ME Ping in log
This commit is contained in:
Alexey
369
src/transport/middle_proxy/handshake.rs
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369
src/transport/middle_proxy/handshake.rs
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@@ -0,0 +1,369 @@
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use std::net::{IpAddr, SocketAddr};
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use std::time::{Duration, Instant};
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use bytes::BytesMut;
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use tokio::io::{AsyncReadExt, AsyncWriteExt, ReadHalf, WriteHalf};
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use tokio::net::TcpStream;
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use tokio::time::timeout;
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use tracing::{debug, info, warn};
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use crate::crypto::{SecureRandom, build_middleproxy_prekey, derive_middleproxy_keys, sha256};
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use crate::error::{ProxyError, Result};
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use crate::protocol::constants::{
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ME_CONNECT_TIMEOUT_SECS, ME_HANDSHAKE_TIMEOUT_SECS, RPC_CRYPTO_AES_U32, RPC_HANDSHAKE_ERROR_U32,
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RPC_HANDSHAKE_U32, RPC_PING_U32, RPC_PONG_U32, RPC_NONCE_U32,
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};
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use super::codec::{
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build_handshake_payload, build_nonce_payload, build_rpc_frame, cbc_decrypt_inplace,
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cbc_encrypt_padded, parse_nonce_payload, read_rpc_frame_plaintext,
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};
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use super::wire::{extract_ip_material, IpMaterial};
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use super::MePool;
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/// Result of a successful ME handshake with timings.
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pub(crate) struct HandshakeOutput {
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pub rd: ReadHalf<TcpStream>,
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pub wr: WriteHalf<TcpStream>,
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pub read_key: [u8; 32],
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pub read_iv: [u8; 16],
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pub write_key: [u8; 32],
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pub write_iv: [u8; 16],
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pub handshake_ms: f64,
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}
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impl MePool {
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/// TCP connect with timeout + return RTT in milliseconds.
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pub(crate) async fn connect_tcp(&self, addr: SocketAddr) -> Result<(TcpStream, f64)> {
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let start = Instant::now();
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let stream = timeout(Duration::from_secs(ME_CONNECT_TIMEOUT_SECS), TcpStream::connect(addr))
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.await
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.map_err(|_| ProxyError::ConnectionTimeout { addr: addr.to_string() })??;
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let connect_ms = start.elapsed().as_secs_f64() * 1000.0;
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stream.set_nodelay(true).ok();
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Ok((stream, connect_ms))
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}
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/// Perform full ME RPC handshake on an established TCP stream.
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/// Returns cipher keys/ivs and split halves; does not register writer.
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pub(crate) async fn handshake_only(
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&self,
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stream: TcpStream,
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addr: SocketAddr,
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rng: &SecureRandom,
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) -> Result<HandshakeOutput> {
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let hs_start = Instant::now();
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let local_addr = stream.local_addr().map_err(ProxyError::Io)?;
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let peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
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let _ = self.maybe_detect_nat_ip(local_addr.ip()).await;
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let reflected = if self.nat_probe {
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self.maybe_reflect_public_addr().await
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} else {
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None
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};
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let local_addr_nat = self.translate_our_addr_with_reflection(local_addr, reflected);
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let peer_addr_nat = SocketAddr::new(self.translate_ip_for_nat(peer_addr.ip()), peer_addr.port());
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let (mut rd, mut wr) = tokio::io::split(stream);
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let my_nonce: [u8; 16] = rng.bytes(16).try_into().unwrap();
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let crypto_ts = std::time::SystemTime::now()
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.duration_since(std::time::UNIX_EPOCH)
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.unwrap_or_default()
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.as_secs() as u32;
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let ks = self.key_selector().await;
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let nonce_payload = build_nonce_payload(ks, crypto_ts, &my_nonce);
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let nonce_frame = build_rpc_frame(-2, &nonce_payload);
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let dump = hex_dump(&nonce_frame[..nonce_frame.len().min(44)]);
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info!(
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key_selector = format_args!("0x{ks:08x}"),
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crypto_ts,
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frame_len = nonce_frame.len(),
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nonce_frame_hex = %dump,
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"Sending ME nonce frame"
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);
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wr.write_all(&nonce_frame).await.map_err(ProxyError::Io)?;
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wr.flush().await.map_err(ProxyError::Io)?;
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let (srv_seq, srv_nonce_payload) = timeout(
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Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS),
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read_rpc_frame_plaintext(&mut rd),
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)
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.await
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.map_err(|_| ProxyError::TgHandshakeTimeout)??;
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if srv_seq != -2 {
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return Err(ProxyError::InvalidHandshake(format!("Expected seq=-2, got {srv_seq}")));
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}
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let (srv_key_select, schema, srv_ts, srv_nonce) = parse_nonce_payload(&srv_nonce_payload)?;
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if schema != RPC_CRYPTO_AES_U32 {
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warn!(schema = format_args!("0x{schema:08x}"), "Unsupported ME crypto schema");
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return Err(ProxyError::InvalidHandshake(format!(
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"Unsupported crypto schema: 0x{schema:x}"
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)));
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}
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if srv_key_select != ks {
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return Err(ProxyError::InvalidHandshake(format!(
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"Server key_select 0x{srv_key_select:08x} != client 0x{ks:08x}"
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)));
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}
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let skew = crypto_ts.abs_diff(srv_ts);
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if skew > 30 {
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return Err(ProxyError::InvalidHandshake(format!(
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"nonce crypto_ts skew too large: client={crypto_ts}, server={srv_ts}, skew={skew}s"
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)));
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}
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info!(
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%local_addr,
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%local_addr_nat,
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reflected_ip = reflected.map(|r| r.ip()).as_ref().map(ToString::to_string),
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%peer_addr,
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%peer_addr_nat,
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key_selector = format_args!("0x{ks:08x}"),
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crypto_schema = format_args!("0x{schema:08x}"),
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skew_secs = skew,
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"ME key derivation parameters"
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);
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let ts_bytes = crypto_ts.to_le_bytes();
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let server_port_bytes = peer_addr_nat.port().to_le_bytes();
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let client_port_bytes = local_addr_nat.port().to_le_bytes();
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let server_ip = extract_ip_material(peer_addr_nat);
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let client_ip = extract_ip_material(local_addr_nat);
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let (srv_ip_opt, clt_ip_opt, clt_v6_opt, srv_v6_opt, hs_our_ip, hs_peer_ip) = match (server_ip, client_ip) {
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(IpMaterial::V4(mut srv), IpMaterial::V4(mut clt)) => {
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srv.reverse();
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clt.reverse();
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(Some(srv), Some(clt), None, None, clt, srv)
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}
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(IpMaterial::V6(srv), IpMaterial::V6(clt)) => {
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let zero = [0u8; 4];
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(None, None, Some(clt), Some(srv), zero, zero)
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}
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_ => {
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return Err(ProxyError::InvalidHandshake(
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"mixed IPv4/IPv6 endpoints are not supported for ME key derivation".to_string(),
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));
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}
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};
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let diag_level: u8 = std::env::var("ME_DIAG").ok().and_then(|v| v.parse().ok()).unwrap_or(0);
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let secret: Vec<u8> = self.proxy_secret.read().await.clone();
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let prekey_client = build_middleproxy_prekey(
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&srv_nonce,
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&my_nonce,
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&ts_bytes,
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srv_ip_opt.as_ref().map(|x| &x[..]),
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&client_port_bytes,
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b"CLIENT",
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clt_ip_opt.as_ref().map(|x| &x[..]),
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&server_port_bytes,
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&secret,
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clt_v6_opt.as_ref(),
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srv_v6_opt.as_ref(),
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);
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let prekey_server = build_middleproxy_prekey(
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&srv_nonce,
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&my_nonce,
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&ts_bytes,
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srv_ip_opt.as_ref().map(|x| &x[..]),
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&client_port_bytes,
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b"SERVER",
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clt_ip_opt.as_ref().map(|x| &x[..]),
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&server_port_bytes,
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&secret,
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clt_v6_opt.as_ref(),
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srv_v6_opt.as_ref(),
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);
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let (wk, wi) = derive_middleproxy_keys(
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&srv_nonce,
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&my_nonce,
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&ts_bytes,
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srv_ip_opt.as_ref().map(|x| &x[..]),
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&client_port_bytes,
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b"CLIENT",
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clt_ip_opt.as_ref().map(|x| &x[..]),
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&server_port_bytes,
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&secret,
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clt_v6_opt.as_ref(),
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srv_v6_opt.as_ref(),
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);
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let (rk, ri) = derive_middleproxy_keys(
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&srv_nonce,
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&my_nonce,
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&ts_bytes,
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srv_ip_opt.as_ref().map(|x| &x[..]),
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&client_port_bytes,
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b"SERVER",
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clt_ip_opt.as_ref().map(|x| &x[..]),
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&server_port_bytes,
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&secret,
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clt_v6_opt.as_ref(),
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srv_v6_opt.as_ref(),
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);
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let hs_payload = build_handshake_payload(hs_our_ip, local_addr.port(), hs_peer_ip, peer_addr.port());
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let hs_frame = build_rpc_frame(-1, &hs_payload);
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if diag_level >= 1 {
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info!(
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write_key = %hex_dump(&wk),
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write_iv = %hex_dump(&wi),
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read_key = %hex_dump(&rk),
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read_iv = %hex_dump(&ri),
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srv_ip = %srv_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
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clt_ip = %clt_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
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srv_port = %hex_dump(&server_port_bytes),
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clt_port = %hex_dump(&client_port_bytes),
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crypto_ts = %hex_dump(&ts_bytes),
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nonce_srv = %hex_dump(&srv_nonce),
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nonce_clt = %hex_dump(&my_nonce),
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prekey_sha256_client = %hex_dump(&sha256(&prekey_client)),
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prekey_sha256_server = %hex_dump(&sha256(&prekey_server)),
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hs_plain = %hex_dump(&hs_frame),
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proxy_secret_sha256 = %hex_dump(&sha256(&secret)),
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"ME diag: derived keys and handshake plaintext"
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);
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}
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if diag_level >= 2 {
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info!(
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prekey_client = %hex_dump(&prekey_client),
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prekey_server = %hex_dump(&prekey_server),
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"ME diag: full prekey buffers"
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);
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}
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let (encrypted_hs, mut write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
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if diag_level >= 1 {
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info!(
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hs_cipher = %hex_dump(&encrypted_hs),
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"ME diag: handshake ciphertext"
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);
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}
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wr.write_all(&encrypted_hs).await.map_err(ProxyError::Io)?;
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wr.flush().await.map_err(ProxyError::Io)?;
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let deadline = Instant::now() + Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS);
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let mut enc_buf = BytesMut::with_capacity(256);
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let mut dec_buf = BytesMut::with_capacity(256);
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let mut read_iv = ri;
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let mut handshake_ok = false;
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while Instant::now() < deadline && !handshake_ok {
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let remaining = deadline - Instant::now();
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let mut tmp = [0u8; 256];
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let n = match timeout(remaining, rd.read(&mut tmp)).await {
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Ok(Ok(0)) => {
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return Err(ProxyError::Io(std::io::Error::new(
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std::io::ErrorKind::UnexpectedEof,
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"ME closed during handshake",
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)));
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}
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Ok(Ok(n)) => n,
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Ok(Err(e)) => return Err(ProxyError::Io(e)),
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Err(_) => return Err(ProxyError::TgHandshakeTimeout),
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};
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enc_buf.extend_from_slice(&tmp[..n]);
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let blocks = enc_buf.len() / 16 * 16;
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if blocks > 0 {
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let mut chunk = vec![0u8; blocks];
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chunk.copy_from_slice(&enc_buf[..blocks]);
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read_iv = cbc_decrypt_inplace(&rk, &read_iv, &mut chunk)?;
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dec_buf.extend_from_slice(&chunk);
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let _ = enc_buf.split_to(blocks);
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}
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while dec_buf.len() >= 4 {
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let fl = u32::from_le_bytes(dec_buf[0..4].try_into().unwrap()) as usize;
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if fl == 4 {
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let _ = dec_buf.split_to(4);
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continue;
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}
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if !(12..=(1 << 24)).contains(&fl) {
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return Err(ProxyError::InvalidHandshake(format!(
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"Bad HS response frame len: {fl}"
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)));
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}
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if dec_buf.len() < fl {
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break;
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}
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let frame = dec_buf.split_to(fl);
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let pe = fl - 4;
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let ec = u32::from_le_bytes(frame[pe..pe + 4].try_into().unwrap());
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let ac = crate::crypto::crc32(&frame[..pe]);
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if ec != ac {
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return Err(ProxyError::InvalidHandshake(format!(
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"HS CRC mismatch: 0x{ec:08x} vs 0x{ac:08x}"
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)));
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}
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let hs_type = u32::from_le_bytes(frame[8..12].try_into().unwrap());
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if hs_type == RPC_HANDSHAKE_ERROR_U32 {
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let err_code = if frame.len() >= 16 {
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i32::from_le_bytes(frame[12..16].try_into().unwrap())
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} else {
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-1
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};
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return Err(ProxyError::InvalidHandshake(format!(
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"ME rejected handshake (error={err_code})"
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)));
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}
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if hs_type != RPC_HANDSHAKE_U32 {
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return Err(ProxyError::InvalidHandshake(format!(
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"Expected HANDSHAKE 0x{RPC_HANDSHAKE_U32:08x}, got 0x{hs_type:08x}"
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)));
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}
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handshake_ok = true;
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break;
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}
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}
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if !handshake_ok {
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return Err(ProxyError::TgHandshakeTimeout);
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}
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let handshake_ms = hs_start.elapsed().as_secs_f64() * 1000.0;
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info!(%addr, "RPC handshake OK");
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Ok(HandshakeOutput {
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rd,
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wr,
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read_key: rk,
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read_iv,
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write_key: wk,
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write_iv,
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handshake_ms,
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})
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}
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}
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fn hex_dump(data: &[u8]) -> String {
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const MAX: usize = 64;
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let mut out = String::with_capacity(data.len() * 2 + 3);
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for (i, b) in data.iter().take(MAX).enumerate() {
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if i > 0 {
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out.push(' ');
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}
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out.push_str(&format!("{b:02x}"));
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}
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if data.len() > MAX {
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out.push_str(" …");
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}
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out
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}
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