Apply Phase 9D security mitigations

- Add fail-closed wolfSSL small-math policy and vectors
- Backport DHCP, EMS, and X.509 allocation fixes
- Extend source override validation and operational documentation

docs/security_hardening.md

@@ -1,6 +1,6 @@
 # Security hardening — Phase 9
 
-**Status: in progress.** Phase 8 is complete at the accepted 8D.22 scope. **9A crash/debug policy, 9B SSH admission/credential handling and 9C library cleanup/protocol policy** are implemented with host/build validation. At the user's request, hardware validation is deferred to **Phase 9 as a whole**, not an approval gate between implementation slices. This document records policy and procedures, not unrun passes or production certification.
+**Status: in progress.** Phase 8 is complete at the accepted 8D.22 scope. **9A crash/debug policy, 9B SSH admission/credential handling and 9C library cleanup/protocol policy** are implemented with host/build validation. At the user's request, hardware validation is deferred to **Phase 9 as a whole**, not an approval gate between implementation slices. **9D maintenance/lifecycle is in progress, with unresolved advisory and distribution/source/notice questions. Phase 9 is not complete or production-ready.** This document records policy and procedures, not unrun passes or production certification.
 
 ## Scope and threat model
 
@@ -71,7 +71,7 @@ Hidden UART0 and shared remote-console prompts now reject overflow or unsupporte
 
 ### Reproducible source corrections
 
-`tools/security_overrides.py` verifies full original-file SHA-256 values and ESP-IDF 5.5.0, applies exact-once edits, and generates four corrected sources under the build directory. `cmake/security_overrides.cmake`, included after `project()`, replaces exactly the corresponding sources in existing IDF/component targets, retaining compilation properties. Installed SDK/managed sources and their notices remain unchanged. Missing, changed or ambiguous sources fail configuration; there is no unpatched fallback. Do not edit derived files or repin a hash merely to make an upgrade build.
+`tools/security_overrides.py` verifies full original-file SHA-256 values and ESP-IDF 5.5.0, applies exact-once edits, and generates seven corrected sources under the build directory (four from 9C plus three advisory backports in 9D). `cmake/security_overrides.cmake`, included after `project()`, replaces exactly the corresponding sources in existing IDF/component targets, retaining compilation properties. Installed SDK/managed sources and their notices remain unchanged. Missing, changed or ambiguous sources fail configuration; there is no unpatched fallback. Do not edit derived files or repin a hash merely to make an upgrade build.
 
 - **HTTPS:** delete TLS on post-handshake transport-allocation failure; fully destroy retained TLS configuration on failed HTTPD start; wipe the copied raw private key before free. Failed stop still retains live ownership.
 - **HTTPD parser:** allocate/copy/wipe/free scratch on resize, preserve the old pointer on allocation failure, wipe final scratch, and handle the null initial parser pointer without undefined subtraction. Pending/unread bytes retain their existing behavior.
@@ -102,6 +102,16 @@ A non-consuming quota/epoch check now runs after valid challenge consumption but
 
 The existing global five-verifications/60-second fixed window is unchanged: malformed requests do not charge it, counter clear does not replenish it, and web service restart does. This differs deliberately from SSH's boot-lifetime buckets. The first boot-minute window remains anchored at uptime zero. Challenge monopolization, global-budget starvation and malformed-body work while budget is available are not solved by this early check.
 
+## 9D maintenance and lifecycle — in progress
+
+- [Security operations](security_operations.md) supplies source-checked provisioning, explicit-save, account/key/identity rotation, recovery, reconstruction and approved erase/decommissioning procedures. There is no implemented configuration backup/export or private-identity restore workflow. Commands and checklists are not device execution evidence; the user will validate Phase 9 as a whole.
+- [wolfSSL/wolfSSH review and implementation addendum](wolf_security_review.md): the **CVE-2025-12888** Xtensa mitigation now selects `CURVE25519_SMALL` and `ED25519_SMALL` consistently for wolfSSL and consumers. The PUBLIC forced-include resolved-settings guard rejects missing small implementations, X25519 blinding (incompatible with small in this pinned version), and unreviewed Curve448/Ed448 enablement. **Still open:** server-recommended message-order correction for **CVE-2025-14942**, parser/ECC review and broader API/feature applicability. No server credential-leak or invalid-curve exploit is demonstrated; target timing/interoperability remains untested.
+- [Focused IDF review and implementation addendum](idf_security_review.md): pinned backports now implement DHCP option bounds (**CVE-2026-45160**), TLS 1.2 EMS failure return (**CVE-2026-50581**) and X.509 OID allocation-failure handling (**CVE-2026-34874**). Explicit nested-target validation places the mbedTLS edits on `mbedtls`/`mbedx509`, retaining source properties and exactly-one-source checks. WS negotiation **CVE-2026-45541** and ASN.1 named-data **CVE-2025-48965** remain unpatched with the review's qualified applicability, not blanket closure.
+- [Dependency license inventory](dependency_licenses.md) is a bounded engineering inventory, not legal or distribution clearance. All seven generated sources now carry prominent modification notices dated **2026-09-15**, with upstream notices retained, including both mbedTLS dual-license headers. That narrow finding is resolved. Radio-blob corresponding-source/exception questions, actual firmware/device/browser notice delivery, preferred-source packaging, wolfSSH package-license discrepancy and icon provenance/full-license work remain open. Existing repository notices alone are not a complete release bundle.
+- No dependency versions were upgraded. Beyond the implemented backports above, proposed upgrades/backports remain candidates, not approved compatible versions. Re-audit coherent source/header changes, effective compile policy, exact-hash overrides and callback/parser contracts, then obtain host/build and whole-phase target evidence. 9A–9C passes below are historical scoped evidence, not closure of these newly recorded findings.
+
+Secure boot and encrypted NVS remain excluded. No runbook, advisory report or license inventory establishes production readiness or authorizes a destructive device operation.
+
 ## Operational profiles
 
 These are handling and validation profiles of the **same supported build baseline**, not separate PlatformIO environments or selectable security overrides.
@@ -118,7 +128,22 @@ Raw flash, RAM and dumps can contain Wi-Fi passwords, private keys, password ver
 
 ## Validation gates
 
-### Host and build — passed 2026-09-15 (9A–9C)
+### Mitigation host/build evidence — 2026-09-15
+
+Supplied parent results (not rerun for this documentation update): `pio run` **PASS**, **94,340 B linked RAM / 1,767,217 B flash**. Against the historical 9C build below, RAM is unchanged and flash is **64,092 B smaller**. Linked size is not runtime headroom or timing evidence.
+
+All four parent commands passed:
+
+```sh
+CCACHE_DISABLE=1 python3 tests/sdk_security_overrides/run.py --build-dir .pio/build/esp32-s3-devkitc-1-n16r8
+CCACHE_DISABLE=1 python3 tests/wolf_crypto_policy/run.py
+CCACHE_DISABLE=1 python3 tests/wolfssh_auth_contract/run.py
+CCACHE_DISABLE=1 python3 tests/ssh_protocol_policy/run.py
+```
+
+The independent reviewer reports the first two suites passed with no blocking implementation defects. Documentation verification separately matched all seven existing generated files to pinned originals plus checked-in edits/notices and checked retained mbedTLS license headers. This is scoped implementation/host/build evidence, not completed wolfSSH ordering/parser/ECC review, license packaging clearance or whole-phase acceptance. No target evidence, upgrade, asset regeneration or device operation is claimed.
+
+### Host and build — historical passes 2026-09-15 (9A–9C)
 
 From the repository root:
 
@@ -136,13 +161,13 @@ python3 tests/ssh_protocol_policy/run.py
 python3 tests/web_cookie_auth/run.py --admission
 ```
 
-Latest 9C `pio run` passed with **94,340 B linked RAM / 1,831,309 B flash**, unchanged linked RAM / +1,384 B flash against 9B. This is linked size, not measured runtime headroom. Five focused suites passed after final HTTPD first-read correction: pinned SDK cleanup/TLS/source registration, 135 generated wolfSSH parser/control-flow cases, secure allocator, SSH policy (including 15 actual context-integration cases), and web early admission/wiping. The allocator's optional installed-SDK extent contract was also run with the installed IDF path and passed; plain invocation reports that optional check skipped. Seventeen integrated regression commands passed before the final first-read addition, including SSH auth/management, HTTPD idle, HTTPS lifecycle, five cookie-auth modes and the 18-case crash-policy matrix. All ten existing cookie-auth domain modes also passed during implementation. Independent reviews found no blocking issues; the identified inherited first-read pointer issue was corrected and tested. Use `CCACHE_DISABLE=1` on host commands if the compiler wrapper's cache is read-only in a sandbox. No upload, erase, eFuse operation or target test was performed.
+Historical final 9C `pio run` passed with **94,340 B linked RAM / 1,831,309 B flash**, unchanged linked RAM / +1,384 B flash against 9B. This is linked size, not measured runtime headroom. Five focused suites passed after final HTTPD first-read correction: pinned SDK cleanup/TLS/source registration, 135 generated wolfSSH parser/control-flow cases, secure allocator, SSH policy (including 15 actual context-integration cases), and web early admission/wiping. The allocator's optional installed-SDK extent contract was also run with the installed IDF path and passed; plain invocation reports that optional check skipped. Seventeen integrated regression commands passed before the final first-read addition, including SSH auth/management, HTTPD idle, HTTPS lifecycle, five cookie-auth modes and the 18-case crash-policy matrix. All ten existing cookie-auth domain modes also passed during implementation. Independent reviews found no blocking issues; the identified inherited first-read pointer issue was corrected and tested. Use `CCACHE_DISABLE=1` on host commands if the compiler wrapper's cache is read-only in a sandbox. No upload, erase, eFuse operation or target test was performed.
 
 Record the revision, compiler/build outcome and effective configuration. Confirm that the matrix accepts the supported configuration, rejects each prohibited option independently, and rejects absent/disabled required settings. Confirm the normal firmware build compiles the guard. A rejected unsafe configuration is an expected negative-test result, not a firmware build pass. Neither these commands nor a successful build proves target panic behavior.
 
 ### Combined Phase 9 target validation — deferred, not run
 
-Retain these checks for the final phase test session; do not stop implementation for a separate 9A/9B/9C sign-off.
+Retain these checks for the user's final whole-phase test session; do not stop implementation for separate slice sign-off. Include the [9D operational rehearsal](security_operations.md#deferred-whole-phase-9-hardware-rehearsal) and targeted message-order/parser/key-validation/interoperability checks for the eventual reviewed advisory mitigations. None is recorded as passed here.
 
 #### Crash and recovery
 
@@ -171,7 +196,7 @@ Retain these checks for the final phase test session; do not stop implementation
 
 ## Staged next work
 
-- **Next — 9D maintenance and lifecycle.** Review current ESP-IDF/wolfSSL/wolfSSH advisories and third-party licenses, then plan any upgrades and source re-audits separately. Complete provisioning, key rotation, backup, factory reset, recovery and decommissioning runbooks without claiming physical-extraction resistance or secure erasure. No external advisory or complete license review has been performed by 9C.
+- **Continue 9D maintenance and lifecycle.** Resolve the [open advisory priorities](wolf_security_review.md#release-decision--current-path-priorities), finish broader dependency coverage beyond the bounded IDF/mbedTLS review and three implemented backports, and address the [release source/notice work](dependency_licenses.md#actionable-release-work-not-performed). Runbooks are documented, not rehearsed; remaining mitigations/reviews, distribution clearance and whole-phase acceptance remain outstanding.
 - **Retained evidence limits:** 9C completes a bounded cleanup/protocol review, not every-library-copy zeroization. Live inline residue, compaction tails, hardware/stack intermediates, global admission starvation and resource/interop measurements remain documented limitations or combined target gates. Any additional hardening must preserve owner lifetimes and bounded recovery.
 - **Phase 10: OTA trust.** Define independent image-signature verification, trust-anchor provisioning, rotation/revocation, rollback/downgrade and recovery policy without secure boot. Authenticated transport alone is not image-signing policy, and OTA signature checks cannot prevent physical firmware replacement.