Files
meshcore-analyzer/cmd/server
Kpa-clawbot bf674ebfa2 feat: validate advert signatures on ingest, reject corrupt packets (#794)
## Summary

Validates ed25519 signatures on ADVERT packets during MQTT ingest.
Packets with invalid signatures are rejected before storage, preventing
corrupt/truncated adverts from polluting the database.

## Changes

### Ingestor (`cmd/ingestor/`)

- **Signature validation on ingest**: After decoding an ADVERT, checks
`SignatureValid` from the decoder. Invalid signatures → packet dropped,
never stored.
- **Config flag**: `validateSignatures` (default `true`). Set to `false`
to disable validation for backward compatibility with existing installs.
- **`dropped_packets` table**: New SQLite table recording every rejected
packet with full attribution:
- `hash`, `raw_hex`, `reason`, `observer_id`, `observer_name`,
`node_pubkey`, `node_name`, `dropped_at`
  - Indexed on `observer_id` and `node_pubkey` for investigation queries
- **`SignatureDrops` counter**: New atomic counter in `DBStats`, logged
in periodic stats output as `sig_drops=N`
- **Retention**: `dropped_packets` pruned alongside metrics on the same
`retention.metricsDays` schedule

### Server (`cmd/server/`)

- **`GET /api/dropped-packets`** (API key required): Returns recent
drops with optional `?observer=` and `?pubkey=` filters, `?limit=`
(default 100, max 500)
- **`signatureDrops`** field added to `/api/stats` response (count from
`dropped_packets` table)

### Tests (8 new)

| Test | What it verifies |
|------|-----------------|
| `TestSigValidation_ValidAdvertStored` | Valid advert passes validation
and is stored |
| `TestSigValidation_TamperedSignatureDropped` | Tampered signature →
dropped, recorded in `dropped_packets` with correct fields |
| `TestSigValidation_TruncatedAppdataDropped` | Truncated appdata
invalidates signature → dropped |
| `TestSigValidation_DisabledByConfig` | `validateSignatures: false`
skips validation, stores tampered packet |
| `TestSigValidation_DropCounterIncrements` | Counter increments
correctly across multiple drops |
| `TestSigValidation_LogContainsFields` | `dropped_packets` row contains
hash, reason, observer, pubkey, name |
| `TestPruneDroppedPackets` | Old entries pruned, recent entries
retained |
| `TestShouldValidateSignatures_Default` | Config helper returns correct
defaults |

### Config example

```json
{
  "validateSignatures": true
}
```

Fixes #793

---------

Co-authored-by: you <you@example.com>
2026-04-18 11:39:13 -07:00
..
2026-04-12 04:02:17 +00:00