Audit and fuzzing of the RF-packet decode -> dispatch -> display/phone paths for
the "crash a node or phone with a crafted packet" surface, beyond the XEdDSA
authenticity work.
Crash fixes (reproduced under AddressSanitizer / UBSan):
- GeoCoord::latLongToUTM/latLongToMGRS read fixed letter tables out of bounds on
extreme latitude_i/longitude_i from a received Position, and narrowed
out-of-range easting/northing doubles to unsigned (float-cast-overflow UB).
Clamp the UTM zone, the easting/northing narrowing, and the band/col/row
indices. Regression: test_geocoord_extreme_coords_no_oob.
- EnvironmentTelemetry/AirQualityTelemetry render attacker floats via
String(float), which on nRF52/RP2040/STM32/portduino formats into a fixed
char[33] (dtostrf) and overflows near FLT_MAX. Clamp the rendered metrics via
UnitConversions::displaySafeFloat (finite + magnitude <= 1e9), unit-tested in
test_type_conversions.
Defense-in-depth + robustness:
- TraceRouteModule::printRoute: fix an snr_back[-1] OOB read (wrong count in the
guard) and stop formatting the INT8_MIN "unknown SNR" sentinel as a dB value.
- WaypointModule/NodeDB: sanitize untrusted strings before the OLED renderer and
the phone-facing ClientNotification (belt-and-suspenders vs PB_VALIDATE_UTF8).
- MeshService::sendToPhone: withhold NODEINFO/WAYPOINT packets whose nested string
won't cleanly decode, protecting strict phone protobuf decoders without
affecting mesh relay.
Tests: new test_fuzz_decode (protobuf decode + UTF-8 sanitizer fuzz) and
test_fuzz_packets (perhapsDecode / module-handler / traceroute / phone-gate fuzz),
all under AddressSanitizer; native-suite-count 25 -> 27. Full suite 515/515 green.
Ben MeadorsandGitHub
b4dd76a4db