One-view tokens: local records in linked zones, zone lookup, view list

A token for one view of a linked zone (an ACME token for external)
couldn't add records: a new record was shared and reached the other
view. A new name and type is now local when the user may not change it
in the other views. A zone name in several views resolves to the only
one the user can see, and the error no longer names views they can't.
GET /views lists the views a user sees zones in (name, colour, count;
limited) without views:read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/engine/expand.go

@@ -76,11 +76,13 @@ func (x *expander) resolveZone(zoneID int64, zone, view string) (*model.Zone, er
 	if zone == "" {
 		return nil, errf(KindBadRequest, "the zone is missing (zone_id or zone)")
 	}
-	return FindZoneRef(x.st, zone, view)
+	return FindZoneRef(x.st, zone, view, func(z *model.Zone) bool { return x.p.CanSeeZone(z.Name, x.st.ViewName(z)) })
 }
 
-// FindZoneRef finds a zone by name and optional view name.
-func FindZoneRef(st *model.State, zone, view string) (*model.Zone, error) {
+// FindZoneRef finds a zone by name and optional view name. Without a
+// view, a name in several views needs one, counting only the zones sees
+// allows (nil: all): a token for one view finds that view's zone.
+func FindZoneRef(st *model.State, zone, view string, sees func(*model.Zone) bool) (*model.Zone, error) {
 	name, err := ParseZoneName(zone)
 	if err != nil {
 		return nil, errf(KindBadRequest, "%v", err)
@@ -97,6 +99,16 @@ func FindZoneRef(st *model.State, zone, view string) (*model.Zone, error) {
 		return z, nil
 	}
 	zs := st.ZonesNamed(name)
+	if sees != nil && len(zs) > 1 {
+		var vis []*model.Zone
+		for _, z := range zs {
+			if sees(z) {
+				vis = append(vis, z)
+			}
+		}
+		zs = vis // none: not found, without naming the views
+	}
+	st.SortByView(zs)
 	switch len(zs) {
 	case 0:
 		return nil, errf(KindNotFound, "zone %s does not exist", dnsname.Display(name))

internal/engine/linked.go

@@ -456,12 +456,30 @@ func (x *expander) unlinkOps(m *model.Zone, summary string) []model.Op {
 
 // localFor works out whether a new record (or set) in zone z is local:
 // as asked, or like the records of the same name and type already there.
+// A new name and type is shared, unless the principal may not change it
+// in every linked view (an ACME token for the external view only): then
+// it is local to z's view, which is all they may change.
 func (x *expander) localFor(z *model.Zone, name, typ string, want *bool) (bool, error) {
-	has := x.st.HasLocal(z.ID, name, typ)
-	if want == nil {
-		return has, nil
+	if want != nil {
+		return *want, nil
 	}
-	return *want, nil
+	if x.st.HasLocal(z.ID, name, typ) {
+		return true, nil
+	}
+	if len(x.st.SharedRecords(z.ID, name, typ)) > 0 {
+		return false, nil
+	}
+	var not []string
+	for _, o := range x.st.LinkedWith(z) {
+		if !x.p.Can(recordAction(x.st, o, name, typ, true)) {
+			not = append(not, x.st.ViewName(o))
+		}
+	}
+	if len(not) > 0 {
+		x.warnings = append(x.warnings, fmt.Sprintf("%s %s is local to view %s: you may not change it in %s", dnsname.Display(name), typ, x.st.ViewName(z), strings.Join(not, ", ")))
+		return true, nil
+	}
+	return false, nil
 }
 
 // shareAllOps returns the operations that start a link with zone z: it

internal/engine/linked_test.go

@@ -413,3 +413,37 @@ func TestDeleteLocalOverride(t *testing.T) {
 		t.Errorf("validation: %+v", probs)
 	}
 }
+
+// An ACME token for one view of a linked zone: its challenge records are
+// local to that view, the zone is found without naming the view, and they
+// go again without touching the other view.
+func TestLinkedACMEToken(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("external"), LinkWith: "internal"}))
+	u := &model.User{Username: "certbot", Grants: []model.Grant{{Resource: auth.ResRecords, Access: "write", Zones: []string{"example.com"}, Views: []string{"external"}, Names: []string{"_acme-challenge.*"}, Types: []string{"TXT"}}}}
+	if err := env.st.CreateUser(env.ctx, u); err != nil {
+		t.Fatal(err)
+	}
+	bot := &auth.Principal{User: u, Method: "token"}
+	name, typ, data := "_acme-challenge", "TXT", "token-value"
+	res := env.submit(bot, NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", Name: &name, Type: &typ, Data: &data}))
+	if !slices.Contains(env.view("external"), "_acme-challenge TXT \"token-value\" L") || slices.ContainsFunc(env.view("internal"), func(s string) bool { return strings.HasPrefix(s, "_acme-challenge") }) {
+		t.Errorf("challenge: internal %q external %q", env.view("internal"), env.view("external"))
+	}
+	if !slices.ContainsFunc(res.Warnings, func(w string) bool { return strings.Contains(w, "local to view external") }) {
+		t.Errorf("warnings %q", res.Warnings)
+	}
+	env.submit(bot, NewRequest(OpRecordDelete, 0, RecordInput{Zone: "example.com", Name: &name, Type: &typ, Data: &data}))
+	if slices.ContainsFunc(env.view("external"), func(s string) bool { return strings.HasPrefix(s, "_acme-challenge") }) {
+		t.Errorf("not deleted: %q", env.view("external"))
+	}
+	// The admin, who may change both, still gets a shared record.
+	env.submit(env.admin, NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", View: "internal", Name: model.Ptr("both"), Type: model.Ptr("A"), Data: model.Ptr("192.0.2.7")}))
+	if !slices.Contains(env.view("external"), "both A 192.0.2.7 S") {
+		t.Errorf("admin: %q", env.view("external"))
+	}
+	// Without a view, the admin is still asked which.
+	if e := env.submitErr(env.admin, NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", Name: model.Ptr("x"), Type: model.Ptr("A"), Data: model.Ptr("192.0.2.8")})); !strings.Contains(e.Message, "several views (internal, external)") {
+		t.Errorf("admin without a view: %v", e)
+	}
+}