R-1254 (ceremony half, HUNT-3 H2): after a failed escrow upload, ask the hub which package it holds before wording the result

The hub holds the new package -> success; another package -> 502 'previous code still works' (now true);
cannot be asked -> 504, no promise. Tests TestR1254_* red before the fix. Commit only; the agent release needs the vouch.

CHANGELOG.md

@@ -1,3 +1,19 @@
+## Unreleased (2026-10-28 night) — R-1254 (the ceremony half, review round 2 HUNT-3 H2): the agent asks the hub which package it holds before it words a failed upload — commit only; the next agent release (needs the operator's vouch)
+
+- **The defect:** the claim's (R-978) and the confirm's (R-1151) package upload can lose its answer, or answer late
+  (30 s), AFTER the hub stored the new package. The agent then answered 502 „the previous code still works" — false: the
+  hub's current package opens only with the NEW code.
+- **Now (`internal/localapi/escrow_ceremony.go`):** after a failed upload the agent asks the hub (`HubHolds`, 15 s,
+  outside the lock, the slot still marked claiming): the hub holds THIS package → a success (the code is handed out /
+  the confirm completes; a WARN line names the lost answer); the hub holds another package → 502 and the old sentence,
+  now true; the hub cannot be asked → **504** with a sentence that promises nothing about either code, and the wait goes
+  on (a retry decides). `cmd/felhom-agent`: `HubHolds` compares the pending package's identity blob with the one the hub
+  serves back (`GET /api/v1/hosts/<id>/escrow`, the read-back the agent already uses; ciphertext only, nothing logged);
+  a package without an identity blob cannot be compared → unknown. Tests `TestR1254_*` (localapi, red before the fix:
+  502 while the hub held the new package) and `TestR1254_HubHoldsComparesTheIdentityBlob` (red-proved by mutation).
+- Needs controller ≥ the R-1254 controller commit (2026-10-28 night) to word 504 for the household; an older controller
+  shows its generic „A kód lekérése nem sikerült." (claim) / its 502 sentence (confirm) for it.
+
 ## v0.167.0 (2026-10-27) — the BYO SSH clean-up in the SAME update (R-1285); a reinstalled box's whole-guest tier is due at once (R-1232); Go 1.27.3 (R-972) — RELEASED (release-agent.sh from a clean clone; agent sha256 28bdd282…d826f0, bundle 9d034416…ed1268; signed updates committed on demo-felhom, Tester 1, demo-hp; VOUCHED by the operator 2026-10-27, Day-0 pin set)
 
 - **R-972: Go 1.27.3** (`go.mod`; released 2026-10-19 with a security fix to `crypto/x509`). `govulncheck` v1.8.0 before:

cmd/felhom-agent/escrow_r1254_test.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+)
+
+// R-1254 H2, the production question: does the hub's current package equal the pending upload body? Compared by the
+// identity blob the hub serves back. A package without an identity, or a hub that cannot answer, is never „held".
+// RED-PROOF: make hubHoldsEscrowPackage return true when the hub has any package → the „another package" case
+// passes as held → FAILS.
+func TestR1254_HubHoldsComparesTheIdentityBlob(t *testing.T) {
+	body := func(id string) []byte {
+		b, _ := json.Marshal(escrowUploadRequest{BlobB64: base64.StdEncoding.EncodeToString([]byte("k")),
+			IdentityBlobB64: base64.StdEncoding.EncodeToString([]byte(id))})
+		return b
+	}
+	hubWith := func(id string, present bool, err error) func(context.Context) (*hub.IdentityEscrowResponse, error) {
+		return func(context.Context) (*hub.IdentityEscrowResponse, error) {
+			if err != nil {
+				return nil, err
+			}
+			return &hub.IdentityEscrowResponse{Present: present, IdentityEscrowB64: base64.StdEncoding.EncodeToString([]byte(id))}, nil
+		}
+	}
+	ctx := context.Background()
+	if held, err := hubHoldsEscrowPackage(ctx, hubWith("NEW", true, nil), body("NEW")); err != nil || !held {
+		t.Fatalf("the hub holds the new package: held=%v err=%v", held, err)
+	}
+	if held, err := hubHoldsEscrowPackage(ctx, hubWith("OLD", true, nil), body("NEW")); err != nil || held {
+		t.Fatalf("the hub holds another package: held=%v err=%v", held, err)
+	}
+	if held, err := hubHoldsEscrowPackage(ctx, hubWith("", false, nil), body("NEW")); err != nil || held {
+		t.Fatalf("the hub holds nothing: held=%v err=%v", held, err)
+	}
+	if _, err := hubHoldsEscrowPackage(ctx, hubWith("", false, errors.New("unreachable")), body("NEW")); err == nil {
+		t.Fatal("a hub that cannot answer must be an error (unknown), never „not held\"")
+	}
+	noID, _ := json.Marshal(escrowUploadRequest{BlobB64: "aw=="})
+	if _, err := hubHoldsEscrowPackage(ctx, hubWith("NEW", true, nil), noID); err == nil {
+		t.Fatal("a package without an identity blob cannot be compared — an error")
+	}
+}

cmd/felhom-agent/main.go

@@ -1250,6 +1250,14 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 		// R-978: the ceremony hands its package back; the claim uploads it with the same PUT the root
 		// subprocess used, under the same per-host key, before the code is handed out.
 		Upload: func(ctx context.Context, pkg []byte) error { return putEscrowBody(ctx, cfg, pkg) },
+		// R-1254 H2: after a failed upload, the hub is asked which package it holds before the household is told
+		// anything — the same per-host GET the identity read-back uses.
+		HubHolds: func(ctx context.Context, pkg []byte) (bool, error) {
+			if client == nil {
+				return false, fmt.Errorf("hub client not configured")
+			}
+			return hubHoldsEscrowPackage(ctx, client.FetchIdentityEscrow, pkg)
+		},
 		DRConfigured: func() bool {
 			if drConfigured != nil {
 				return drConfigured()
@@ -3366,6 +3374,32 @@ func escrowUploadBody(res escrow.CreateResult, resticPwSHA256 string) []byte {
 
 // putEscrowBody PUTs an escrow upload body to this host's hub record (the per-host key). Used by the
 // text-mode ceremony at once, and by the daemon when the customer claims the code (R-978).
+// hubHoldsEscrowPackage (R-1254 H2) reports whether the hub's CURRENT package is the upload body pkg, by its identity
+// blob — the part the hub serves back (GET /api/v1/hosts/<id>/escrow). Ciphertext only; nothing is logged. A package
+// without an identity blob cannot be compared: an error (the caller then promises nothing).
+func hubHoldsEscrowPackage(ctx context.Context, fetch func(context.Context) (*hub.IdentityEscrowResponse, error), pkg []byte) (bool, error) {
+	var up escrowUploadRequest
+	if err := json.Unmarshal(pkg, &up); err != nil {
+		return false, fmt.Errorf("reading the pending package: %w", err)
+	}
+	mine, err := base64.StdEncoding.DecodeString(up.IdentityBlobB64)
+	if err != nil || len(mine) == 0 {
+		return false, fmt.Errorf("the pending package carries no identity blob to compare")
+	}
+	resp, err := fetch(ctx)
+	if err != nil {
+		return false, err
+	}
+	if !resp.Present || resp.IdentityEscrowB64 == "" {
+		return false, nil
+	}
+	theirs, err := base64.StdEncoding.DecodeString(resp.IdentityEscrowB64)
+	if err != nil {
+		return false, fmt.Errorf("decoding the hub's package: %w", err)
+	}
+	return bytes.Equal(mine, theirs), nil
+}
+
 func putEscrowBody(ctx context.Context, cfg config.Config, body []byte) error {
 	if cfg.Hub.URL == "" || cfg.Hub.HostID == "" || cfg.Hub.APIKey == "" {
 		return fmt.Errorf("hub not configured (url/host_id/api_key)")

internal/localapi/escrow_ceremony.go

@@ -72,12 +72,56 @@ type EscrowCeremonyConfig struct {
 	// host's hub record — called by the claim, BEFORE the code is handed out (R-978). nil → a claim of
 	// a pending package is refused (503): a code must never be handed out for a package the hub lacks.
 	Upload func(ctx context.Context, pkg []byte) error
+	// HubHolds (R-1254 H2) asks the hub whether its CURRENT package is exactly pkg — asked after a failed upload,
+	// whose answer may have been lost AFTER the hub stored it. nil or an error → the outcome is unknown.
+	HubHolds func(ctx context.Context, pkg []byte) (bool, error)
 }
 
 // escrowUploadTimeout bounds the claim-time package upload (one small PUT; the subprocess's whole
 // ceremony incl. its upload was measured at ~2.4 s).
 const escrowUploadTimeout = 30 * time.Second
 
+// escrowHoldTimeout bounds the hub question after a failed upload (R-1254 H2).
+const escrowHoldTimeout = 15 * time.Second
+
+// uploadOutcome is what a claim or confirm upload did, as the HUB tells it (R-1254 H2): an upload whose answer was lost
+// or late may have been stored all the same.
+type uploadOutcome int
+
+const (
+	uploadStored    uploadOutcome = iota // the hub holds the new package
+	uploadNotStored                      // the hub answered and holds another package: the previous code still works
+	uploadUnknown                        // the hub cannot be asked: nothing may be promised about either code
+)
+
+// escrowUnknownOutcomeMsg is the answer when the hub cannot say which package it holds — never „the previous code
+// still works", which is false when the lost answer came after the store.
+const escrowUnknownOutcomeMsg = "the hub did not answer in time — it is not known whether it stored the new recovery package; try again (until a try succeeds, do not rely on the previous code alone)"
+
+// outcomeAfterFailedUpload asks the hub whether it holds pkg after Upload returned an error. Called with the slot
+// marked claiming (escrowClaiming), outside escrowMu — it is a network call.
+func (s *Server) outcomeAfterFailedUpload(pkg []byte) uploadOutcome {
+	if s.escrowCeremony.HubHolds == nil {
+		return uploadUnknown
+	}
+	base := s.baseCtx
+	if base == nil {
+		base = context.Background()
+	}
+	ctx, cancel := context.WithTimeout(base, escrowHoldTimeout)
+	defer cancel()
+	held, err := s.escrowCeremony.HubHolds(ctx, pkg)
+	switch {
+	case err != nil:
+		s.logger.Warn("local-api: escrow — the hub cannot say which package it holds after a failed upload (R-1254)", "err", err)
+		return uploadUnknown
+	case held:
+		return uploadStored
+	default:
+		return uploadNotStored
+	}
+}
+
 // ceremonyRunner executes the fixed-argv sudo self-invocation. stdout is SECRET-BEARING until
 // parsed (it carries R inside the JSON object); the caller must zero it. Tests inject canned
 // spike-shaped output; production is runCeremonySubprocess.
@@ -524,15 +568,30 @@ func (s *Server) handleEscrowCeremonyClaim(w http.ResponseWriter, r *http.Reques
 		uctx, cancel := context.WithTimeout(base, escrowUploadTimeout)
 		err := s.escrowCeremony.Upload(uctx, pkg)
 		cancel()
+		outcome := uploadStored
+		if err != nil {
+			outcome = s.outcomeAfterFailedUpload(pkg) // R-1254 H2: the answer may be lost AFTER the store
+		}
 
 		s.escrowMu.Lock()
 		s.escrowClaiming = false
-		if err != nil {
+		switch outcome {
+		case uploadNotStored:
 			s.escrowMu.Unlock()
 			s.logger.Warn("local-api: escrow claim — package upload to the hub failed; code kept claimable, previous package stays current (R-978)",
 				"vmid", vmid, "job_id", jobID, "err", err, "duration_ms", time.Since(start).Milliseconds())
 			writeErr(w, http.StatusBadGateway, "the new recovery package could not be stored on the hub — the previous code still works; try again")
 			return
+		case uploadUnknown:
+			s.escrowMu.Unlock()
+			s.logger.Warn("local-api: escrow claim — upload failed and the hub cannot say which package it holds; code kept claimable (R-1254)",
+				"vmid", vmid, "job_id", jobID, "err", err, "duration_ms", time.Since(start).Milliseconds())
+			writeErr(w, http.StatusGatewayTimeout, escrowUnknownOutcomeMsg)
+			return
+		}
+		if err != nil {
+			s.logger.Warn("local-api: escrow claim — the upload's answer was lost, but the hub holds the new package; handing out the code (R-1254)",
+				"vmid", vmid, "job_id", jobID, "err", err)
 		}
 		s.escrowPending = nil
 		if s.escrowJob != nil && s.escrowJob.JobID == jobID {
@@ -631,15 +690,30 @@ func (s *Server) handleEscrowCeremonyConfirm(w http.ResponseWriter, r *http.Requ
 	uctx, cancel := context.WithTimeout(base, escrowUploadTimeout)
 	err := s.escrowCeremony.Upload(uctx, pkg)
 	cancel()
+	outcome := uploadStored
+	if err != nil {
+		outcome = s.outcomeAfterFailedUpload(pkg) // R-1254 H2
+	}
 
 	s.escrowMu.Lock()
 	s.escrowClaiming = false
-	if err != nil {
+	switch outcome {
+	case uploadNotStored:
 		s.escrowMu.Unlock()
 		s.logger.Warn("local-api: escrow confirm — package upload to the hub failed; still waiting, previous package stays current (R-1151)",
 			"vmid", vmid, "job_id", jobID, "err", err, "duration_ms", time.Since(start).Milliseconds())
 		writeErr(w, http.StatusBadGateway, "the new recovery package could not be stored on the hub — the previous code still works; try again")
 		return
+	case uploadUnknown:
+		s.escrowMu.Unlock()
+		s.logger.Warn("local-api: escrow confirm — upload failed and the hub cannot say which package it holds; still waiting (R-1254)",
+			"vmid", vmid, "job_id", jobID, "err", err, "duration_ms", time.Since(start).Milliseconds())
+		writeErr(w, http.StatusGatewayTimeout, escrowUnknownOutcomeMsg)
+		return
+	}
+	if err != nil {
+		s.logger.Warn("local-api: escrow confirm — the upload's answer was lost, but the hub holds the new package (R-1254)",
+			"vmid", vmid, "job_id", jobID, "err", err)
 	}
 	s.escrowPending = nil
 	s.wipeEscrowConfirmLocked()

internal/localapi/escrow_ceremony_test.go

@@ -41,9 +41,13 @@ type fakeEscrowHub struct {
 	mu      sync.Mutex
 	current []byte
 	uploads int
-	err     error         // non-nil → the upload fails, nothing stored
-	gate    chan struct{} // non-nil → the upload blocks until closed
-	entered chan struct{} // non-nil → closed when an upload starts
+	err     error // non-nil → the upload fails, nothing stored
+	// R-1254 H2: lost → the upload STORES the package and then fails (the answer is lost on the way back);
+	// holdsErr → the hub cannot be asked which package it holds.
+	lost     bool
+	holdsErr error
+	gate     chan struct{} // non-nil → the upload blocks until closed
+	entered  chan struct{} // non-nil → closed when an upload starts
 }
 
 func (f *fakeEscrowHub) upload(ctx context.Context, pkg []byte) error {
@@ -61,9 +65,23 @@ func (f *fakeEscrowHub) upload(ctx context.Context, pkg []byte) error {
 	}
 	f.current = append([]byte(nil), pkg...)
 	f.uploads++
+	if f.lost {
+		return context.DeadlineExceeded
+	}
 	return nil
 }
 
+// holds answers „is the hub's current package exactly pkg?" — the R-1254 question (production compares the identity
+// blob the hub serves back).
+func (f *fakeEscrowHub) holds(_ context.Context, pkg []byte) (bool, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if f.holdsErr != nil {
+		return false, f.holdsErr
+	}
+	return string(f.current) == string(pkg), nil
+}
+
 // opensWith reports whether the hub's CURRENT package opens with code r — the customer's question.
 func (f *fakeEscrowHub) opensWith(r string) bool {
 	f.mu.Lock()
@@ -100,6 +118,7 @@ func newEscrowTestServerHub(t *testing.T, run ceremonyRunner, hub *fakeEscrowHub
 		HubConfigured: true,
 		DRConfigured:  func() bool { return true },
 		Upload:        hub.upload,
+		HubHolds:      hub.holds,
 	}
 	srv.ceremonyRun = run
 	srv.escrowSudoCheck = func(context.Context) error { return nil }

internal/localapi/escrow_r1254_test.go

@@ -0,0 +1,98 @@
+package localapi
+
+import (
+	"errors"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+// R-1254 (the ceremony half, review round 2 HUNT-3 H2): the upload's answer can be lost or late (30 s) AFTER the hub
+// stored the new package. The household was then told „the previous code still works" — false: the hub now holds the
+// package the NEW code opens. The agent asks the hub which package it holds before it words the result:
+//   - the hub holds the new package → success (the code is handed out / the confirm completes);
+//   - the hub holds another package → the old sentence, now true;
+//   - the hub cannot be asked → 504 and a sentence that does NOT promise the previous code; the wait goes on.
+
+// RED-PROOF: remove the hub question from the claim's failure branch → 502 „the previous code still works" while the
+// hub holds the new package → FAILS.
+func TestR1254_ALostAnswerAtTheClaimIsASuccessWhenTheHubHoldsTheNewPackage(t *testing.T) {
+	hub := &fakeEscrowHub{lost: true}
+	srv, _ := newEscrowTestServerHub(t, sequenceRunner(firstR), hub)
+	h := srv.Handler()
+	startAndWait(t, srv, h)
+	code, body := claimCode(t, h)
+	if !hub.opensWith(firstR) {
+		t.Fatal("fixture: the hub must hold the new package (the answer was lost after the store)")
+	}
+	if code != http.StatusOK || !strings.Contains(body, firstR) {
+		t.Fatalf("claim after a lost answer, the hub holding the new package: %d %s — want 200 with the code", code, body)
+	}
+	if strings.Contains(body, "previous code still works") {
+		t.Fatalf("the household was told the previous code still works: %s", body)
+	}
+	if st := do(t, h, "GET", "/escrow/ceremony/status", "A", "").Body.String(); !strings.Contains(st, `"uploaded":true`) {
+		t.Fatalf("the job must read uploaded: %s", st)
+	}
+}
+
+// The hub cannot be asked: no promise about the previous code, 504, the code stays claimable (a retry decides).
+// RED-PROOF: as above → 502 with „the previous code still works" → FAILS.
+func TestR1254_AnUnknownOutcomeAtTheClaimPromisesNothing(t *testing.T) {
+	hub := &fakeEscrowHub{lost: true, holdsErr: errors.New("hub unreachable")}
+	srv, _ := newEscrowTestServerHub(t, sequenceRunner(firstR), hub)
+	h := srv.Handler()
+	startAndWait(t, srv, h)
+	code, body := claimCode(t, h)
+	if code != http.StatusGatewayTimeout {
+		t.Fatalf("claim with an unknown outcome: %d %s — want 504", code, body)
+	}
+	if strings.Contains(body, "previous code still works") {
+		t.Fatalf("an unknown outcome promised the previous code: %s", body)
+	}
+	assertNoRIn(t, "unknown-outcome claim payload", body, firstR)
+	if st := do(t, h, "GET", "/escrow/ceremony/status", "A", "").Body.String(); !strings.Contains(st, `"claimable":true`) {
+		t.Fatalf("the code must stay claimable: %s", st)
+	}
+	// The hub answers again: the retry finds the new package already stored and hands the code out.
+	hub.mu.Lock()
+	hub.holdsErr = nil
+	hub.mu.Unlock()
+	if code, body := claimCode(t, h); code != http.StatusOK || !strings.Contains(body, firstR) {
+		t.Fatalf("retry: %d %s", code, body)
+	}
+}
+
+// The hub holds ANOTHER package (the upload really failed): the old sentence stays, and is now true.
+func TestR1254_AFailedUploadTheHubDidNotStoreKeepsTheOldSentence(t *testing.T) {
+	hub := &fakeEscrowHub{err: errors.New("hub returned HTTP 502")}
+	srv, _ := newEscrowTestServerHub(t, sequenceRunner(firstR), hub)
+	h := srv.Handler()
+	startAndWait(t, srv, h)
+	if code, body := claimCode(t, h); code != http.StatusBadGateway || !strings.Contains(body, "previous code still works") {
+		t.Fatalf("a failed upload: %d %s — want 502 and the previous code named", code, body)
+	}
+}
+
+// The same at the typed-back confirm (R-1151).
+// RED-PROOF: remove the hub question from the confirm's failure branch → 502 → FAILS.
+func TestR1254_ALostAnswerAtTheConfirmIsASuccessWhenTheHubHoldsTheNewPackage(t *testing.T) {
+	hub := &fakeEscrowHub{lost: true}
+	srv, _ := newEscrowTestServerHub(t, sequenceRunner(secondR), hub)
+	h := srv.Handler()
+	startAndWait(t, srv, h)
+	c := claimDeferred(t, h)
+	if code := confirm(t, h, c.typedBack(t)); code != http.StatusOK || !hub.opensWith(secondR) {
+		t.Fatalf("confirm after a lost answer: %d (opens: %v) — want 200", code, hub.opensWith(secondR))
+	}
+	hub.mu.Lock()
+	hub.lost, hub.holdsErr = true, errors.New("hub unreachable")
+	hub.mu.Unlock()
+	srv2, _ := newEscrowTestServerHub(t, sequenceRunner(firstR), hub)
+	h2 := srv2.Handler()
+	startAndWait(t, srv2, h2)
+	c2 := claimDeferred(t, h2)
+	if code := confirm(t, h2, c2.typedBack(t)); code != http.StatusGatewayTimeout {
+		t.Fatalf("confirm with an unknown outcome: %d — want 504", code)
+	}
+}