molluskandClaude Opus 4.8
3034c42f71
Documents the focused security review of the protocol-versioning migration and the cargo-deny policy addition. Result: no high-confidence vulnerabilities — the versioned_topic XOR transform is entropy-preserving, signature binding uses the raw topic_id consistently, and the ALPN/domain changes are handshake-level compatibility only. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2.4 KiB
Security Review: security-scan branch (PeerSpeak)
Date: 2026-06-18
Scope: Protocol-versioning migration (src/protocol.rs, versioned_topic,
ALPN/domain centralization, gossip topic namespacing) and the deny.toml
supply-chain policy addition.
Result: No high-confidence security vulnerabilities found.
Each plausible attack surface introduced by this branch was investigated and confirmed safe:
1. versioned_topic XOR transform — topic secrecy preserved
src/protocol.rs:46, used at src/network/gossip.rs:255
The room topic_id is a uniformly random 32-byte secret (rand::random(),
src/core/mod.rs:1012) acting as the room capability. XOR-ing it with the public
constant GOSSIP_PROTO.to_le_bytes() cyclically is bijective and
entropy-preserving — the result is still uniformly random; no byte becomes
predictable and no entropy is lost. The room secret is no more recoverable by an
observer than before the change (previously the raw topic_id was the on-wire
topic; now it's a trivial public XOR of it). Bijectivity also preserves room
distinctness, so isolation is not weakened. Not a vulnerability.
2. Signature topic-binding — no raw/versioned confusion
src/network/gossip.rs
active_topic_bytes stores the raw ticket.topic_id (line 293), and both
sign_gossip and verify_gossip bind against that raw value. Only the
subscribed swarm topic (line 255) uses the versioned value. There is one swarm
per join and every peer signs/verifies against the same raw topic, so no second
topic exists to enable a raw↔versioned replay/confusion attack. Code matches
VERSIONING.md's claim. Not a vulnerability.
3. GOSSIP_SIG_DOMAIN — moved verbatim
Value identical ("peerspeak-gossip-v1", src/protocol.rs:34); cross-version
cryptographic domain separation preserved. Not a vulnerability.
4. ALPN changes — handshake compatibility only
Audio peerspeak-audio → peerspeak/audio/1, friends /0 → /1. No security
check keys off the old ALPN strings (audio admission is gated by live room
membership per S8, not the ALPN literal); no residual references to old strings
in non-test code. Not a vulnerability.
5. deny.toml
Ignores only two unmaintained advisories (RUSTSEC-2024-0436,
RUSTSEC-2026-0150) on compile-time/FFI-only crates — documented, and dependency
advisories are out of scope. Not a vulnerability.
The versioning migration is a clean, security-preserving change.