feat(metarefresh): simplify random logic

Signed-off-by: Xe Iaso <me@xeiaso.net>

docs/docs/CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add the `DIFFICULTY_IN_JWT` option, which allows one to add the `difficulty` field in the JWT claims which indicates the difficulty of the token ([#1063](https://github.com/TecharoHQ/anubis/pull/1063)).
 - Ported the client-side JS to TypeScript to avoid egregious errors in the future.
 - Fixes concurrency problems with very old browsers ([#1082](https://github.com/TecharoHQ/anubis/issues/1082)).
+- Randomly use the Refresh header instead of the meta refresh tag in the metarefresh challenge.
 - Update OpenRC service to truncate the runtime directory before starting Anubis.
 
 ### Bug Fixes

lib/challenge/interface.go

@@ -61,7 +61,7 @@ type Impl interface {
 	Setup(mux *http.ServeMux)
 
 	// Issue a new challenge to the user, called by the Anubis.
-	Issue(r *http.Request, lg *slog.Logger, in *IssueInput) (templ.Component, error)
+	Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *IssueInput) (templ.Component, error)
 
 	// Validate a challenge, making sure that it passes muster.
 	Validate(r *http.Request, lg *slog.Logger, in *ValidateInput) error

lib/challenge/metarefresh/metarefresh.go

@@ -23,7 +23,7 @@ type Impl struct{}
 
 func (i *Impl) Setup(mux *http.ServeMux) {}
 
-func (i *Impl) Issue(r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
+func (i *Impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
 	u, err := r.URL.Parse(anubis.BasePrefix + "/.within.website/x/cmd/anubis/api/pass-challenge")
 	if err != nil {
 		return nil, fmt.Errorf("can't render page: %w", err)
@@ -35,9 +35,15 @@ func (i *Impl) Issue(r *http.Request, lg *slog.Logger, in *challenge.IssueInput)
 	q.Set("id", in.Challenge.ID)
 	u.RawQuery = q.Encode()
 
+	showMeta := in.Challenge.RandomData[0]%2 == 0
+
+	if !showMeta {
+		w.Header().Add("Refresh", fmt.Sprintf("%d; url=%s", in.Rule.Challenge.Difficulty+1, u.String()))
+	}
+
 	loc := localization.GetLocalizer(r)
 
-	result := page(u.String(), in.Rule.Challenge.Difficulty, loc)
+	result := page(u.String(), in.Rule.Challenge.Difficulty, showMeta, loc)
 
 	return result, nil
 }

lib/challenge/metarefresh/metarefresh.templ

@@ -7,12 +7,14 @@ import (
 	"github.com/TecharoHQ/anubis/lib/localization"
 )
 
-templ page(redir string, difficulty int, loc *localization.SimpleLocalizer) {
+templ page(redir string, difficulty int, showMeta bool, loc *localization.SimpleLocalizer) {
 	<div class="centered-div">
 		<img id="image" style="width:100%;max-width:256px;" src={ anubis.BasePrefix + "/.within.website/x/cmd/anubis/static/img/pensive.webp?cacheBuster=" + anubis.Version }/>
 		<img style="display:none;" style="width:100%;max-width:256px;" src={ anubis.BasePrefix + "/.within.website/x/cmd/anubis/static/img/happy.webp?cacheBuster=" + anubis.Version }/>
 		<p id="status">{ loc.T("loading") }</p>
 		<p>{ loc.T("connection_security") }</p>
-		<meta http-equiv="refresh" content={ fmt.Sprintf("%d; url=%s", difficulty+1, redir) }/>
+		if showMeta {
+			<meta http-equiv="refresh" content={ fmt.Sprintf("%d; url=%s", difficulty+1, redir) }/>
+		}
 	</div>
 }

lib/challenge/metarefresh/metarefresh_templ.go

@@ -15,7 +15,7 @@ import (
 	"github.com/TecharoHQ/anubis/lib/localization"
 )
 
-func page(redir string, difficulty int, loc *localization.SimpleLocalizer) templ.Component {
+func page(redir string, difficulty int, showMeta bool, loc *localization.SimpleLocalizer) templ.Component {
 	return templruntime.GeneratedTemplate(func(templ_7745c5c3_Input templruntime.GeneratedComponentInput) (templ_7745c5c3_Err error) {
 		templ_7745c5c3_W, ctx := templ_7745c5c3_Input.Writer, templ_7745c5c3_Input.Context
 		if templ_7745c5c3_CtxErr := ctx.Err(); templ_7745c5c3_CtxErr != nil {
@@ -88,20 +88,30 @@ func page(redir string, difficulty int, loc *localization.SimpleLocalizer) templ
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 5, "</p><meta http-equiv=\"refresh\" content=\"")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 5, "</p>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		var templ_7745c5c3_Var6 string
-		templ_7745c5c3_Var6, templ_7745c5c3_Err = templ.JoinStringErrs(fmt.Sprintf("%d; url=%s", difficulty+1, redir))
-		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `metarefresh.templ`, Line: 16, Col: 85}
+		if showMeta {
+			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 6, "<meta http-equiv=\"refresh\" content=\"")
+			if templ_7745c5c3_Err != nil {
+				return templ_7745c5c3_Err
+			}
+			var templ_7745c5c3_Var6 string
+			templ_7745c5c3_Var6, templ_7745c5c3_Err = templ.JoinStringErrs(fmt.Sprintf("%d; url=%s", difficulty+1, redir))
+			if templ_7745c5c3_Err != nil {
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `metarefresh.templ`, Line: 17, Col: 86}
+			}
+			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var6))
+			if templ_7745c5c3_Err != nil {
+				return templ_7745c5c3_Err
+			}
+			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 7, "\">")
+			if templ_7745c5c3_Err != nil {
+				return templ_7745c5c3_Err
+			}
 		}
-		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var6))
-		if templ_7745c5c3_Err != nil {
-			return templ_7745c5c3_Err
-		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 6, "\"></div>")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 8, "</div>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}

lib/challenge/preact/preact.go

@@ -38,7 +38,7 @@ type impl struct{}
 
 func (i *impl) Setup(mux *http.ServeMux) {}
 
-func (i *impl) Issue(r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
+func (i *impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
 	u, err := r.URL.Parse(anubis.BasePrefix + "/.within.website/x/cmd/anubis/api/pass-challenge")
 	if err != nil {
 		return nil, fmt.Errorf("can't render page: %w", err)

lib/challenge/proofofwork/proofofwork.go

@@ -27,7 +27,7 @@ type Impl struct {
 
 func (i *Impl) Setup(mux *http.ServeMux) {}
 
-func (i *Impl) Issue(r *http.Request, lg *slog.Logger, in *chall.IssueInput) (templ.Component, error) {
+func (i *Impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *chall.IssueInput) (templ.Component, error) {
 	loc := localization.GetLocalizer(r)
 	return page(loc), nil
 }

lib/challenge/proofofwork/proofofwork_test.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"log/slog"
 	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"github.com/TecharoHQ/anubis/lib/challenge"
@@ -133,7 +134,7 @@ func TestBasic(t *testing.T) {
 				},
 			}
 
-			if _, err := i.Issue(cs.req, lg, inp); err != nil {
+			if _, err := i.Issue(httptest.NewRecorder(), cs.req, lg, inp); err != nil {
 				t.Errorf("can't issue challenge: %v", err)
 			}
 

lib/http.go

@@ -29,19 +29,19 @@ var domainMatchRegexp = regexp.MustCompile(`^((xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+[
 // internal glob matcher. Matching is case-insensitive on hostnames.
 func matchRedirectDomain(allowed []string, host string) bool {
 	h := strings.ToLower(strings.TrimSpace(host))
- 	for _, pat := range allowed {
- 		p := strings.ToLower(strings.TrimSpace(pat))
- 		if strings.Contains(p, glob.GLOB) {
- 			if glob.Glob(p, h) {
- 				return true
- 			}
- 			continue
- 		}
- 		if p == h {
- 			return true
- 		}
- 	}
- 	return false
+	for _, pat := range allowed {
+		p := strings.ToLower(strings.TrimSpace(pat))
+		if strings.Contains(p, glob.GLOB) {
+			if glob.Glob(p, h) {
+				return true
+			}
+			continue
+		}
+		if p == h {
+			return true
+		}
+	}
+	return false
 }
 
 type CookieOpts struct {
@@ -214,7 +214,7 @@ func (s *Server) RenderIndex(w http.ResponseWriter, r *http.Request, cr policy.C
 		Store:     s.store,
 	}
 
-	component, err := impl.Issue(r, lg, in)
+	component, err := impl.Issue(w, r, lg, in)
 	if err != nil {
 		lg.Error("[unexpected] challenge component render failed, please open an issue", "err", err) // This is likely a bug in the template. Should never be triggered as CI tests for this.
 		s.respondWithError(w, r, fmt.Sprintf("%s \"RenderIndex\"", localizer.T("internal_server_error")))