- Karn's algorithm: drop_acked_frames no longer samples RTT from frames
that were retransmitted (last_sent is bumped on each retransmit, so an
ACK for the original transmission would measure a spuriously small RTT
and drag SRTT/RTO down). Added CongestionController::on_ack_no_rtt for
the case where every acked frame was ambiguous, so the window still
advances without polluting the RTT estimator. Refactored the shared
window-growth into grow_window.
- Frame decode: header+payload+pad length now uses checked_add. payload_len
is a u32 from the header and on 32-bit targets (MIPS/ARMv7 routers are
supported) the sum could wrap usize and slip past the truncation check.
- Replay cache: a full cache used to reject ALL new handshakes globally
until the next tick, letting one flooding key-holder deny service to
everyone. Now it reclaims expired entries and, if still full, evicts the
single oldest — new handshakes always get in. Fixed the mislabelled
"100000" log (cap is 50000) and named it REPLAY_CACHE_MAX.
The resumption module (SessionTicket/TicketValidator) was never wired into
the client or server — nothing issued or validated tickets, and no Resume
frame was ever sent. But it "encrypted" tickets by XOR-ing them with a
single static keystream SHA256(psk || const) and had no MAC (despite a doc
comment claiming HMAC): a textbook many-time-pad, trivially broken from a
couple of captured tickets, and malleable. Leaving it in-tree invited
someone to wire up a broken 0-RTT path later.
Removed the module, its FrameKind::Resume wire variant, and the protocol
handler for it. 0-RTT can be reintroduced later on a real AEAD-sealed
ticket if desired.
Two classes of issue:
- Hot-path/attacker-triggerable events logged at info/error with internal
detail: a per-handshake info! byte dump (raw_vec[0..6]) and a per-packet
error! on session-id mismatch that dumped expected/got session ids.
Both are log-flood + info-leak surfaces; downgraded to debug and
stripped of the sensitive detail. Close/Resume frame handling likewise
moved from info to debug.
- The access key (a shared secret) was written to logs verbatim in three
places (session drop, key-created UI event, API create-user) and as an
8-char prefix in one. Added key_fp() — a short SHA-256 fingerprint — and
routed all key logging through it so operators can still correlate
events without the secret ever hitting the log.
Every datagram from an unrecognized source ran the full key-trial loop:
for each registered access key, an HKDF (derive_all_secrets) plus two
HMACs (junk markers) plus a Noise read. A garbage flood from spoofed
sources could therefore force unbounded O(N_keys) crypto per packet — a
CPU-amplification DoS with no throttle (the existing token bucket only
guarded the roaming path, not this one).
Two mitigations:
- Memoize the per-key derived secrets (pure function of key+version) and
the per-window junk markers, so the trial loop is now cheap comparisons
plus one Noise read per key instead of HKDF+2*HMAC per key per packet.
Also speeds up every legitimate new connection. Caches are pruned in
on_tick when keys are deleted.
- Gate the trial path behind a global token bucket (TRIAL_RATE=100/s,
same burst). The established-session fast path and roaming are not
gated, so live sessions are unaffected; only unknown-datagram trials
are bounded. Over-budget datagrams are dropped silently.
CRITICAL forward-secrecy fix. Session transport keys were derived as
SHA256(get_handshake_hash() || label). The Noise handshake hash `h` only
ever absorbs PUBLIC transcript data (ephemeral pubkeys + on-wire
ciphertexts, via MixHash); the ephemeral ee DH result is mixed via MixKey
into the chaining key `ck` ONLY, never into `h` (confirmed in snow 0.9.6
symmetricstate.rs). So the data-transport keys depended on the PSK and the
public transcript but NOT on the DH secret, meaning:
- zero forward secrecy: anyone who later learns the access-key PSK can
decrypt all recorded past sessions from the observed handshake alone;
- any PSK holder can passively decrypt any other session on that key;
- the ephemeral Diffie-Hellman was cryptographically wasted.
Fix: take the two directional keys from Noise's Split() over the final `ck`
via snow's dangerously_get_raw_split (risky-raw-split feature). These keys
depend on ee, restoring forward secrecy. The custom out-of-order AEAD,
explicit nonces, session_id AAD, framing and reordering are all unchanged
- only the key SOURCE moved. The dead into_transport()/handshake_hash()
paths and the unreachable NoiseSession::Transport variant are removed.
Wire-breaking: PROTOCOL_VERSION 4 -> 5 so pre-fix peers derive different
keys and cannot interop (version gate is invisible on the wire).
Added noise unit tests for the .0/.1 -> send/recv role mapping and the
not-finished guard.
The junk marker was a per-key CONSTANT sent in plaintext at a fixed offset in
junk frames. Junk is meant to look like random noise (zapret-style), but a
constant prefix is a recognizable per-user structure: an on-path observer
watching one user sees the same 4 bytes on every junk packet, i.e. an OSTP
fingerprint. (The earlier fix only removed the GLOBAL constant.)
Now the marker rotates every 60s window: junk_marker = HKDF(key, ver, 0x04 ||
window). To an observer the prefix changes each window (no fixed signature),
and a captured marker is only valid for ~1 window — the "bit of protection"
against a leaked marker. Only a key holder can compute it, so an outsider still
can't forge a silently-dropped junk packet (and silent-drop is cheaper than
normal processing anyway, so junk spam was never a DoS lever to begin with).
- core: derive_junk_marker(key, window) + current_junk_window() (60s window),
same version-gated HKDF scheme; junk_marker dropped from DerivedSecrets.
- client: stamps junk with the current window's marker.
- server: checks current AND previous window per key (absorbs ~1 window of
clock skew) before falling through to unauthorized-probe handling.
- Not a wire break: only junk framing changes; real handshake/data untouched.
During mixed rollout, unmatched junk merely logs as a probe (cosmetic).
security / protocol:
- Derive a PER-KEY junk marker (obfuscation.rs, info byte 0x04) instead of the
global constant [0x88,0x1A,0x93,0x5D]. A fixed marker was a universal DPI
signature identifying ALL OSTP users at once — exactly what the HKDF version
gate avoids for the handshake. Server drops junk via a new DispatchOutcome::Junk
inside the existing key-trial loop (secrets already derived → zero extra cost);
client stamps its own key's marker.
- §E: configurable junk/fragmentation params (junk_pc / junk_ps / frag_chunk / frag_sleep).
GUI (desktop):
- Light theme + toggle, GUI version footer in Settings.
- Fix mouse-wheel scroll on Settings (flex child needed min-height: 0).
- Drop the false "process exclusions unsupported in TUN mode" warning — they DO
work (native_handler maps port->process via GetExtendedTcpTable).
release / infra:
- build.ps1: add -PreRelease (tag CURRENT version as v<ver>-beta.N, no bump, no
master commit); guard the panel build when ostp-control ships no source; bump
the real ostp-gui/package.json instead of the nonexistent ostp-control one.
- release.yml: mark hyphenated tags as GitHub pre-releases; don't hard-fail the
web-panel step when there is no source (use committed dist/).
- Versions aligned to 0.4.1; README license badge BSL 1.1 -> AGPL v3.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
In the Closing state the old code force-transitioned to Closed after a
SINGLE inbound packet, so any data/ACKs the peer still had in flight when we
initiated Close were dropped (Closed returns Noop for everything). Stay in
Closing and process inbound normally; handle_inbound already owns the
Close->Closed transition when it actually receives the peer's Close frame.
Also handle Tick in Closing so our own Close frame is retransmitted until
acknowledged.
Ported surgically from 47d44fa — only the Closing-state correctness fix, NOT
that commit's bundled RFC-6298 RTO / congestion rewrite (a behavioural change
to the working base) or the sent_history BTreeMap perf swap (broad hot-path
change for a perf-only gain). cargo test -p ostp-core: 36/36 incl.
test_close_sequence.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The base already derives all secrets from the access key, so derived
secrets were never the gap — the gap was that nothing distinguished a
current handshake from an older-format one, so an old client could still
connect to a new server.
Rather than the plan's literal "plaintext version byte before the crypto
layer" (which would add a constant, DPI-visible marker and defeat the
project's stealth north-star), fold the version INTO the HKDF derivation:
- Add PROTOCOL_VERSION (= 4 for 0.4.0), mixed into the IKM of
derive_all_secrets so a different version yields a completely different
obfuscation key / psk / padding. No marker ever appears on the wire —
the output stays indistinguishable from random.
- A pre-0.4.0 peer derives a different obfuscation key, so the 0.4.0
server cannot recover its handshake header and drops it as an
unauthorized probe. Bump PROTOCOL_VERSION on any future wire break.
Verified:
- cargo test -p ostp-core: 36/36 incl. new test_protocol_version_gates_
old_clients (old-version obf key does NOT recover the session_id).
- Loopback E2E: new client <-> new server connects and tunnels HTTPS
(curl via SOCKS5 returns egress IP).
- Old v0.2.98 client vs new server: handshake times out / aborts, server
accepts 0 clients — exactly the plan's §C criterion.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Clean-rebuild on the stably-working v0.2.98 base. The project's stealth
path is zapret-like (packet obfuscation / junk / fragmentation), NOT
TLS-mimicry, so WSS and Reality are dropped entirely.
- Delete dead orphan files: ostp-client/src/transport/xhttp.rs and
ostp-core/src/crypto/reality.rs (never declared as modules → not even
compiled), plus ostp-core/src/framing/wss.rs.
- Scrub the `wss` transport field from client config/bridge, the unified
CLI (ostp/src/main.rs), the Tauri GUI backend, the GUI frontend
(index.html/main.js), and the Flutter UI; also drop the Reality
pbk/sid plumbing and XTLS auto-search modes from both frontends.
- Drop now-unused client deps (x25519-dalek, chacha20poly1305, hex).
- Bump workspace to version 0.4.0 and license AGPL-3.0; make ostp's
ostp-core dep path-only so the version bump resolves.
- gitignore ostp-control/ (panel assets built separately; a dummy dist
is created for the rust-embed build).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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
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