fix(lib): make Anubis less paranoid (#365)v1.17.0-beta1

Previously Anubis would aggressively make sure that the client cookie
matched exactly what it should. This has turned out to be too paranoid
in practice and has caused problems with Happy Eyeballs et. al.

This is a potential fix to #303 and #289.

1 files changed, 1 insertions, 42 deletions

diff --git a/lib/anubis.go b/lib/anubis.go
index 70eb37e..026783e 100644
--- a/lib/anubis.go
+++ b/lib/anubis.go
@@ -353,48 +353,7 @@ func (s *Server) maybeReverseProxy(w http.ResponseWriter, r *http.Request, httpS
 		return
 	}
 
-	if randomJitter() {
-		r.Header.Add("X-Anubis-Status", "PASS-BRIEF")
-		lg.Debug("cookie is not enrolled into secondary screening")
-		s.ServeHTTPNext(w, r)
-		return
-	}
-
-	claims, ok := token.Claims.(jwt.MapClaims)
-	if !ok {
-		lg.Debug("invalid token claims type", "path", r.URL.Path)
-		s.ClearCookie(w)
-		s.RenderIndex(w, r, rule, httpStatusOnly)
-		return
-	}
-	challenge := s.challengeFor(r, rule.Challenge.Difficulty)
-
-	if claims["challenge"] != challenge {
-		lg.Debug("invalid challenge", "path", r.URL.Path)
-		s.ClearCookie(w)
-		s.RenderIndex(w, r, rule, httpStatusOnly)
-		return
-	}
-
-	var nonce int
-
-	if v, ok := claims["nonce"].(float64); ok {
-		nonce = int(v)
-	}
-
-	calcString := fmt.Sprintf("%s%d", challenge, nonce)
-	calculated := internal.SHA256sum(calcString)
-
-	if subtle.ConstantTimeCompare([]byte(claims["response"].(string)), []byte(calculated)) != 1 {
-		lg.Debug("invalid response", "path", r.URL.Path)
-		failedValidations.Inc()
-		s.ClearCookie(w)
-		s.RenderIndex(w, r, rule, httpStatusOnly)
-		return
-	}
-
-	slog.Debug("all checks passed")
-	r.Header.Add("X-Anubis-Status", "PASS-FULL")
+	r.Header.Add("X-Anubis-Status", "PASS")
 	s.ServeHTTPNext(w, r)
 }