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suricata/rust/src/rdp/rdp.rs

711 lines
26 KiB
Rust

/* Copyright (C) 2019-2022 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.
*/
// Author: Zach Kelly <zach.kelly@lmco.com>
//! RDP application layer
use crate::applayer::{self, *};
use crate::core::{
sc_app_layer_parser_trigger_raw_stream_inspection, ALPROTO_UNKNOWN, IPPROTO_TCP,
};
use crate::direction::Direction;
use crate::flow::Flow;
use crate::rdp::parser::*;
use nom7::Err;
use std;
use std::collections::VecDeque;
use suricata_sys::sys::{
AppLayerParserState, AppProto, SCAppLayerParserConfParserEnabled,
SCAppLayerParserRegisterLogger, SCAppLayerProtoDetectConfProtoDetectionEnabled,
};
use tls_parser::{parse_tls_plaintext, TlsMessage, TlsMessageHandshake, TlsRecordType};
static mut ALPROTO_RDP: AppProto = ALPROTO_UNKNOWN;
//
// transactions
//
#[derive(Debug, PartialEq, Eq)]
pub struct CertificateBlob {
pub data: Vec<u8>,
}
#[derive(Debug, PartialEq, Eq)]
pub enum RdpTransactionItem {
X224ConnectionRequest(X224ConnectionRequest),
X224ConnectionConfirm(X224ConnectionConfirm),
McsConnectRequest(McsConnectRequest),
McsConnectResponse(McsConnectResponse),
TlsCertificateChain(Vec<CertificateBlob>),
}
#[derive(Debug, PartialEq, Eq)]
pub struct RdpTransaction {
pub id: u64,
pub item: RdpTransactionItem,
// managed by macros `export_tx_get_detect_state!` and `export_tx_set_detect_state!`
tx_data: AppLayerTxData,
}
impl Transaction for RdpTransaction {
fn id(&self) -> u64 {
self.id
}
}
impl RdpTransaction {
fn new(id: u64, item: RdpTransactionItem) -> Self {
Self {
id,
item,
tx_data: AppLayerTxData::new(),
}
}
}
unsafe extern "C" fn rdp_state_get_tx(
state: *mut std::os::raw::c_void, tx_id: u64,
) -> *mut std::os::raw::c_void {
let state = cast_pointer!(state, RdpState);
match state.get_tx(tx_id) {
Some(tx) => {
return tx as *const _ as *mut _;
}
None => {
return std::ptr::null_mut();
}
}
}
unsafe extern "C" fn rdp_state_get_tx_count(state: *mut std::os::raw::c_void) -> u64 {
let state = cast_pointer!(state, RdpState);
return state.next_id;
}
extern "C" fn rdp_tx_get_progress(
_tx: *mut std::os::raw::c_void, _direction: u8,
) -> std::os::raw::c_int {
// tx complete when `rs_rdp_tx_get_progress(...) == rs_rdp_tx_get_progress_complete(...)`
// here, all transactions are immediately complete on insert
return 1;
}
//
// state
//
#[derive(Debug, PartialEq, Eq)]
pub struct RdpState {
state_data: AppLayerStateData,
next_id: u64,
transactions: VecDeque<RdpTransaction>,
tls_parsing: bool,
bypass_parsing: bool,
}
impl State<RdpTransaction> for RdpState {
fn get_transaction_count(&self) -> usize {
self.transactions.len()
}
fn get_transaction_by_index(&self, index: usize) -> Option<&RdpTransaction> {
self.transactions.get(index)
}
}
impl RdpState {
fn new() -> Self {
Self {
state_data: AppLayerStateData::new(),
next_id: 0,
transactions: VecDeque::new(),
tls_parsing: false,
bypass_parsing: false,
}
}
fn free_tx(&mut self, tx_id: u64) {
let len = self.transactions.len();
let mut found = false;
let mut index = 0;
for ii in 0..len {
let tx = &self.transactions[ii];
if tx.id == tx_id {
found = true;
index = ii;
break;
}
}
if found {
self.transactions.remove(index);
}
}
fn get_tx(&self, tx_id: u64) -> Option<&RdpTransaction> {
self.transactions.iter().find(|&tx| tx.id == tx_id)
}
fn new_tx(&mut self, item: RdpTransactionItem) -> RdpTransaction {
self.next_id += 1;
let tx = RdpTransaction::new(self.next_id, item);
return tx;
}
/// parse buffer captures from client to server
fn parse_ts(&mut self, flow: *mut Flow, input: &[u8]) -> AppLayerResult {
// no need to process input buffer
if self.bypass_parsing {
return AppLayerResult::ok();
}
let mut available = input;
loop {
if available.is_empty() {
return AppLayerResult::ok();
}
if self.tls_parsing {
match parse_tls_plaintext(available) {
Ok((remainder, _tls)) => {
// bytes available for further parsing are what remain
available = remainder;
}
Err(Err::Incomplete(_)) => {
// nom need not compatible with applayer need, request one more byte
return AppLayerResult::incomplete(
(input.len() - available.len()) as u32,
(available.len() + 1) as u32,
);
}
Err(Err::Failure(_)) | Err(Err::Error(_)) => {
return AppLayerResult::err();
}
}
} else {
// every message should be encapsulated within a T.123 tpkt
match parse_t123_tpkt(available) {
// success
Ok((remainder, t123)) => {
// bytes available for further parsing are what remain
available = remainder;
// evaluate message within the tpkt
match t123.child {
// X.224 connection request
T123TpktChild::X224ConnectionRequest(x224) => {
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
T123TpktChild::Data(x223) => {
#[allow(clippy::single_match)]
match x223.child {
X223DataChild::McsConnectRequest(mcs) => {
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
_ => (),
}
}
// unknown message in T.123, skip
_ => (),
}
}
Err(Err::Incomplete(_)) => {
// nom need not compatible with applayer need, request one more byte
return AppLayerResult::incomplete(
(input.len() - available.len()) as u32,
(available.len() + 1) as u32,
);
}
Err(Err::Failure(_)) | Err(Err::Error(_)) => {
if probe_tls_handshake(available) {
self.tls_parsing = true;
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;
return AppLayerResult::incomplete(r.consumed + consumed, r.needed);
} else {
return r;
}
} else {
return AppLayerResult::err();
}
}
}
}
}
}
/// parse buffer captures from server to client
fn parse_tc(&mut self, flow: *mut Flow, input: &[u8]) -> AppLayerResult {
// no need to process input buffer
if self.bypass_parsing {
return AppLayerResult::ok();
}
let mut available = input;
loop {
if available.is_empty() {
return AppLayerResult::ok();
}
if self.tls_parsing {
match parse_tls_plaintext(available) {
Ok((remainder, tls)) => {
// bytes available for further parsing are what remain
available = remainder;
for message in &tls.msg {
#[allow(clippy::single_match)]
match message {
TlsMessage::Handshake(TlsMessageHandshake::Certificate(
contents,
)) => {
let mut chain = Vec::new();
for cert in &contents.cert_chain {
chain.push(CertificateBlob {
data: cert.data.to_vec(),
});
}
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;
}
_ => {}
}
}
}
Err(Err::Incomplete(_)) => {
// nom need not compatible with applayer need, request one more byte
return AppLayerResult::incomplete(
(input.len() - available.len()) as u32,
(available.len() + 1) as u32,
);
}
Err(Err::Failure(_)) | Err(Err::Error(_)) => {
return AppLayerResult::err();
}
}
} else {
// every message should be encapsulated within a T.123 tpkt
match parse_t123_tpkt(available) {
// success
Ok((remainder, t123)) => {
// bytes available for further parsing are what remain
available = remainder;
// evaluate message within the tpkt
match t123.child {
// X.224 connection confirm
T123TpktChild::X224ConnectionConfirm(x224) => {
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
T123TpktChild::Data(x223) => {
#[allow(clippy::single_match)]
match x223.child {
X223DataChild::McsConnectResponse(mcs) => {
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();
}
// unknown message in X.223, skip
_ => (),
}
}
// unknown message in T.123, skip
_ => (),
}
}
Err(Err::Incomplete(_)) => {
// nom need not compatible with applayer need, request one more byte
return AppLayerResult::incomplete(
(input.len() - available.len()) as u32,
(available.len() + 1) as u32,
);
}
Err(Err::Failure(_)) | Err(Err::Error(_)) => {
if probe_tls_handshake(available) {
self.tls_parsing = true;
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;
return AppLayerResult::incomplete(r.consumed + consumed, r.needed);
} else {
return r;
}
} else {
return AppLayerResult::err();
}
}
}
}
}
}
}
extern "C" fn rdp_state_new(
_orig_state: *mut std::os::raw::c_void, _orig_proto: AppProto,
) -> *mut std::os::raw::c_void {
let state = RdpState::new();
let boxed = Box::new(state);
return Box::into_raw(boxed) as *mut _;
}
extern "C" fn rdp_state_free(state: *mut std::os::raw::c_void) {
std::mem::drop(unsafe { Box::from_raw(state as *mut RdpState) });
}
unsafe extern "C" fn rdp_state_tx_free(state: *mut std::os::raw::c_void, tx_id: u64) {
let state = cast_pointer!(state, RdpState);
state.free_tx(tx_id);
}
//
// probe
//
/// probe for T.123 type identifier, as each message is encapsulated in T.123
fn probe_rdp(input: &[u8]) -> bool {
!input.is_empty() && input[0] == TpktVersion::T123 as u8
}
/// probe for T.123 message, whether to client or to server
unsafe extern "C" fn rdp_probe_ts_tc(
_flow: *const Flow, _direction: u8, input: *const u8, input_len: u32, _rdir: *mut u8,
) -> AppProto {
if !input.is_null() {
// probe bytes for `rdp` protocol pattern
let slice = build_slice!(input, input_len as usize);
// Some sessions immediately (first byte) switch to TLS/SSL, e.g.
// https://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=view&target=rdp-ssl.pcap.gz
// but this callback will not be exercised, so `probe_tls_handshake` not needed here.
if probe_rdp(slice) {
return ALPROTO_RDP;
}
}
return ALPROTO_UNKNOWN;
}
/// probe for TLS
fn probe_tls_handshake(input: &[u8]) -> bool {
!input.is_empty() && input[0] == u8::from(TlsRecordType::Handshake)
}
//
// parse
//
unsafe extern "C" fn rdp_parse_ts(
flow: *mut Flow, state: *mut std::os::raw::c_void, _pstate: *mut AppLayerParserState,
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(flow, buf);
}
unsafe extern "C" fn rdp_parse_tc(
flow: *mut Flow, state: *mut std::os::raw::c_void, _pstate: *mut AppLayerParserState,
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(flow, buf);
}
export_tx_data_get!(rdp_get_tx_data, RdpTransaction);
export_state_data_get!(rdp_get_state_data, RdpState);
//
// registration
//
const PARSER_NAME: &[u8] = b"rdp\0";
#[no_mangle]
pub unsafe extern "C" fn SCRegisterRdpParser() {
let default_port = std::ffi::CString::new("[3389]").unwrap();
let parser = RustParser {
name: PARSER_NAME.as_ptr() as *const std::os::raw::c_char,
default_port: default_port.as_ptr(),
ipproto: IPPROTO_TCP,
probe_ts: Some(rdp_probe_ts_tc),
probe_tc: Some(rdp_probe_ts_tc),
min_depth: 0,
max_depth: 16,
state_new: rdp_state_new,
state_free: rdp_state_free,
tx_free: rdp_state_tx_free,
parse_ts: rdp_parse_ts,
parse_tc: rdp_parse_tc,
get_tx_count: rdp_state_get_tx_count,
get_tx: rdp_state_get_tx,
tx_comp_st_ts: 1,
tx_comp_st_tc: 1,
tx_get_progress: rdp_tx_get_progress,
get_eventinfo: None,
get_eventinfo_byid: None,
localstorage_new: None,
localstorage_free: None,
get_tx_files: None,
get_tx_iterator: Some(applayer::state_get_tx_iterator::<RdpState, RdpTransaction>),
get_tx_data: rdp_get_tx_data,
get_state_data: rdp_get_state_data,
apply_tx_config: None,
flags: 0,
get_frame_id_by_name: None,
get_frame_name_by_id: None,
get_state_id_by_name: None,
get_state_name_by_id: None,
};
let ip_proto_str = std::ffi::CString::new("tcp").unwrap();
if SCAppLayerProtoDetectConfProtoDetectionEnabled(ip_proto_str.as_ptr(), parser.name) != 0 {
let alproto = AppLayerRegisterProtocolDetection(&parser, 1);
ALPROTO_RDP = alproto;
if SCAppLayerParserConfParserEnabled(ip_proto_str.as_ptr(), parser.name) != 0 {
let _ = AppLayerRegisterParser(&parser, alproto);
}
SCAppLayerParserRegisterLogger(IPPROTO_TCP, ALPROTO_RDP);
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::rdp::parser::{RdpCookie, X224ConnectionRequest};
#[test]
fn test_probe_rdp() {
let buf: &[u8] = &[0x03, 0x00];
assert!(probe_rdp(buf));
}
#[test]
fn test_probe_rdp_other() {
let buf: &[u8] = &[0x04, 0x00];
assert!(!probe_rdp(buf));
}
#[test]
fn test_probe_tls_handshake() {
let buf: &[u8] = &[0x16, 0x00];
assert!(probe_tls_handshake(buf));
}
#[test]
fn test_probe_tls_handshake_other() {
let buf: &[u8] = &[0x17, 0x00];
assert!(!probe_tls_handshake(buf));
}
#[test]
fn test_parse_ts_rdp() {
let buf_1: &[u8] = &[0x03, 0x00, 0x00, 0x25, 0x20, 0xe0, 0x00, 0x00];
let buf_2: &[u8] = &[
0x03, 0x00, 0x00, 0x25, 0x20, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x43, 0x6f, 0x6f,
0x6b, 0x69, 0x65, 0x3a, 0x20, 0x6d, 0x73, 0x74, 0x73, 0x68, 0x61, 0x73, 0x68, 0x3d,
0x75, 0x73, 0x65, 0x72, 0x31, 0x32, 0x33, 0x0d, 0x0a,
];
let mut state = RdpState::new();
// will consume 0, request length + 1
assert_eq!(
AppLayerResult::incomplete(0, 9),
state.parse_ts(std::ptr::null_mut(), buf_1)
);
assert_eq!(0, state.transactions.len());
// exactly aligns with transaction
assert_eq!(
AppLayerResult::ok(),
state.parse_ts(std::ptr::null_mut(), buf_2)
);
assert_eq!(1, state.transactions.len());
let item = RdpTransactionItem::X224ConnectionRequest(X224ConnectionRequest {
cdt: 0,
dst_ref: 0,
src_ref: 0,
class: 0,
options: 0,
cookie: Some(RdpCookie {
mstshash: String::from("user123"),
}),
negotiation_request: None,
data: Vec::new(),
});
assert_eq!(item, state.transactions[0].item);
}
#[test]
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(std::ptr::null_mut(), buf));
}
#[test]
fn test_parse_tc_rdp() {
let buf_1: &[u8] = &[0x03, 0x00, 0x00, 0x09, 0x02];
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(std::ptr::null_mut(), buf_1)
);
assert_eq!(0, state.transactions.len());
// exactly aligns with transaction
assert_eq!(
AppLayerResult::ok(),
state.parse_tc(std::ptr::null_mut(), buf_2)
);
assert_eq!(1, state.transactions.len());
let item = RdpTransactionItem::McsConnectResponse(McsConnectResponse {});
assert_eq!(item, state.transactions[0].item);
}
#[test]
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(std::ptr::null_mut(), buf));
}
#[test]
fn test_state_new_tx() {
let mut state = RdpState::new();
let item0 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let item1 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let tx0 = state.new_tx(item0);
let tx1 = state.new_tx(item1);
assert_eq!(2, state.next_id);
state.transactions.push_back(tx0);
state.transactions.push_back(tx1);
assert_eq!(2, state.transactions.len());
assert_eq!(1, state.transactions[0].id);
assert_eq!(2, state.transactions[1].id);
assert!(!state.tls_parsing);
assert!(!state.bypass_parsing);
}
#[test]
fn test_state_get_tx() {
let mut state = RdpState::new();
let item0 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let item1 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let item2 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let tx0 = state.new_tx(item0);
let tx1 = state.new_tx(item1);
let tx2 = state.new_tx(item2);
state.transactions.push_back(tx0);
state.transactions.push_back(tx1);
state.transactions.push_back(tx2);
assert_eq!(Some(&state.transactions[1]), state.get_tx(2));
}
#[test]
fn test_state_free_tx() {
let mut state = RdpState::new();
let item0 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let item1 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let item2 = RdpTransactionItem::McsConnectRequest(McsConnectRequest {
children: Vec::new(),
});
let tx0 = state.new_tx(item0);
let tx1 = state.new_tx(item1);
let tx2 = state.new_tx(item2);
state.transactions.push_back(tx0);
state.transactions.push_back(tx1);
state.transactions.push_back(tx2);
state.free_tx(1);
assert_eq!(3, state.next_id);
assert_eq!(2, state.transactions.len());
assert_eq!(2, state.transactions[0].id);
assert_eq!(3, state.transactions[1].id);
assert_eq!(None, state.get_tx(1));
}
}