Add a board-aware battery SOC system replacing the two independent
linear approximations that existed in the UI helpers.
New helpers/battery_curve.{h,c}: a 21-point (5% step) OCV lookup table
with integer linear interpolation. The default generic LiPo curve is a
weak symbol — any board can override it by dropping a battery_curve.c
into its board directory. CMakeLists.txt selects the board-specific file
when present, falling back to the generic.
Board.h gains getBattPercent() (default 0); ZephyrBoard implements it
via battery_curve_lookup().
Board-specific curves added for boards with measured cell data:
t1000_e, rak_wismesh_tag, thinknode_m6, sensecap_solar, wio_tracker_l1.
ADC multiplier corrections applied across all nRF52840 boards:
- Boards using a correctly-derived 3600×ratio formula get +0.5% to
compensate for nRF SAADC gain error (7200→7236, 6300→6332, etc.)
- rak_wismesh_tag, rak3401_1watt, gat562_30s had multipliers copied
from Arduino's 3.0V AREF formula; corrected to 3600×1.73×1.005=6259
- xiao_nrf52840 (10911) left unchanged — empirically calibrated value
above the theoretical, assumed already correct for that hardware
get adc.multiplier now reports current mV reading and the board's
curve 100% target, making field calibration self-guiding.
A device-side cable yank often skips the DTR=0 line-state change, so the
companion stayed stuck on the USB interface and rejected every BLE
connection until reboot. Treat USBD_MSG_VBUS_REMOVED as a DTR drop.
extract_via_aes_ctr used the void Utils::sha256, which silently zeroes
its output on PSA failure -> an all-zero AES key -> a constant,
device-shared Ed25519 identity that the degenerate check misses.
Re-inline psa_hash_compute with its status check so a failure reboots.
Production (LOG=n, ASSERT=n, RTT=n, reboot-on-fatal) is now the prj.conf
default; debug.conf is the opt-in bundle. Removed prod.conf and the
logging.conf auto-include; relocated RTT/ASSERT out of the always-on
platform confs so they no longer override the prod defaults.
Add CONFIG_ZEPHCORE_COMPANION_USB so the USB CDC companion transport
compiles independently of logging (default-y on USB-capable companions,
opt-in on ESP32-S3 via esp32s3_usb.conf). Gate all USB sites behind one
ZEPHCORE_USB_STACK macro.
Rework BLE/USB interface arbitration to first-come-first-served: neither
transport evicts a live session. Make active_iface mutation thread-safe
(mutex + atomic claim) across the BLE callback thread and USB workqueue.
Share the ESP32-S3 USB OTG / console DTS via common dtsi includes; enable
uart0 (GPIO43/44) on station_g2 and xiao so the console reroute works.
getEstAirtimeFor() set LDRO from `sf >= 11`, correct only at BW125. Now
matches the driver's should_enable_ldro() (t_sym > 16.38 ms) so the
estimate's DE tracks hardware DE on every SF/BW. Also drop dead
calcRxDelay() + unused MAX_RX_DELAY_MILLIS.
- Lift duplicated identity-gen block from main_companion.cpp +
main_repeater.cpp into ZephyrRNG::generateFirstBootIdentity().
Both mains shrink from ~40 lines to a 3-line helper call.
- Add LocalIdentity::fromSeed() so seed-derived keygen doesn't need
a one-shot RNG wrapper; delete SeededRNG.
- Drop the per-byte ADC sampling loop: getBattMilliVolts() does an
8-sample average + 10ms regulator settle internally, costing
300-480ms of real wall-time and actively destroying the LSB jitter
it was meant to harvest. Jitter mixer already dwarfs it.
- Centralize the printk + sys_reboot pattern as
Utils::cryptoPanicReboot(); drop the 2000ms pre-reboot k_msleep
(printk is synchronous, sleep just blocked the mesh thread on
the ZephyrRNG::random() retry-failure path).
- Inline sample_cpu_jitter health check via online scalars instead
of a 512-byte deltas[] array. Saves 1.5KB stack churn across boot
and tracks every sample instead of only the first 128.
- extract_via_aes_ctr now uses Utils::sha256 instead of open-coding
psa_hash_compute.
Audit-driven sweep found additional compiler-optimization-sensitive
patterns beyond the login password compare just fixed:
P4.F3 (HIGH) — Utils::MACThenDecrypt verified packet MACs with
plain memcmp. Runs on EVERY encrypted-then-MAC'd packet in the
mesh; a timing oracle here lets attackers forge MACs byte-by-byte
across the whole mesh layer. Replaced with constantTimeEqual.
P4.F4 (MEDIUM) — Multiple memset(secret, 0, ...) calls on
stack-resident crypto buffers (Ed25519 seed, ADC noise pool, AES
key derived in extract_via_aes_ctr, HWINFO unique ID) were
subject to dead-store elimination under -Os. GCC/Clang routinely
elide these when the buffer is never read after; the wipe vanishes
and the secret persists on stack until next call overwrites.
Replaced with secureZeroize using volatile pointer writes.
P4.F5 (LOW) — Identity::validatePrivateKey boot self-test compared
shared secrets with plain memcmp. Boot-only, no attacker
observation channel, but hygiene matters and the fix is one line.
Also added secret-wipe for ss1/ss2 on all return paths.
Promoted the local ct_memeq() previously added to RepeaterMesh.cpp
into Utils::constantTimeEqual + Utils::secureZeroize (Utils.h/cpp)
so the login compare and MAC compare share the same audited helper.
Both helpers verified by Thumb-2 disassembly on rak3401_1watt:
- constantTimeEqual: loop branches on iterator, accumulator
load-modify-stored to stack every iteration, final return uses
CLZ+LSR (no conditional branch on result).
- secureZeroize: STRB.W to memory in a counted loop, not replaced
with memset builtin and not eliminated.
Adds a layered entropy mixer for first-boot identity Ed25519 keygen,
primarily to address ESP32 where the hardware TRNG (WDEV_RND_REG) is
only fed real entropy once the internal WiFi/BT radio is enabled —
but identity gen runs before that on companion and indefinitely
before that on a bare repeater. ESP-IDF's bootloader_random_enable()
is not compiled by Zephyr-Espressif HAL, ruling out that workaround.
Design reviewed with nextgens (author of upstream meshcore-dev/
MeshCore#2280 which fixes the same issue via BT/WiFi init/pull/deinit).
ZephyrRNG::random — retry sys_csrand_get up to 4x with k_msleep
backoff; cold-reboot on persistent failure. Previously fell back
silently to sys_rand_get (xoshiro PRNG), which would have produced
a weak Ed25519 seed on CSPRNG error. BUILD_ASSERT enforces
CONFIG_CSPRNG_ENABLED.
ZephyrRNG::mixIdentitySeed — layered entropy mixer for one-shot
identity keygen. Combines sys_csrand_get (early + late),
HWINFO unique device ID, caller-supplied ADC LSB noise, 200ms of
CPU cycle-counter jitter (NIST SP 800-90B class source), and
50ms more jitter in an independent timing window. Conditioned via
AES-256-CTR (NIST SP 800-108 KDF-in-Counter-Mode): SHA-256 of the
pool extracts a 32-byte AES key; AES-256-ECB on an incrementing
128-bit counter expands to the requested output length. Uses PSA
crypto already enabled in zephcore_common.conf. NIST-style
repetition-count + variance health check on jitter samples;
reboot on degenerate output. ~280ms one-time cost at first boot.
LoRa radio TRNG was considered as an additional source but rejected
on expert advice — radio sources are attacker-influenceable
(jamming/spoofing).
ui-joystick BLE passkey — switch from sys_rand32_get (non-crypto
xoshiro) to sys_csrand_get. The 6-digit passkey is the MITM
protection the rest of the BLE config enforces; predictable PINs
weaken it.
Identity reserved-prefix loop — replace the silent 10-attempt cap
(which committed whatever it had on fall-through) with a
bounded-retry-then-reboot pattern.
Also: fix a pre-existing scope bug at main_companion.cpp:357 in
the MESH_EVENT_PREFS_DIRTY handler — data_store was referenced
inside mesh_event_loop() but declared 50+ lines later. Moved the
call into a forward-declared helper defined after the statics.
Unrelated to crypto work but uncovered during build verification;
every companion build was broken.
Single ZephyrUSBCDC module owns the usbd context, 1200-baud DFU
detection, and DTR transitions for both roles. The boot banner
now blocks on a k_event signalled by the usbd_msg_callback when
DTR transitions high — host attached → wakes immediately; no host
→ bounded timeout (2 s repeater, 1 s companion). Replaces the
fixed k_sleep delays in both mains.
Deletes the companion's 10 s DTR-polling work — line state changes
arrive as events now, same callback handles disconnect (resets V3
parser, flips active_iface) and DFU touch (reboots to bootloader).
Side effect: prod companion no longer enumerates a phantom CDC ACM
port (CONFIG_LOG=n skips the whole stack instead of auto-initing
an unused device).
liquidraver