control: Generalize cookie and csrf handling

internal/dis/component/auth/auth.go

@@ -19,14 +19,18 @@ type Auth struct {
 	}
 
 	store lazy.Lazy[sessions.Store]
-	csrf  lazy.Lazy[func(http.Handler) http.Handler]
 }
 
 var (
 	_ component.Routeable = (*Auth)(nil)
 )
 
-func (auth *Auth) Routes() []string { return []string{"/auth/"} }
+func (auth *Auth) Routes() component.Routes {
+	return component.Routes{
+		Paths: []string{"/auth/"},
+		CSRF:  true,
+	}
+}
 
 func (auth *Auth) HandleRoute(ctx context.Context, route string) (http.Handler, error) {
 	router := httprouter.New()

internal/dis/component/auth/panel/panel.go

@@ -22,7 +22,13 @@ var (
 	_ component.Routeable = (*UserPanel)(nil)
 )
 
-func (panel *UserPanel) Routes() []string { return []string{"/user/"} }
+func (panel *UserPanel) Routes() component.Routes {
+	return component.Routes{
+		Paths:     []string{"/user/"},
+		CSRF:      true,
+		Decorator: panel.Dependencies.Auth.Require(nil),
+	}
+}
 
 func (panel *UserPanel) HandleRoute(ctx context.Context, route string) (http.Handler, error) {
 	router := httprouter.New()

internal/dis/component/auth/panel/password.go

@@ -33,7 +33,6 @@ func (panel *UserPanel) routePassword(ctx context.Context) http.Handler {
 			{Name: "new2", Type: httpx.PasswordField, EmptyOnError: true, Label: "New Password (again)"},
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
-		CSRF:          true,
 
 		RenderTemplate:        passwordTemplate,
 		RenderTemplateContext: panel.UserFormContext,

internal/dis/component/auth/panel/totp.go

@@ -22,7 +22,6 @@ func (panel *UserPanel) routeTOTPEnable(ctx context.Context) http.Handler {
 			{Name: "password", Type: httpx.PasswordField, EmptyOnError: true, Label: "Current Password"},
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
-		CSRF:          true,
 
 		SkipForm: func(r *http.Request) (data struct{}, skip bool) {
 			user, err := panel.Dependencies.Auth.UserOf(r)
@@ -80,7 +79,6 @@ func (panel *UserPanel) routeTOTPEnroll(ctx context.Context) http.Handler {
 			{Name: "otp", Type: httpx.TextField, EmptyOnError: true, Label: "Passcode"},
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
-		CSRF:          true,
 
 		SkipForm: func(r *http.Request) (data struct{}, skip bool) {
 			user, err := panel.Dependencies.Auth.UserOf(r)
@@ -150,7 +148,6 @@ func (panel *UserPanel) routeTOTPDisable(ctx context.Context) http.Handler {
 			{Name: "otp", Type: httpx.TextField, EmptyOnError: true, Label: "Current Passcode"},
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
-		CSRF:          true,
 
 		SkipForm: func(r *http.Request) (data struct{}, skip bool) {
 			user, err := panel.Dependencies.Auth.UserOf(r)

internal/dis/component/auth/protect.go

@@ -72,6 +72,14 @@ func (auth *Auth) Protect(handler http.Handler, perm Permission) http.Handler {
 	})
 }
 
+// Require returns a slice containing one decorator that acts like Protect(perm) on every request.
+// It returns
+func (auth *Auth) Require(perm Permission) func(http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		return auth.Protect(h, perm)
+	}
+}
+
 // Admin represents a permission that checks if a user is an administrator and has totp enabled.
 var Admin Permission = func(user *AuthUser, r *http.Request) (ok Grant, err error) {
 	return Bool2Grant(user != nil && user.IsAdmin() && user.IsTOTPEnabled(), "user needs to have admin permissions and passcode enabled"), nil

internal/dis/component/auth/session.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"net/http"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/dis/component/control"
 	"github.com/FAU-CDI/wisski-distillery/internal/dis/component/control/static"
 	"github.com/FAU-CDI/wisski-distillery/pkg/httpx"
 	"github.com/gorilla/sessions"
@@ -30,7 +31,7 @@ func (auth *Auth) UserOf(r *http.Request) (user *AuthUser, err error) {
 	}
 
 	// try to read the name from the session
-	name, ok := sess.Values[sessionUserKey]
+	name, ok := sess.Values[control.SessionUserKey]
 	if !ok {
 		return nil, nil
 	}
@@ -57,18 +58,14 @@ func (auth *Auth) UserOf(r *http.Request) (user *AuthUser, err error) {
 	return user, nil
 }
 
-const sessionCookieName = "distillery-session"
-
 // session returns the session that belongs to a given request.
 // If the session is not set, creates a new session.
 func (auth *Auth) session(r *http.Request) (*sessions.Session, error) {
 	return auth.store.Get(func() sessions.Store {
 		return sessions.NewCookieStore([]byte(auth.Config.SessionSecret))
-	}).Get(r, sessionCookieName)
+	}).Get(r, control.SessionCookie)
 }
 
-const sessionUserKey = "user"
-
 type contextUserKey struct{}
 
 var ctxUserKey = contextUserKey{}
@@ -84,7 +81,7 @@ func (auth *Auth) Login(w http.ResponseWriter, r *http.Request, user *AuthUser)
 	if err != nil {
 		return err
 	}
-	sess.Values[sessionUserKey] = user.User.User
+	sess.Values[control.SessionUserKey] = user.User.User
 	return sess.Save(r, w)
 }
 
@@ -121,7 +118,6 @@ func (auth *Auth) authLogin(ctx context.Context) http.Handler {
 			{Name: "otp", Type: httpx.TextField, EmptyOnError: true, Label: "Passcode (optional)"},
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
-		CSRF:          true,
 
 		RenderForm: func(context httpx.FormContext, w http.ResponseWriter, r *http.Request) {
 			if context.Err != nil {

internal/dis/component/control/admin/admin.go

@@ -36,19 +36,24 @@ var (
 	_ component.Routeable         = (*Admin)(nil)
 )
 
-func (*Admin) Routes() []string { return []string{"/admin/"} }
+func (admin *Admin) Routes() component.Routes {
+	return component.Routes{
+		Paths:     []string{"/admin/"},
+		CSRF:      true,
+		Decorator: admin.Dependencies.Auth.Require(auth.Admin),
+	}
+}
 
 func (admin *Admin) HandleRoute(ctx context.Context, route string) (handler http.Handler, err error) {
 
 	router := httprouter.New()
 
 	{
-		socket := &httpx.WebSocket{
+		handler = &httpx.WebSocket{
 			Context:  ctx,
 			Fallback: router,
 			Handler:  admin.serveSocket,
 		}
-		handler = admin.Dependencies.Auth.Protect(socket, auth.Admin)
 	}
 
 	// handle everything

internal/dis/component/control/admin/users.go

@@ -64,8 +64,6 @@ func (admin *Admin) createUser(ctx context.Context) http.Handler {
 		},
 		FieldTemplate: httpx.PureCSSFieldTemplate,
 
-		CSRF: true,
-
 		RenderTemplate: userCreateTemplate,
 
 		Validate: func(r *http.Request, values map[string]string) (cu createUserResult, err error) {

internal/dis/component/control/cookies.go

@@ -0,0 +1,14 @@
+package control
+
+// CSRFCookie, CSRFCookieField, SessionCookie and SessionUserKey
+// hold the names of the cookies and fields used for specific cookies.
+//
+// These are intentionally kept short to conserve bandwidth.
+const (
+	CSRFCookie      = "F" // CSRF cookie sent on a lot of requests
+	CSRFCookieField = "@" // form field name __should not be used by anything else__
+	// to pay respect
+
+	SessionCookie  = "x" // name of the cookie to use ; to doubt
+	SessionUserKey = "@" // key within the session data to hold the username
+)

internal/dis/component/control/home/home.go

@@ -25,7 +25,12 @@ var (
 	_ component.Routeable = (*Home)(nil)
 )
 
-func (*Home) Routes() []string { return []string{"/"} }
+func (*Home) Routes() component.Routes {
+	return component.Routes{
+		Paths: []string{"/"},
+		CSRF:  false,
+	}
+}
 
 func (home *Home) HandleRoute(ctx context.Context, route string) (http.Handler, error) {
 	return home, nil

internal/dis/component/control/server.go

@@ -18,28 +18,38 @@ func (control *Control) Server(ctx context.Context, progress io.Writer) (http.Ha
 	// create a new mux
 	mux := http.NewServeMux()
 
-	// add all the servable routes!
+	// create a csrf protector
+	csrfProtector := control.CSRF()
+
+	// iterate over all the handler
 	for _, s := range control.Dependencies.Routeables {
-		for _, route := range s.Routes() {
+		routes := s.Routes()
-			zerolog.Ctx(ctx).Info().Str("component", s.Name()).Str("route", route).Msg("mounting route")
+		zerolog.Ctx(ctx).Info().Str("component", s.Name()).Strs("paths", routes.Paths).Bool("csrf", routes.CSRF).Bool("decorator", routes.Decorator != nil).Msg("mounting route")
-			handler, err := s.HandleRoute(ctx, route)
+
+		for _, path := range routes.Paths {
+			handler, err := s.HandleRoute(ctx, path)
 			if err != nil {
 				return nil, err
 			}
-			mux.Handle(route, handler)
+			mux.Handle(path, routes.Decorate(handler, csrfProtector))
 		}
 	}
 
-	return func(handler http.HandlerFunc) http.Handler {
+	// apply the given context function
-		// setup a csrf protector for everything with POST
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		var opts []csrf.Option
-		if !control.Config.HTTPSEnabled() {
-			opts = append(opts, csrf.Secure(false))
-		}
-		opts = append(opts, csrf.SameSite(csrf.SameSiteStrictMode))
-		return csrf.Protect(control.Config.CSRFSecret(), opts...)(handler)
-	}(func(w http.ResponseWriter, r *http.Request) {
 		r = r.WithContext(cancel.ValuesOf(r.Context(), ctx))
 		mux.ServeHTTP(w, r)
 	}), nil
 }
+
+// CSRF returns a CSRF handler for the given function
+func (control *Control) CSRF() func(http.Handler) http.Handler {
+	var opts []csrf.Option
+	if !control.Config.HTTPSEnabled() {
+		opts = append(opts, csrf.Secure(false))
+	}
+	opts = append(opts, csrf.SameSite(csrf.SameSiteStrictMode))
+	opts = append(opts, csrf.CookieName(CSRFCookie))
+	opts = append(opts, csrf.FieldName(CSRFCookieField))
+	return csrf.Protect(control.Config.CSRFSecret(), opts...)
+}

internal/dis/component/control/static/static.go

@@ -18,7 +18,12 @@ var (
 	_ component.Routeable = (*Static)(nil)
 )
 
-func (*Static) Routes() []string { return []string{"/static/"} }
+func (*Static) Routes() component.Routes {
+	return component.Routes{
+		Paths: []string{"/static/"},
+		CSRF:  false,
+	}
+}
 
 //go:embed dist
 var staticFS embed.FS

internal/dis/component/resolver/resolver.go

@@ -32,7 +32,12 @@ var (
 	_ component.Cronable  = (*Resolver)(nil)
 )
 
-func (resolver *Resolver) Routes() []string { return []string{"/go/", "/wisski/get/"} }
+func (resolver *Resolver) Routes() component.Routes {
+	return component.Routes{
+		Paths: []string{"/go/", "/wisski/get/"},
+		CSRF:  false,
+	}
+}
 
 func (resolver *Resolver) HandleRoute(ctx context.Context, route string) (http.Handler, error) {
 	logger := zerolog.Ctx(ctx)

internal/dis/component/server.go

@@ -9,9 +9,35 @@ import (
 type Routeable interface {
 	Component
 
-	// Routes returns the routes served by this servable
+	// Routes returns information about the routes to be handled by this Routeable
-	Routes() []string
+	Routes() Routes
 
-	// HandleRoute returns the handler for the requested route
+	// HandleRoute returns the handler for the requested path
-	HandleRoute(ctx context.Context, route string) (http.Handler, error)
+	HandleRoute(ctx context.Context, path string) (http.Handler, error)
+}
+
+// Routes represents information about a single Routeable
+type Routes struct {
+	// Paths are the paths handled by this routeable.
+	// Each path is passed to HandleRoute() individually.
+	Paths []string
+
+	// CSRF indicates if this route should be protected by CSRF.
+	// CSRF protection is applied prior to any custom decorator being called.
+	CSRF bool
+
+	// Decorators is a function applied to the handler returned by HandleRoute.
+	// When nil, it is not applied.
+	Decorator func(http.Handler) http.Handler
+}
+
+// Decorate decorates the provided handler with the options specified in this handler.
+func (routes Routes) Decorate(handler http.Handler, csrf func(http.Handler) http.Handler) http.Handler {
+	if routes.CSRF && csrf != nil {
+		handler = csrf(handler)
+	}
+	if routes.Decorator != nil {
+		handler = routes.Decorator(handler)
+	}
+	return handler
 }

pkg/httpx/form.go

@@ -24,8 +24,8 @@ type Form[D any] struct {
 	// FieldTemplate may be nil; in which case [DefaultFieldTemplate] is used.
 	FieldTemplate *template.Template
 
-	// CSRF indicates if a CSRF field should be added automatically
+	// SkipCSRF if CSRF should be explicitly omitted
-	CSRF bool
+	SkipCSRF bool
 
 	// SkipForm, if non-nil, is called on every get request to determine if form parsing should be skipped entirely.
 	// If skip is true, RenderSuccess is directly called with the given values map.
@@ -124,7 +124,7 @@ func (form *Form[D]) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 // renderForm renders the form into a request
 func (form *Form[D]) renderForm(err error, values map[string]string, w http.ResponseWriter, r *http.Request) {
 	template := form.Template(values, err != nil)
-	if form.CSRF {
+	if !form.SkipCSRF {
 		template += csrf.TemplateField(r)
 	}