[proxy] validate header auth on proxy (#7263)

proxy/server.go

@@ -20,6 +20,7 @@ import (
 	"net/url"
 	"path/filepath"
 	"reflect"
+	"slices"
 	"sync"
 	"time"
 
@@ -2062,9 +2063,7 @@ func (s *Server) updateMapping(ctx context.Context, mapping *proto.ProxyMapping)
 	if mapping.GetAuth().GetOidc() {
 		schemes = append(schemes, auth.NewOIDC(s.mgmtClient, svcID, accountID, s.ForwardedProto))
 	}
-	for _, ha := range mapping.GetAuth().GetHeaderAuths() {
-		schemes = append(schemes, auth.NewHeader(s.mgmtClient, svcID, accountID, ha.GetHeader()))
-	}
+	schemes = append(schemes, headerAuthSchemes(mapping.GetAuth().GetHeaderAuths())...)
 
 	ipRestrictions := s.parseRestrictions(mapping)
 	s.warnIfGeoUnavailable(mapping.GetDomain(), mapping.GetAccessRestrictions())
@@ -2088,6 +2087,32 @@ func (s *Server) updateMapping(ctx context.Context, mapping *proto.ProxyMapping)
 	return nil
 }
 
+// headerAuthSchemes builds one scheme per canonical header name, carrying every
+// hash configured for that name so any of them is accepted — the OR semantics
+// management applied while it still validated the credential itself. No entry is
+// ever dropped: a name that arrives blank, or without a hash, still yields a
+// scheme, because a mapping that lost its only scheme would fall through
+// Protect's no-schemes pass-through and serve the domain unauthenticated.
+func headerAuthSchemes(headerAuths []*proto.HeaderAuth) []auth.Scheme {
+	names := make([]string, 0, len(headerAuths))
+	hashes := make(map[string][]string, len(headerAuths))
+	for _, ha := range headerAuths {
+		name := http.CanonicalHeaderKey(ha.GetHeader())
+		if !slices.Contains(names, name) {
+			names = append(names, name)
+		}
+		if hash := ha.GetHashedValue(); hash != "" {
+			hashes[name] = append(hashes[name], hash)
+		}
+	}
+
+	schemes := make([]auth.Scheme, 0, len(names))
+	for _, name := range names {
+		schemes = append(schemes, auth.NewHeader(name, hashes[name]))
+	}
+	return schemes
+}
+
 // initMiddlewareManager wires the middleware subsystem at boot. It configures
 // the per-process FactoryContext concrete middlewares consult, installs the
 // live-service check, and binds the resolver to the registry concrete