpState { let tx = self.new_tx(RdpTransactionItem::TlsCertificateChain(chain)); self.transactions.push_back(tx); + if !flow.is_null() { + sc_app_layer_parser_trigger_raw_stream_inspection(flow, Direction::ToClient as i32); + } self.bypass_parsing = true; } _ => {} @@ -320,6 +330,9 @@ impl RdpState { let tx = self.new_tx(RdpTransactionItem::X224ConnectionConfirm(x224)); self.transactions.push_back(tx); + if !flow.is_null() { + sc_app_layer_parser_trigger_raw_stream_inspection(flow, Direction::ToClient as i32); + } } // X.223 data packet, evaluate what it encapsulates @@ -330,6 +343,9 @@ impl RdpState { let tx = self .new_tx(RdpTransactionItem::McsConnectResponse(mcs)); self.transactions.push_back(tx); + if !flow.is_null() { + sc_app_layer_parser_trigger_raw_stream_inspection(flow, Direction::ToClient as i32); + } self.bypass_parsing = true; return AppLayerResult::ok(); } @@ -355,7 +371,7 @@ impl RdpState { Err(Err::Failure(_)) | Err(Err::Error(_)) => { if probe_tls_handshake(available) { self.tls_parsing = true; - let r = self.parse_tc(available); + let r = self.parse_tc(flow, available); if r.status == 1 { //adds bytes already consumed to incomplete result let consumed = (input.len() - available.len()) as u32; @@ -425,25 +441,25 @@ fn probe_tls_handshake(input: &[u8]) -> bool { // unsafe extern "C" fn rdp_parse_ts( - _flow: *const Flow, state: *mut std::os::raw::c_void, _pstate: *mut std::os::raw::c_void, + flow: *const Flow, state: *mut std::os::raw::c_void, _pstate: *mut std::os::raw::c_void, stream_slice: StreamSlice, _data: *const std::os::raw::c_void ) -> AppLayerResult { let state = cast_pointer!(state, RdpState); let buf = stream_slice.as_slice(); // attempt to parse bytes as `rdp` protocol - return state.parse_ts(buf); + return state.parse_ts(flow, buf); } unsafe extern "C" fn rdp_parse_tc( - _flow: *const Flow, state: *mut std::os::raw::c_void, _pstate: *mut std::os::raw::c_void, + flow: *const Flow, state: *mut std::os::raw::c_void, _pstate: *mut std::os::raw::c_void, stream_slice: StreamSlice, _data: *const std::os::raw::c_void ) -> AppLayerResult { let state = cast_pointer!(state, RdpState); let buf = stream_slice.as_slice(); // attempt to parse bytes as `rdp` protocol - return state.parse_tc(buf); + return state.parse_tc(flow, buf); } export_tx_data_get!(rdp_get_tx_data, RdpTransaction); @@ -543,10 +559,10 @@ mod tests { ]; let mut state = RdpState::new(); // will consume 0, request length + 1 - assert_eq!(AppLayerResult::incomplete(0, 9), state.parse_ts(buf_1)); + assert_eq!(AppLayerResult::incomplete(0, 9), state.parse_ts(std::ptr::null(), buf_1)); assert_eq!(0, state.transactions.len()); // exactly aligns with transaction - assert_eq!(AppLayerResult::ok(), state.parse_ts(buf_2)); + assert_eq!(AppLayerResult::ok(), state.parse_ts(std::ptr::null(), buf_2)); assert_eq!(1, state.transactions.len()); let item = RdpTransactionItem::X224ConnectionRequest(X224ConnectionRequest { cdt: 0, @@ -567,7 +583,7 @@ mod tests { fn test_parse_ts_other() { let buf: &[u8] = &[0x03, 0x00, 0x00, 0x01, 0x00]; let mut state = RdpState::new(); - assert_eq!(AppLayerResult::err(), state.parse_ts(buf)); + assert_eq!(AppLayerResult::err(), state.parse_ts(std::ptr::null(), buf)); } #[test] @@ -576,10 +592,10 @@ mod tests { let buf_2: &[u8] = &[0x03, 0x00, 0x00, 0x09, 0x02, 0xf0, 0x80, 0x7f, 0x66]; let mut state = RdpState::new(); // will consume 0, request length + 1 - assert_eq!(AppLayerResult::incomplete(0, 6), state.parse_tc(buf_1)); + assert_eq!(AppLayerResult::incomplete(0, 6), state.parse_tc(std::ptr::null(), buf_1)); assert_eq!(0, state.transactions.len()); // exactly aligns with transaction - assert_eq!(AppLayerResult::ok(), state.parse_tc(buf_2)); + assert_eq!(AppLayerResult::ok(), state.parse_tc(std::ptr::null(), buf_2)); assert_eq!(1, state.transactions.len()); let item = RdpTransactionItem::McsConnectResponse(McsConnectResponse {}); assert_eq!(item, state.transactions[0].item); @@ -589,7 +605,7 @@ mod tests { fn test_parse_tc_other() { let buf: &[u8] = &[0x03, 0x00, 0x00, 0x01, 0x00]; let mut state = RdpState::new(); - assert_eq!(AppLayerResult::err(), state.parse_tc(buf)); + assert_eq!(AppLayerResult::err(), state.parse_tc(std::ptr::null(), buf)); } #[test]