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).
1. USB takeover opcode mismatch
ZephyrCompanionUSB.cpp checked payload[0] == 0x03 with a comment
claiming CMD_APP_START, but CMD_APP_START is 0x01 (0x03 is
CMD_SEND_CHANNEL_TXT_MSG). The USB handshake silently dropped the
companion app's first frame on every connection; the app appeared
broken over USB until the user happened to send a channel message.
2. CMD_SET_ADVERT_NAME didn't propagate to BLE adv data
Name changes were persisted to prefs but the advertising payload
and GATT device name kept the old value until reboot. Added
zephcore_ble_update_name() and called it from the handler.
3. No advertising-health watchdog
If bt_le_adv_start() ever failed transiently (HCI timeout,
controller pacing), the device would silently stop advertising
and stay undiscoverable until reboot. Added an adv_running flag
and a 5s watchdog in the companion housekeeping handler that
nudges adv back on if it stops outside a connection. Tracks
Arduino nrf52's equivalent 10s watchdog.
every LBT-retried flood packet loses its priority (fixed)
witching between LBT and non-LBT mode (or any cad.mode change) could silently skip full reconfiguration and leave the radio in the wrong mode (fixed)
Add .gitattributes rules so .c/.h/.cpp/.hpp are always stored as LF
(prevents EOL drift from editors with autocrlf-true defaults), and
renormalize the 30 source files that had drifted to CRLF in the index.
Pure mechanical change — `git diff --ignore-cr-at-eol` is empty.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
stolen from Zephyr main:
1. Issue StopTimerOnPreamble=1 before SetRxDutyCycle so the chip's
timer is not reset on every preamble detect (per §13.1 of the
datasheet). Without this, duty cycle effectively never sleeps in
noisy RF and current draw spikes.
2. On IRQ_RX_TX_TIMEOUT during duty-cycle RX, re-arm via
sx126x_restart_rx() instead of falling through to set_sleep().
The old path silently killed duty cycle after the first preamble
false-positive.
3. On recv_duty_cycle(NULL) cancel, wake the radio before issuing
SetStandby — BUSY stays asserted during the sleep phase and the
standby command was being dropped.
Also adds a dc_timeout_restarts atomic counter incremented on the Fix 2
path, exposed end-to-end: sx126x_ext.h accessors → LoRaRadioBase vtable
→ SX126xRadio override → CommonCLICallbacks → RepeaterMesh. Query via
`get dc.restarts` on the repeater CLI; cleared by `clear stats`. High
values indicate a noisy environment or a too-loose preamble threshold.
(+increase ESP BT stack because future zephyr pin advance will trip that mine)
liquidraver