Xe/demote temporal assurance

docs/docs/CHANGELOG.md

@@ -11,12 +11,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+<!-- This changes the project to: -->
+
 - Document missing environment variables in installation guide: `SLOG_LEVEL`, `COOKIE_PREFIX`, `FORCED_LANGUAGE`, and `TARGET_DISABLE_KEEPALIVE` ([#1086](https://github.com/TecharoHQ/anubis/pull/1086))
 - Fixed `robots2policy` to properly group consecutive user agents into `any:` instead of only processing the last one ([#925](https://github.com/TecharoHQ/anubis/pull/925))
+- Add the [`s3api` storage backend](./admin/policies.mdx#s3api) to allow Anubis to use S3 API compatible object storage as its storage backend.
 
-<!-- This changes the project to: -->
+### Bug Fixes
 
-- Add the [`s3api` storage backend](./admin/policies.mdx#s3api) to allow Anubis to use S3 API compatible object storage as its storage backend.
+Sometimes the enhanced temporal assurance in [#1038](https://github.com/TecharoHQ/anubis/pull/1038) and [#1068](https://github.com/TecharoHQ/anubis/pull/1068) could backfire because Chromium and its ilk randomize the amount of time they wait in order to avoid a timing side channel attack. This has been fixed by both increasing the amount of time a client has to wait for the metarefresh and preact challenges as well as making the server side logic more permissive.
 
 ## v1.22.0: Yda Hext
 

lib/challenge/metarefresh/metarefresh.go

@@ -43,7 +43,7 @@ func (i *Impl) Issue(r *http.Request, lg *slog.Logger, in *challenge.IssueInput)
 }
 
 func (i *Impl) Validate(r *http.Request, lg *slog.Logger, in *challenge.ValidateInput) error {
-	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 950 * time.Millisecond)
+	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 800 * time.Millisecond)
 
 	if time.Now().Before(wantTime) {
 		return challenge.NewError("validate", "insufficent time", fmt.Errorf("%w: wanted user to wait until at least %s", challenge.ErrFailed, wantTime.Format(time.RFC3339)))

lib/challenge/metarefresh/metarefresh.templ

@@ -13,6 +13,6 @@ templ page(redir string, difficulty int, loc *localization.SimpleLocalizer) {
 		<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, redir) }/>
+		<meta http-equiv="refresh" content={ fmt.Sprintf("%d; url=%s", difficulty+1, redir) }/>
 	</div>
 }

lib/challenge/preact/js/app.jsx

@@ -32,7 +32,7 @@ const App = () => {
   useEffect(() => {
     const timer = setTimeout(() => {
       setPassed(true);
-    }, state.difficulty * 100);
+    }, state.difficulty * 125);
 
     return () => clearTimeout(timer);
   }, [challenge]);

lib/challenge/preact/preact.go

@@ -57,7 +57,7 @@ func (i *impl) Issue(r *http.Request, lg *slog.Logger, in *challenge.IssueInput)
 }
 
 func (i *impl) Validate(r *http.Request, lg *slog.Logger, in *challenge.ValidateInput) error {
-	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 95 * time.Millisecond)
+	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 80 * time.Millisecond)
 
 	if time.Now().Before(wantTime) {
 		return challenge.NewError("validate", "insufficent time", fmt.Errorf("%w: wanted user to wait until at least %s", challenge.ErrFailed, wantTime.Format(time.RFC3339)))