The core bug: server sent 5 TLS records in server_hello but client only
read the first one (ServerHello), then passed remaining bytes (CCS + fake
records) into RealityStream. RealityStream saw 0x14 (CCS) != 0x17 and
immediately returned an error, killing the connection.
Changes:
- reality.rs: append ChangeCipherSpec after ClientHello (RFC 8446 D.4)
export REALITY_SERVER_HANDSHAKE_RECORDS=5 constant
- xhttp.rs: drain all 5 server handshake records before creating RealityStream
- uot.rs: rebuild server_hello as proper 5-record TLS 1.3 flight:
ServerHello + CCS + fake EE (108B) + fake Cert (812B) + fake Fin (52B)
drain client CCS from raw stream before wrapping in RealityStream
- Boxed HandshakeState in NoiseSession to reduce enum variant sizes
- Used is_ok() instead of let Ok(_) pattern
- Applied automatic clippy fixes for minor warnings
8 new integration tests in ostp-core::protocol::tests:
- test_full_handshake: Noise handshake -> Established state
- test_data_exchange_client_to_server: encrypt/decrypt data frame C->S
- test_data_exchange_server_to_client: encrypt/decrypt data frame S->C
- test_close_sequence: Close frame -> Closed state
- test_wrong_psk_handshake_fails: bad PSK rejected, never reaches Established
- test_congestion_controller_after_handshake: CC budget >= 2 in SlowStart
- test_multiple_data_frames: 10 sequential frames, payload integrity verified
- test_tick_no_crash: Tick event stable on both sides
Total: 43 tests, 0 failures
TUN Interface:
- Fixed adapter name to always be 'ostp_tun' by cleaning up stale
adapters before launch (prevents 'ostp_tun 2', 'ostp_tun 3', etc.)
- Parallelized route setup with tun2socks launch to save ~3 seconds
- Replaced fixed 2-second sleep with adapter readiness polling
- Added -NoProfile to all PowerShell calls for faster execution
Speed:
- Reduced handshake timeout from 10s to 5s
- Reduced tun2socks spawn buffer from 300ms to 0 (removed)
GUI:
- Added i18n support: English and Russian translations
- Language toggle button in header (EN/RU)
- Merged 'IP Ranges' field into 'Bypass IPs / CIDR Ranges'
- Removed separate IP ranges field
- All static text uses data-i18n attributes
- Status messages, labels, toasts all translated
- Replaced alert() calls with toast notifications
CI/CD:
- Added separate GUI build job for Windows x64 and arm64
- Produces ostp-windows-gui-{arch}.zip with: ostp-gui.exe + wintun.dll + tun2socks.exe
- Uses Tauri CLI v2 for build
Applied Kerckhoffs's principle: the protocol's security and obfuscation
now depend SOLELY on the access key. An adversary who reverse-engineers
the binary cannot build a DPI filter without knowing the key.
Changes:
- Replaced hardcoded salt string ('-ostp-psk-salt') with HKDF-SHA256.
The salt is now derived from the key hash itself — no protocol-specific
strings remain in the binary.
- Unified all secret derivation into derive_all_secrets() which produces
PSK, obfuscation key, and handshake padding range from a single HKDF
invocation.
- Handshake padding range is now key-derived: different access keys
produce different size distributions (min: 16-79, max: +48..+175).
A universal size-based filter is impossible without the key.
- HKDF-SHA256 (RFC 5869) implemented inline using existing hmac+sha2
dependencies — no new crate required.
What remains identifiable in the binary:
- 'Noise_NNpsk0_25519_ChaChaPoly_BLAKE2s' — standard Noise pattern
string, shared with many other projects, NOT OSTP-specific.
- Generic HMAC/SHA-256/ChaCha20-Poly1305 code — standard crypto
primitives used by millions of applications.
Previously handshake obfuscation used a FIXED mask derived from
HMAC(obf_key, u64::MAX). This meant bytes [4..6] (noise_len XOR
fixed_mask) produced the SAME 2-byte value on every handshake from
the same access key — a correlation fingerprint for DPI.
Now BOTH data and handshake packets use the same payload-sampling
approach:
mask = HMAC-SHA256(obf_key, payload_sample[0..32])
For data packets: payload_sample = AEAD ciphertext (random per packet)
For handshake packets: payload_sample = Noise ephemeral key (random per connection)
Result: every single byte on the wire is cryptographically independent
across packets. No fixed patterns, no correlation between connections.
Wire analysis after this change:
- Packet sizes: random (84-182 for handshake, variable for data)
- All header bytes: unique per packet (XOR with unique HMAC mask)
- Payload bytes: AEAD ciphertext / Noise handshake (indistinguishable from random)
- No protocol signatures, no version fields, no magic bytes visible on wire
The previous commit added random padding after Noise handshake payloads
but the receiver passed the entire raw buffer (including padding) to
snow::read_handshake(), which cannot handle trailing bytes.
New wire format:
[session_id:4][noise_len:2][noise_payload:N][random_padding:32-128]
Changes:
- wrap_datagram_handshake: puts noise_len (u16 BE) at bytes [4..6]
before the Noise payload, followed by 32-128 random padding bytes
- handle_inbound: reads noise_len from [4..6], passes only
raw_vec[6..6+noise_len] to snow, ignoring trailing padding
- obfuscation: handshake mask extended from 4 to 6 bytes to also
cover the noise_len field (prevents DPI from seeing constant u16)
- dispatcher: key-trial loop updated to deobfuscate 6-byte header
Both client and server now produce/consume the same padded format.
DPI/TSPU resistance:
- Handshake packets now padded with 32-128 random bytes (prevents size
fingerprinting — previously every handshake was exactly 52 bytes)
- Frame header reserved bytes randomized instead of always 0 (prevents
known-plaintext oracle inside encrypted payload)
- Padding jitter cap increased from 96 to 256 bytes for better traffic
pattern masking
GUI Windows app (tunnel/proxy not starting):
- CRITICAL: Added CREATE_NO_WINDOW flag to all reg.exe calls in sysproxy.rs.
In Tauri GUI context (no console window), Command::new('reg') was silently
failing because there was no attached console. This prevented the Windows
system proxy from being enabled.
- Added ProxyOverride bypass list (localhost;127.*;10.*;192.168.*;<local>)
to prevent proxy loop for local traffic
- Added comprehensive logging for all registry operations
- Set initial connection_state to 1 (connecting) instead of 0 — prevents
UI polling from immediately flipping back to 'disconnected' before the
handshake has a chance to begin
Code quality:
- Fixed log file paths: log_to_core_file() and log_to_file() now write next
to the executable instead of CWD. In GUI context, CWD could be
C:\Windows\System32, causing write failures or misplaced log files.
- Removed stale KeyExchange re-export from crypto/mod.rs (kex.rs
only exports HybridSharedSecret and HybridKex after stub refactor)
- Removed unused imports in ostp-server/lib.rs (AsyncWriteExt,
tcp::OwnedWriteHalf)
- Suppressed dead_code warning on HelperMsg::Log variant (IPC spec)
- Verified: cargo check passes with zero errors and zero warnings
Critical fixes (6):
- protocol.rs: in_flight_count() now counts only retransmittable Data frames,
not Ack/Nack control frames — eliminates false backpressure under load
- protocol.rs: NACK is now rate-limited to once per 30ms — prevents
retransmission storm during normal UDP jitter
- protocol.rs: zombie frames exceeding max_retries+4 are evicted each tick —
prevents unbounded memory growth and stale retransmits
- protocol.rs: Closing state now processes final in-flight packets instead
of silently dropping them — prevents data loss at session teardown
- server/lib.rs: stream_tx changed from bounded(10000) to unbounded_channel —
prevents TCP-reader collapse during Speedtest with 50+ streams
- bridge.rs: liveness timeout raised from 30s to 60s — prevents false
reconnect during heavy Speedtest load
Medium fixes (8):
- protocol.rs: ACK range truncation preserves cumulative range (index 0)
- bridge.rs: Ping now uses send_datagram() for correct TURN wrapping
- dispatcher.rs: replay_cache hard-capped at 100k entries (DoS protection)
- dispatcher.rs: old addr cleaned from addr_to_session on roaming
- server/lib.rs: TCP connect_target() now has 10s timeout
- config.rs: TURN section parsed during hot-reload
- proxy.rs: HTTP header parsing uses 512-byte chunks instead of 1-byte reads
- proxy.rs: stream_id wrap-around skips active IDs to prevent collision
- runner.rs: is_essential_log matches actual log strings from bridge.rs
Other:
- kex.rs: clearly marked as dead PQ stub (not used by protocol)
- README.md + README.ru.md: complete rewrite with architecture diagram
- docs/en/specification.md: updated ARQ section with all new semantics
ospab