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Middle-End Fixes 

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>
This commit is contained in:
Alexey 2026-02-21 03:36:13 +03:00
parent c9a043d8d5
commit 83fc9d6db3
No known key found for this signature in database
7 changed files with 300 additions and 73 deletions
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61
src/config/defaults.rs
View File

@ -118,6 +118,67 @@ pub(crate) fn default_max_client_frame() -> usize {
16 * 1024 * 1024
}
pub(crate) fn default_tls_new_session_tickets() -> u8 {
0
}
pub(crate) fn default_server_hello_delay_min_ms() -> u64 {
0
}
pub(crate) fn default_server_hello_delay_max_ms() -> u64 {
0
}
pub(crate) fn default_alpn_enforce() -> bool {
true
}
pub(crate) fn default_stun_servers() -> Vec<String> {
vec![
"stun.l.google.com:19302".to_string(),
"stun1.l.google.com:19302".to_string(),
"stun2.l.google.com:19302".to_string(),
"stun.stunprotocol.org:3478".to_string(),
"stun.voip.eutelia.it:3478".to_string(),
]
}
pub(crate) fn default_http_ip_detect_urls() -> Vec<String> {
vec![
"https://ifconfig.me/ip".to_string(),
"https://api.ipify.org".to_string(),
]
}
pub(crate) fn default_cache_public_ip_path() -> String {
"cache/public_ip.txt".to_string()
}
pub(crate) fn default_proxy_secret_reload_secs() -> u64 {
12 * 60 * 60
}
pub(crate) fn default_proxy_config_reload_secs() -> u64 {
12 * 60 * 60
}
pub(crate) fn default_ntp_check() -> bool {
true
}
pub(crate) fn default_ntp_servers() -> Vec<String> {
vec!["pool.ntp.org".to_string()]
}
pub(crate) fn default_fast_mode_min_tls_record() -> usize {
0
}
pub(crate) fn default_degradation_min_unavailable_dc_groups() -> u8 {
2
}
// Custom deserializer helpers
#[derive(Deserialize)]

75
src/config/types.rs
View File

@ -96,6 +96,22 @@ pub struct NetworkConfig {
#[serde(default)]
pub multipath: bool,
/// STUN servers list for public IP discovery.
#[serde(default = "default_stun_servers")]
pub stun_servers: Vec<String>,
/// Enable TCP STUN fallback when UDP is blocked.
#[serde(default)]
pub stun_tcp_fallback: bool,
/// HTTP-based public IP detection endpoints (fallback after STUN).
#[serde(default = "default_http_ip_detect_urls")]
pub http_ip_detect_urls: Vec<String>,
/// Cache file path for detected public IP.
#[serde(default = "default_cache_public_ip_path")]
pub cache_public_ip_path: String,
}
impl Default for NetworkConfig {
@ -105,6 +121,10 @@ impl Default for NetworkConfig {
ipv6: None,
prefer: 4,
multipath: false,
stun_servers: default_stun_servers(),
stun_tcp_fallback: true,
http_ip_detect_urls: default_http_ip_detect_urls(),
cache_public_ip_path: default_cache_public_ip_path(),
}
}
}
@ -227,6 +247,34 @@ pub struct GeneralConfig {
/// [general.links] — proxy link generation overrides.
#[serde(default)]
pub links: LinksConfig,
/// Minimum TLS record size when fast_mode coalescing is enabled (0 = disabled).
#[serde(default = "default_fast_mode_min_tls_record")]
pub fast_mode_min_tls_record: usize,
/// Automatically reload proxy-secret every N seconds.
#[serde(default = "default_proxy_secret_reload_secs")]
pub proxy_secret_auto_reload_secs: u64,
/// Automatically reload proxy-multi.conf every N seconds.
#[serde(default = "default_proxy_config_reload_secs")]
pub proxy_config_auto_reload_secs: u64,
/// Enable NTP drift check at startup.
#[serde(default = "default_ntp_check")]
pub ntp_check: bool,
/// NTP servers for drift check.
#[serde(default = "default_ntp_servers")]
pub ntp_servers: Vec<String>,
/// Enable auto-degradation from ME to Direct-DC.
#[serde(default = "default_true")]
pub auto_degradation_enabled: bool,
/// Minimum unavailable ME DC groups before degrading.
#[serde(default = "default_degradation_min_unavailable_dc_groups")]
pub degradation_min_unavailable_dc_groups: u8,
}
impl Default for GeneralConfig {
@ -262,6 +310,13 @@ impl Default for GeneralConfig {
links: LinksConfig::default(),
crypto_pending_buffer: default_crypto_pending_buffer(),
max_client_frame: default_max_client_frame(),
fast_mode_min_tls_record: default_fast_mode_min_tls_record(),
proxy_secret_auto_reload_secs: default_proxy_secret_reload_secs(),
proxy_config_auto_reload_secs: default_proxy_config_reload_secs(),
ntp_check: default_ntp_check(),
ntp_servers: default_ntp_servers(),
auto_degradation_enabled: true,
degradation_min_unavailable_dc_groups: default_degradation_min_unavailable_dc_groups(),
}
}
}
@ -406,6 +461,22 @@ pub struct AntiCensorshipConfig {
/// Directory to store TLS front cache (on disk).
#[serde(default = "default_tls_front_dir")]
pub tls_front_dir: String,
/// Minimum server_hello delay in milliseconds (anti-fingerprint).
#[serde(default = "default_server_hello_delay_min_ms")]
pub server_hello_delay_min_ms: u64,
/// Maximum server_hello delay in milliseconds.
#[serde(default = "default_server_hello_delay_max_ms")]
pub server_hello_delay_max_ms: u64,
/// Number of NewSessionTicket messages to emit post-handshake.
#[serde(default = "default_tls_new_session_tickets")]
pub tls_new_session_tickets: u8,
/// Enforce ALPN echo of client preference.
#[serde(default = "default_alpn_enforce")]
pub alpn_enforce: bool,
}
impl Default for AntiCensorshipConfig {
@ -420,6 +491,10 @@ impl Default for AntiCensorshipConfig {
fake_cert_len: default_fake_cert_len(),
tls_emulation: false,
tls_front_dir: default_tls_front_dir(),
server_hello_delay_min_ms: default_server_hello_delay_min_ms(),
server_hello_delay_max_ms: default_server_hello_delay_max_ms(),
tls_new_session_tickets: default_tls_new_session_tickets(),
alpn_enforce: default_alpn_enforce(),
}
}
}

3
src/main.rs
View File

@ -213,6 +213,9 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
"Modes: classic={} secure={} tls={}",
config.general.modes.classic, config.general.modes.secure, config.general.modes.tls
);
if config.general.modes.classic {
warn!("Classic mode is vulnerable to DPI detection; enable only for legacy clients");
}
info!("TLS domain: {}", config.censorship.tls_domain);
if let Some(ref sock) = config.censorship.mask_unix_sock {
info!("Mask: {} -> unix:{}", config.censorship.mask, sock);

164
src/protocol/tls.rs
View File

@ -32,6 +32,7 @@ pub const TIME_SKEW_MAX: i64 = 10 * 60; // 10 minutes after
mod extension_type {
pub const KEY_SHARE: u16 = 0x0033;
pub const SUPPORTED_VERSIONS: u16 = 0x002b;
pub const ALPN: u16 = 0x0010;
}
/// TLS Cipher Suites
@ -62,6 +63,7 @@ pub struct TlsValidation {
// ============= TLS Extension Builder =============
/// Builder for TLS extensions with correct length calculation
#[derive(Clone)]
struct TlsExtensionBuilder {
extensions: Vec<u8>,
}
@ -108,6 +110,27 @@ impl TlsExtensionBuilder {
self
}
/// Add ALPN extension with a single selected protocol.
fn add_alpn(&mut self, proto: &[u8]) -> &mut Self {
// Extension type: ALPN (0x0010)
self.extensions.extend_from_slice(&extension_type::ALPN.to_be_bytes());
// ALPN extension format:
// extension_data length (2 bytes)
// protocols length (2 bytes)
// protocol name length (1 byte)
// protocol name bytes
let proto_len = proto.len() as u8;
let list_len: u16 = 1 + proto_len as u16;
let ext_len: u16 = 2 + list_len;
self.extensions.extend_from_slice(&ext_len.to_be_bytes());
self.extensions.extend_from_slice(&list_len.to_be_bytes());
self.extensions.push(proto_len);
self.extensions.extend_from_slice(proto);
self
}
/// Build final extensions with length prefix
fn build(self) -> Vec<u8> {
@ -144,6 +167,8 @@ struct ServerHelloBuilder {
compression: u8,
/// Extensions
extensions: TlsExtensionBuilder,
/// Selected ALPN protocol (if any)
alpn: Option<Vec<u8>>,
}
impl ServerHelloBuilder {
@ -154,6 +179,7 @@ impl ServerHelloBuilder {
cipher_suite: cipher_suite::TLS_AES_128_GCM_SHA256,
compression: 0x00,
extensions: TlsExtensionBuilder::new(),
alpn: None,
}
}
@ -167,10 +193,19 @@ impl ServerHelloBuilder {
self.extensions.add_supported_versions(0x0304);
self
}
fn with_alpn(mut self, proto: Option<Vec<u8>>) -> Self {
self.alpn = proto;
self
}
/// Build ServerHello message (without record header)
fn build_message(&self) -> Vec<u8> {
let extensions = self.extensions.extensions.clone();
let mut ext_builder = self.extensions.clone();
if let Some(ref alpn) = self.alpn {
ext_builder.add_alpn(alpn);
}
let extensions = ext_builder.extensions.clone();
let extensions_len = extensions.len() as u16;
// Calculate total length
@ -350,6 +385,8 @@ pub fn build_server_hello(
session_id: &[u8],
fake_cert_len: usize,
rng: &SecureRandom,
alpn: Option<Vec<u8>>,
new_session_tickets: u8,
) -> Vec<u8> {
const MIN_APP_DATA: usize = 64;
const MAX_APP_DATA: usize = 16640; // RFC 8446 §5.2 upper bound
@ -360,6 +397,7 @@ pub fn build_server_hello(
let server_hello = ServerHelloBuilder::new(session_id.to_vec())
.with_x25519_key(&x25519_key)
.with_tls13_version()
.with_alpn(alpn)
.build_record();
// Build Change Cipher Spec record
@ -380,13 +418,31 @@ pub fn build_server_hello(
// deterministic DPI fingerprints (fixed inner content type markers).
app_data_record.extend_from_slice(&fake_cert);
// Build optional NewSessionTicket records (TLS 1.3 handshake messages are encrypted;
// here we mimic with opaque ApplicationData records of plausible size).
let mut tickets = Vec::new();
if new_session_tickets > 0 {
for _ in 0..new_session_tickets {
let ticket_len: usize = rng.range(48) + 48; // 48-95 bytes
let mut record = Vec::with_capacity(5 + ticket_len);
record.push(TLS_RECORD_APPLICATION);
record.extend_from_slice(&TLS_VERSION);
record.extend_from_slice(&(ticket_len as u16).to_be_bytes());
record.extend_from_slice(&rng.bytes(ticket_len));
tickets.push(record);
}
}
// Combine all records
let mut response = Vec::with_capacity(
server_hello.len() + change_cipher_spec.len() + app_data_record.len()
server_hello.len() + change_cipher_spec.len() + app_data_record.len() + tickets.iter().map(|r| r.len()).sum::<usize>()
);
response.extend_from_slice(&server_hello);
response.extend_from_slice(&change_cipher_spec);
response.extend_from_slice(&app_data_record);
for t in &tickets {
response.extend_from_slice(t);
}
// Compute HMAC for the response
let mut hmac_input = Vec::with_capacity(TLS_DIGEST_LEN + response.len());
@ -480,85 +536,53 @@ pub fn extract_sni_from_client_hello(handshake: &[u8]) -> Option<String> {
None
}
/// Extract ALPN protocol list from TLS ClientHello.
pub fn extract_alpn_from_client_hello(handshake: &[u8]) -> Option<Vec<String>> {
if handshake.len() < 43 || handshake[0] != TLS_RECORD_HANDSHAKE {
return None;
}
/// Extract ALPN protocol list from ClientHello, return in offered order.
pub fn extract_alpn_from_client_hello(handshake: &[u8]) -> Vec<Vec<u8>> {
let mut pos = 5; // after record header
if handshake.get(pos).copied()? != 0x01 {
return None; // not ClientHello
if handshake.get(pos) != Some(&0x01) {
return Vec::new();
}
// Handshake length bytes
pos += 4; // type + len (3)
// version (2) + random (32)
pos += 2 + 32;
if pos + 1 > handshake.len() {
return None;
}
let session_id_len = *handshake.get(pos)? as usize;
pos += 4; // type + len
pos += 2 + 32; // version + random
if pos >= handshake.len() { return Vec::new(); }
let session_id_len = *handshake.get(pos).unwrap_or(&0) as usize;
pos += 1 + session_id_len;
if pos + 2 > handshake.len() {
return None;
}
let cipher_suites_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
pos += 2 + cipher_suites_len;
if pos + 1 > handshake.len() {
return None;
}
let comp_len = *handshake.get(pos)? as usize;
if pos + 2 > handshake.len() { return Vec::new(); }
let cipher_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
pos += 2 + cipher_len;
if pos >= handshake.len() { return Vec::new(); }
let comp_len = *handshake.get(pos).unwrap_or(&0) as usize;
pos += 1 + comp_len;
if pos + 2 > handshake.len() {
return None;
}
let ext_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
if pos + 2 > handshake.len() { return Vec::new(); }
let ext_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
pos += 2;
let ext_end = pos + ext_len;
if ext_end > handshake.len() {
return None;
}
if ext_end > handshake.len() { return Vec::new(); }
let mut out = Vec::new();
while pos + 4 <= ext_end {
let etype = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]);
let elen = u16::from_be_bytes([handshake[pos + 2], handshake[pos + 3]]) as usize;
let etype = u16::from_be_bytes([handshake[pos], handshake[pos+1]]);
let elen = u16::from_be_bytes([handshake[pos+2], handshake[pos+3]]) as usize;
pos += 4;
if pos + elen > ext_end {
if pos + elen > ext_end { break; }
if etype == extension_type::ALPN && elen >= 3 {
let list_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
let mut lp = pos + 2;
let list_end = (pos + 2).saturating_add(list_len).min(pos + elen);
while lp + 1 <= list_end {
let plen = handshake[lp] as usize;
lp += 1;
if lp + plen > list_end { break; }
out.push(handshake[lp..lp+plen].to_vec());
lp += plen;
}
break;
}
if etype == 0x0010 && elen >= 3 {
// ALPN
let list_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
let mut alpn_pos = pos + 2;
let list_end = std::cmp::min(alpn_pos + list_len, pos + elen);
let mut protocols = Vec::new();
while alpn_pos < list_end {
let proto_len = *handshake.get(alpn_pos)? as usize;
alpn_pos += 1;
if alpn_pos + proto_len > list_end {
break;
}
if let Ok(p) = std::str::from_utf8(&handshake[alpn_pos..alpn_pos + proto_len]) {
protocols.push(p.to_string());
}
alpn_pos += proto_len;
}
return Some(protocols);
}
pos += elen;
}
None
out
}
/// Check if bytes look like a TLS ClientHello
pub fn is_tls_handshake(first_bytes: &[u8]) -> bool {
if first_bytes.len() < 3 {
@ -737,7 +761,7 @@ mod tests {
let session_id = vec![0xAA; 32];
let rng = SecureRandom::new();
let response = build_server_hello(secret, &client_digest, &session_id, 2048, &rng);
let response = build_server_hello(secret, &client_digest, &session_id, 2048, &rng, None, 0);
// Should have at least 3 records
assert!(response.len() > 100);
@ -770,8 +794,8 @@ mod tests {
let session_id = vec![0xAA; 32];
let rng = SecureRandom::new();
let response1 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
let response2 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
let response1 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng, None, 0);
let response2 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng, None, 0);
// Digest position should have non-zero data
let digest1 = &response1[TLS_DIGEST_POS..TLS_DIGEST_POS + TLS_DIGEST_LEN];

36
src/proxy/handshake.rs
View File

@ -7,6 +7,7 @@ use tracing::{debug, warn, trace, info};
use zeroize::Zeroize;
use crate::crypto::{sha256, AesCtr, SecureRandom};
use rand::Rng;
use crate::protocol::constants::*;
use crate::protocol::tls;
use crate::stream::{FakeTlsReader, FakeTlsWriter, CryptoReader, CryptoWriter};
@ -119,6 +120,23 @@ where
None
};
let alpn_list = if config.censorship.alpn_enforce {
tls::extract_alpn_from_client_hello(handshake)
} else {
Vec::new()
};
let selected_alpn = if config.censorship.alpn_enforce {
if alpn_list.iter().any(|p| p == b"h2") {
Some(b"h2".to_vec())
} else if alpn_list.iter().any(|p| p == b"http/1.1") {
Some(b"http/1.1".to_vec())
} else {
None
}
} else {
None
};
let response = if let Some(cached_entry) = cached {
emulator::build_emulated_server_hello(
secret,
@ -126,6 +144,8 @@ where
&validation.session_id,
&cached_entry,
rng,
selected_alpn.clone(),
config.censorship.tls_new_session_tickets,
)
} else {
tls::build_server_hello(
@ -134,9 +154,25 @@ where
&validation.session_id,
config.censorship.fake_cert_len,
rng,
selected_alpn.clone(),
config.censorship.tls_new_session_tickets,
)
};
// Optional anti-fingerprint delay before sending ServerHello.
if config.censorship.server_hello_delay_max_ms > 0 {
let min = config.censorship.server_hello_delay_min_ms;
let max = config.censorship.server_hello_delay_max_ms.max(min);
let delay_ms = if max == min {
max
} else {
rand::rng().random_range(min..=max)
};
if delay_ms > 0 {
tokio::time::sleep(std::time::Duration::from_millis(delay_ms)).await;
}
}
debug!(peer = %peer, response_len = response.len(), "Sending TLS ServerHello");
if let Err(e) = writer.write_all(&response).await {

28
src/tls_front/emulator.rs
View File

@ -34,6 +34,8 @@ pub fn build_emulated_server_hello(
session_id: &[u8],
cached: &CachedTlsData,
rng: &SecureRandom,
alpn: Option<Vec<u8>>,
new_session_tickets: u8,
) -> Vec<u8> {
// --- ServerHello ---
let mut extensions = Vec::new();
@ -48,6 +50,15 @@ pub fn build_emulated_server_hello(
extensions.extend_from_slice(&0x002bu16.to_be_bytes());
extensions.extend_from_slice(&(2u16).to_be_bytes());
extensions.extend_from_slice(&0x0304u16.to_be_bytes());
if let Some(alpn_proto) = &alpn {
extensions.extend_from_slice(&0x0010u16.to_be_bytes());
let list_len: u16 = 1 + alpn_proto.len() as u16;
let ext_len: u16 = 2 + list_len;
extensions.extend_from_slice(&ext_len.to_be_bytes());
extensions.extend_from_slice(&list_len.to_be_bytes());
extensions.push(alpn_proto.len() as u8);
extensions.extend_from_slice(alpn_proto);
}
let extensions_len = extensions.len() as u16;
@ -118,10 +129,25 @@ pub fn build_emulated_server_hello(
}
// --- Combine ---
let mut response = Vec::with_capacity(server_hello.len() + change_cipher_spec.len() + app_data.len());
// Optional NewSessionTicket mimic records (opaque ApplicationData for fingerprint).
let mut tickets = Vec::new();
if new_session_tickets > 0 {
for _ in 0..new_session_tickets {
let ticket_len: usize = rng.range(48) + 48;
let mut rec = Vec::with_capacity(5 + ticket_len);
rec.push(TLS_RECORD_APPLICATION);
rec.extend_from_slice(&TLS_VERSION);
rec.extend_from_slice(&(ticket_len as u16).to_be_bytes());
rec.extend_from_slice(&rng.bytes(ticket_len));
tickets.extend_from_slice(&rec);
}
}
let mut response = Vec::with_capacity(server_hello.len() + change_cipher_spec.len() + app_data.len() + tickets.len());
response.extend_from_slice(&server_hello);
response.extend_from_slice(&change_cipher_spec);
response.extend_from_slice(&app_data);
response.extend_from_slice(&tickets);
// --- HMAC ---
let mut hmac_input = Vec::with_capacity(TLS_DIGEST_LEN + response.len());

6
src/transport/middle_proxy/pool.rs
View File

@ -567,12 +567,14 @@ impl MePool {
let cancel_keepalive = cancel_keepalive_token;
tokio::spawn(async move {
// Per-writer jittered start to avoid phase sync.
let initial_jitter_ms = rand::rng().random_range(0..=keepalive_jitter.as_millis().max(1) as u64);
let jitter_cap_ms = keepalive_interval.as_millis() / 2;
let effective_jitter_ms = keepalive_jitter.as_millis().min(jitter_cap_ms).max(1);
let initial_jitter_ms = rand::rng().random_range(0..=effective_jitter_ms as u64);
tokio::time::sleep(Duration::from_millis(initial_jitter_ms)).await;
loop {
tokio::select! {
_ = cancel_keepalive.cancelled() => break,
_ = tokio::time::sleep(keepalive_interval + Duration::from_millis(rand::rng().random_range(0..=keepalive_jitter.as_millis() as u64))) => {}
_ = tokio::time::sleep(keepalive_interval + Duration::from_millis(rand::rng().random_range(0..=effective_jitter_ms as u64))) => {}
}
if tx_keepalive.send(WriterCommand::Keepalive).await.is_err() {
break;