diff --git a/backend/src/BigRegister.Api/Domain/Authorization/IIdentityProvider.cs b/backend/src/BigRegister.Api/Domain/Authorization/IIdentityProvider.cs
index 5d4f047..a69a16d 100644
--- a/backend/src/BigRegister.Api/Domain/Authorization/IIdentityProvider.cs
+++ b/backend/src/BigRegister.Api/Domain/Authorization/IIdentityProvider.cs
@@ -4,9 +4,14 @@ namespace BigRegister.Domain.Authorization;
/// Resolves the acting for a request (WP-53) — one of the two actor
/// kinds (WP-62, ADR-0002 §3): a zorgverlener (real DigiD claims in production) or a medewerker
/// (real employee SSO/eHerkenning claims in production). is
-/// the only implementation today.
+/// the only implementation today, and is registered only in Development (Program.cs,
+/// RB-09/BIO-002).
///
public interface IIdentityProvider
{
- CallerIdentity Resolve(HttpContext ctx);
+ /// Null when the request carries no identity a real implementation can vouch for —
+ /// e.g. no credential at all. Returning null, rather than inventing a default, is what makes
+ /// "unauthenticated" representable; the identity-resolution middleware (Program.cs)
+ /// turns a null into a 401 instead of a silent identity substitution.
+ CallerIdentity? Resolve(HttpContext ctx);
}
diff --git a/backend/src/BigRegister.Api/Domain/Authorization/StubIdentityProvider.cs b/backend/src/BigRegister.Api/Domain/Authorization/StubIdentityProvider.cs
index d3ba6ff..0a721cd 100644
--- a/backend/src/BigRegister.Api/Domain/Authorization/StubIdentityProvider.cs
+++ b/backend/src/BigRegister.Api/Domain/Authorization/StubIdentityProvider.cs
@@ -13,6 +13,11 @@ namespace BigRegister.Domain.Authorization;
/// A real system builds this from verified DigiD claims (zorgverlener) / employee SSO claims
/// (medewerker); every consumer of carries over unchanged once that
/// swap happens.
+///
+/// Registered only in Development (Program.cs, RB-09/BIO-002) — it always invents a
+/// caller for a request with no credential, which is a deliberate developer convenience, not
+/// something a production build may do. Its own return type stays non-nullable: unlike
+/// , this stub never has "no identity" to report.
///
public sealed class StubIdentityProvider : IIdentityProvider
{
diff --git a/backend/src/BigRegister.Api/Program.cs b/backend/src/BigRegister.Api/Program.cs
index 270eacd..e630dd6 100644
--- a/backend/src/BigRegister.Api/Program.cs
+++ b/backend/src/BigRegister.Api/Program.cs
@@ -51,7 +51,22 @@ Db.ConnectionString = builder.Configuration.GetConnectionString("AppDb") ?? Db.C
// every store call site that used to hardcode DocumentStore.DemoOwner. Stub today (X-Role/
// X-Subject for a zorgverlener, X-Medewerker/X-Rollen for a medewerker); a real
// DigiD/employee-SSO provider swaps in without touching a consumer.
-builder.Services.AddSingleton();
+//
+// RB-09/BIO-002: StubIdentityProvider invents a citizen identity for any request with no
+// credential at all — a production behandelportal build sends no X-Medewerker header, so it
+// used to authenticate every request as the seeded citizen (open on that citizen's own rights,
+// including CanRevealBigNummer). Registering the stub only in Development, and failing to
+// start in Production rather than falling through to a per-request 401, means a misconfigured
+// deploy never serves a single request. The real DigiD/employee-SSO provider is out of scope
+// for this POC (BIO-002's remediation says so explicitly) — until one exists, Production simply
+// cannot start, which is the correct fail-closed behaviour for "no identity provider available".
+if (builder.Environment.IsDevelopment())
+ builder.Services.AddSingleton();
+else if (builder.Environment.IsProduction())
+ throw new InvalidOperationException(
+ "No IIdentityProvider is registered for a Production environment. StubIdentityProvider " +
+ "is Development-only (RB-09/BIO-002); there is no real DigiD/employee-SSO provider in " +
+ "this POC yet. Register one before deploying to Production.");
// WP-49: the cases (zaken) READ path goes through IZaakSource so a real ZGW backend
// (OpenZaak) can replace the local SQLite store behind the same DTO contract — the FE never
@@ -111,11 +126,19 @@ app.Use(async (ctx, next) =>
// WP-53: resolve the acting citizen once per request, right after correlation — everything
// downstream (Authz.ResolvePrincipal, the endpoints below) reads it via ctx.Caller() instead of
-// re-deriving "who" itself.
+// re-deriving "who" itself. RB-09/BIO-002: a null resolution is "no identity", not "the seeded
+// citizen" — this is the one place that turns it into a response (401) rather than letting it
+// flow downstream as a silent identity substitution.
var identityProvider = app.Services.GetRequiredService();
app.Use(async (ctx, next) =>
{
- ctx.SetCaller(identityProvider.Resolve(ctx));
+ var identity = identityProvider.Resolve(ctx);
+ if (identity is null)
+ {
+ ctx.Response.StatusCode = StatusCodes.Status401Unauthorized;
+ return;
+ }
+ ctx.SetCaller(identity);
await next(ctx);
});
diff --git a/backend/tests/BigRegister.Tests/StubIdentityProviderTests.cs b/backend/tests/BigRegister.Tests/StubIdentityProviderTests.cs
index 529a154..28fef57 100644
--- a/backend/tests/BigRegister.Tests/StubIdentityProviderTests.cs
+++ b/backend/tests/BigRegister.Tests/StubIdentityProviderTests.cs
@@ -1,6 +1,8 @@
using BigRegister.Api.Data;
using BigRegister.Domain.Authorization;
+using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Testing;
namespace BigRegister.Tests;
@@ -93,4 +95,32 @@ public class StubIdentityProviderTests
var caller = Resolve(role: "admin", medewerker: "m.jansen");
Assert.Equal(PrincipalRole.Admin, caller.Role);
}
+
+ /// RB-09/BIO-002: IIdentityProvider.Resolve can now return null ("no identity"), but this
+ /// stub's own contract stays non-nullable — it is a developer convenience that always invents
+ /// a caller, never a source of "no identity" itself. A request with genuinely no headers at
+ /// all still resolves to the seeded citizen, unchanged.
+ [Fact]
+ public void Never_returns_null_even_with_no_headers_at_all()
+ {
+ Assert.NotNull(new StubIdentityProvider().Resolve(new DefaultHttpContext()));
+ }
+}
+
+/// RB-09/BIO-002: in Production, StubIdentityProvider is not registered at all (it is
+/// Development-only) and there is no real DigiD/employee-SSO IIdentityProvider in this POC yet —
+/// so a Production build must fail at startup rather than silently resolving every request to
+/// the seeded citizen (the failure mode BIO-002 documents).
+public class ProductionIdentityProviderTests
+{
+ [Fact]
+ public void Production_environment_with_no_real_identity_provider_fails_at_startup()
+ {
+ using var factory = new WebApplicationFactory()
+ .WithWebHostBuilder(builder => builder.UseEnvironment("Production"));
+
+ // The throw happens while the app builds services, before any request can be served —
+ // triggered here by the test host materialising that host to hand out a client.
+ Assert.ThrowsAny(() => factory.CreateClient());
+ }
}
diff --git a/docs/project/refactor-backlog-setup/refactor-backlog/implementation/rb-09.md b/docs/project/refactor-backlog-setup/refactor-backlog/implementation/rb-09.md
new file mode 100644
index 0000000..8e7fd85
--- /dev/null
+++ b/docs/project/refactor-backlog-setup/refactor-backlog/implementation/rb-09.md
@@ -0,0 +1,123 @@
+# RB-09 — make "no identity" representable; stub Development-only; fail fast in Production
+
+Status: **implemented** · 2026-08-27 · Source findings: `07-bio2-compliance.md` BIO-002 (folds in BIO-001(a)/(b)) · `99-backlog.md` RB-09
+
+## What was wrong
+
+`IIdentityProvider.Resolve` returned a non-nullable `CallerIdentity`
+(`IIdentityProvider.cs:12`, pre-change), so the interface could not express "no identity" — any
+implementation, stub or real, was forced to invent one for an unauthenticated request.
+`StubIdentityProvider` was registered unconditionally, for every environment.
+
+Consequence, traced end to end: `apps/behandelportal/src/app/app.config.ts:57-63` puts
+`medewerkerInterceptor` inside the `isDevMode()` provider array, so a production
+behandelportal build sends **no** `X-Medewerker`/`X-Rollen` header. With neither header,
+`StubIdentityProvider.Resolve` fell through to
+`new ZorgverlenerCaller(DocumentStore.DemoOwner, ..., PrincipalRole.Drafter)` — the single
+seeded citizen, role `drafter`. That:
+
+- **Fails closed, correctly, on backoffice capabilities** — `Authz.CanBeoordelen` is
+ `caller is MedewerkerCaller`, so a zorgverlener caller is always `false` regardless of role.
+ This part of the design was right and is untouched.
+- **Fails open on every citizen-scoped endpoint** — `GET/PUT/DELETE /applications*`,
+ `POST /applications/{id}/submit`, `DELETE /uploads/{id}`, `GET|PUT /brief`,
+ `POST /brief/submit|send|reset` all resolve `ctx.Zorgverlener().Bsn` to the seeded citizen's
+ BSN. An employee with no employee identity was granted a citizen's own read/write rights.
+- **Holds `CanRevealBigNummer`** — that capability is `Role == PrincipalRole.Drafter`, and
+ `drafter` is exactly the no-header default.
+
+`CallerIdentityHttpContextExtensions.Caller()` (`CallerIdentity.cs:44-50`) already throws
+loudly when the identity middleware didn't run — the codebase reached for fail-loud one layer
+up and then defaulted one layer down, which is the shape of the bug.
+
+## What changed
+
+| File | Change |
+| ------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `Domain/Authorization/IIdentityProvider.cs` | `Resolve` returns `CallerIdentity?`; doc comment states what null means and where it's turned into a response |
+| `Domain/Authorization/StubIdentityProvider.cs` | **implementation signature unchanged** (`CallerIdentity`, non-nullable) — a valid, narrower override of the nullable interface method (return-type covariance; the compiler accepts it with zero warnings); doc comment records it is Development-only and never itself returns null |
+| `Program.cs` — registration | `StubIdentityProvider` registered only under `builder.Environment.IsDevelopment()`; an `else if (builder.Environment.IsProduction())` branch throws `InvalidOperationException` immediately, before `builder.Build()` — the earliest possible failure point |
+| `Program.cs` — identity middleware | resolves the identity once; if `null`, sets `401` and returns without calling `next()`, instead of passing a null (or invented) caller downstream |
+| `tests/BigRegister.Tests/StubIdentityProviderTests.cs` | **new** `Never_returns_null_even_with_no_headers_at_all`; **new** `ProductionIdentityProviderTests.Production_environment_with_no_real_identity_provider_fails_at_startup` |
+
+No consumer beyond the middleware itself calls `IIdentityProvider.Resolve` (`grep -rn
+"IIdentityProvider\|identityProvider\."` over `backend/src` confirms exactly one call site) —
+`Authz.ResolvePrincipal`, `ZgwTokenProvider.Mint`, and every endpoint read `ctx.Caller()` /
+`ctx.Zorgverlener()`, which already throw on a missing identity and are untouched. The 401
+now happens _before_ those are ever reached for a request the middleware rejects.
+
+## Judgement calls
+
+- **`StubIdentityProvider`'s own method signature stays `CallerIdentity`, not
+ `CallerIdentity?`.** The interface needed the nullable shape to make "no identity"
+ representable in general; the stub itself never has that case (it is a developer
+ convenience that always invents a caller by design) and returning a narrower,
+ non-nullable type from an override of a nullable-returning interface method is valid C#
+ nullable-reference-type covariance — verified with a clean `dotnet build` (0 warnings).
+ This kept every existing `StubIdentityProviderTests` call site (`private static
+CallerIdentity Resolve(...)`) compiling with zero changes, rather than sprinkling
+ null-forgiving operators through a file whose entire point is "the stub always resolves."
+- **The Production-only check is `IsProduction()`, not `!IsDevelopment()`.** The ticket and
+ BIO-002 both say "Production must fail at startup" specifically. A third environment (e.g.
+ a hypothetical `Staging`) falls through neither branch, registers no `IIdentityProvider` at
+ all, and would still fail — one line later, when `app.Services.GetRequiredService<
+IIdentityProvider>()` throws .NET's own "no service for type" exception — just with a less
+ specific message than the one this ticket adds for Production. That fallback is a safety
+ net, not the intended fail-fast message; if a real non-Production, non-Development
+ environment is added later, giving it the same explicit message is a one-line follow-up,
+ not a design gap today.
+- **The throw sits before `builder.Build()`**, not after (where `GetRequiredService` already
+ runs today). Both satisfy "throw during service registration / app build so a misconfigured
+ deploy never serves a request" — throwing earlier was free and gives a message naming the
+ actual cause (no real identity provider) rather than a generic DI resolution failure.
+- **The 401 short-circuits before `ctx.SetCaller`, not after.** `next(ctx)` is never called,
+ so no downstream middleware or endpoint runs for a request with no identity — a citizen or
+ behandelaar endpoint reached this way now gets a clean 401 instead of ever executing.
+- **`TestWebApplicationFactory` needed no change.** `WebApplicationFactory` defaults its
+ test host to the `Development` environment when nothing overrides it (confirmed
+ empirically: `dotnet test` — every non-Production test, all 253 of them pre-existing plus
+ 2 new, passed unchanged), so the entire existing test suite continues to exercise the
+ Development path exactly as before. The Production test builds its own
+ `WebApplicationFactory().WithWebHostBuilder(b => b.UseEnvironment("Production"))`
+ rather than touching the shared fixture.
+
+## Known residual — explicitly out of scope, confirmed and written up per the ticket
+
+**RB-01's residual is this ticket's territory but is explicitly out of scope for this
+ticket**, per the task: `GET /uploads/{documentId}/content` is reached by a plain browser
+navigation (`` in `beoordeling-documenten.component.ts`, `previewUrl` in
+`libs/shared/src/upload/upload.adapter.ts`) that sends no identity header and never passes
+through an Angular interceptor.
+
+- **In Development, this is unchanged** — verified by reading the endpoint
+ (`Program.cs:253-266`) and confirming `StubIdentityProvider` is still registered and still
+ resolves the same non-null seeded-citizen default it always did when no headers are
+ present. `dotnet test`'s full pass (255/255, excluding the pre-existing OpenZaak failure)
+ including `UploadAccessTests` — which exercises exactly this endpoint — confirms it
+ byte-for-byte.
+- **The Production consequence, for the next ticket:** today Production cannot start at
+ all (this ticket's fail-fast), so the question is moot until a real `IIdentityProvider`
+ exists. Once one does, this endpoint's plain-navigation callers carry no credential a real
+ provider could resolve — the identity middleware would treat that as "no identity" and
+ return 401 before the endpoint ever runs, breaking both preview links outright. Making the
+ stub Development-only does not itself break anything (nothing in Production exists yet to
+ break), but it does mean **whoever builds the real provider must also solve this endpoint's
+ credential-carrying problem in the same change**, or ship it broken. This is not a
+ signed-URL or cookie scheme, and no such scheme was designed here, per the ticket's explicit
+ instruction — it is recorded so the next ticket (RB-13, or whichever lands the real
+ provider) picks it up deliberately rather than discovering it in a production incident.
+
+## Verification
+
+- **Reverted the registration change only** (kept `AddSingleton()` unconditional, left the new tests in place) and ran
+ `ProductionIdentityProviderTests`: it failed red — `Assert.ThrowsAny() Failure: No exception
+was thrown` (the stub gets registered in every environment, so the host builds fine and
+ `factory.CreateClient()` never throws). Restored the fix and re-ran: green.
+- `dotnet build`: clean, **0 warnings** (confirms the nullable-covariance judgement call
+ above compiles cleanly).
+- `dotnet format BigRegister.slnx --verify-no-changes`: clean.
+- `dotnet test` (full suite): **255 passed, 1 failed** — the pre-existing
+ `OpenZaakIntegrationTests.Admin_cases_returns_the_seeded_zaak_mapped_through_real_HTTP_and_JWT`
+ (needs a live OpenZaak container; fails identically on a clean tree). CI's actual filter,
+ `dotnet test BigRegister.slnx --filter "Category!=Integration"`: **255 passed, 0 failed**.