Syna Security & License Audit Report
Version audited: v0.9.1 (candidate) Date: 2026-08-10 Scope: full codebase (common / Android / desktop / server / native NDK / tests)
1. Code review & bug-fix summary
Three independent review passes (network/protocol, storage/UI/voice, Shield/server) plus verification against the full test suite. ~60 confirmed issues found; all fixed.
Critical fixes (data safety & lockout)
| # | Issue | Fix |
|---|---|---|
| 1 | TOTP seed / key pins / audit / fail-counter encrypted with the session key — after lock-out (no session key) 2FA verification, TOFU checks and audit loading could never decrypt → permanent 2FA lockout | New encryptWithMaster/decryptWithMaster channel; all metadata now uses the master key (Keystore) — data files keep session-key gating |
| 2 | Honeypot decoy write did rewriteNow() with empty memory → overwrote real chat history permanently | Decoy only rewrites disk when real messages exist in memory (hasMessagesInMemory), else memory-only |
| 3 | burnSweepMarks was never written → the 60 s burn TTL fallback was dead code (unviewed burn messages never destroyed) | Marks written on enqueue |
| 4 | Server-history replay was killed by the replay guard (join → old history invisible) | routeServerFrame(..., fromHistory = true) bypasses replay for persisted history |
| 5 | Mesh group file transfer misdetected as "server group disconnected" → group files never sent | Server-group detection now uses explicit serverGroupId |
| 6 | ACK retransmission counter was reset to 0 on every recursion → infinite retransmission; ACK race could resurrect the entry; TEXT never used ACK at all | Insert-once + recheck-before-resend + TEXT wired into ACK/retry |
| 7 | UDP key exchange sent to a dead default port (45878) → encryption could never establish in UDP mode | Key frames carry the announcement's real UDP port |
| 8 | 64 KB file chunks exceed the 65 KB UDP payload → UDP file transfer unusable | Chunk size 40 KB in UDP mode |
| 9 | Debounced rewrite could overwrite disk with empty memory during the 500 ms window (lock/memory-wipe) → history wipe | rewriteJob cancelled in releaseMemory |
| 10 | Burn-purge path never persisted → destroyed messages resurrected on restart | scheduleRewrite added to remove/purge paths |
Shield & state machine
| # | Issue | Fix |
|---|---|---|
| 11 | Devices without biometrics: every unlock tap counted as brute-force → 5 taps = self-destruct | ERROR_NO_BIOMETRICS/HW_UNAVAILABLE/NO_DEVICE_CREDENTIAL no longer counted |
| 12 | disablePending residue: unlock after an interrupted disable flow silently turned the Shield off | Any new LOCKED transition clears the disable flow |
| 13 | WATCHDOG_TRIP never cleared → permanent 30 s re-lock loop | Auto-cleared when the heartbeat recovers (3 s) |
| 14 | Self-destruct order: audit event written after the file wipe → audit "resurrected" with a recreated key | Shield disabled at the end of full destruct; key pins & voice cache added to wipe list |
| 15 | Screen-capture callback unregister was a no-op (activity nulled first) | Order fixed |
| 16 | Group admins could promote/demote admins & kick the creator (privilege escalation) | SET_ADMIN/REMOVE_ADMIN creator-only on both ends; creator protected |
| 17 | verifyIdentity no-op when Shield disabled → burn messages un-sendable | Null-safe fallthrough |
| 18 | Burn send verification failure still cleared the input | Input cleared only inside doSend |
| 19 | Voice recording: no cleanup path (microphone leak, unbounded WAV buffer on desktop) | DisposableEffect cancels recording; start-failure handled; AMR-on-desktop play gives explicit notice |
Server
| # | Issue | Fix |
|---|---|---|
| 20 | Zombie sessions (no read timeout) could exhaust the connection cap | 180 s read timeout |
| 21 | Kick only closed the first session of a multi-session user | All sessions kicked |
| 22 | Any member could forge from = groupId (server impersonation) | Relay requires from == authenticated userId |
| 23 | BURN_ACK could purge any message; RECALL could recall anyone's message | Ownership + burn-type checks |
| 24 | SRV_AUTH_OK history read unsynchronized → CME crashed joins | Locked snapshot |
| 25 | Expired burn history visible for the first hour after start | Immediate sweep on boot |
Robustness
fileAssemblers→ concurrent map; watchdog cascade trip fixed;ShieldGate.beatatomic; persistence writes mutexed (random tmp suffix) +fd.sync;MAGICboundary;openflag volatile; outbox flush semantics; UDP send exception guard;removeMessageByIdCAS; purge paths persist.
2. License (contamination) audit
Result: CLEAN — no license contamination
| Check | Result |
|---|---|
| Direct & transitive runtime dependencies | 100% Apache-2.0 (JetBrains Kotlin/Compose, androidx, com.russhwolf:multiplatform-settings, com.google.guava:listenablefuture, org.jspecify:jspecify) |
| Copyleft (AGPL/GPL/LGPL) dependencies | None |
| Native toolchain (NDK / CMake) | Apache-2.0 tooling, no runtime linkage |
| In-tree third-party code | None — SHA-256, base32, TOTP, native anti-hook layer, voice recorders all original |
| Icon assets | assets/icons/Syna_logo_2.png (user-provided project asset) |
| License file | LICENSE — GPL-3.0 full text present |
| SPDX headers | All source files carry SPDX-License-Identifier: GPL-3.0-only (3 test files were missing headers — fixed) |
| AI-generated-code notice | README notice present |
GPL-3.0 compatibility note: Apache-2.0 dependencies are compatible with a GPL-3.0 project (GPL-3.0 may link Apache-2.0 code; the reverse direction would be the concern, which does not apply here).
3. Test status
- 76/76 automated tests passing (serial execution; multicast flakiness eliminated)
- Coverage includes: ACK flow, group admin (kick/mute/admins), TOFU pin/reject/retrust,
TOTP vectors + 2FA flow, hash-chain tamper, gate fail-closed, honeypot, brute-force, watchdog, burn/temp chat, server join/kick/ban, file transfer, offline outbox.