* fix(homecore-assist): bound untrusted utterance length, fail closed (ADR-133 security)
The intent recognizers accept utterances from untrusted callers (voice
transcripts, the WebSocket `assist` command). Neither the regex nor the
semantic path bounded utterance length, so a pathological multi-megabyte
utterance forced an unbounded `to_lowercase()` clone plus a per-registered-
pattern scan (and, in the semantic path, full tokenisation + feature-hash
embedding) — an allocation/CPU amplification on attacker-controlled input.
The `regex` crate is linear-time (no catastrophic backtracking), so this was
a throughput/memory DoS rather than a hang, but it was still unbounded.
Fix: introduce MAX_UTTERANCE_BYTES (4 KiB — far above any real spoken
command) and check it at both recognizer boundaries BEFORE any allocation or
scan. An over-length utterance fails closed: Ok(None) (no intent, no action),
identical to an unrecognised phrase. No legitimate command is affected.
Pinned by fails-on-old tests:
- recognizer::over_length_utterance_fails_closed — an over-length utterance
that contains a valid command resolves to None (would have matched before)
- semantic_recognizer::over_length_utterance_fails_closed_semantic
Co-Authored-By: claude-flow <ruv@ruv.net>
* test(homecore-assist): pin clean security dimensions with evidence (ADR-133)
Adds regression tests documenting the dimensions reviewed and found clean,
so the properties cannot silently regress:
- runner: no subprocess surface exists. RufloRunnerOpts.{script_path,env}
are inert and never executed; even a hostile script_path/env spawns
nothing. And the entity_id capture class [a-z0-9_ .] strips every shell
metacharacter, so a resolved slot can never carry ; | & $ ` / etc into a
(future) argv — sanitisation by construction.
(shell_metachars_never_survive_into_a_resolved_slot,
runner_opts_are_inert_no_process_spawned)
- recognizer: the regex crate is a linear-time finite automaton; a classic
catastrophic-backtracking shape (a+)+$ on adversarial input completes in
bounded time — no ReDoS.
(pathological_backtracking_pattern_completes_in_bounded_time)
- embedding: embeddings are structurally finite (FNV feature-hash + guarded
L2 normalise, no external float input, no unguarded division), so a crafted
utterance cannot inject NaN/Inf to poison cosine k-NN; cosine against the
zero vector is a finite 0.0, never NaN.
(embeddings_are_structurally_finite, cosine_with_zero_vector_is_finite_not_nan,
empty_utterance_against_empty_index_no_panic_no_match)
- pipeline: injection-shaped utterances never deliver a metacharacter into a
service call; the worst case resolves to a clean entity token, and an
unrecognised utterance fails closed to not_understood (no action).
(pipeline_injection_shaped_utterance_carries_no_metachars_to_service)
Co-Authored-By: claude-flow <ruv@ruv.net>
* docs(homecore-assist): record ADR-133 security review (HC-ASSIST-01 + clean dims)
CHANGELOG [Unreleased] Security entry + ADR-133 section 6 review notes for the
homecore-assist voice/intent pipeline review.
Co-Authored-By: claude-flow <ruv@ruv.net>
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|---|---|---|
| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||
README.md
homecore-assist
Voice-activated intent recognition and execution pipeline for HOMECORE with Ruflo agent bridge (P2).
P1 scaffold: intent recognition via regex patterns, 5 built-in intent handlers (turn on/off, set brightness, cancel), and Ruflo runner trait surface. Real tokio::process subprocess integration (P2) allows orchestration with Ruflo agents for complex multi-step actions.
What this crate does
homecore-assist is the voice/NLU gateway for HOMECORE. It takes natural language utterances, recognizes which intent they represent, and executes the appropriate action. It provides:
- IntentRecognizer trait — abstraction for matching utterances to intents
- RegexIntentRecognizer — P1 built-in; uses regex patterns (HA classic style)
- IntentHandler trait — abstraction for handling recognized intents
- 5 built-in handlers —
HassTurnOn,HassTurnOff,HassLightSet,HassNevermind,HassCancelAll(mirrors HA's classic intents) - RufloRunner trait — abstraction for delegating complex actions to Ruflo agents
- NoopRunner — P1 stub; real
tokio::processsubprocess integration in P2 - AssistPipeline — wires utterance → recognizer → handler → response
Each component is trait-based so recognizers can be swapped (regex in P1, semantic embeddings in P2) without changing the pipeline.
Features
- Regex pattern recognition — utterance matching via compiled regex (P1)
- 5 built-in intents — Turn On, Turn Off, Set Brightness, Nevermind, Cancel All
- Intent entities + slots — recognized patterns capture entity names and parameters (e.g., "turn on light.kitchen" → entity: light.kitchen)
- Intent responses — structured response with optional text, card (tile data), and conversation context
- Ruflo agent bridge — submit complex intents to Ruflo agents for multi-step workflows (P2 subprocess)
- Trait-based recognizers — pluggable:
RegexIntentRecognizer(P1),SemanticIntentRecognizer(P2, ruvector embeddings) - Trait-based handlers — extensible: built-in HA-mirroring handlers + custom handlers
- No external STT/TTS — this module handles NLU only; STT/TTS via homecore-api or external service
Capabilities
| Capability | Type | Method | Notes |
|---|---|---|---|
| Recognize intent | Recognizer | RegexIntentRecognizer::recognize(utterance) |
Returns Intent enum or error |
| Handle intent | Handler | IntentHandler::handle(intent, context) → service call |
Execute service, set state, or defer to Ruflo |
| Call Ruflo agent | Runner | RufloRunner::run(intent, opts) (P2) |
Subprocess with JSON request/response |
| Build response | Response | IntentResponse::new(text, entities, card) |
Conversational response + optional card data |
| Run pipeline | Pipeline | AssistPipeline::process(utterance) |
Full utterance → recognizer → handler → response |
Comparison to Home Assistant
| Aspect | Home Assistant | homecore-assist |
|---|---|---|
| Intent framework | HA Assist pipeline (Python) | Rust async trait-based pipeline |
| Recognizer type | Regex (classic) + ML sentence transformer (2024+) | Regex (P1); semantic embeddings (P2) |
| Built-in intents | HassTurnOn, HassTurnOff, HassLight*, etc. |
5 core intents mirroring HA classic |
| Custom intents | YAML + Python script integration | Trait + handler registration |
| Agent orchestration | N/A (HA has no agent framework) | RufloRunner + subprocess bridge (P2) |
| STT/TTS | Via conversation integration + webhooks |
Separate; HOMECORE-ASSIST handles NLU only |
| Slot extraction | regex groups + sentence-transformers | Regex groups (P1); ruvector embeddings (P2) |
| Response format | Text + TTS synthesis | Structured IntentResponse with card data |
Performance
- Intent recognition latency — < 10 ms per utterance (regex compilation cached)
- Handler execution — < 20 ms per intent (service call latency dominates)
- Ruflo agent subprocess (P2) — ~500 ms per agent call (process spawn + IPC overhead)
- Memory overhead per intent — ~500 bytes (Intent struct + handler state)
- Concurrent utterances — 100+ per second on single machine (tokio task per utterance)
- No per-crate benchmarks yet — a follow-up issue tracks baseline measurements
Usage
Regex intent recognition (P1):
use homecore_assist::{RegexIntentRecognizer, IntentName, IntentRecognizer};
#[tokio::main]
async fn main() {
let mut recognizer = RegexIntentRecognizer::new();
// Register patterns
recognizer.register(IntentName::HassTurnOn, r"turn (?:on|up) (?:the )?(\w+)").unwrap();
// Recognize utterance
let intent = recognizer.recognize("turn on the kitchen light").await.unwrap();
println!("Intent: {:?}", intent.intent_name);
println!("Entities: {:?}", intent.entities);
}
Built-in handler (P1):
use homecore_assist::{HassTurnOn, IntentHandler, Intent, IntentResponse};
use homecore::HomeCore;
#[tokio::main]
async fn main() {
let homecore = HomeCore::new();
let handler = HassTurnOn::new(homecore);
let intent = Intent {
intent_name: IntentName::HassTurnOn,
entities: vec![("entity_id".to_string(), "light.kitchen".to_string())].into_iter().collect(),
slots: Default::default(),
..Default::default()
};
let response = handler.handle(&intent).await.unwrap();
println!("Response: {}", response.text.unwrap_or_default());
}
Full pipeline (P1):
use homecore_assist::AssistPipeline;
use homecore::HomeCore;
#[tokio::main]
async fn main() {
let homecore = HomeCore::new();
let pipeline = AssistPipeline::new(homecore);
let response = pipeline.process("turn on the kitchen light").await.unwrap();
println!("Assistant: {}", response.text.unwrap_or_default());
}
Relation to other HOMECORE crates
homecore-assist (intent pipeline + Ruflo bridge)
├─ homecore (state machine; handlers call services)
├─ homecore-api (exposes intent endpoints via REST/WS, P2)
├─ homecore-automation (complex intents can trigger automations)
├─ homecore-server (registers AssistPipeline at startup)
└─ ruflo (Ruflo agent subprocess for multi-step workflows, P2)