Harden SSH Admission And Credential Input

docs/agent/architecture.md

@@ -126,9 +126,9 @@ Cookie login/logout replaces Basic/cache. Digest-only records carry copied princ
 
 Typed SSH settings use the existing ID dispatcher and original-login result slot, never HTTPD wolfSSH calls or owner waits. Conditional lifecycle/session controls compare a saturated service generation and exact nonreused session ID under canonical locks. `ssh_transport_replace_identity` reserves service then identity before stop, retaining the command mutex across stop → commit → conditional restart. Failed stop skips mutation/start; failed persistence may follow disconnection; committed identity is never rolled back after restart failure. Only the SSH owner frees context after all slots retire, and start rejects orphan handles. Direct security/CLI/deferred SSH callers share task-bound identity reservations; crypto/NVS run outside security locks. HTTPS remains available, so no self-cutting HTTP ACK gate is needed. [SSH contracts](../web_administration.md#ssh).
 
-`ssh_transport` uses wolfSSH on port 22 with two fixed session/handshake slots. Initialization calls `wolfSSH_Init()` in the caller before task creation; after that, one owner task pinned to core 1 exclusively owns runtime contexts/sessions and wolfSSH calls. It enforces bounded handshakes, authentication attempts, receive work, and session buffers.
+`ssh_transport` uses wolfSSH on port 22 with two fixed session/handshake slots. Initialization calls `wolfSSH_Init()` in the caller before task creation; after that, one owner task pinned to core 1 exclusively owns runtime contexts/sessions and wolfSSH calls. It enforces bounded handshakes, authentication attempts, receive work, and session buffers. Phase 9B adds owner-only boot-lifetime token buckets for handshake admission, password/signed-key checks and unsigned probes; reconnect/service restart/counter clear do not reset them. Rate rejection closes the authenticating connection without sleeping the owner. Global starvation remains a tradeoff; see [admission policy](../security_hardening.md#9b-ssh-admission-and-credential-handling).
 
-Authentication uses user-database passwords or stored Ed25519/ECDSA-P256 public keys. Public-key lookup authorizes a username/key pair, while wolfSSH verifies signed proof of possession. SSH host identity is a separate persisted P-256 key managed by `ssh_security`.
+Authentication uses user-database passwords or stored Ed25519/ECDSA-P256 public keys. Public-key lookup authorizes a username/key pair, while wolfSSH verifies signed proof of possession. SSH host identity is a separate persisted P-256 key managed by `ssh_security`. A pending-result marker gates exactly-once signed-key completion/currentness; the reviewed wolfSSH version/feature profile is guarded and keyboard-interactive has an explicit rejecting callback (advertisement is not a dispatch filter). Consumed admin staging bytes and retired slots are wiped; this is not a full library-memory wipe guarantee.
 
 Routing follows the authenticated role:
 

docs/agent/code-map.md

@@ -111,7 +111,8 @@ Shared UI regression: `tests/web_ui_session/run.py` and its domain `.cjs` fixtur
 
 **Responsibility:** authenticate SSH, route users to serial and administrators to the command dispatcher, and own wolfSSH lifecycle.
 
-- Files: `src/ssh_transport.{h,c}`, `src/ssh_security.{h,c}`, `src/ssh_console.{h,c}`
+- Files: `src/ssh_transport.{h,c}`, `src/ssh_auth_policy.{h,c}`, `src/ssh_security.{h,c}`, `src/ssh_console.{h,c}`
+- Phase 9B admission: three owner-only boot-lifetime token buckets (handshakes, password/signed-key requests, unsigned probes); no restart/counter-clear reset. Explicit keyboard rejection, pending-result marker and version/feature guard preserve reviewed callback order. Consumed admin RX/accepted TX and retired slots are wiped. Tests: `tests/ssh_auth_policy/run.py`, `tests/ssh_auth_transport/run.py`, `tests/wolfssh_auth_contract/run.py` (requires installed vendor source and production compile database). [Policy/counters/limits](../security_hardening.md#9b-ssh-admission-and-credential-handling).
 - Interfaces: init/start/stop, session snapshots/disconnect/revocation, host-key replacement, counters; `ssh_transport_get_management_snapshot()` / `ssh_transport_manage_current()` fence lifecycle and exact session admission. `ssh_transport_replace_identity()` reserves service before task-bound security identity across stop/commit/restart, retains context until all slots retire and rejects orphan starts. Tests: `tests/ssh_management/run.py`, `tests/ssh_management/security.py`, `tests/ssh_management/runtime.py`.
 - Called by: startup, network clients, user revocation, console/local UI
 - Dependencies: user database, broker, admin SSH console, secure random, wolfSSH/wolfSSL; boot start gate requires Wi-Fi and SSH security/runtime readiness, independently of HTTPS identity readiness (verified in `main.c` after accepted legacy cleanup).
@@ -142,6 +143,7 @@ Shared UI regression: `tests/web_ui_session/run.py` and its domain `.cjs` fixtur
 - Flow: `UART0/admin SSH/browser admin -> bounded request queue -> one dispatcher -> esp_console_run()`
 - Ownership: dispatcher is sole `esp_console_run()` caller; the SSH owner exclusively performs post-initialization wolfSSH runtime calls.
 - Lifecycle: remote session tokens include slot generation; fixed output/history/prompt state is wiped immediately on idle close or after an executing handler returns. Admin SSH `exit` and Ctrl+D on an empty command line request bounded deferred self-disconnect after best-effort output draining.
+- Hidden input: UART0 and shared remote prompts reject overflow/unsupported bytes on submit with wiped output, sticky across edits; visible editing is unchanged. Tests: `tests/hidden_input/run.py` plus console boundary regressions.
 - Constraint: one slow command or prompt serializes all administration. Admin SSH is unavailable until command registration and UART frontend creation complete; supported deferred actions wait only for a bounded application-buffer drain heuristic.
 
 ## Wi-Fi

docs/agent/current-state.md

@@ -2,6 +2,17 @@
 
 Working memory, not an implementation timeline. Source is authoritative; begin with [code map](code-map.md), then [architecture](architecture.md) and [decisions](design-decisions.md).
 
+## Phase 9B — SSH admission / credential handling — 2026-09-15
+
+- User requested continued Phase 9 work and will validate **the phase as a whole**. Do not pause between slices for target approval; all target gates remain unrun and collected in `docs/security_hardening.md`. Secure boot/encrypted NVS remain excluded; Phase 8 sign-off stays closed. Initial Git status for this slice was clean.
+- `ssh_auth_policy.{c,h}`: 72-byte owner-only boot-lifetime state, independent handshake and password/signed-key buckets (capacity6, refill1/10s), unsigned-probe bucket(capacity12, refill1/5s). No waits, allocations, per-peer maps or NVS writes. Reconnect, stop/start/rotation/counter clear do not replenish; no refunds, idle saturation/no excess credit, clock regression fails closed. Global starvation is a deliberate documented tradeoff; natural refill only after hostile traffic subsides, not fairness/zeroCPU protection.
+- `ssh_transport` gates handshake before wolfSSH allocation and credentials before database/ordinary signature work; keeps existing per-slot three-counted-attempt closure and 15s deadline. Explicit pending-result marker fences duplicate/unexpected completion. wolfSSH1.4.20 and certificates/none-disabled guard; keyboard prompt rejection callback/context prevents unregistered callback dispatch while keeping password/publickey advertisement. New aggregate admission/probe/throttle/limit/backend/method counters via `ssh counters`; `add_counter` saturates (do not generalize to unrelated direct lifecycle increments).
+- Admin RX consumed spans / TX positively accepted spans are securely wiped; pending retry and serial hot-path bytes unchanged. Whole retired slot securely wiped before generation/fd restoration. `console_input` and shared remote hidden prompts reject overflow/unsupported bytes on submit, sticky across editing; visible CLI behavior preserved; existing callers prevent prefix persistence. Input errors wipe output and return zero length.
+- Source audit verified actual pinned wolfSSH auth callback order and `SendChannelData` positive copied/consumed behavior. Tests pin `internal.c` SHA256 and execute extracted vendor parser/send functions with crypto/IO doubles plus actual compiler-feature preprocessing. Followup resolved reviewer concern about keyboard error-path one-byte write: inline buffer initialized, framed packets retain padding reserve, exact-sized protocol-identification pending state cannot reach auth, rejection purges without advancing length. This is a narrow invariant audit, not library security certification.
+- Validation: parent `pio run` PASS **94,340 B linked RAM / 1,829,925 B flash** (+144RAM/+1,360flash vs9A; not runtime reserve). Parent and independent review PASS all four new suites `ssh_auth_policy`, `ssh_auth_transport`, `wolfssh_auth_contract` (35 vendor cases+resolved feature profile), `hidden_input`; token policy UB-sanitizer trap mode passed, standard UBSan runtime absent. Related 11 command suite PASS: SSH management/security/runtime, console boundary/accounts/lifecycle, admin SSH policy, web cookie SSH/accounts, web admin transport+tickets, security build policy18. `git diff --check` PASS. No blocking review findings; no upload/erase/device operations/deps/generated assets/commit.
+- **Next:** complete remaining secret-lifetime and protocol review; inspect pinned library private-key/password-packet/buffer-growth/destruction before claiming comprehensive zeroization. Focused application audit found and fixed admin staging retention and hidden-input truncation; other checked key/candidate handoffs already wipe. TLS/SSH algorithm/certificate/header/password/KDF policy and web receive-before-throttle/challenge fairness remain review items. Dependency advisory/license review and lifecycle runbooks still planned, not performed. No need to await 9B hardware sign-off to continue.
+- Final target checklist includes real SSH clients offering several keys, bad signatures/passwords, keyboard decline, each pool/refill/restart-clear persistence, established mixed transport/USB/UART0 responsiveness and reserve measurements, hidden-input errors/CRLF timing and crash recovery. UART0 paired/delayed LF relies on next-prompt flush; host UART fake does not model timing. No real-crypto/live packet-network or target claims from extracted-function tests.
+
 ## Phase 9A — crash/debug baseline — 2026-09-15
 
 - User requested Phase 9 and explicitly excluded secure boot and encrypted NVS. Roadmap now marks Phase 9 in progress; Phase 8 acceptance remains closed. Physical extraction/firmware replacement stay outside the threat model even after hardening; no encryption/eFuse/partition changes.
@@ -9,7 +20,7 @@ Working memory, not an implementation timeline. Source is authoritative; begin w
 - `docs/security_hardening.md` defines shared operational profiles, secret-bearing artifact handling, evidence limits and target gates. Reserved partitions unchanged; old dump/credential copies are not erased. No generated assets/dependency changes.
 - Validation: `pio run` PASS **94,196 B linked RAM / 1,828,565 B flash**. Host policy matrix PASS17; actual generated SDK header PASS as eighteenth case. Initial host test hit read-only ccache storage; `CCACHE_DISABLE=1` rerun passed. Independent review found no actionable issues and repeated both host modes and diff check. No upload, erase, hardware validation or commit.
 - **9A target gate remains open:** synthetic-secret controlled panic, no register/UART/flash dump, reboot rather than halt, UART0/USB/network recovery and broker behavior. No test-only panic command was added to production.
-- **Next implementation: SSH cross-connection authentication throttling.** Read-only audit verified three counted attempts per slot reset on reconnect, with unsigned key probes uncounted; web already gates five verifications per fixed global 60-second window. Choose bounded monotonic admission and explicit counters without sleeping the SSH owner, preserve currentness/slot ownership and test real wolfSSH callback ordering. No auth behavior changed in 9A. Remaining zeroization/crypto/dependency/license/lifecycle audits are planned, not completed.
+- 9A changed no authentication behavior; its planned SSH follow-up is now implemented in 9B above. Whole-phase target validation remains deferred.
 
 ## Web popup cosmetics — 2026-09-14
 

docs/agent/design-decisions.md

@@ -104,6 +104,18 @@ Only constraints supported by implementation or current project documentation be
 
 **Consequence:** Shared remote-console slots require transport-qualified tokens and immutable owner adapters. Validate owner currentness outside console locks, then recheck identity. Owner-side HTTPD/SSH IO and generation-safe cleanup remain mandatory; session liveness checks do not cancel executing handlers. Browser-shell permissions are parsed and narrower than typed Settings. [Authentication](../web_administration.md#authentication-and-admission), [console policy](../web_administration.md#browser-shell-policy).
 
+## SSH admission budgets survive service and session lifetimes
+
+**Decision:** Three fixed-size owner-only token buckets independently admit handshakes, password/signed-key requests and unsigned probes. Budgets last for the boot, not the slot/service/counter epoch. Rejection closes without sleeping; no per-account/IP storage or persistent lockout is added. Signed-key completion has an explicit pending-result marker and retains authoritative principal checks. Pinned library version/feature/source-contract tests protect callback order; keyboard-interactive is explicitly rejected.
+
+**Consequence:** This bounds admitted work but permits global-budget starvation; restarting SSH is not an immediate recovery override. Established streams bypass admission, while actual load/latency still needs whole-phase device evidence. Counters are observations, never enforcement state. [Policy and tests](../security_hardening.md#9b-ssh-admission-and-credential-handling).
+
+## Hidden input must not accept a truncated credential
+
+**Decision:** Hidden console prompts reject overflow/unsupported bytes at submit, wiping output; rejection stays sticky after edits. Submission, Backspace/Delete and Ctrl-C retain their roles. Visible CLI editing is unchanged. Consumed SSH admin RX and accepted TX spans are wiped without touching pending retry bytes; slot retirement securely wipes before restoring generation/sentinels.
+
+**Consequence:** Overlong/unsupported pastes must be retried; caller errors prevent prefix persistence. Application wipes do not establish library/stack/PSRAM zeroization. The pinned wolfSSH positive-send contract is copied/consumed bytes, not peer receipt. UART0 paired-CRLF timing remains a target check. Tests: `tests/hidden_input/run.py`, `tests/ssh_auth_transport/run.py`, `tests/wolfssh_auth_contract/run.py`.
+
 ## Typed serial mutations share the administration dispatcher
 
 **Decision:** Typed domains queue IDs to the existing serialized dispatcher, never CLI strings or secrets. One original-login slot per domain and a nonreused ID fence stale work; session/deadline checks precede canonical admission. Results are replaceable observations, not durable history/idempotency.