v0.108.0: hub-verified escrow auto-confirm on current-password hash match (SLICE 3)

EscrowAutoConfirmer flips pending->escrowed ONLY when sha256(local repo password) matches the ACK's restic_pw_sha256 (blob-presence alone never confirms — red-proofed). Mismatch warns once per hash naming the ceremony; never un-confirms; wipes the staged secret on flip. Pinned cross-repo hash vector; manual confirm deprecated to a legacy-blob fallback. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6
2026-07-09 23:19:17 +02:00
parent fec2e8fd84
commit febf6757dc
8 changed files with 327 additions and 4 deletions
@@ -1,5 +1,26 @@
 ## Changelog

+### v0.108.0 — SLICE 3: hub-verified escrow auto-confirm (current-password hash match) (2026-07-09)
+
+Replaces operator trust with a verified fact (pairs with agent v0.79.0 + hub v0.40.0): the report ACK now
+carries `escrow:{identity_blob_present, restic_pw_sha256, created_at}` and the controller flips offbox
+`EscrowState` pending→escrowed ONLY when `sha256(local repo_password) == restic_pw_sha256` — i.e. the
+stored escrow provably covers the CURRENT key, not merely "a blob exists" (a stale blob would re-open the
+un-recoverable-ciphertext gap fork-4 closed).
+
+- **`internal/report`:** `PushResponse.Escrow` + `EscrowAutoConfirmer` (long-lived; runs on every ACK):
+  match → flip (`UpdateOffboxStatus`) + wipe the agent-staged secret (the v0.107.0 DELETE path, best-effort
+  loud); mismatch → stays pending + a LOUD warn naming the fix ("run the escrow ceremony"), **deduped per
+  distinct hash** (not per 15-min cycle); no row / NULL hash / hash-without-identity-blob / no local
+  password file → stays pending silently (fail-closed); non-pending → total no-op (**never un-confirms**).
+  **Companion red-proof:** modeled the blob-present-only check → the stale-blob and hash-less scenarios
+  flipped when they must not → tests FAILED. Reverted — hash-match is the load-bearing core.
+- **`internal/backup`:** `HashResticPassword` (canonical: sha256 hex over the TRIMMED string — **pinned
+  cross-repo test vector**, same vector asserted in felhom-agent) + `Manager.OffboxRepoPasswordHash`.
+- **`internal/web`:** the manual `POST /backup/offbox/confirm-escrow` is now a documented **deprecated
+  fallback** for legacy hash-less blobs (e.g. the demo's) — auto-confirm is primary.
+- Hashes are safe to log (non-reversible over a 256-bit random secret); passwords never appear in logs.
+
 ### v0.107.0 — offsite hardening: key-auth-first bridge + staged-secret wipe on confirm (2026-07-09)

 Part of the offsite-provisioning hardening bundle (pairs with hub v0.39.0 + agent v0.78.0).
@@ -384,6 +384,32 @@ func main() {
 	var hubPusher *report.Pusher
 	if cfg.Hub.URL != "" && cfg.Hub.APIKey != "" {
 		hubPusher = report.NewPusher(&cfg.Hub, logger, cfg.Logging.Level == "debug")
+		// SLICE 3 — hub-verified escrow auto-confirm (long-lived: the mismatch warn dedupes per hash,
+		// not per 15-min cycle). Flips offbox pending→escrowed ONLY when the hub-recorded hash of the
+		// escrowed password matches the local repo password's hash; never un-confirms.
+		escrowConfirmer := &report.EscrowAutoConfirmer{
+			Pending: func() bool {
+				return backupMgr != nil && backupMgr.OffboxConfigured() &&
+					sett.GetOffboxTarget() != nil && sett.GetOffboxTarget().EscrowState == "pending"
+			},
+			LocalHash: func() (string, bool) {
+				if backupMgr == nil {
+					return "", false
+				}
+				return backupMgr.OffboxRepoPasswordHash()
+			},
+			Flip: func() error {
+				return sett.UpdateOffboxStatus(func(o *settings.OffboxTarget) { o.EscrowState = "escrowed" })
+			},
+			Wipe: func(ctx context.Context) error {
+				ac, err := agentapi.New(cfg.LocalAPI.Endpoint, cfg.LocalAPI.Token, cfg.LocalAPI.Fingerprint)
+				if err != nil {
+					return err
+				}
+				return ac.WipeStagedEscrowSecret(ctx)
+			},
+			Logger: logger,
+		}
 		// Wire hub verification: update settings when hub reports customer status
 		hubPusher.OnPushResponse = func(resp *report.PushResponse) {
 			if resp.CustomerBlocked {
@@ -414,6 +440,9 @@ func main() {
 				Logger:  logger,
 			}
 			cr.Reconcile(resp.ConfigVersion)
+			// SLICE 3: run the escrow auto-confirm on the same ACK (after the config refresh decision —
+			// a refresh-restart re-enters here anyway on the next cycle).
+			escrowConfirmer.Reconcile(resp.Escrow)
 		}
 		// Wire hub push status into alert manager for dashboard alerts
 		alertMgr.SetHubPushStatus(func() web.HubPushStatusData {
@@ -3,6 +3,7 @@ package backup
 import (
 	"context"
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
@@ -188,6 +189,26 @@ func (m *Manager) ApplyOffsiteTarget(ctx context.Context, tgt *settings.OffboxTa
 	return nil
 }

+// HashResticPassword is the CANONICAL hasher for the offsite repo password (SLICE 3 hub-verified escrow
+// auto-confirm): sha256 hex of the TRIMMED password string — the SAME convention as the agent's
+// escrow.HashResticPassword (both sides TrimSpace their file reads; pinned by the SAME cross-repo test
+// vector in felhom-agent). The hash of a 256-bit random secret is non-reversible and non-brute-forceable —
+// safe to log/compare; the PASSWORD itself is never logged.
+func HashResticPassword(pw string) string {
+	sum := sha256.Sum256([]byte(strings.TrimSpace(pw)))
+	return hex.EncodeToString(sum[:])
+}
+
+// OffboxRepoPasswordHash returns the canonical hash of the local repo password (false when no password
+// file exists — nothing to match; the auto-confirm check skips).
+func (m *Manager) OffboxRepoPasswordHash() (string, bool) {
+	pw, err := os.ReadFile(m.offboxPwPath())
+	if err != nil {
+		return "", false
+	}
+	return HashResticPassword(string(pw)), true
+}
+
 // PushOffboxPasswordForEscrow reads the 0600 repo password and hands it to `stage` (the agent push), so
 // the web/handler caller never sees the value — used by the enable flow to escrow-stage the offsite key.
 func (m *Manager) PushOffboxPasswordForEscrow(ctx context.Context, stage func(ctx context.Context, pw string) error) error {
@@ -47,6 +47,45 @@ func argsContainTimeout(args []string) bool {
 	return strings.Contains(strings.Join(args, " "), "-oConnectTimeout=")
 }

+// PINNED CROSS-REPO TEST VECTOR (SLICE 3): the same vector is asserted in felhom-agent's
+// escrow.HashResticPassword test — if either hasher drifts (newline, encoding, trim), its half fails and
+// the escrow auto-confirm can never silently mismatch. Convention: sha256 hex over the TRIMMED string.
+func TestHashResticPassword_PinnedVector(t *testing.T) {
+	const vector = "cafef00ddeadbeef0123456789abcdef0123456789abcdef0123456789abcdef"
+	const want = "dbfc02f987e1ac0c91911d5761267089b1144628745a3343e4d96194e43c08e4"
+	if got := HashResticPassword(vector); got != want {
+		t.Fatalf("pinned vector drift: got %s want %s", got, want)
+	}
+	if got := HashResticPassword("  " + vector + "\n"); got != want {
+		t.Fatalf("whitespace must not change the hash (trim convention), got %s", got)
+	}
+}
+
+// OffboxRepoPasswordHash: hashes the on-disk password file (the auto-confirm's local side); absent → ok=false.
+func TestOffboxRepoPasswordHash(t *testing.T) {
+	// bare manager (no secrets written yet) → no password file → ok=false
+	logger := log.New(os.Stderr, "", 0)
+	dataDir := t.TempDir()
+	sett, err := settings.Load(filepath.Join(dataDir, "settings.json"), logger)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfg := &config.Config{}
+	cfg.Paths.DataDir = dataDir
+	m := NewManager(cfg, sett, logger)
+	if _, ok := m.OffboxRepoPasswordHash(); ok {
+		t.Fatal("no password file → ok must be false")
+	}
+	const pw = "cafef00ddeadbeef0123456789abcdef0123456789abcdef0123456789abcdef"
+	if err := m.InjectOffboxPassword(pw, false); err != nil {
+		t.Fatal(err)
+	}
+	got, ok := m.OffboxRepoPasswordHash()
+	if !ok || got != "dbfc02f987e1ac0c91911d5761267089b1144628745a3343e4d96194e43c08e4" {
+		t.Fatalf("hash of the injected password wrong: ok=%v got=%s", ok, got)
+	}
+}
+
 // TestOffbox_BaseArgsCarryConnectTimeout asserts the mandatory fail-fast + hardening args are present.
 func TestOffbox_BaseArgsCarryConnectTimeout(t *testing.T) {
 	m, sett := newOffboxManager(t)
@@ -0,0 +1,88 @@
+package report
+
+import (
+	"context"
+	"log"
+	"sync"
+	"time"
+)
+
+// SLICE 3 — hub-verified escrow auto-confirm. Replaces operator trust ("I ran the ceremony, click
+// confirm") with a verified fact: the hub's report ACK carries the sha256 of the repo password the
+// stored escrow blob COVERS (recorded at ceremony time); the controller flips pending→escrowed ONLY
+// when that hash matches sha256 of its CURRENT local repo password. Blob-presence alone must never
+// confirm — a blob can predate the current password (re-provision, inject, drive history) and a
+// truthful-looking claim on a stale blob would re-open the exact un-recoverable-ciphertext gap fork-4
+// closed. Hashes are non-reversible (256-bit random secrets) and safe to log; passwords never are.
+
+// EscrowStatus mirrors the hub ACK's `escrow` object (nil when the hub has no escrow row).
+type EscrowStatus struct {
+	IdentityBlobPresent bool   `json:"identity_blob_present"`
+	ResticPwSHA256      string `json:"restic_pw_sha256"`
+	CreatedAt           string `json:"created_at"`
+}
+
+// EscrowAutoConfirmer runs the auto-confirm check on each report ACK. Long-lived (one per process) so
+// the mismatch warning dedupes per distinct hash instead of firing every 15-minute cycle.
+type EscrowAutoConfirmer struct {
+	// Pending reports whether the offbox target is configured AND EscrowState=="pending" — the ONLY
+	// state this confirmer acts on. "escrowed" is never revisited (auto-UN-confirm does not exist).
+	Pending func() bool
+	// LocalHash returns the canonical hash of the local repo password (ok=false → no password file).
+	LocalHash func() (hash string, ok bool)
+	// Flip transitions EscrowState pending→escrowed (settings.UpdateOffboxStatus).
+	Flip func() error
+	// Wipe removes the agent-staged secret (best-effort — the flip is the primary effect).
+	Wipe   func(ctx context.Context) error
+	Logger *log.Logger
+
+	mu         sync.Mutex
+	warnedHash string // last mismatched hub hash we warned about (dedupe)
+}
+
+func (c *EscrowAutoConfirmer) logf(f string, a ...any) {
+	if c.Logger != nil {
+		c.Logger.Printf(f, a...)
+	}
+}
+
+// Reconcile applies one ACK's escrow status. Scenarios: match → flip+wipe (A); mismatch → stay pending
+// + warn once per hash (B); no status / no hash / no local file → stay pending silently (C, normal
+// onboarding); not pending → no-op (E — already escrowed or offbox not configured).
+func (c *EscrowAutoConfirmer) Reconcile(es *EscrowStatus) {
+	if es == nil || !c.Pending() {
+		return
+	}
+	// Fail-closed: the hash must exist AND ride a present identity blob (the hash-bearing container).
+	// A hash-less blob is a legacy/password-less escrow — the deprecated manual confirm covers those.
+	if es.ResticPwSHA256 == "" || !es.IdentityBlobPresent {
+		return
+	}
+	localHash, ok := c.LocalHash()
+	if !ok {
+		return // no local repo password file — nothing to verify against
+	}
+	if localHash != es.ResticPwSHA256 {
+		// The stored escrow does NOT cover the current key — flipping would be a false custody claim.
+		c.mu.Lock()
+		warned := c.warnedHash == es.ResticPwSHA256
+		c.warnedHash = es.ResticPwSHA256
+		c.mu.Unlock()
+		if !warned {
+			c.logf("[WARN] [escrow-confirm] the hub's escrow blob does not cover the CURRENT repo password (hub hash %.12s… != local %.12s…) — run the escrow ceremony (felhom-agent --selftest=escrow-create --upload); staying pending", es.ResticPwSHA256, localHash)
+		}
+		return
+	}
+	if err := c.Flip(); err != nil {
+		c.logf("[ERROR] [escrow-confirm] hash matched but the escrowed flip failed (retries next cycle): %v", err)
+		return
+	}
+	c.logf("[INFO] [escrow-confirm] hub-verified: the escrow covers the current repo password (hash %.12s…) — EscrowState auto-confirmed escrowed; offsite runs enabled", es.ResticPwSHA256)
+	if c.Wipe != nil {
+		wctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+		defer cancel()
+		if err := c.Wipe(wctx); err != nil {
+			c.logf("[ERROR] [escrow-confirm] escrowed but the agent-staged secret was NOT wiped: %v", err)
+		}
+	}
+}
@@ -0,0 +1,121 @@
+package report
+
+import (
+	"bytes"
+	"context"
+	"log"
+	"strings"
+	"testing"
+)
+
+const (
+	hubHash   = "dbfc02f987e1ac0c91911d5761267089b1144628745a3343e4d96194e43c08e4"
+	otherHash = "1111111111111111111111111111111111111111111111111111111111111111"
+)
+
+type confirmerHarness struct {
+	c       *EscrowAutoConfirmer
+	pending bool
+	local   string
+	localOK bool
+	flips   int
+	wipes   int
+	logbuf  *bytes.Buffer
+}
+
+func newConfirmer(t *testing.T) *confirmerHarness {
+	t.Helper()
+	h := &confirmerHarness{pending: true, local: hubHash, localOK: true, logbuf: &bytes.Buffer{}}
+	h.c = &EscrowAutoConfirmer{
+		Pending:   func() bool { return h.pending },
+		LocalHash: func() (string, bool) { return h.local, h.localOK },
+		Flip:      func() error { h.flips++; h.pending = false; return nil },
+		Wipe:      func(context.Context) error { h.wipes++; return nil },
+		Logger:    log.New(h.logbuf, "", 0),
+	}
+	return h
+}
+
+func matchStatus(hash string) *EscrowStatus {
+	return &EscrowStatus{IdentityBlobPresent: true, ResticPwSHA256: hash, CreatedAt: "2026-07-09T20:00:00Z"}
+}
+
+// Scenario A — hash match → flip to escrowed + wipe the staged secret; and a repeat ACK is a no-op
+// (state is no longer pending).
+func TestEscrowConfirm_AutoConfirmsOnMatch(t *testing.T) {
+	h := newConfirmer(t)
+	h.c.Reconcile(matchStatus(hubHash))
+	if h.flips != 1 || h.wipes != 1 {
+		t.Fatalf("match must flip once + wipe once, got flips=%d wipes=%d", h.flips, h.wipes)
+	}
+	if !strings.Contains(h.logbuf.String(), "auto-confirmed") {
+		t.Fatal("the flip must log the hub-verified auto-confirm")
+	}
+	h.c.Reconcile(matchStatus(hubHash)) // now escrowed → no-op
+	if h.flips != 1 {
+		t.Fatal("an already-escrowed target must never be re-flipped")
+	}
+}
+
+// Scenario B — blob present but the hash does NOT cover the current password → stay pending + a LOUD
+// warn naming the ceremony; deduped per distinct hash (not per 15-min cycle).
+func TestEscrowConfirm_StaleBlobStaysPending(t *testing.T) {
+	h := newConfirmer(t)
+	h.local = otherHash // local password differs from what the blob covers
+	h.c.Reconcile(matchStatus(hubHash))
+	if h.flips != 0 || h.wipes != 0 {
+		t.Fatalf("a mismatched hash must NEVER flip (false custody claim): flips=%d", h.flips)
+	}
+	if !strings.Contains(h.logbuf.String(), "does not cover the CURRENT repo password") ||
+		!strings.Contains(h.logbuf.String(), "escrow ceremony") {
+		t.Fatalf("mismatch must warn loudly naming the fix, got: %s", h.logbuf.String())
+	}
+	// dedupe: the same hash again → no second warn
+	before := strings.Count(h.logbuf.String(), "does not cover")
+	h.c.Reconcile(matchStatus(hubHash))
+	if strings.Count(h.logbuf.String(), "does not cover") != before {
+		t.Fatal("repeated ACKs with the same mismatched hash must warn ONCE (dedupe)")
+	}
+	// a NEW distinct hash → warns again
+	h.c.Reconcile(matchStatus("2222222222222222222222222222222222222222222222222222222222222222"))
+	if strings.Count(h.logbuf.String(), "does not cover") != before+1 {
+		t.Fatal("a new distinct mismatched hash must warn again")
+	}
+}
+
+// Scenario C — no status / hash-less blob / no local password file → stay pending SILENTLY.
+func TestEscrowConfirm_SilentPendingCases(t *testing.T) {
+	h := newConfirmer(t)
+	h.c.Reconcile(nil) // no escrow row on the hub
+	h.c.Reconcile(&EscrowStatus{IdentityBlobPresent: true})                            // hash NULL (legacy blob)
+	h.c.Reconcile(&EscrowStatus{IdentityBlobPresent: false, ResticPwSHA256: hubHash})  // hash without identity blob — fail-closed
+	h.localOK = false
+	h.c.Reconcile(matchStatus(hubHash)) // no local password file
+	if h.flips != 0 || h.logbuf.Len() != 0 {
+		t.Fatalf("all no-verify cases must stay pending SILENTLY: flips=%d log=%q", h.flips, h.logbuf.String())
+	}
+}
+
+// Scenario E — not pending (already escrowed / offbox unconfigured) → no-op; NEVER un-confirms.
+func TestEscrowConfirm_NeverActsOutsidePending(t *testing.T) {
+	h := newConfirmer(t)
+	h.pending = false // already escrowed (the demo's live state)
+	h.c.Reconcile(matchStatus(hubHash))
+	h.c.Reconcile(matchStatus(otherHash)) // even a MISMATCH on an escrowed target must not warn/touch
+	if h.flips != 0 || h.wipes != 0 || h.logbuf.Len() != 0 {
+		t.Fatalf("non-pending must be a total no-op: flips=%d wipes=%d log=%q", h.flips, h.wipes, h.logbuf.String())
+	}
+}
+
+// A wipe failure after the flip is loud but does not undo the confirm (the flip is primary).
+func TestEscrowConfirm_WipeFailureKeepsConfirm(t *testing.T) {
+	h := newConfirmer(t)
+	h.c.Wipe = func(context.Context) error { return context.DeadlineExceeded }
+	h.c.Reconcile(matchStatus(hubHash))
+	if h.flips != 1 {
+		t.Fatal("the flip must land even when the wipe fails")
+	}
+	if !strings.Contains(h.logbuf.String(), "NOT wiped") {
+		t.Fatal("a failed wipe must log the loud NOT-wiped signal")
+	}
+}
@@ -37,6 +37,9 @@ type PushResponse struct {
 	// delivery — the hub never connects into the box). 0 = the hub didn't advertise it (old hub, or a
 	// report-only customer with no config row) → the controller does nothing.
 	ConfigVersion int `json:"config_version"`
+	// Escrow (SLICE 3) is the hub's escrow status for this customer — the input to the hub-verified
+	// auto-confirm (EscrowAutoConfirmer). nil = no escrow row on the hub (or an old hub) → stays pending.
+	Escrow *EscrowStatus `json:"escrow"`
 }

 // Pusher sends reports to the central hub.
@@ -108,10 +108,11 @@ func (s *Server) offboxConfigHandler(w http.ResponseWriter, r *http.Request) {
 	offboxRedirect(w, r, "A NAS mentési cél elmentve."+stageErr, stageErr != "")
 }

-// offboxConfirmEscrowHandler marks the offsite repo password as escrowed under R (fork-4). The operator
-// calls this after a successful escrow-create ceremony; offsite runs stay gated until then. (The
-// provisioning task should replace this with a hub-verified auto-confirm to remove the operator-forgets/
-// operator-lies footgun.)
+// offboxConfirmEscrowHandler marks the offsite repo password as escrowed under R (fork-4).
+// DEPRECATED FALLBACK (SLICE 3): the PRIMARY path is the hub-verified auto-confirm
+// (report.EscrowAutoConfirmer — flips on a hash match in the report ACK, no operator involved). This
+// manual endpoint stays for LEGACY blobs recorded before the hash existed (e.g. the demo's) — they have
+// no restic_pw_sha256 and can never auto-confirm; the operator vouches by hand after a verified ceremony.
 func (s *Server) offboxConfirmEscrowHandler(w http.ResponseWriter, r *http.Request) {
 	if s.backupMgr == nil || !s.backupMgr.OffboxConfigured() {
 		offboxRedirect(w, r, "A NAS mentési cél nincs beállítva.", true)