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