* fix(nvsim): guard degenerate input — config-induced panic + NaN-state poisoning
Beyond-SOTA security review of the ADR-089 NV-diamond simulator (milestone #9,
crate 2 of 4). Two real degenerate-input findings, each pinned fails-on-old:
NVSIM-DT-01 (config panic/DoS, pipeline.rs): an external f_s_hz == 0 made
dt == +Inf, dt_us saturated to u64::MAX, and `sample * dt_us` panicked with
"attempt to multiply with overflow" at sample >= 2 (debug/WASM panic=abort;
garbage t_us in release). Fix: sanitise dt (non-finite/non-positive -> 1 µs
fallback), cap the u64 cast, and saturating_mul the timestamp.
NVSIM-NAN-01 (NaN-state poisoning, digitiser.rs): a non-finite scene parameter
(NaN dipole position / Inf moment / NaN loop radius) bypasses the near-field
clamp (NaN < R_MIN_M is false) and yields a NaN field; at the ADC `NaN as i32`
== 0 silently emitted b_pt=[0,0,0] with ADC_SATURATED CLEAR — indistinguishable
from a legit zero-field reading. Fix at the funnel: adc_quantise treats any
non-finite input as out-of-range -> clamps to code 0 AND raises the saturation
flag, so the corruption is visible downstream.
Determinism integrity, panic-free MagFrame deserialisation, and RNG seeding
confirmed clean with evidence. The published cross-machine witness
(cc8de9b0…93b4) is unchanged — guards only affect degenerate inputs.
cargo test -p nvsim --no-default-features: 50 -> 53 passed, 0 failed.
Workspace green; Python deterministic proof unchanged (f8e76f21…46f7a,
nvsim off the signal proof path). Needs ADR slot 177.
Co-Authored-By: claude-flow <ruv@ruv.net>
* docs(adr): ADR-177 — nvsim degenerate-input hardening
Records the 2 MEASURED MEDIUM fixes in 37764be55 (NVSIM-DT-01 config-induced
overflow panic / WASM-abort DoS; NVSIM-NAN-01 non-finite scene param →
silent fake zero-field reading with saturation flag clear) + 3 pins, and the
clean-with-evidence determinism/deser/div-by-zero verdict. Cross-machine
witness cc8de9b0…93b4 reproduces unchanged.
Co-Authored-By: claude-flow <ruv@ruv.net>
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