Feature 04 task 2: Household week and local-time utilities (#18)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
Co-committed-by: dev_agent <dev_agent@cubecraftlabs.com>

README.md

@@ -30,12 +30,6 @@ export MEALQUEST_PUBLIC_URL=http://localhost:5173
 export MEALQUEST_DATA_DIR="$HOME/.mealquest-dev"
 export MEALQUEST_SHUTDOWN_TIMEOUT=10s
 export MEALQUEST_SECRET_KEY_FILE="$HOME/.mealquest-dev/secret_key"
-# Authentik OAuth2/OpenID provider for MealQuest (redirect URI:
-# $MEALQUEST_PUBLIC_URL/auth/callback). Save its client secret to the file.
-export MEALQUEST_OIDC_ISSUER=https://auth.example.com/application/o/mealquest/
-export MEALQUEST_OIDC_CLIENT_ID=mealquest
-export MEALQUEST_OIDC_CLIENT_SECRET_FILE="$HOME/.mealquest-dev/oidc_client_secret"
-export MEALQUEST_OIDC_ALLOWED_GROUPS=mealquest-admin
 make dev
 ```
 
@@ -43,9 +37,7 @@ make dev
 (which proxies `/api`, `/auth` and `/media` to `:8080`). Open
 http://localhost:5173. Configuration is environment-only and fails fast:
 every variable above is required, and secrets are read only from files named
-by `*_FILE` variables. `MEALQUEST_PUBLIC_URL`, `MEALQUEST_OIDC_ISSUER` and the
-endpoints the issuer advertises must be `https://`; plain `http://` is
-accepted only for `localhost`, `127.0.0.1` and `[::1]`.
+by `*_FILE` variables.
 
 ## Common commands
 

cmd/server/boot_test.go

@@ -3,15 +3,21 @@ package main
 import (
 	"bytes"
 	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
 	"io/fs"
 	"log/slog"
-	"net/url"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"testing/fstest"
 	"time"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/config"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/secretbox"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/migrations"
 )
 
@@ -24,6 +30,37 @@ func useBootMigrations(t *testing.T, m fstest.MapFS) {
 	t.Cleanup(func() { bootMigrations = saved })
 }
 
+// loadConfig loads a configuration through config.Load whose secret key file
+// holds keyFile. Tests that call it must not run in parallel.
+func loadConfig(t *testing.T, keyFile string) config.Config {
+	t.Helper()
+	keyPath := filepath.Join(t.TempDir(), "secret_key")
+	if err := os.WriteFile(keyPath, []byte(keyFile), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv(config.EnvHTTPAddr, "127.0.0.1:0")
+	t.Setenv(config.EnvPublicURL, "http://localhost")
+	t.Setenv(config.EnvDataDir, t.TempDir())
+	t.Setenv(config.EnvShutdownTimeout, "1s")
+	t.Setenv(config.EnvSecretKeyFile, keyPath)
+	cfg, err := config.Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return cfg
+}
+
+// validKeyFile returns secret key file contents as written by the README:
+// base64 of 32 random bytes followed by a newline.
+func validKeyFile(t *testing.T) string {
+	t.Helper()
+	key := make([]byte, secretbox.KeySize)
+	if _, err := rand.Read(key); err != nil {
+		t.Fatal(err)
+	}
+	return base64.StdEncoding.EncodeToString(key) + "\n"
+}
+
 var brokenMigrations = fstest.MapFS{
 	"0000_good.sql":   {Data: []byte("CREATE TABLE good (id INTEGER PRIMARY KEY);")},
 	"0001_broken.sql": {Data: []byte("CREATE TABLE broken (id INTEGER PRIMARY KEY;")},
@@ -73,12 +110,7 @@ func TestRunMigrationFailureReturnsBeforeListening(t *testing.T) {
 	useBootMigrations(t, brokenMigrations)
 
 	var logs bytes.Buffer
-	cfg := config.Config{
-		HTTPAddr:        "127.0.0.1:0",
-		PublicURL:       &url.URL{Scheme: "http", Host: "localhost"},
-		DataDir:         t.TempDir(),
-		ShutdownTimeout: time.Second,
-	}
+	cfg := loadConfig(t, validKeyFile(t))
 	errc := make(chan error, 1)
 	go func() { errc <- run(cfg, slog.New(slog.NewJSONHandler(&logs, nil))) }()
 
@@ -94,3 +126,70 @@ func TestRunMigrationFailureReturnsBeforeListening(t *testing.T) {
 		t.Errorf("run started listening despite the migration failure: %s", logs.String())
 	}
 }
+
+func TestOpenSecretBoxAcceptsReadmeKey(t *testing.T) {
+	cfg := loadConfig(t, validKeyFile(t))
+	box, err := openSecretBox(cfg.SecretKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	token, err := box.Encrypt([]byte("x"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := box.Decrypt(token); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestRunBadSecretKeyStopsBoot(t *testing.T) {
+	short := base64.StdEncoding.EncodeToString(make([]byte, 31))
+	tests := []struct {
+		name    string
+		keyFile string
+		want    error
+	}{
+		{"not base64", "this is not a base64 key!\n", secretbox.ErrKeyEncoding},
+		{"wrong length", short + "\n", secretbox.ErrKeyLength},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := loadConfig(t, tt.keyFile)
+			var logs bytes.Buffer
+			errc := make(chan error, 1)
+			go func() { errc <- run(cfg, slog.New(slog.NewJSONHandler(&logs, nil))) }()
+
+			var err error
+			select {
+			case err = <-errc:
+			case <-time.After(10 * time.Second):
+				t.Fatal("run kept going with a bad secret key")
+			}
+			if !errors.Is(err, tt.want) {
+				t.Fatalf("run error = %v, want %v", err, tt.want)
+			}
+			if !strings.Contains(err.Error(), config.EnvSecretKeyFile) {
+				t.Errorf("error does not name %s: %v", config.EnvSecretKeyFile, err)
+			}
+			if key := strings.TrimSpace(tt.keyFile); strings.Contains(err.Error(), key) {
+				t.Errorf("error leaks the key: %v", err)
+			}
+			if strings.Contains(logs.String(), `"listening"`) {
+				t.Errorf("run started listening despite the bad key: %s", logs.String())
+			}
+			if _, statErr := os.Stat(filepath.Join(cfg.DataDir, store.FileName)); !errors.Is(statErr, fs.ErrNotExist) {
+				t.Errorf("run opened the database before rejecting the key (stat: %v)", statErr)
+			}
+		})
+	}
+}
+
+func TestLoadMissingSecretKeyFileStopsBoot(t *testing.T) {
+	loadConfig(t, validKeyFile(t)) // sets every other variable
+	t.Setenv(config.EnvSecretKeyFile, filepath.Join(t.TempDir(), "missing"))
+	_, err := config.Load()
+	var cfgErr *config.Error
+	if !errors.As(err, &cfgErr) || !strings.Contains(err.Error(), config.EnvSecretKeyFile) {
+		t.Fatalf("Load error = %v, want a config error naming %s", err, config.EnvSecretKeyFile)
+	}
+}

cmd/server/main.go

@@ -13,9 +13,9 @@ import (
 	"syscall"
 	"time"
 
-	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/auth"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/config"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/frontend"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/secretbox"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/server"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/migrations"
@@ -42,6 +42,10 @@ func run(cfg config.Config, logger *slog.Logger) error {
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop()
 
+	if _, err := openSecretBox(cfg.SecretKey); err != nil {
+		return err
+	}
+
 	db, err := openStore(ctx, cfg.DataDir)
 	if err != nil {
 		return err
@@ -52,18 +56,7 @@ func run(cfg config.Config, logger *slog.Logger) error {
 		}
 	}()
 
-	authFlow, err := auth.New(ctx, auth.Config{
-		Issuer:       cfg.OIDCIssuer.String(),
-		ClientID:     cfg.OIDCClientID,
-		ClientSecret: cfg.OIDCClientSecret.Reveal(),
-		PublicURL:    cfg.PublicURL,
-		SecretKey:    []byte(cfg.SecretKey.Reveal()),
-	}, sessionsPending{}, logger)
-	if err != nil {
-		return err
-	}
-
-	router, err := server.NewRouter(logger, version, authFlow, frontend.Assets())
+	router, err := server.NewRouter(logger, version, frontend.Assets())
 	if err != nil {
 		return err
 	}
@@ -98,6 +91,16 @@ func run(cfg config.Config, logger *slog.Logger) error {
 	return nil
 }
 
+// openSecretBox builds the secret box from the configured key, naming the
+// variable whose file holds a bad key. The key itself is never reported.
+func openSecretBox(key config.Secret) (*secretbox.Box, error) {
+	box, err := secretbox.New(key.Reveal())
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", config.EnvSecretKeyFile, err)
+	}
+	return box, nil
+}
+
 // bootMigrations is the migration set applied at boot. Tests replace it to
 // prove a failing migration stops the boot.
 var bootMigrations fs.FS = migrations.FS
@@ -115,14 +118,6 @@ func openStore(ctx context.Context, dataDir string) (*store.Store, error) {
 	return db, nil
 }
 
-// sessionsPending refuses every login until the session layer (Feature 03
-// task 2) replaces it.
-type sessionsPending struct{}
-
-func (sessionsPending) StartSession(http.ResponseWriter, *http.Request, auth.Claims) error {
-	return errors.New("session layer not implemented")
-}
-
 // logListening logs the startup line. Only the public URL's origin is logged
 // so no credential-bearing URL component can reach the log.
 func logListening(logger *slog.Logger, cfg config.Config) {

go.mod

@@ -3,16 +3,13 @@ module code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest
 go 1.25.0
 
 require (
-	github.com/coreos/go-oidc/v3 v3.21.0
 	github.com/go-chi/chi/v5 v5.3.1
 	github.com/oklog/ulid/v2 v2.1.2
-	golang.org/x/oauth2 v0.36.0
 	modernc.org/sqlite v1.59.0
 )
 
 require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
-	github.com/go-jose/go-jose/v4 v4.1.4 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/mattn/go-isatty v0.0.24 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect

go.sum

@@ -1,11 +1,7 @@
-github.com/coreos/go-oidc/v3 v3.21.0 h1:wZo4Q9Pum8dYEj0eMUPrqR+kvuGkeUplbLpNCkBqoWM=
-github.com/coreos/go-oidc/v3 v3.21.0/go.mod h1:DYCf24+ncYi+XkIH97GY1+dqoRlbaSI26KVTCI9SrY4=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/go-chi/chi/v5 v5.3.1 h1:3j4HZLGZQ3JpMCrPJF/Jl3mYJfWLKBfNJ6quurUGCf8=
 github.com/go-chi/chi/v5 v5.3.1/go.mod h1:R+tYY2hNuVUUjxoPtqUdgBqevM9s9njzkTLutVsOCto=
-github.com/go-jose/go-jose/v4 v4.1.4 h1:moDMcTHmvE6Groj34emNPLs/qtYXRVcd6S7NHbHz3kA=
-github.com/go-jose/go-jose/v4 v4.1.4/go.mod h1:x4oUasVrzR7071A4TnHLGSPpNOm2a21K9Kf04k1rs08=
 github.com/google/pprof v0.0.0-20260802141513-ef3492d7dac3 h1:LMLX+LgTNWpfvCBdFebv6EsYotImrt/Ppc5cXIriCSo=
 github.com/google/pprof v0.0.0-20260802141513-ef3492d7dac3/go.mod h1:jl5iWTm0/hd5PjEYEOuwAJ57L/CibdZfrqZ5XA5GrCk=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
@@ -23,8 +19,6 @@ github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 golang.org/x/mod v0.38.0 h1:MECBjubtXD7yj4HrhIUcywNaGeNVUdfVnxmPajOk4yk=
 golang.org/x/mod v0.38.0/go.mod h1:V6Xz0pq8TQ3dGqVQ1FVHuelZpAL0uNhSkk9ogYP3c40=
-golang.org/x/oauth2 v0.36.0 h1:peZ/1z27fi9hUOFCAZaHyrpWG5lwe0RJEEEeH0ThlIs=
-golang.org/x/oauth2 v0.36.0/go.mod h1:YDBUJMTkDnJS+A4BP4eZBjCqtokkg1hODuPjwiGPO7Q=
 golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
 golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=

internal/auth/auth.go

@@ -1,299 +0,0 @@
-// Package auth signs the household in with Authentik over OpenID Connect.
-// The service is a confidential client: the authorization code, tokens and
-// client secret stay on the server and never reach JavaScript.
-package auth
-
-import (
-	"context"
-	"crypto/rand"
-	"crypto/subtle"
-	"errors"
-	"fmt"
-	"log/slog"
-	"net/http"
-	"net/url"
-	"time"
-
-	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/go-chi/chi/v5"
-	"golang.org/x/oauth2"
-
-	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/secureurl"
-)
-
-// Routes owned by this package.
-const (
-	LoginPath    = "/auth/login"
-	CallbackPath = "/auth/callback"
-)
-
-// providerTimeout bounds every request to the identity provider.
-const providerTimeout = 10 * time.Second
-
-// scopes requested at login.
-var scopes = []string{oidc.ScopeOpenID, "profile", "email", "groups", oidc.ScopeOfflineAccess}
-
-// Claims are the verified ID token claims handed to the session layer.
-type Claims struct {
-	Subject           string   `json:"sub"`
-	Email             string   `json:"email"`
-	EmailVerified     bool     `json:"email_verified"`
-	Name              string   `json:"name"`
-	PreferredUsername string   `json:"preferred_username"`
-	Groups            []string `json:"groups"`
-}
-
-// SessionStarter is the session layer's entry point. StartSession is called
-// once per successful login with claims from a verified ID token; it must set
-// the session cookie on w. A returned error aborts the login with 500.
-type SessionStarter interface {
-	StartSession(w http.ResponseWriter, r *http.Request, claims Claims) error
-}
-
-// Config is what New needs to reach the identity provider.
-type Config struct {
-	// Issuer is the exact issuer URL; discovery runs against it.
-	Issuer       string
-	ClientID     string
-	ClientSecret string
-	// PublicURL is the service's public URL; its origin prefixes CallbackPath
-	// to form the redirect URI.
-	PublicURL *url.URL
-	// SecretKey is the server key the login cookie's signing key derives from.
-	SecretKey []byte
-}
-
-// Auth serves the login and callback routes.
-type Auth struct {
-	oauth    oauth2.Config
-	verifier *oidc.IDTokenVerifier
-	client   *http.Client
-	cookie   loginCookie
-	sessions SessionStarter
-	logger   *slog.Logger
-}
-
-// New discovers the provider at cfg.Issuer and returns the login flow. It
-// fails if discovery fails or the issuer the provider reports differs.
-func New(ctx context.Context, cfg Config, sessions SessionStarter, logger *slog.Logger) (*Auth, error) {
-	switch {
-	case cfg.Issuer == "", cfg.ClientID == "", cfg.ClientSecret == "":
-		return nil, errors.New("auth: issuer, client ID and client secret are required")
-	case cfg.PublicURL == nil:
-		return nil, errors.New("auth: public URL is required")
-	case len(cfg.SecretKey) == 0:
-		return nil, errors.New("auth: secret key is required")
-	case sessions == nil:
-		return nil, errors.New("auth: session starter is required")
-	}
-
-	if err := checkEndpoint("issuer", cfg.Issuer); err != nil {
-		return nil, err
-	}
-
-	client := &http.Client{Timeout: providerTimeout, CheckRedirect: checkRedirect}
-	provider, err := oidc.NewProvider(oidc.ClientContext(ctx, client), cfg.Issuer)
-	if err != nil {
-		return nil, fmt.Errorf("auth: OIDC discovery: %w", err)
-	}
-	endpoint := provider.Endpoint()
-	var discovered struct {
-		JWKSURI string `json:"jwks_uri"`
-	}
-	if err := provider.Claims(&discovered); err != nil {
-		return nil, fmt.Errorf("auth: OIDC discovery: %w", err)
-	}
-	// The token endpoint receives the client secret and the key set decides
-	// which tokens verify, so every endpoint used must pass the same rule.
-	for _, e := range []struct{ name, raw string }{
-		{"authorization endpoint", endpoint.AuthURL},
-		{"token endpoint", endpoint.TokenURL},
-		{"JWKS endpoint", discovered.JWKSURI},
-	} {
-		if err := checkEndpoint(e.name, e.raw); err != nil {
-			return nil, err
-		}
-	}
-	// client_secret_basic, the OIDC default; no auto-detection retries.
-	endpoint.AuthStyle = oauth2.AuthStyleInHeader
-
-	return &Auth{
-		oauth: oauth2.Config{
-			ClientID:     cfg.ClientID,
-			ClientSecret: cfg.ClientSecret,
-			Endpoint:     endpoint,
-			RedirectURL:  cfg.PublicURL.Scheme + "://" + cfg.PublicURL.Host + CallbackPath,
-			Scopes:       scopes,
-		},
-		verifier: provider.Verifier(&oidc.Config{
-			ClientID:             cfg.ClientID,
-			SupportedSigningAlgs: []string{oidc.RS256},
-		}),
-		client:   client,
-		cookie:   newLoginCookie(cfg.SecretKey),
-		sessions: sessions,
-		logger:   logger,
-	}, nil
-}
-
-// checkEndpoint applies secureurl.Check to the provider URL raw, naming the
-// endpoint in the error.
-func checkEndpoint(name, raw string) error {
-	u, err := url.Parse(raw)
-	if err != nil {
-		return fmt.Errorf("auth: OIDC %s %q is not a valid URL", name, raw)
-	}
-	if err := secureurl.Check(u); err != nil {
-		return fmt.Errorf("auth: OIDC %s %q: %w", name, raw, err)
-	}
-	return nil
-}
-
-// maxRedirects matches net/http's default redirect limit.
-const maxRedirects = 10
-
-// checkRedirect is the provider client's redirect policy. On a 307 or 308 to
-// the same host Go resends the body and Authorization header, which carry the
-// code and client secret, so every target must pass secureurl.Check and an
-// https:// request never follows a redirect to plain http://, even loopback.
-func checkRedirect(req *http.Request, via []*http.Request) error {
-	if len(via) >= maxRedirects {
-		return fmt.Errorf("stopped after %d redirects", maxRedirects)
-	}
-	if err := secureurl.Check(req.URL); err != nil {
-		return fmt.Errorf("redirect refused: %w", err)
-	}
-	if via[len(via)-1].URL.Scheme == "https" && req.URL.Scheme != "https" {
-		return errors.New("redirect refused: https:// to plain http:// downgrade")
-	}
-	return nil
-}
-
-// Mount registers GET LoginPath and GET CallbackPath on r.
-func (a *Auth) Mount(r chi.Router) {
-	r.Get(LoginPath, a.login)
-	r.Get(CallbackPath, a.callback)
-}
-
-// login starts the authorization code flow with PKCE (S256). The optional
-// "return" query parameter must be a same-origin path; anything else fails
-// the login with 400.
-func (a *Auth) login(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Cache-Control", "no-store")
-
-	returnTo, err := returnPath(r.URL.Query().Get("return"))
-	if err != nil {
-		http.Error(w, "invalid return path", http.StatusBadRequest)
-		return
-	}
-	state := loginState{
-		State:    rand.Text(),
-		Nonce:    rand.Text(),
-		Verifier: oauth2.GenerateVerifier(),
-		Return:   returnTo,
-	}
-	if err := a.cookie.set(w, state, time.Now()); err != nil {
-		a.logger.ErrorContext(r.Context(), "set login cookie", "error", err)
-		http.Error(w, "internal error", http.StatusInternalServerError)
-		return
-	}
-	http.Redirect(w, r, a.oauth.AuthCodeURL(state.State,
-		oidc.Nonce(state.Nonce),
-		oauth2.S256ChallengeOption(state.Verifier),
-	), http.StatusFound)
-}
-
-// callback completes the flow: it checks state against the login cookie,
-// exchanges the code, verifies the ID token and nonce, then starts a session.
-func (a *Auth) callback(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Cache-Control", "no-store")
-	ctx := r.Context()
-	// The login cookie is single-use.
-	a.cookie.clear(w)
-
-	state, err := a.cookie.read(r, time.Now())
-	if err != nil {
-		a.logger.WarnContext(ctx, "login callback without a valid login cookie", "error", err)
-		http.Error(w, "sign-in expired; start again", http.StatusBadRequest)
-		return
-	}
-	q := r.URL.Query()
-	if subtle.ConstantTimeCompare([]byte(q.Get("state")), []byte(state.State)) != 1 {
-		a.logger.WarnContext(ctx, "login callback state mismatch")
-		http.Error(w, "sign-in state mismatch; start again", http.StatusBadRequest)
-		return
-	}
-	if q.Get("error") != "" {
-		// error and error_description are provider-supplied text; only the
-		// fixed category is logged.
-		a.logger.WarnContext(ctx, "identity provider returned an authorization error")
-		http.Error(w, "sign-in was refused", http.StatusUnauthorized)
-		return
-	}
-	code := q.Get("code")
-	if code == "" {
-		http.Error(w, "missing authorization code", http.StatusBadRequest)
-		return
-	}
-
-	claims, err := a.verify(ctx, code, state)
-	if err != nil {
-		a.logger.WarnContext(ctx, "sign-in failed", "error", err)
-		http.Error(w, "sign-in failed", http.StatusUnauthorized)
-		return
-	}
-	if err := a.sessions.StartSession(w, r, claims); err != nil {
-		a.logger.ErrorContext(ctx, "start session", "error", err)
-		http.Error(w, "internal error", http.StatusInternalServerError)
-		return
-	}
-	http.Redirect(w, r, state.Return, http.StatusSeeOther)
-}
-
-// verify exchanges code for tokens and returns the verified ID token claims.
-// The verifier enforces RS256, issuer, audience and expiry; nonce is checked
-// here.
-func (a *Auth) verify(ctx context.Context, code string, state loginState) (Claims, error) {
-	token, err := a.oauth.Exchange(context.WithValue(ctx, oauth2.HTTPClient, a.client), code,
-		oauth2.VerifierOption(state.Verifier))
-	if err != nil {
-		return Claims{}, exchangeError(err)
-	}
-	raw, ok := token.Extra("id_token").(string)
-	if !ok || raw == "" {
-		return Claims{}, errors.New("token response has no id_token")
-	}
-	idToken, err := a.verifier.Verify(ctx, raw)
-	if err != nil {
-		return Claims{}, fmt.Errorf("verify ID token: %w", err)
-	}
-	if subtle.ConstantTimeCompare([]byte(idToken.Nonce), []byte(state.Nonce)) != 1 {
-		return Claims{}, errors.New("ID token nonce mismatch")
-	}
-	var claims Claims
-	if err := idToken.Claims(&claims); err != nil {
-		return Claims{}, fmt.Errorf("decode ID token claims: %w", err)
-	}
-	if claims.Subject == "" {
-		return Claims{}, errors.New("ID token has no subject")
-	}
-	return claims, nil
-}
-
-// exchangeError reduces a failed code exchange to a fixed category and safe
-// metadata. The oauth2 error text can carry the token endpoint's response
-// body or error_description, which may echo credentials, so it is dropped.
-func exchangeError(err error) error {
-	var retrieve *oauth2.RetrieveError
-	var transport *url.Error
-	switch {
-	case errors.As(err, &retrieve):
-		return fmt.Errorf("exchange code: token endpoint rejected the request (HTTP %d)", retrieve.Response.StatusCode)
-	case errors.As(err, &transport):
-		// Request failures never carry the response. The URL is dropped: after
-		// a refused redirect it is the provider-supplied Location.
-		return fmt.Errorf("exchange code: token request failed: %s: %w", transport.Op, transport.Err)
-	default:
-		return errors.New("exchange code: token endpoint returned an unusable response")
-	}
-}

internal/auth/auth_test.go

@@ -1,901 +0,0 @@
-package auth
-
-import (
-	"bytes"
-	"context"
-	"crypto"
-	"crypto/hmac"
-	"crypto/rand"
-	"crypto/rsa"
-	"crypto/sha256"
-	"encoding/base64"
-	"encoding/json"
-	"errors"
-	"io"
-	"log/slog"
-	"maps"
-	"math/big"
-	"net/http"
-	"net/http/httptest"
-	"net/url"
-	"slices"
-	"strings"
-	"sync"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/go-chi/chi/v5"
-)
-
-const (
-	testClientID     = "mealquest"
-	testClientSecret = "client-s3cret"
-	testKID          = "test-key"
-)
-
-var testPublicURL = &url.URL{Scheme: "https", Host: "meals.example.com"}
-
-// fakeProvider is an OIDC provider serving discovery, JWKS and a token
-// endpoint. Each issued code maps to the ID token the token endpoint returns.
-type fakeProvider struct {
-	t   *testing.T
-	srv *httptest.Server
-	key *rsa.PrivateKey
-
-	mu    sync.Mutex
-	codes map[string]issuedCode
-	// discoveryOverrides replace fields of the discovery document.
-	discoveryOverrides map[string]any
-	// tokenReply, when set, is returned by the token endpoint instead of a
-	// token.
-	tokenReply *tokenReply
-}
-
-type tokenReply struct {
-	status int
-	body   string
-}
-
-type issuedCode struct {
-	challenge string
-	idToken   string
-}
-
-func newFakeProvider(t *testing.T) *fakeProvider {
-	t.Helper()
-	key, err := rsa.GenerateKey(rand.Reader, 2048)
-	if err != nil {
-		t.Fatal(err)
-	}
-	p := &fakeProvider{t: t, key: key, codes: map[string]issuedCode{}}
-	mux := http.NewServeMux()
-	mux.HandleFunc("GET /.well-known/openid-configuration", p.discovery)
-	mux.HandleFunc("GET /jwks", p.jwks)
-	mux.HandleFunc("POST /token", p.token)
-	p.srv = httptest.NewServer(mux)
-	t.Cleanup(p.srv.Close)
-	return p
-}
-
-func (p *fakeProvider) issuer() string { return p.srv.URL }
-
-func (p *fakeProvider) discovery(w http.ResponseWriter, _ *http.Request) {
-	doc := map[string]any{
-		"issuer":                                p.issuer(),
-		"authorization_endpoint":                p.issuer() + "/authorize",
-		"token_endpoint":                        p.issuer() + "/token",
-		"jwks_uri":                              p.issuer() + "/jwks",
-		"response_types_supported":              []string{"code"},
-		"subject_types_supported":               []string{"public"},
-		"id_token_signing_alg_values_supported": []string{"RS256", "HS256"},
-	}
-	p.mu.Lock()
-	maps.Copy(doc, p.discoveryOverrides)
-	p.mu.Unlock()
-	writeJSON(w, doc)
-}
-
-func (p *fakeProvider) jwks(w http.ResponseWriter, _ *http.Request) {
-	writeJSON(w, map[string]any{"keys": []map[string]string{{
-		"kty": "RSA",
-		"kid": testKID,
-		"use": "sig",
-		"alg": "RS256",
-		"n":   b64(p.key.N.Bytes()),
-		"e":   b64(big.NewInt(int64(p.key.E)).Bytes()),
-	}}})
-}
-
-// token checks client authentication, the code and the PKCE verifier before
-// returning the code's ID token.
-func (p *fakeProvider) token(w http.ResponseWriter, r *http.Request) {
-	p.mu.Lock()
-	reply := p.tokenReply
-	p.mu.Unlock()
-	if reply != nil {
-		w.Header().Set("Content-Type", "application/json")
-		w.WriteHeader(reply.status)
-		io.WriteString(w, reply.body)
-		return
-	}
-	id, secret, ok := r.BasicAuth()
-	if !ok || id != testClientID || secret != testClientSecret {
-		http.Error(w, `{"error":"invalid_client"}`, http.StatusUnauthorized)
-		return
-	}
-	if err := r.ParseForm(); err != nil {
-		http.Error(w, `{"error":"invalid_request"}`, http.StatusBadRequest)
-		return
-	}
-	p.mu.Lock()
-	issued, ok := p.codes[r.PostForm.Get("code")]
-	delete(p.codes, r.PostForm.Get("code"))
-	p.mu.Unlock()
-	if r.PostForm.Get("grant_type") != "authorization_code" || !ok ||
-		challengeS256(r.PostForm.Get("code_verifier")) != issued.challenge {
-		w.Header().Set("Content-Type", "application/json")
-		w.WriteHeader(http.StatusBadRequest)
-		io.WriteString(w, `{"error":"invalid_grant"}`)
-		return
-	}
-	writeJSON(w, map[string]any{
-		"access_token": "access-token",
-		"token_type":   "Bearer",
-		"expires_in":   3600,
-		"id_token":     issued.idToken,
-	})
-}
-
-// authorize stands in for the user signing in at the provider: it records a
-// code bound to the PKCE challenge and returns it.
-func (p *fakeProvider) authorize(challenge, idToken string) string {
-	code := rand.Text()
-	p.mu.Lock()
-	p.codes[code] = issuedCode{challenge: challenge, idToken: idToken}
-	p.mu.Unlock()
-	return code
-}
-
-// claims returns valid ID token claims for nonce.
-func (p *fakeProvider) claims(nonce string) map[string]any {
-	now := time.Now()
-	return map[string]any{
-		"iss":                p.issuer(),
-		"sub":                "user-123",
-		"aud":                testClientID,
-		"iat":                now.Unix(),
-		"exp":                now.Add(5 * time.Minute).Unix(),
-		"nonce":              nonce,
-		"email":              "cook@example.com",
-		"email_verified":     true,
-		"name":               "Home Cook",
-		"preferred_username": "cook",
-		"groups":             []string{"mealquest-admin"},
-	}
-}
-
-func (p *fakeProvider) signRS256(claims map[string]any) string {
-	return signRS256(p.t, p.key, claims)
-}
-
-func signRS256(t *testing.T, key *rsa.PrivateKey, claims map[string]any) string {
-	t.Helper()
-	signing := jwtSigningInput(t, "RS256", claims)
-	digest := sha256.Sum256([]byte(signing))
-	sig, err := rsa.SignPKCS1v15(rand.Reader, key, crypto.SHA256, digest[:])
-	if err != nil {
-		t.Fatal(err)
-	}
-	return signing + "." + b64(sig)
-}
-
-// signHS256 signs with the client secret, as in an algorithm-confusion attack.
-func (p *fakeProvider) signHS256(claims map[string]any) string {
-	signing := jwtSigningInput(p.t, "HS256", claims)
-	mac := hmac.New(sha256.New, []byte(testClientSecret))
-	mac.Write([]byte(signing))
-	return signing + "." + b64(mac.Sum(nil))
-}
-
-func jwtSigningInput(t *testing.T, alg string, claims map[string]any) string {
-	t.Helper()
-	header, err := json.Marshal(map[string]string{"alg": alg, "typ": "JWT", "kid": testKID})
-	if err != nil {
-		t.Fatal(err)
-	}
-	body, err := json.Marshal(claims)
-	if err != nil {
-		t.Fatal(err)
-	}
-	return b64(header) + "." + b64(body)
-}
-
-func challengeS256(verifier string) string {
-	sum := sha256.Sum256([]byte(verifier))
-	return b64(sum[:])
-}
-
-func b64(b []byte) string { return base64.RawURLEncoding.EncodeToString(b) }
-
-func writeJSON(w http.ResponseWriter, v any) {
-	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(v)
-}
-
-// memorySessions is an in-memory SessionStarter that records the claims it
-// was handed.
-type memorySessions struct {
-	mu     sync.Mutex
-	claims []Claims
-	err    error
-}
-
-func (m *memorySessions) StartSession(w http.ResponseWriter, _ *http.Request, claims Claims) error {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	if m.err != nil {
-		return m.err
-	}
-	m.claims = append(m.claims, claims)
-	http.SetCookie(w, &http.Cookie{Name: "test_session", Value: claims.Subject})
-	return nil
-}
-
-func (m *memorySessions) started() []Claims {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	return slices.Clone(m.claims)
-}
-
-type harness struct {
-	provider *fakeProvider
-	sessions *memorySessions
-	router   http.Handler
-	logs     *syncBuffer
-}
-
-// syncBuffer is a bytes.Buffer safe for concurrent log writes.
-type syncBuffer struct {
-	mu  sync.Mutex
-	buf bytes.Buffer
-}
-
-func (b *syncBuffer) Write(p []byte) (int, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.buf.Write(p)
-}
-
-func (b *syncBuffer) String() string {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.buf.String()
-}
-
-func newHarness(t *testing.T) *harness {
-	t.Helper()
-	p := newFakeProvider(t)
-	sessions := &memorySessions{}
-	logs := &syncBuffer{}
-	a, err := New(context.Background(), Config{
-		Issuer:       p.issuer(),
-		ClientID:     testClientID,
-		ClientSecret: testClientSecret,
-		PublicURL:    testPublicURL,
-		SecretKey:    []byte("server-secret-key"),
-	}, sessions, slog.New(slog.NewTextHandler(logs, nil)))
-	if err != nil {
-		t.Fatal(err)
-	}
-	r := chi.NewRouter()
-	a.Mount(r)
-	return &harness{provider: p, sessions: sessions, router: r, logs: logs}
-}
-
-func (h *harness) get(target string, cookies ...*http.Cookie) *http.Response {
-	req := httptest.NewRequest(http.MethodGet, target, nil)
-	for _, c := range cookies {
-		req.AddCookie(c)
-	}
-	rec := httptest.NewRecorder()
-	h.router.ServeHTTP(rec, req)
-	return rec.Result()
-}
-
-// login is a started login: the authorize URL's query and the login cookie.
-type login struct {
-	query  url.Values
-	cookie *http.Cookie
-}
-
-func (h *harness) login(t *testing.T, target string) login {
-	t.Helper()
-	resp := h.get(target)
-	if resp.StatusCode != http.StatusFound {
-		t.Fatalf("GET %s status = %d, want 302", target, resp.StatusCode)
-	}
-	loc, err := url.Parse(resp.Header.Get("Location"))
-	if err != nil {
-		t.Fatal(err)
-	}
-	if got, want := loc.Scheme+"://"+loc.Host+loc.Path, h.provider.issuer()+"/authorize"; got != want {
-		t.Fatalf("redirect to %s, want %s", got, want)
-	}
-	var cookie *http.Cookie
-	for _, c := range resp.Cookies() {
-		if c.Name == loginCookieName {
-			cookie = c
-		}
-	}
-	if cookie == nil {
-		t.Fatalf("login set no %s cookie", loginCookieName)
-	}
-	return login{query: loc.Query(), cookie: cookie}
-}
-
-// callback completes l at the provider with idToken and calls the callback.
-func (h *harness) callback(l login, state, idToken string) *http.Response {
-	code := h.provider.authorize(l.query.Get("code_challenge"), idToken)
-	q := url.Values{"code": {code}, "state": {state}}
-	return h.get(CallbackPath+"?"+q.Encode(), l.cookie)
-}
-
-func TestLoginRedirect(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	l := h.login(t, LoginPath+"?return=/plan")
-
-	want := map[string]string{
-		"client_id":             testClientID,
-		"response_type":         "code",
-		"scope":                 "openid profile email groups offline_access",
-		"redirect_uri":          "https://meals.example.com/auth/callback",
-		"code_challenge_method": "S256",
-	}
-	for k, v := range want {
-		if got := l.query.Get(k); got != v {
-			t.Errorf("authorize %s = %q, want %q", k, got, v)
-		}
-	}
-	for _, k := range []string{"state", "nonce", "code_challenge"} {
-		if l.query.Get(k) == "" {
-			t.Errorf("authorize URL has no %s", k)
-		}
-	}
-
-	c := l.cookie
-	if !c.HttpOnly || !c.Secure || c.SameSite != http.SameSiteLaxMode || c.Path != "/" {
-		t.Errorf("login cookie HttpOnly=%v Secure=%v SameSite=%v Path=%q, want HttpOnly, Secure, Lax, /",
-			c.HttpOnly, c.Secure, c.SameSite, c.Path)
-	}
-	if c.MaxAge <= 0 || c.MaxAge > 600 {
-		t.Errorf("login cookie MaxAge = %d, want 1-600 seconds", c.MaxAge)
-	}
-}
-
-func TestLoginStateIsFreshEachTime(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	a, b := h.login(t, LoginPath), h.login(t, LoginPath)
-	for _, k := range []string{"state", "nonce", "code_challenge"} {
-		if a.query.Get(k) == b.query.Get(k) {
-			t.Errorf("%s repeated across logins", k)
-		}
-	}
-}
-
-func TestCallbackSuccess(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	l := h.login(t, LoginPath+"?return="+url.QueryEscape("/plan?week=2026-W40"))
-
-	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
-
-	if resp.StatusCode != http.StatusSeeOther {
-		t.Fatalf("callback status = %d, want 303", resp.StatusCode)
-	}
-	if got := resp.Header.Get("Location"); got != "/plan?week=2026-W40" {
-		t.Errorf("callback redirect = %q, want the return path", got)
-	}
-	started := h.sessions.started()
-	want := Claims{
-		Subject:           "user-123",
-		Email:             "cook@example.com",
-		EmailVerified:     true,
-		Name:              "Home Cook",
-		PreferredUsername: "cook",
-		Groups:            []string{"mealquest-admin"},
-	}
-	if len(started) != 1 || started[0].Subject != want.Subject || started[0].Email != want.Email ||
-		started[0].Name != want.Name || started[0].PreferredUsername != want.PreferredUsername ||
-		!started[0].EmailVerified || !slices.Equal(started[0].Groups, want.Groups) {
-		t.Errorf("session started with %+v, want [%+v]", started, want)
-	}
-	assertLoginCookieCleared(t, resp)
-}
-
-func TestCallbackDefaultReturnPath(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	l := h.login(t, LoginPath)
-	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
-	if resp.StatusCode != http.StatusSeeOther || resp.Header.Get("Location") != "/" {
-		t.Errorf("callback = %d to %q, want 303 to /", resp.StatusCode, resp.Header.Get("Location"))
-	}
-}
-
-func TestCallbackRejected(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name string
-		// state returns the state sent to the callback.
-		state func(l login) string
-		// token returns the ID token the provider issues.
-		token      func(p *fakeProvider, l login) string
-		wantStatus int
-	}{
-		{
-			name:       "mismatched state",
-			state:      func(login) string { return "attacker-state" },
-			wantStatus: http.StatusBadRequest,
-		},
-		{
-			name: "wrong nonce",
-			token: func(p *fakeProvider, _ login) string {
-				return p.signRS256(p.claims("other-nonce"))
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "missing nonce",
-			token: func(p *fakeProvider, _ login) string {
-				c := p.claims("")
-				delete(c, "nonce")
-				return p.signRS256(c)
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "HS256-signed token",
-			token: func(p *fakeProvider, l login) string {
-				return p.signHS256(p.claims(l.query.Get("nonce")))
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "expired token",
-			token: func(p *fakeProvider, l login) string {
-				c := p.claims(l.query.Get("nonce"))
-				c["iat"] = time.Now().Add(-2 * time.Hour).Unix()
-				c["exp"] = time.Now().Add(-time.Hour).Unix()
-				return p.signRS256(c)
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "wrong issuer",
-			token: func(p *fakeProvider, l login) string {
-				c := p.claims(l.query.Get("nonce"))
-				c["iss"] = "https://evil.example.com"
-				return p.signRS256(c)
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "wrong audience",
-			token: func(p *fakeProvider, l login) string {
-				c := p.claims(l.query.Get("nonce"))
-				c["aud"] = "another-client"
-				return p.signRS256(c)
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-		{
-			name: "signed by an unknown key",
-			token: func(p *fakeProvider, l login) string {
-				key, err := rsa.GenerateKey(rand.Reader, 2048)
-				if err != nil {
-					p.t.Fatal(err)
-				}
-				return signRS256(p.t, key, p.claims(l.query.Get("nonce")))
-			},
-			wantStatus: http.StatusUnauthorized,
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-			h := newHarness(t)
-			l := h.login(t, LoginPath)
-			state := l.query.Get("state")
-			if tc.state != nil {
-				state = tc.state(l)
-			}
-			token := h.provider.signRS256(h.provider.claims(l.query.Get("nonce")))
-			if tc.token != nil {
-				token = tc.token(h.provider, l)
-			}
-
-			resp := h.callback(l, state, token)
-
-			if resp.StatusCode != tc.wantStatus {
-				t.Errorf("callback status = %d, want %d", resp.StatusCode, tc.wantStatus)
-			}
-			if n := len(h.sessions.started()); n != 0 {
-				t.Errorf("%d sessions started, want none", n)
-			}
-			assertLoginCookieCleared(t, resp)
-		})
-	}
-}
-
-func TestCallbackWithoutLoginCookie(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	l := h.login(t, LoginPath)
-	l.cookie = &http.Cookie{Name: "unrelated", Value: "x"}
-	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
-	if resp.StatusCode != http.StatusBadRequest {
-		t.Errorf("callback status = %d, want 400", resp.StatusCode)
-	}
-	if n := len(h.sessions.started()); n != 0 {
-		t.Errorf("%d sessions started, want none", n)
-	}
-}
-
-func TestCallbackTamperedLoginCookie(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	l := h.login(t, LoginPath)
-	payload, sig, _ := strings.Cut(l.cookie.Value, ".")
-	data, err := base64.RawURLEncoding.DecodeString(payload)
-	if err != nil {
-		t.Fatal(err)
-	}
-	var s loginState
-	if err := json.Unmarshal(data, &s); err != nil {
-		t.Fatal(err)
-	}
-	s.Return = "/somewhere-else"
-	data, err = json.Marshal(s)
-	if err != nil {
-		t.Fatal(err)
-	}
-	l.cookie = &http.Cookie{Name: loginCookieName, Value: b64(data) + "." + sig}
-
-	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
-	if resp.StatusCode != http.StatusBadRequest {
-		t.Errorf("callback status = %d, want 400", resp.StatusCode)
-	}
-}
-
-// The provider's error and error_description are untrusted text and never
-// reach the logs; only the fixed category does.
-func TestCallbackProviderError(t *testing.T) {
-	t.Parallel()
-	const (
-		errorMarker       = "provider-error-marker"
-		descriptionMarker = "description-marker-" + testClientSecret
-	)
-	h := newHarness(t)
-	l := h.login(t, LoginPath)
-	q := url.Values{
-		"error":             {errorMarker},
-		"error_description": {descriptionMarker},
-		"state":             {l.query.Get("state")},
-	}
-	resp := h.get(CallbackPath+"?"+q.Encode(), l.cookie)
-	if resp.StatusCode != http.StatusUnauthorized {
-		t.Errorf("callback status = %d, want 401", resp.StatusCode)
-	}
-	assertLoginCookieCleared(t, resp)
-	if n := len(h.sessions.started()); n != 0 {
-		t.Errorf("started %d sessions, want 0", n)
-	}
-	logs := h.logs.String()
-	for _, marker := range []string{errorMarker, descriptionMarker} {
-		if strings.Contains(logs, marker) {
-			t.Errorf("logs contain provider text %q: %s", marker, logs)
-		}
-	}
-	if !strings.Contains(logs, "identity provider returned an authorization error") {
-		t.Errorf("logs = %q, want the authorization error category", logs)
-	}
-}
-
-func TestCallbackSessionError(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	h.sessions.err = errors.New("database down")
-	l := h.login(t, LoginPath)
-	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
-	if resp.StatusCode != http.StatusInternalServerError {
-		t.Errorf("callback status = %d, want 500", resp.StatusCode)
-	}
-}
-
-// A failed code exchange is logged by category and status only: the token
-// endpoint's body and error_description may echo credentials.
-func TestCallbackExchangeFailureDoesNotLogProviderResponse(t *testing.T) {
-	t.Parallel()
-	const leaked = "leaked-" + testClientSecret
-	tests := []struct {
-		name     string
-		reply    tokenReply
-		wantLogs string
-	}{
-		{
-			name:     "error response",
-			reply:    tokenReply{http.StatusBadRequest, `{"error":"invalid_grant","error_description":"` + leaked + `"}`},
-			wantLogs: "HTTP 400",
-		},
-		{
-			name:     "unparseable error response",
-			reply:    tokenReply{http.StatusInternalServerError, leaked},
-			wantLogs: "HTTP 500",
-		},
-		{
-			name:     "success without access token",
-			reply:    tokenReply{http.StatusOK, `{"id_token":"` + leaked + `"}`},
-			wantLogs: "unusable response",
-		},
-	}
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-			h := newHarness(t)
-			h.provider.mu.Lock()
-			h.provider.tokenReply = &tc.reply
-			h.provider.mu.Unlock()
-			l := h.login(t, LoginPath)
-
-			resp := h.callback(l, l.query.Get("state"), "unused")
-
-			if resp.StatusCode != http.StatusUnauthorized {
-				t.Errorf("callback status = %d, want 401", resp.StatusCode)
-			}
-			logs := h.logs.String()
-			if strings.Contains(logs, leaked) {
-				t.Errorf("logs contain the provider response: %s", logs)
-			}
-			if !strings.Contains(logs, tc.wantLogs) {
-				t.Errorf("logs = %q, want %q", logs, tc.wantLogs)
-			}
-		})
-	}
-}
-
-func TestLoginCookieExpires(t *testing.T) {
-	t.Parallel()
-	c := newLoginCookie([]byte("server-secret-key"))
-	now := time.Now()
-	rec := httptest.NewRecorder()
-	if err := c.set(rec, loginState{State: "s", Nonce: "n", Verifier: "v", Return: "/"}, now); err != nil {
-		t.Fatal(err)
-	}
-	req := httptest.NewRequest(http.MethodGet, CallbackPath, nil)
-	req.AddCookie(rec.Result().Cookies()[0])
-
-	if _, err := c.read(req, now.Add(loginCookieTTL-time.Second)); err != nil {
-		t.Errorf("read before expiry: %v", err)
-	}
-	if _, err := c.read(req, now.Add(loginCookieTTL)); err == nil {
-		t.Error("read at expiry succeeded")
-	}
-}
-
-func TestLoginRejectsOffOriginReturn(t *testing.T) {
-	t.Parallel()
-	h := newHarness(t)
-	for _, ret := range []string{
-		"https://evil.example.com/",
-		"http://meals.example.com/plan",
-		"//evil.example.com/",
-		"/\\evil.example.com",
-		"\\\\evil.example.com",
-		"javascript:alert(1)",
-		"plan",
-		"/plan\r\nSet-Cookie: x=y",
-	} {
-		resp := h.get(LoginPath + "?return=" + url.QueryEscape(ret))
-		if resp.StatusCode != http.StatusBadRequest {
-			t.Errorf("return=%q: status = %d, want 400", ret, resp.StatusCode)
-		}
-		if loc := resp.Header.Get("Location"); loc != "" {
-			t.Errorf("return=%q: redirected to %q", ret, loc)
-		}
-		if len(resp.Cookies()) != 0 {
-			t.Errorf("return=%q: set cookies %v", ret, resp.Cookies())
-		}
-	}
-}
-
-func TestNewFailsWhenDiscoveryFails(t *testing.T) {
-	t.Parallel()
-	srv := httptest.NewServer(http.NotFoundHandler())
-	t.Cleanup(srv.Close)
-	_, err := New(context.Background(), Config{
-		Issuer:       srv.URL,
-		ClientID:     testClientID,
-		ClientSecret: testClientSecret,
-		PublicURL:    testPublicURL,
-		SecretKey:    []byte("k"),
-	}, &memorySessions{}, slog.New(slog.DiscardHandler))
-	if err == nil {
-		t.Fatal("New succeeded without a discovery document")
-	}
-}
-
-func TestNewFailsOnIssuerMismatch(t *testing.T) {
-	t.Parallel()
-	p := newFakeProvider(t)
-	// Discovery trims the trailing slash, so this fetches the provider's
-	// document, which reports the issuer without it.
-	_, err := New(context.Background(), Config{
-		Issuer:       p.issuer() + "/",
-		ClientID:     testClientID,
-		ClientSecret: testClientSecret,
-		PublicURL:    testPublicURL,
-		SecretKey:    []byte("k"),
-	}, &memorySessions{}, slog.New(slog.DiscardHandler))
-	if err == nil {
-		t.Fatal("New accepted a provider reporting a different issuer")
-	}
-}
-
-func assertLoginCookieCleared(t *testing.T, resp *http.Response) {
-	t.Helper()
-	for _, c := range resp.Cookies() {
-		if c.Name == loginCookieName && c.MaxAge < 0 {
-			return
-		}
-	}
-	t.Errorf("callback did not clear the %s cookie", loginCookieName)
-}
-
-func TestNewRejectsRemoteHTTPIssuer(t *testing.T) {
-	t.Parallel()
-	for _, issuer := range []string{"http://auth.example.com/application/o/mealquest/", "http://192.0.2.10"} {
-		_, err := New(context.Background(), Config{
-			Issuer:       issuer,
-			ClientID:     testClientID,
-			ClientSecret: testClientSecret,
-			PublicURL:    testPublicURL,
-			SecretKey:    []byte("k"),
-		}, &memorySessions{}, slog.New(slog.DiscardHandler))
-		if err == nil || !strings.Contains(err.Error(), "issuer") {
-			t.Errorf("New(issuer %q) error = %v, want issuer rejected", issuer, err)
-		}
-	}
-}
-
-func TestNewRejectsRemoteHTTPEndpoint(t *testing.T) {
-	t.Parallel()
-	tests := []struct {
-		field, name string
-	}{
-		{"authorization_endpoint", "authorization endpoint"},
-		{"token_endpoint", "token endpoint"},
-		{"jwks_uri", "JWKS endpoint"},
-	}
-	for _, tc := range tests {
-		t.Run(tc.field, func(t *testing.T) {
-			t.Parallel()
-			p := newFakeProvider(t)
-			p.discoveryOverrides = map[string]any{tc.field: "http://auth.example.com/" + tc.field}
-			_, err := New(context.Background(), Config{
-				Issuer:       p.issuer(),
-				ClientID:     testClientID,
-				ClientSecret: testClientSecret,
-				PublicURL:    testPublicURL,
-				SecretKey:    []byte("k"),
-			}, &memorySessions{}, slog.New(slog.DiscardHandler))
-			if err == nil || !strings.Contains(err.Error(), tc.name) {
-				t.Errorf("New error = %v, want %s rejected", err, tc.name)
-			}
-		})
-	}
-}
-
-// A token endpoint on https:// that redirects the code exchange to plain
-// http:// must not receive a follow-up request: Go would resend the client
-// secret in the Authorization header. The plaintext target is loopback, so
-// only the downgrade rule stops it.
-func TestCallbackRefusesTokenRedirectToHTTP(t *testing.T) {
-	t.Parallel()
-	for _, status := range []int{http.StatusTemporaryRedirect, http.StatusPermanentRedirect} {
-		t.Run(http.StatusText(status), func(t *testing.T) {
-			t.Parallel()
-			var plaintextHits atomic.Int32
-			plaintext := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-				plaintextHits.Add(1)
-				http.Error(w, "unreachable", http.StatusTeapot)
-			}))
-			t.Cleanup(plaintext.Close)
-			var tlsHits atomic.Int32
-			tlsToken := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				tlsHits.Add(1)
-				http.Redirect(w, r, plaintext.URL+"/token", status)
-			}))
-			t.Cleanup(tlsToken.Close)
-
-			p := newFakeProvider(t)
-			p.discoveryOverrides = map[string]any{"token_endpoint": tlsToken.URL + "/token"}
-			sessions := &memorySessions{}
-			logs := &syncBuffer{}
-			a, err := New(context.Background(), Config{
-				Issuer:       p.issuer(),
-				ClientID:     testClientID,
-				ClientSecret: testClientSecret,
-				PublicURL:    testPublicURL,
-				SecretKey:    []byte("server-secret-key"),
-			}, sessions, slog.New(slog.NewTextHandler(logs, nil)))
-			if err != nil {
-				t.Fatal(err)
-			}
-			// Trust the test server's certificate; the redirect policy stays.
-			a.client.Transport = tlsToken.Client().Transport
-			r := chi.NewRouter()
-			a.Mount(r)
-			h := &harness{provider: p, sessions: sessions, router: r, logs: logs}
-			l := h.login(t, LoginPath)
-
-			resp := h.callback(l, l.query.Get("state"), "unused")
-
-			if resp.StatusCode != http.StatusUnauthorized {
-				t.Errorf("callback status = %d, want 401", resp.StatusCode)
-			}
-			if n := tlsHits.Load(); n != 1 {
-				t.Errorf("https token endpoint hit %d times, want 1", n)
-			}
-			if n := plaintextHits.Load(); n != 0 {
-				t.Errorf("plaintext endpoint hit %d times, want 0", n)
-			}
-			if n := len(sessions.started()); n != 0 {
-				t.Errorf("started %d sessions, want 0", n)
-			}
-			if got := logs.String(); !strings.Contains(got, "downgrade") {
-				t.Errorf("logs = %q, want the downgrade refusal", got)
-			}
-		})
-	}
-}
-
-func TestCheckRedirect(t *testing.T) {
-	t.Parallel()
-	request := func(raw string) *http.Request {
-		req, err := http.NewRequest(http.MethodPost, raw, nil)
-		if err != nil {
-			t.Fatal(err)
-		}
-		return req
-	}
-	tests := []struct {
-		from, to string
-		ok       bool
-	}{
-		{"https://auth.example.com/token", "https://auth2.example.com/token", true},
-		{"http://127.0.0.1:9000/token", "http://localhost:9001/token", true},
-		{"http://127.0.0.1:9000/token", "https://auth.example.com/token", true},
-		{"https://auth.example.com/token", "http://auth.example.com/token", false},
-		{"https://127.0.0.1:9000/token", "http://127.0.0.1:9001/token", false},
-		{"http://127.0.0.1:9000/token", "http://auth.example.com/token", false},
-		{"https://auth.example.com/token", "ftp://auth.example.com/token", false},
-	}
-	for _, tc := range tests {
-		err := checkRedirect(request(tc.to), []*http.Request{request(tc.from)})
-		if (err == nil) != tc.ok {
-			t.Errorf("redirect %s -> %s: error = %v, want ok=%v", tc.from, tc.to, err, tc.ok)
-		}
-	}
-	via := make([]*http.Request, maxRedirects)
-	for i := range via {
-		via[i] = request("https://auth.example.com/token")
-	}
-	if err := checkRedirect(request("https://auth.example.com/token"), via); err == nil {
-		t.Errorf("redirect after %d hops: error = nil, want limit", maxRedirects)
-	}
-}

internal/auth/cookie.go

@@ -1,124 +0,0 @@
-package auth
-
-import (
-	"crypto/hmac"
-	"crypto/sha256"
-	"encoding/base64"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net/http"
-	"net/url"
-	"strings"
-	"time"
-)
-
-const (
-	loginCookieName = "__Host-mealquest_login"
-	loginCookieTTL  = 10 * time.Minute
-	// loginCookieKeyLabel separates the login cookie's signing key from other
-	// keys derived from the same server secret.
-	loginCookieKeyLabel = "mealquest auth login cookie v1"
-)
-
-// loginState travels from login to callback in the signed login cookie.
-type loginState struct {
-	State    string `json:"s"`
-	Nonce    string `json:"n"`
-	Verifier string `json:"v"`
-	Return   string `json:"r"`
-	Expires  int64  `json:"e"` // Unix seconds
-}
-
-// loginCookie signs and verifies the login cookie with HMAC-SHA256.
-type loginCookie struct {
-	key []byte
-}
-
-func newLoginCookie(secretKey []byte) loginCookie {
-	mac := hmac.New(sha256.New, secretKey)
-	mac.Write([]byte(loginCookieKeyLabel))
-	return loginCookie{key: mac.Sum(nil)}
-}
-
-func (c loginCookie) sign(payload string) string {
-	mac := hmac.New(sha256.New, c.key)
-	mac.Write([]byte(payload))
-	return base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
-}
-
-func (c loginCookie) set(w http.ResponseWriter, s loginState, now time.Time) error {
-	s.Expires = now.Add(loginCookieTTL).Unix()
-	data, err := json.Marshal(s)
-	if err != nil {
-		return err
-	}
-	payload := base64.RawURLEncoding.EncodeToString(data)
-	http.SetCookie(w, &http.Cookie{
-		Name:     loginCookieName,
-		Value:    payload + "." + c.sign(payload),
-		Path:     "/",
-		MaxAge:   int(loginCookieTTL / time.Second),
-		Secure:   true,
-		HttpOnly: true,
-		// Lax so the cookie rides the provider's top-level redirect back.
-		SameSite: http.SameSiteLaxMode,
-	})
-	return nil
-}
-
-func (c loginCookie) clear(w http.ResponseWriter) {
-	http.SetCookie(w, &http.Cookie{
-		Name:     loginCookieName,
-		Path:     "/",
-		MaxAge:   -1,
-		Secure:   true,
-		HttpOnly: true,
-		SameSite: http.SameSiteLaxMode,
-	})
-}
-
-func (c loginCookie) read(r *http.Request, now time.Time) (loginState, error) {
-	cookie, err := r.Cookie(loginCookieName)
-	if err != nil {
-		return loginState{}, errors.New("login cookie missing")
-	}
-	payload, sig, ok := strings.Cut(cookie.Value, ".")
-	if !ok || !hmac.Equal([]byte(sig), []byte(c.sign(payload))) {
-		return loginState{}, errors.New("login cookie signature invalid")
-	}
-	data, err := base64.RawURLEncoding.DecodeString(payload)
-	if err != nil {
-		return loginState{}, fmt.Errorf("login cookie encoding: %w", err)
-	}
-	var s loginState
-	if err := json.Unmarshal(data, &s); err != nil {
-		return loginState{}, fmt.Errorf("login cookie payload: %w", err)
-	}
-	if now.Unix() >= s.Expires {
-		return loginState{}, errors.New("login cookie expired")
-	}
-	return s, nil
-}
-
-// returnPath validates the optional post-login return path. Empty means "/".
-// Only same-origin absolute paths are allowed: no scheme, host, protocol-
-// relative "//" prefix, backslashes or control characters.
-func returnPath(raw string) (string, error) {
-	if raw == "" {
-		return "/", nil
-	}
-	if !strings.HasPrefix(raw, "/") || strings.HasPrefix(raw, "//") || strings.ContainsRune(raw, '\\') {
-		return "", errors.New("return path must be a same-origin path")
-	}
-	for _, c := range raw {
-		if c < 0x20 || c == 0x7f {
-			return "", errors.New("return path contains a control character")
-		}
-	}
-	u, err := url.Parse(raw)
-	if err != nil || u.Scheme != "" || u.Host != "" || u.User != nil {
-		return "", errors.New("return path must be a same-origin path")
-	}
-	return raw, nil
-}

internal/config/config.go

@@ -11,8 +11,6 @@ import (
 	"strconv"
 	"strings"
 	"time"
-
-	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/secureurl"
 )
 
 // Environment variable names.
@@ -22,11 +20,6 @@ const (
 	EnvDataDir         = "MEALQUEST_DATA_DIR"
 	EnvShutdownTimeout = "MEALQUEST_SHUTDOWN_TIMEOUT"
 	EnvSecretKeyFile   = "MEALQUEST_SECRET_KEY_FILE"
-
-	EnvOIDCIssuer           = "MEALQUEST_OIDC_ISSUER"
-	EnvOIDCClientID         = "MEALQUEST_OIDC_CLIENT_ID"
-	EnvOIDCClientSecretFile = "MEALQUEST_OIDC_CLIENT_SECRET_FILE"
-	EnvOIDCAllowedGroups    = "MEALQUEST_OIDC_ALLOWED_GROUPS"
 )
 
 // Config is the validated service configuration.
@@ -36,13 +29,6 @@ type Config struct {
 	DataDir         string
 	ShutdownTimeout time.Duration
 	SecretKey       Secret
-
-	// OIDCIssuer is the Authentik issuer URL used for discovery.
-	OIDCIssuer       *url.URL
-	OIDCClientID     string
-	OIDCClientSecret Secret
-	// OIDCAllowedGroups lists the groups whose members may sign in.
-	OIDCAllowedGroups []string
 }
 
 // PublicOrigin returns the scheme and host of PublicURL, the only parts of it
@@ -61,15 +47,10 @@ func load(lookup func(string) (string, bool)) (Config, error) {
 	r := reader{lookup: lookup}
 	cfg := Config{
 		HTTPAddr:        r.listenAddr(EnvHTTPAddr),
-		PublicURL:       r.secureURL(EnvPublicURL),
+		PublicURL:       r.httpURL(EnvPublicURL),
 		DataDir:         r.dir(EnvDataDir),
 		ShutdownTimeout: r.duration(EnvShutdownTimeout),
 		SecretKey:       r.secretFile(EnvSecretKeyFile),
-
-		OIDCIssuer:        r.secureURL(EnvOIDCIssuer),
-		OIDCClientID:      r.str(EnvOIDCClientID),
-		OIDCClientSecret:  r.secretFile(EnvOIDCClientSecretFile),
-		OIDCAllowedGroups: r.list(EnvOIDCAllowedGroups),
 	}
 	if len(r.problems) > 0 {
 		return Config{}, &Error{Problems: r.problems}
@@ -133,29 +114,6 @@ func (r *reader) required(name string) (string, bool) {
 	return v, true
 }
 
-func (r *reader) str(name string) string {
-	v, _ := r.required(name)
-	return v
-}
-
-// list parses a comma-separated list. Every entry must be non-empty after
-// trimming spaces.
-func (r *reader) list(name string) []string {
-	v, ok := r.required(name)
-	if !ok {
-		return nil
-	}
-	items := strings.Split(v, ",")
-	for i, item := range items {
-		items[i] = strings.TrimSpace(item)
-		if items[i] == "" {
-			r.fail(name, "empty entry in comma-separated list %q", v)
-			return nil
-		}
-	}
-	return items
-}
-
 func (r *reader) listenAddr(name string) string {
 	v, ok := r.required(name)
 	if !ok {
@@ -197,21 +155,15 @@ func validHostname(h string) bool {
 	return true
 }
 
-// secureURL reads an absolute URL that must pass secureurl.Check: https://,
-// or http:// to a loopback host only.
-func (r *reader) secureURL(name string) *url.URL {
+func (r *reader) httpURL(name string) *url.URL {
 	v, ok := r.required(name)
 	if !ok {
 		return nil
 	}
 	// The value is never echoed: it may carry credentials.
 	u, err := url.Parse(v)
-	if err != nil {
-		r.fail(name, "invalid URL (want absolute https:// URL)")
-		return nil
-	}
-	if err := secureurl.Check(u); err != nil {
-		r.fail(name, "invalid URL: %v", err)
+	if err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Hostname() == "" {
+		r.fail(name, "invalid URL (want absolute http:// or https:// URL)")
 		return nil
 	}
 	if u.User != nil {

internal/config/config_test.go

@@ -6,7 +6,6 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
-	"reflect"
 	"slices"
 	"strings"
 	"testing"
@@ -22,10 +21,6 @@ func TestLoad(t *testing.T) {
 		t.Fatal(err)
 	}
 	unreadablePath := filepath.Join(dir, "missing_secret")
-	clientSecretPath := filepath.Join(dir, "oidc_client_secret")
-	if err := os.WriteFile(clientSecretPath, []byte("client-s3cret\n"), 0o600); err != nil {
-		t.Fatal(err)
-	}
 	emptyPath := filepath.Join(dir, "empty_secret")
 	if err := os.WriteFile(emptyPath, []byte("\n"), 0o600); err != nil {
 		t.Fatal(err)
@@ -38,11 +33,6 @@ func TestLoad(t *testing.T) {
 			EnvDataDir:         dir,
 			EnvShutdownTimeout: "15s",
 			EnvSecretKeyFile:   secretPath,
-
-			EnvOIDCIssuer:           "https://auth.example.com/application/o/mealquest/",
-			EnvOIDCClientID:         "mealquest",
-			EnvOIDCClientSecretFile: clientSecretPath,
-			EnvOIDCAllowedGroups:    "mealquest-admin",
 		}
 	}
 	with := func(changes map[string]string, unset ...string) map[string]string {
@@ -80,7 +70,6 @@ func TestLoad(t *testing.T) {
 			env:  map[string]string{},
 			badVars: []string{
 				EnvHTTPAddr, EnvPublicURL, EnvDataDir, EnvShutdownTimeout, EnvSecretKeyFile,
-				EnvOIDCIssuer, EnvOIDCClientID, EnvOIDCClientSecretFile, EnvOIDCAllowedGroups,
 			},
 		},
 		{
@@ -150,24 +139,6 @@ func TestLoad(t *testing.T) {
 			env:     with(map[string]string{EnvPublicURL: "http://:8080"}),
 			badVars: []string{EnvPublicURL},
 		},
-		{
-			name:    "plain HTTP public URL on a remote host",
-			env:     with(map[string]string{EnvPublicURL: "http://meals.example.com"}),
-			badVars: []string{EnvPublicURL},
-		},
-		{
-			name:    "plain HTTP public URL on a non-loopback IP",
-			env:     with(map[string]string{EnvPublicURL: "http://192.168.1.20:8080"}),
-			badVars: []string{EnvPublicURL},
-		},
-		{
-			name: "plain HTTP public URL on 127.0.0.1",
-			env:  with(map[string]string{EnvPublicURL: "http://127.0.0.1:8080"}),
-		},
-		{
-			name: "plain HTTP public URL on [::1]",
-			env:  with(map[string]string{EnvPublicURL: "http://[::1]:8080"}),
-		},
 		{
 			name:    "relative public URL",
 			env:     with(map[string]string{EnvPublicURL: "meals.example.com"}),
@@ -198,54 +169,6 @@ func TestLoad(t *testing.T) {
 			env:     with(map[string]string{"MEALQUEST_SECRET_KEY": "inline"}),
 			badVars: []string{"MEALQUEST_SECRET_KEY"},
 		},
-		{
-			name:    "inline OIDC client secret rejected",
-			env:     with(map[string]string{"MEALQUEST_OIDC_CLIENT_SECRET": "inline"}),
-			badVars: []string{"MEALQUEST_OIDC_CLIENT_SECRET"},
-		},
-		{
-			name:    "unreadable OIDC client secret file",
-			env:     with(map[string]string{EnvOIDCClientSecretFile: unreadablePath}),
-			badVars: []string{EnvOIDCClientSecretFile},
-		},
-		{
-			name:    "relative OIDC issuer",
-			env:     with(map[string]string{EnvOIDCIssuer: "auth.example.com"}),
-			badVars: []string{EnvOIDCIssuer},
-		},
-		{
-			name:    "non-http OIDC issuer",
-			env:     with(map[string]string{EnvOIDCIssuer: "ftp://auth.example.com"}),
-			badVars: []string{EnvOIDCIssuer},
-		},
-		{
-			name:    "plain HTTP OIDC issuer on a remote host",
-			env:     with(map[string]string{EnvOIDCIssuer: "http://auth.example.com/application/o/mealquest/"}),
-			badVars: []string{EnvOIDCIssuer},
-		},
-		{
-			name: "plain HTTP OIDC issuer on localhost",
-			env:  with(map[string]string{EnvOIDCIssuer: "http://localhost:9000/application/o/mealquest/"}),
-		},
-		{
-			name: "several allowed groups",
-			env:  with(map[string]string{EnvOIDCAllowedGroups: "mealquest-admin, family"}),
-		},
-		{
-			name:    "empty allowed group entry",
-			env:     with(map[string]string{EnvOIDCAllowedGroups: "mealquest-admin,,family"}),
-			badVars: []string{EnvOIDCAllowedGroups},
-		},
-		{
-			name:    "trailing comma in allowed groups",
-			env:     with(map[string]string{EnvOIDCAllowedGroups: "mealquest-admin,"}),
-			badVars: []string{EnvOIDCAllowedGroups},
-		},
-		{
-			name:    "blank OIDC client ID",
-			env:     with(map[string]string{EnvOIDCClientID: "  "}),
-			badVars: []string{EnvOIDCClientID},
-		},
 		{
 			name: "several invalid values are all named",
 			env: with(map[string]string{
@@ -288,7 +211,7 @@ func TestLoad(t *testing.T) {
 					t.Errorf("error message %q does not name %s", err.Error(), v)
 				}
 			}
-			if !reflect.ValueOf(cfg).IsZero() {
+			if cfg != (Config{}) {
 				t.Errorf("load() returned non-zero Config alongside error: %+v", cfg)
 			}
 		})
@@ -303,21 +226,12 @@ func TestLoadValues(t *testing.T) {
 	if err := os.WriteFile(secretPath, []byte("s3cret-value\r\n"), 0o600); err != nil {
 		t.Fatal(err)
 	}
-	clientSecretPath := filepath.Join(dir, "oidc_client_secret")
-	if err := os.WriteFile(clientSecretPath, []byte("client-s3cret\n"), 0o600); err != nil {
-		t.Fatal(err)
-	}
 	env := map[string]string{
 		EnvHTTPAddr:        "127.0.0.1:9000",
 		EnvPublicURL:       "http://localhost:9000",
 		EnvDataDir:         dir,
 		EnvShutdownTimeout: "1m30s",
 		EnvSecretKeyFile:   secretPath,
-
-		EnvOIDCIssuer:           "https://auth.example.com/application/o/mealquest/",
-		EnvOIDCClientID:         "mealquest",
-		EnvOIDCClientSecretFile: clientSecretPath,
-		EnvOIDCAllowedGroups:    " mealquest-admin ,family",
 	}
 	cfg, err := load(func(k string) (string, bool) { v, ok := env[k]; return v, ok })
 	if err != nil {
@@ -339,18 +253,6 @@ func TestLoadValues(t *testing.T) {
 	if cfg.SecretKey.Reveal() != "s3cret-value" {
 		t.Errorf("SecretKey.Reveal() = %q, want trailing newline trimmed", cfg.SecretKey.Reveal())
 	}
-	if got, want := cfg.OIDCIssuer.String(), "https://auth.example.com/application/o/mealquest/"; got != want {
-		t.Errorf("OIDCIssuer = %q, want %q", got, want)
-	}
-	if cfg.OIDCClientID != "mealquest" {
-		t.Errorf("OIDCClientID = %q", cfg.OIDCClientID)
-	}
-	if cfg.OIDCClientSecret.Reveal() != "client-s3cret" {
-		t.Errorf("OIDCClientSecret.Reveal() = %q", cfg.OIDCClientSecret.Reveal())
-	}
-	if want := []string{"mealquest-admin", "family"}; !slices.Equal(cfg.OIDCAllowedGroups, want) {
-		t.Errorf("OIDCAllowedGroups = %q, want %q", cfg.OIDCAllowedGroups, want)
-	}
 }
 
 func TestSecretRedacted(t *testing.T) {
@@ -358,7 +260,7 @@ func TestSecretRedacted(t *testing.T) {
 
 	s := Secret{value: "s3cret-value"}
 	for _, format := range []string{"%v", "%s", "%+v", "%#v"} {
-		cfg := Config{SecretKey: s, OIDCClientSecret: s}
+		cfg := Config{SecretKey: s}
 		for _, out := range []string{fmt.Sprintf(format, s), fmt.Sprintf(format, cfg)} {
 			if strings.Contains(out, "s3cret-value") {
 				t.Errorf("format %s leaked secret: %s", format, out)

internal/household/week.go

@@ -0,0 +1,130 @@
+// Package household owns household-local calendar and clock logic. Every
+// function works in the household's IANA zone, passed explicitly, and never
+// in the process zone (time.Local).
+//
+// Weeks are ISO weeks: Monday to Sunday, numbered by ISO 8601, so the period
+// key of 2026-12-28 is "2026-W53" and of 2027-01-04 is "2027-W01".
+//
+// Calendar arithmetic is done on UTC midnights, which have no DST, so a date
+// plus seven days is always the same weekday a week later.
+package household
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+)
+
+// Today returns the household-local date at instant now in zone loc.
+func Today(now time.Time, loc *time.Location) store.LocalDate {
+	return store.LocalDateOf(now.In(loc))
+}
+
+// WeekStart returns the ISO Monday of the week containing d. It panics if d is
+// the zero LocalDate.
+func WeekStart(d store.LocalDate) store.LocalDate {
+	t := midnightUTC(d)
+	// Weekday counts from Sunday = 0; shift so Monday = 0 and Sunday = 6.
+	sinceMonday := (int(t.Weekday()) + 6) % 7
+	return store.LocalDateOf(t.AddDate(0, 0, -sinceMonday))
+}
+
+// WeekDays returns the seven dates Monday to Sunday of the week starting on
+// weekStart. It is an error if weekStart is not a Monday.
+func WeekDays(weekStart store.LocalDate) ([7]store.LocalDate, error) {
+	t, err := monday(weekStart)
+	if err != nil {
+		return [7]store.LocalDate{}, err
+	}
+	var days [7]store.LocalDate
+	for i := range days {
+		days[i] = store.LocalDateOf(t.AddDate(0, 0, i))
+	}
+	return days, nil
+}
+
+// WeekLabel returns the display label of the week starting on weekStart, such
+// as "Week 41 · Oct 5 – 11", or "Week 40 · Sep 28 – Oct 4" when the week
+// spans two months. It is an error if weekStart is not a Monday.
+func WeekLabel(weekStart store.LocalDate) (string, error) {
+	start, err := monday(weekStart)
+	if err != nil {
+		return "", err
+	}
+	_, week := start.ISOWeek()
+	end := start.AddDate(0, 0, 6)
+	if end.Month() == start.Month() {
+		return fmt.Sprintf("Week %d · %s – %d", week, start.Format("Jan 2"), end.Day()), nil
+	}
+	return fmt.Sprintf("Week %d · %s – %s", week, start.Format("Jan 2"), end.Format("Jan 2")), nil
+}
+
+// PeriodKey returns the ISO week key of the week containing d, such as
+// "2026-W41". The year is the ISO week-numbering year, which differs from the
+// calendar year around New Year. It panics if d is the zero LocalDate.
+func PeriodKey(d store.LocalDate) string {
+	year, week := midnightUTC(d).ISOWeek()
+	return fmt.Sprintf("%04d-W%02d", year, week)
+}
+
+// LocalTime returns the instant at which household clocks in zone loc read
+// hhmm (24-hour "HH:MM") on date d.
+//
+// DST rule: a wall time that does not exist (spring forward) or occurs twice
+// (fall back) is read with the UTC offset in effect before the transition. A
+// skipped time therefore moves forward by the length of the gap (02:30 on a
+// day clocks jump 02:00→03:00 is 03:30), and a repeated time is its first
+// occurrence. The rule assumes at most one offset change in the 48 hours
+// around the wall time, which holds for every real zone.
+func LocalTime(loc *time.Location, d store.LocalDate, hhmm string) (time.Time, error) {
+	if d.IsZero() {
+		return time.Time{}, errors.New("household: zero date")
+	}
+	clock, err := time.Parse("15:04", hhmm)
+	if err != nil || clock.Format("15:04") != hhmm {
+		return time.Time{}, fmt.Errorf("household: invalid time %q: want HH:MM", hhmm)
+	}
+	y, m, day := d.Date()
+	// wall is the wall-clock reading expressed as if it were UTC; the real
+	// instant is wall minus the zone's UTC offset at that instant.
+	wall := time.Date(y, m, day, clock.Hour(), clock.Minute(), 0, 0, time.UTC)
+	before := offset(wall.Add(-24*time.Hour), loc)
+	after := offset(wall.Add(24*time.Hour), loc)
+	early := wall.Add(-before)
+	late := wall.Add(-after)
+	// Use the post-transition offset only when the pre-transition reading is
+	// not a real wall time and the post-transition one is.
+	if offset(early, loc) != before && offset(late, loc) == after {
+		return late.In(loc), nil
+	}
+	return early.In(loc), nil
+}
+
+// offset returns the UTC offset of zone loc at instant t.
+func offset(t time.Time, loc *time.Location) time.Duration {
+	_, secs := t.In(loc).Zone()
+	return time.Duration(secs) * time.Second
+}
+
+// midnightUTC returns d as midnight UTC. It panics if d is the zero LocalDate.
+func midnightUTC(d store.LocalDate) time.Time {
+	if d.IsZero() {
+		panic("household: zero date")
+	}
+	y, m, day := d.Date()
+	return time.Date(y, m, day, 0, 0, 0, 0, time.UTC)
+}
+
+// monday returns weekStart as midnight UTC, or an error if it is not a Monday.
+func monday(weekStart store.LocalDate) (time.Time, error) {
+	if weekStart.IsZero() {
+		return time.Time{}, errors.New("household: zero week start")
+	}
+	t := midnightUTC(weekStart)
+	if t.Weekday() != time.Monday {
+		return time.Time{}, fmt.Errorf("household: week start %s is a %s, want Monday", weekStart, t.Weekday())
+	}
+	return t, nil
+}

internal/household/week_test.go

@@ -0,0 +1,311 @@
+package household
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+)
+
+// TestMain runs the package with the process zone set to UTC, so any use of
+// time.Local in place of the household zone shows up as a failure.
+func TestMain(m *testing.M) {
+	time.Local = time.UTC
+	m.Run()
+}
+
+func loadZone(t *testing.T, name string) *time.Location {
+	t.Helper()
+	loc, err := time.LoadLocation(name)
+	if err != nil {
+		t.Fatalf("LoadLocation(%q): %v", name, err)
+	}
+	return loc
+}
+
+func date(t *testing.T, s string) store.LocalDate {
+	t.Helper()
+	d, err := store.ParseLocalDate(s)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return d
+}
+
+func utc(t *testing.T, s string) time.Time {
+	t.Helper()
+	ts, err := time.Parse(time.RFC3339, s)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return ts
+}
+
+func TestTodayUsesHouseholdZone(t *testing.T) {
+	chicago := loadZone(t, "America/Chicago")
+	auckland := loadZone(t, "Pacific/Auckland")
+	for _, tc := range []struct {
+		now  string
+		loc  *time.Location
+		want string
+	}{
+		// 2026-10-05T04:30Z is Sunday 23:30 in Chicago (CDT, UTC−5) and
+		// Monday 17:30 in Auckland (NZDT, UTC+13).
+		{"2026-10-05T04:30:00Z", chicago, "2026-10-04"},
+		{"2026-10-05T04:30:00Z", auckland, "2026-10-05"},
+		// 2026-10-04T11:30Z is Sunday 06:30 in Chicago and already Monday
+		// 00:30 in Auckland.
+		{"2026-10-04T11:30:00Z", chicago, "2026-10-04"},
+		{"2026-10-04T11:30:00Z", auckland, "2026-10-05"},
+	} {
+		if got := Today(utc(t, tc.now), tc.loc).String(); got != tc.want {
+			t.Errorf("Today(%s, %s) = %s, want %s", tc.now, tc.loc, got, tc.want)
+		}
+	}
+}
+
+func TestSundayNightMondayMorningWeekAssignment(t *testing.T) {
+	for _, tc := range []struct {
+		zone, now     string
+		wantDay       string
+		wantWeekStart string
+		wantPeriodKey string
+		wantWeekday   time.Weekday
+	}{
+		// Sunday 23:59 local belongs to the week that started the previous
+		// Monday; one minute later, Monday 00:00 starts a new week.
+		{"America/Chicago", "2026-10-12T04:59:00Z", "2026-10-11", "2026-10-05", "2026-W41", time.Sunday},
+		{"America/Chicago", "2026-10-12T05:00:00Z", "2026-10-12", "2026-10-12", "2026-W42", time.Monday},
+		{"Pacific/Auckland", "2026-10-11T10:59:00Z", "2026-10-11", "2026-10-05", "2026-W41", time.Sunday},
+		{"Pacific/Auckland", "2026-10-11T11:00:00Z", "2026-10-12", "2026-10-12", "2026-W42", time.Monday},
+	} {
+		loc := loadZone(t, tc.zone)
+		now := utc(t, tc.now)
+		if wd := now.In(loc).Weekday(); wd != tc.wantWeekday {
+			t.Fatalf("%s in %s is %s, want %s", tc.now, tc.zone, wd, tc.wantWeekday)
+		}
+		today := Today(now, loc)
+		if today.String() != tc.wantDay {
+			t.Errorf("Today(%s, %s) = %s, want %s", tc.now, tc.zone, today, tc.wantDay)
+		}
+		if got := WeekStart(today).String(); got != tc.wantWeekStart {
+			t.Errorf("WeekStart(%s) = %s, want %s", today, got, tc.wantWeekStart)
+		}
+		if got := PeriodKey(today); got != tc.wantPeriodKey {
+			t.Errorf("PeriodKey(%s) = %s, want %s", today, got, tc.wantPeriodKey)
+		}
+	}
+}
+
+func TestWeekStartEveryWeekday(t *testing.T) {
+	for _, d := range []string{
+		"2026-10-05", "2026-10-06", "2026-10-07", "2026-10-08",
+		"2026-10-09", "2026-10-10", "2026-10-11",
+	} {
+		if got := WeekStart(date(t, d)).String(); got != "2026-10-05" {
+			t.Errorf("WeekStart(%s) = %s, want 2026-10-05", d, got)
+		}
+	}
+	if got := WeekStart(date(t, "2026-10-12")).String(); got != "2026-10-12" {
+		t.Errorf("WeekStart(2026-10-12) = %s, want 2026-10-12", got)
+	}
+}
+
+func TestWeekDays(t *testing.T) {
+	days, err := WeekDays(date(t, "2026-09-28"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{
+		"2026-09-28", "2026-09-29", "2026-09-30", "2026-10-01",
+		"2026-10-02", "2026-10-03", "2026-10-04",
+	}
+	for i, d := range days {
+		if d.String() != want[i] {
+			t.Errorf("WeekDays[%d] = %s, want %s", i, d, want[i])
+		}
+	}
+}
+
+func TestWeekDaysAcrossDSTChange(t *testing.T) {
+	// Chicago falls back on Sunday 2026-11-01 and Auckland springs forward on
+	// Sunday 2026-09-27; neither shifts the dates of those weeks.
+	for _, tc := range []struct{ start, last string }{
+		{"2026-10-26", "2026-11-01"},
+		{"2026-09-21", "2026-09-27"},
+		{"2026-03-02", "2026-03-08"},
+	} {
+		days, err := WeekDays(date(t, tc.start))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if days[0].String() != tc.start || days[6].String() != tc.last {
+			t.Errorf("WeekDays(%s) = %s … %s, want %s … %s", tc.start, days[0], days[6], tc.start, tc.last)
+		}
+	}
+}
+
+func TestISOWeekYearBoundary(t *testing.T) {
+	for _, tc := range []struct{ day, weekStart, key string }{
+		{"2026-12-27", "2026-12-21", "2026-W52"},
+		{"2026-12-28", "2026-12-28", "2026-W53"},
+		{"2026-12-31", "2026-12-28", "2026-W53"},
+		{"2027-01-01", "2026-12-28", "2026-W53"},
+		{"2027-01-03", "2026-12-28", "2026-W53"},
+		{"2027-01-04", "2027-01-04", "2027-W01"},
+		{"2027-01-10", "2027-01-04", "2027-W01"},
+		{"2026-01-01", "2025-12-29", "2026-W01"},
+		{"2026-10-07", "2026-10-05", "2026-W41"},
+	} {
+		d := date(t, tc.day)
+		if got := WeekStart(d).String(); got != tc.weekStart {
+			t.Errorf("WeekStart(%s) = %s, want %s", tc.day, got, tc.weekStart)
+		}
+		if got := PeriodKey(d); got != tc.key {
+			t.Errorf("PeriodKey(%s) = %s, want %s", tc.day, got, tc.key)
+		}
+	}
+	days, err := WeekDays(date(t, "2026-12-28"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if days[6].String() != "2027-01-03" {
+		t.Errorf("W53 Sunday = %s, want 2027-01-03", days[6])
+	}
+}
+
+func TestWeekLabel(t *testing.T) {
+	for _, tc := range []struct{ start, want string }{
+		{"2026-10-05", "Week 41 · Oct 5 – 11"},
+		{"2026-09-28", "Week 40 · Sep 28 – Oct 4"},
+		{"2026-12-28", "Week 53 · Dec 28 – Jan 3"},
+		{"2027-01-04", "Week 1 · Jan 4 – 10"},
+	} {
+		got, err := WeekLabel(date(t, tc.start))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got != tc.want {
+			t.Errorf("WeekLabel(%s) = %q, want %q", tc.start, got, tc.want)
+		}
+	}
+}
+
+func TestWeekStartRequired(t *testing.T) {
+	for _, d := range []store.LocalDate{date(t, "2026-10-07"), date(t, "2026-10-11"), {}} {
+		if _, err := WeekDays(d); err == nil {
+			t.Errorf("WeekDays(%s) succeeded, want error", d)
+		}
+		if _, err := WeekLabel(d); err == nil {
+			t.Errorf("WeekLabel(%s) succeeded, want error", d)
+		}
+	}
+}
+
+func TestZeroDatePanics(t *testing.T) {
+	for name, fn := range map[string]func(){
+		"WeekStart": func() { WeekStart(store.LocalDate{}) },
+		"PeriodKey": func() { PeriodKey(store.LocalDate{}) },
+	} {
+		func() {
+			defer func() {
+				if recover() == nil {
+					t.Errorf("%s(zero) did not panic", name)
+				}
+			}()
+			fn()
+		}()
+	}
+}
+
+func TestLocalTime(t *testing.T) {
+	for _, tc := range []struct {
+		zone, day, hhmm string
+		want            string // UTC instant
+		wantWall        string // local wall clock of the result
+	}{
+		// Ordinary days.
+		{"America/Chicago", "2026-10-05", "18:30", "2026-10-05T23:30:00Z", "2026-10-05 18:30 CDT"},
+		{"America/Chicago", "2026-12-28", "00:00", "2026-12-28T06:00:00Z", "2026-12-28 00:00 CST"},
+		{"Pacific/Auckland", "2026-10-05", "18:30", "2026-10-05T05:30:00Z", "2026-10-05 18:30 NZDT"},
+		{"Pacific/Auckland", "2026-07-01", "23:59", "2026-07-01T11:59:00Z", "2026-07-01 23:59 NZST"},
+
+		// Chicago spring forward, Sunday 2026-03-08: 02:00 CST → 03:00 CDT.
+		{"America/Chicago", "2026-03-08", "01:59", "2026-03-08T07:59:00Z", "2026-03-08 01:59 CST"},
+		{"America/Chicago", "2026-03-08", "02:00", "2026-03-08T08:00:00Z", "2026-03-08 03:00 CDT"},
+		{"America/Chicago", "2026-03-08", "02:30", "2026-03-08T08:30:00Z", "2026-03-08 03:30 CDT"},
+		{"America/Chicago", "2026-03-08", "03:00", "2026-03-08T08:00:00Z", "2026-03-08 03:00 CDT"},
+		{"America/Chicago", "2026-03-08", "03:30", "2026-03-08T08:30:00Z", "2026-03-08 03:30 CDT"},
+
+		// Chicago fall back, Sunday 2026-11-01: 02:00 CDT → 01:00 CST, so
+		// 01:00–01:59 happens twice; the first (CDT) occurrence is chosen.
+		{"America/Chicago", "2026-11-01", "00:59", "2026-11-01T05:59:00Z", "2026-11-01 00:59 CDT"},
+		{"America/Chicago", "2026-11-01", "01:00", "2026-11-01T06:00:00Z", "2026-11-01 01:00 CDT"},
+		{"America/Chicago", "2026-11-01", "01:30", "2026-11-01T06:30:00Z", "2026-11-01 01:30 CDT"},
+		{"America/Chicago", "2026-11-01", "02:00", "2026-11-01T08:00:00Z", "2026-11-01 02:00 CST"},
+
+		// Auckland spring forward, Sunday 2026-09-27: 02:00 NZST → 03:00 NZDT.
+		{"Pacific/Auckland", "2026-09-27", "01:59", "2026-09-26T13:59:00Z", "2026-09-27 01:59 NZST"},
+		{"Pacific/Auckland", "2026-09-27", "02:30", "2026-09-26T14:30:00Z", "2026-09-27 03:30 NZDT"},
+		{"Pacific/Auckland", "2026-09-27", "03:00", "2026-09-26T14:00:00Z", "2026-09-27 03:00 NZDT"},
+
+		// Auckland fall back, Sunday 2026-04-05: 03:00 NZDT → 02:00 NZST, so
+		// 02:00–02:59 happens twice; the first (NZDT) occurrence is chosen.
+		{"Pacific/Auckland", "2026-04-05", "01:59", "2026-04-04T12:59:00Z", "2026-04-05 01:59 NZDT"},
+		{"Pacific/Auckland", "2026-04-05", "02:30", "2026-04-04T13:30:00Z", "2026-04-05 02:30 NZDT"},
+		{"Pacific/Auckland", "2026-04-05", "03:00", "2026-04-04T15:00:00Z", "2026-04-05 03:00 NZST"},
+	} {
+		loc := loadZone(t, tc.zone)
+		got, err := LocalTime(loc, date(t, tc.day), tc.hhmm)
+		if err != nil {
+			t.Fatalf("LocalTime(%s, %s, %s): %v", tc.zone, tc.day, tc.hhmm, err)
+		}
+		if !got.Equal(utc(t, tc.want)) {
+			t.Errorf("LocalTime(%s, %s, %s) = %s, want %s", tc.zone, tc.day, tc.hhmm, got.UTC().Format(time.RFC3339), tc.want)
+		}
+		if wall := got.Format("2006-01-02 15:04 MST"); wall != tc.wantWall {
+			t.Errorf("LocalTime(%s, %s, %s) wall = %s, want %s", tc.zone, tc.day, tc.hhmm, wall, tc.wantWall)
+		}
+		if got.Location() != loc {
+			t.Errorf("LocalTime(%s, …) location = %s, want %s", tc.zone, got.Location(), loc)
+		}
+	}
+}
+
+func TestLocalTimeDeterministic(t *testing.T) {
+	// The same ambiguous or skipped input always resolves to the same instant.
+	chicago := loadZone(t, "America/Chicago")
+	for _, tc := range []struct{ day, hhmm string }{{"2026-03-08", "02:30"}, {"2026-11-01", "01:30"}} {
+		first, err := LocalTime(chicago, date(t, tc.day), tc.hhmm)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for range 100 {
+			again, err := LocalTime(chicago, date(t, tc.day), tc.hhmm)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !again.Equal(first) {
+				t.Fatalf("LocalTime(%s, %s) = %s then %s", tc.day, tc.hhmm, first, again)
+			}
+		}
+	}
+}
+
+func TestLocalTimeRejectsInvalid(t *testing.T) {
+	chicago := loadZone(t, "America/Chicago")
+	d := date(t, "2026-10-05")
+	for _, hhmm := range []string{
+		"", "9:30", "09:3", "24:00", "23:60", "09:30:00", "0930", " 09:30", "09:30 ", "9am", "-1:00",
+	} {
+		if got, err := LocalTime(chicago, d, hhmm); err == nil {
+			t.Errorf("LocalTime(%q) = %s, want error", hhmm, got)
+		} else if !strings.Contains(err.Error(), "HH:MM") {
+			t.Errorf("LocalTime(%q) error %q does not name the HH:MM form", hhmm, err)
+		}
+	}
+	if _, err := LocalTime(chicago, store.LocalDate{}, "09:30"); err == nil {
+		t.Error("LocalTime(zero date) succeeded")
+	}
+}

internal/secretbox/secretbox.go

@@ -0,0 +1,81 @@
+// Package secretbox encrypts secrets at rest with AES-256-GCM. It is the only
+// owner of secret encryption: every _ct column holds a token produced by
+// Box.Encrypt, laid out as nonce ‖ ciphertext.
+//
+// Errors from this package never contain plaintext, ciphertext or key
+// material.
+package secretbox
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+)
+
+// KeySize is the decoded key length in bytes (AES-256).
+const KeySize = 32
+
+var (
+	// ErrKeyEncoding means the key is not valid standard base64.
+	ErrKeyEncoding = errors.New("secretbox: key is not valid standard base64")
+	// ErrKeyLength means the decoded key is not exactly KeySize bytes.
+	ErrKeyLength = errors.New("secretbox: key must decode to exactly 32 bytes")
+	// ErrMalformed means a token is too short to hold a nonce and tag.
+	ErrMalformed = errors.New("secretbox: token is too short")
+	// ErrDecrypt means a token failed authentication: it was corrupted or
+	// sealed under a different key.
+	ErrDecrypt = errors.New("secretbox: token failed authentication")
+)
+
+// Box seals and opens secrets under one key. It is safe for concurrent use.
+type Box struct {
+	aead cipher.AEAD
+}
+
+// New returns a Box for encodedKey, the standard-base64 encoding of a
+// KeySize-byte key.
+func New(encodedKey string) (*Box, error) {
+	key, err := base64.StdEncoding.Strict().DecodeString(encodedKey)
+	if err != nil {
+		// The decoder's error is not wrapped: it describes the key's content.
+		return nil, ErrKeyEncoding
+	}
+	if len(key) != KeySize {
+		return nil, fmt.Errorf("%w, got %d", ErrKeyLength, len(key))
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("secretbox: %w", err)
+	}
+	aead, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("secretbox: %w", err)
+	}
+	return &Box{aead: aead}, nil
+}
+
+// Encrypt seals plaintext under a fresh random nonce and returns
+// nonce ‖ ciphertext.
+func (b *Box) Encrypt(plaintext []byte) ([]byte, error) {
+	nonce := make([]byte, b.aead.NonceSize(), b.aead.NonceSize()+len(plaintext)+b.aead.Overhead())
+	if _, err := rand.Read(nonce); err != nil {
+		return nil, fmt.Errorf("secretbox: generate nonce: %w", err)
+	}
+	return b.aead.Seal(nonce, nonce, plaintext, nil), nil
+}
+
+// Decrypt authenticates and opens a token produced by Encrypt.
+func (b *Box) Decrypt(token []byte) ([]byte, error) {
+	n := b.aead.NonceSize()
+	if len(token) < n+b.aead.Overhead() {
+		return nil, ErrMalformed
+	}
+	plaintext, err := b.aead.Open(nil, token[:n], token[n:], nil)
+	if err != nil {
+		return nil, ErrDecrypt
+	}
+	return plaintext, nil
+}

internal/secretbox/secretbox_test.go

@@ -0,0 +1,200 @@
+package secretbox
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"strings"
+	"testing"
+)
+
+// newKey returns a fresh random key and its standard-base64 encoding.
+func newKey(t *testing.T) ([]byte, string) {
+	t.Helper()
+	key := make([]byte, KeySize)
+	if _, err := rand.Read(key); err != nil {
+		t.Fatal(err)
+	}
+	return key, base64.StdEncoding.EncodeToString(key)
+}
+
+func newBox(t *testing.T) (*Box, []byte, string) {
+	t.Helper()
+	key, encoded := newKey(t)
+	box, err := New(encoded)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return box, key, encoded
+}
+
+// assertNoLeak fails if err's message contains any of the secrets, either
+// raw or base64-encoded.
+func assertNoLeak(t *testing.T, err error, secrets ...[]byte) {
+	t.Helper()
+	msg := err.Error()
+	for _, s := range secrets {
+		if len(s) == 0 {
+			continue
+		}
+		for _, form := range []string{string(s), base64.StdEncoding.EncodeToString(s), base64.RawStdEncoding.EncodeToString(s)} {
+			if strings.Contains(msg, form) {
+				t.Errorf("error %q leaks secret material %q", msg, form)
+			}
+		}
+	}
+}
+
+func TestRoundTrip(t *testing.T) {
+	box, _, _ := newBox(t)
+	for _, plaintext := range [][]byte{
+		[]byte("ya29.oauth-refresh-token"),
+		{},
+		bytes.Repeat([]byte{0x00, 0xff}, 4096),
+	} {
+		token, err := box.Encrypt(plaintext)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(plaintext) > 0 && bytes.Contains(token, plaintext) {
+			t.Errorf("token contains the plaintext")
+		}
+		got, err := box.Decrypt(token)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !bytes.Equal(got, plaintext) {
+			t.Errorf("Decrypt = %q, want %q", got, plaintext)
+		}
+	}
+}
+
+func TestTokenLayout(t *testing.T) {
+	box, _, _ := newBox(t)
+	plaintext := []byte("secret")
+	token, err := box.Encrypt(plaintext)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// nonce (12) ‖ ciphertext (len(plaintext)) ‖ GCM tag (16).
+	if want := 12 + len(plaintext) + 16; len(token) != want {
+		t.Errorf("token length = %d, want %d", len(token), want)
+	}
+}
+
+func TestEncryptUsesFreshNonce(t *testing.T) {
+	box, _, _ := newBox(t)
+	plaintext := []byte("same plaintext")
+	a, err := box.Encrypt(plaintext)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, err := box.Encrypt(plaintext)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if bytes.Equal(a, b) {
+		t.Fatal("two encryptions of the same plaintext are identical")
+	}
+	if bytes.Equal(a[:12], b[:12]) {
+		t.Error("two encryptions reused the same nonce")
+	}
+}
+
+func TestDecryptRejectsFlippedByte(t *testing.T) {
+	box, key, encoded := newBox(t)
+	plaintext := []byte("do-not-leak-me")
+	token, err := box.Encrypt(plaintext)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Flip one bit in every position: nonce, ciphertext and tag.
+	for i := range token {
+		tampered := bytes.Clone(token)
+		tampered[i] ^= 0x01
+		got, err := box.Decrypt(tampered)
+		if !errors.Is(err, ErrDecrypt) {
+			t.Fatalf("byte %d flipped: Decrypt = %q, %v; want ErrDecrypt", i, got, err)
+		}
+		if got != nil {
+			t.Errorf("byte %d flipped: Decrypt returned plaintext alongside the error", i)
+		}
+		assertNoLeak(t, err, plaintext, key, []byte(encoded), tampered)
+	}
+}
+
+func TestDecryptRejectsWrongKey(t *testing.T) {
+	box, key, encoded := newBox(t)
+	other, otherKey, otherEncoded := newBox(t)
+	plaintext := []byte("do-not-leak-me")
+	token, err := box.Encrypt(plaintext)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := other.Decrypt(token)
+	if !errors.Is(err, ErrDecrypt) {
+		t.Fatalf("Decrypt with wrong key = %q, %v; want ErrDecrypt", got, err)
+	}
+	assertNoLeak(t, err, plaintext, key, []byte(encoded), otherKey, []byte(otherEncoded), token)
+}
+
+func TestDecryptRejectsShortToken(t *testing.T) {
+	box, _, _ := newBox(t)
+	for _, n := range []int{0, 1, 12, 12 + 15} {
+		token := bytes.Repeat([]byte{0xab}, n)
+		if _, err := box.Decrypt(token); !errors.Is(err, ErrMalformed) {
+			t.Errorf("Decrypt(%d bytes) error = %v, want ErrMalformed", n, err)
+		}
+	}
+}
+
+func TestNewRejectsBadKey(t *testing.T) {
+	key, _ := newKey(t)
+	tests := []struct {
+		name    string
+		encoded string
+		want    error
+	}{
+		{"empty", "", ErrKeyLength},
+		{"not base64", "not*base64!" + strings.Repeat("A", 33), ErrKeyEncoding},
+		{"url-safe alphabet", strings.Repeat("_-", 22), ErrKeyEncoding},
+		{"unpadded", base64.RawStdEncoding.EncodeToString(key), ErrKeyEncoding},
+		{"raw key bytes", string(key), ErrKeyEncoding},
+		{"too short", base64.StdEncoding.EncodeToString(key[:31]), ErrKeyLength},
+		{"too long", base64.StdEncoding.EncodeToString(append(bytes.Clone(key), 0x00)), ErrKeyLength},
+		{"AES-128 length", base64.StdEncoding.EncodeToString(key[:16]), ErrKeyLength},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			box, err := New(tt.encoded)
+			if !errors.Is(err, tt.want) {
+				t.Fatalf("New error = %v, want %v", err, tt.want)
+			}
+			if box != nil {
+				t.Error("New returned a Box alongside the error")
+			}
+			assertNoLeak(t, err, key, []byte(tt.encoded))
+		})
+	}
+}
+
+func TestNewAcceptsBase64Key(t *testing.T) {
+	key, encoded := newKey(t)
+	box, err := New(encoded)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// A Box built from the same key opens tokens sealed by the first.
+	token, err := box.Encrypt([]byte("x"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	again, err := New(base64.StdEncoding.EncodeToString(key))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := again.Decrypt(token); err != nil {
+		t.Errorf("same key failed to decrypt: %v", err)
+	}
+}

internal/secureurl/secureurl.go

@@ -1,32 +0,0 @@
-// Package secureurl holds the one transport rule for URLs that carry
-// credentials or session cookies: HTTPS, or plain HTTP to a loopback host for
-// local development and tests.
-package secureurl
-
-import (
-	"errors"
-	"fmt"
-	"net/url"
-	"strings"
-)
-
-// loopbackHosts are the only hosts plain HTTP is allowed for, compared
-// case-insensitively. url.URL's Hostname strips the brackets from "[::1]".
-var loopbackHosts = map[string]bool{"localhost": true, "127.0.0.1": true, "::1": true}
-
-// Check reports an error unless u is an absolute https:// URL, or an http://
-// URL whose host is localhost, 127.0.0.1 or ::1.
-func Check(u *url.URL) error {
-	switch {
-	case u.Hostname() == "":
-		return errors.New("URL has no host")
-	case u.Scheme == "https":
-		return nil
-	case u.Scheme == "http" && loopbackHosts[strings.ToLower(u.Hostname())]:
-		return nil
-	case u.Scheme == "http":
-		return errors.New("plain http:// is allowed only for localhost, 127.0.0.1 or [::1]; use https://")
-	default:
-		return fmt.Errorf("unsupported scheme %q (want https://)", u.Scheme)
-	}
-}

internal/secureurl/secureurl_test.go

@@ -1,40 +0,0 @@
-package secureurl
-
-import (
-	"net/url"
-	"testing"
-)
-
-func TestCheck(t *testing.T) {
-	t.Parallel()
-	tests := []struct {
-		raw string
-		ok  bool
-	}{
-		{"https://meals.example.com", true},
-		{"https://auth.example.com/application/o/mealquest/", true},
-		{"https://192.0.2.10:8443", true},
-		{"http://localhost:8080", true},
-		{"http://LOCALHOST:8080", true},
-		{"http://127.0.0.1:8080/path", true},
-		{"http://[::1]:8080", true},
-		{"http://[::1]", true},
-		{"http://meals.example.com", false},
-		{"http://192.0.2.10", false},
-		{"http://127.0.0.2", false},
-		{"http://localhost.example.com", false},
-		{"http://0.0.0.0:8080", false},
-		{"ftp://localhost", false},
-		{"https://", false},
-		{"meals.example.com", false},
-	}
-	for _, tc := range tests {
-		u, err := url.Parse(tc.raw)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if err := Check(u); (err == nil) != tc.ok {
-			t.Errorf("Check(%q) error = %v, want ok=%v", tc.raw, err, tc.ok)
-		}
-	}
-}

internal/server/server.go

@@ -16,15 +16,9 @@ import (
 // SPA's index.html.
 var reservedPrefixes = []string{"/api", "/auth", "/media", "/health"}
 
-// RouteMounter registers its own routes on the router.
-type RouteMounter interface {
-	Mount(r chi.Router)
-}
-
 // NewRouter returns the HTTP handler for the service. version is reported by
-// GET /health; auth mounts the /auth routes; assets is the web build served
-// for every other GET.
-func NewRouter(logger *slog.Logger, version string, auth RouteMounter, assets fs.FS) (http.Handler, error) {
+// GET /health; assets is the web build served for every other GET.
+func NewRouter(logger *slog.Logger, version string, assets fs.FS) (http.Handler, error) {
 	notFound := apiErrorHandler(logger, http.StatusNotFound, "not_found", "not found")
 	methodNotAllowed := apiErrorHandler(logger, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
 
@@ -38,14 +32,12 @@ func NewRouter(logger *slog.Logger, version string, auth RouteMounter, assets fs
 	r.NotFound(notFound)
 
 	r.Get("/health", health(logger, version))
-	auth.Mount(r)
 	r.Route("/api", func(r chi.Router) {
 		r.MethodNotAllowed(methodNotAllowed)
 		r.NotFound(notFound)
 	})
-	// Catch-all for the PWA. Unknown /auth paths and /media (no routes yet)
-	// reach the frontend handler, which passes them to notFound rather than
-	// the SPA fallback.
+	// Catch-all for the PWA. /auth and /media have no routes yet; the frontend
+	// handler passes them to notFound rather than the SPA fallback.
 	r.Method(http.MethodGet, "/*", web)
 	r.Method(http.MethodHead, "/*", web)
 	return r, nil

internal/server/server_test.go

@@ -10,8 +10,6 @@ import (
 	"strings"
 	"testing"
 	"testing/fstest"
-
-	"github.com/go-chi/chi/v5"
 )
 
 const (
@@ -27,39 +25,13 @@ func newTestRouter(t *testing.T, version string) http.Handler {
 		"index.html":             {Data: []byte(fixtureIndex)},
 		"assets/index-AbC123.js": {Data: []byte(fixtureAsset)},
 	}
-	r, err := NewRouter(logger, version, stubAuth{}, assets)
+	r, err := NewRouter(logger, version, assets)
 	if err != nil {
 		t.Fatal(err)
 	}
 	return r
 }
 
-// stubAuth mounts a fixed GET /auth/login in place of the real auth flow.
-type stubAuth struct{}
-
-func (stubAuth) Mount(r chi.Router) {
-	r.Get("/auth/login", func(w http.ResponseWriter, _ *http.Request) {
-		io.WriteString(w, "stub login")
-	})
-}
-
-func TestAuthRoutesMounted(t *testing.T) {
-	t.Parallel()
-
-	router := newTestRouter(t, "dev")
-	rec := httptest.NewRecorder()
-	router.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/auth/login", nil))
-	if rec.Code != http.StatusOK || rec.Body.String() != "stub login" {
-		t.Errorf("GET /auth/login = %d %q, want the mounted handler", rec.Code, rec.Body.String())
-	}
-
-	rec = httptest.NewRecorder()
-	router.ServeHTTP(rec, httptest.NewRequest(http.MethodPost, "/auth/login", nil))
-	if rec.Code != http.StatusMethodNotAllowed {
-		t.Errorf("POST /auth/login status = %d, want 405", rec.Code)
-	}
-}
-
 func TestHealth(t *testing.T) {
 	t.Parallel()
 
@@ -127,7 +99,7 @@ func TestReservedPathsNotFound(t *testing.T) {
 		{http.MethodGet, "/api"},
 		{http.MethodGet, "/api/unknown"},
 		{http.MethodPost, "/api/unknown"},
-		{http.MethodGet, "/auth/unknown"},
+		{http.MethodGet, "/auth/callback"},
 		{http.MethodGet, "/media/photo.jpg"},
 		{http.MethodGet, "/health/deep"},
 		{http.MethodGet, "/auth/../quests/42"},

internal/store/time.go

@@ -86,6 +86,17 @@ func ParseLocalDate(s string) (LocalDate, error) {
 	return LocalDate{t.Year(), t.Month(), t.Day()}, nil
 }
 
+// LocalDateOf returns the calendar date of t in t's own location.
+func LocalDateOf(t time.Time) LocalDate {
+	y, m, d := t.Date()
+	return LocalDate{y, m, d}
+}
+
+// Date returns the year, month and day of d.
+func (d LocalDate) Date() (year int, month time.Month, day int) {
+	return d.year, d.month, d.day
+}
+
 // String returns the YYYY-MM-DD form.
 func (d LocalDate) String() string {
 	return fmt.Sprintf("%04d-%02d-%02d", d.year, int(d.month), d.day)
@@ -96,11 +107,15 @@ func (d LocalDate) IsZero() bool {
 	return d == LocalDate{}
 }
 
-// Value implements driver.Valuer. The zero LocalDate is an error.
+// Value implements driver.Valuer. The zero LocalDate is an error, as is a
+// year outside 0000–9999, which the four-digit stored form cannot represent.
 func (d LocalDate) Value() (driver.Value, error) {
 	if d.IsZero() {
 		return nil, errors.New("store: zero LocalDate")
 	}
+	if d.year < 0 || d.year > 9999 {
+		return nil, fmt.Errorf("store: LocalDate year %d outside 0000-9999", d.year)
+	}
 	return d.String(), nil
 }
 

internal/store/time_test.go

@@ -102,6 +102,25 @@ func TestLocalDateRoundTrip(t *testing.T) {
 	}
 }
 
+func TestLocalDateOf(t *testing.T) {
+	auckland, err := time.LoadLocation("Pacific/Auckland")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 2026-10-03T20:00Z is already 2026-10-04 in Auckland (UTC+13).
+	instant := time.Date(2026, time.October, 3, 20, 0, 0, 0, time.UTC)
+	if got := LocalDateOf(instant).String(); got != "2026-10-03" {
+		t.Errorf("LocalDateOf(UTC) = %s, want 2026-10-03", got)
+	}
+	d := LocalDateOf(instant.In(auckland))
+	if got := d.String(); got != "2026-10-04" {
+		t.Errorf("LocalDateOf(Auckland) = %s, want 2026-10-04", got)
+	}
+	if y, m, day := d.Date(); y != 2026 || m != time.October || day != 4 {
+		t.Errorf("Date() = %d-%d-%d, want 2026-10-4", y, m, day)
+	}
+}
+
 func TestLocalDateRejectsInvalid(t *testing.T) {
 	for _, str := range []string{
 		"", "2026-02-30", "2026-02-29", "2026-13-01", "2026-00-10", "2026-10-00",
@@ -119,6 +138,12 @@ func TestLocalDateRejectsInvalid(t *testing.T) {
 	if _, err := (LocalDate{}).Value(); err == nil {
 		t.Error("zero LocalDate Value succeeded")
 	}
+	for _, y := range []int{-1, 10000} {
+		d := LocalDateOf(time.Date(y, time.January, 1, 0, 0, 0, 0, time.UTC))
+		if _, err := d.Value(); err == nil {
+			t.Errorf("LocalDate year %d Value succeeded", y)
+		}
+	}
 	var d LocalDate
 	if err := d.Scan(nil); err == nil {
 		t.Error("Scan(nil) succeeded")