ota_check_auth() previously returned true when s_ota_psk[0] == '\0'
("permissive for dev"). A freshly-flashed node — or any node where
nobody had provisioned an OTA PSK yet — accepted attacker-controlled
firmware over plain HTTP on port 8032 from any host on the WiFi. No
Secure Boot V2, no signed-image verification, no transport encryption.
Single LAN call could brick or backdoor a node.
This was flagged in the deep security review of PR #596 but was a
PRE-EXISTING bug in main, not new code from that PR — so it stood as
a critical-severity production issue until this commit.
Fix:
- ota_check_auth() now returns false when no PSK is provisioned, with
ESP_LOGW("OTA rejected: no PSK in NVS …") at the call site so the
operator can diagnose the rejection from serial logs
- ota_update_init() ESP_LOGW message updated to surface the new posture
at boot ("upload endpoint will REJECT all requests until provisioned")
- Doc comment on ota_check_auth() rewritten to make the contract
explicit and reference the audit
The OTA HTTP server itself still starts even when no PSK is set. That
lets the operator run `provision.py --ota-psk <hex>` over USB-CDC to
write the NVS key without reflashing the firmware. The upload endpoint
just refuses every request in the meantime.
Breaking change for any deployment that depended on the unauthenticated
OTA path working out of the box. Documented in CHANGELOG under
[Unreleased] / Security so it's visible at the next release cut.
Fix-marker RuView#596-ota-fail-closed (scripts/fix-markers.json)
requires the new behaviour and forbids the old "permissive for dev"
fallback strings, so a future revert fails CI.
281c4cb0ce