Implement object deep inspector (#8456)

internal/ingress/inspector/ingress.go

@@ -0,0 +1,62 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inspector
+
+import (
+	"fmt"
+
+	networking "k8s.io/api/networking/v1"
+)
+
+// InspectIngress is used to do the deep inspection of an ingress object, walking through all
+// of the spec fields and checking for matching strings and configurations that may represent
+// an attempt to escape configs
+func InspectIngress(ingress *networking.Ingress) error {
+	for _, rule := range ingress.Spec.Rules {
+		if rule.Host != "" {
+			if err := CheckRegex(rule.Host); err != nil {
+				return fmt.Errorf("invalid host in ingress %s/%s: %s", ingress.Namespace, ingress.Name, err)
+			}
+		}
+		if rule.HTTP != nil {
+			if err := inspectIngressRule(rule.HTTP); err != nil {
+				return fmt.Errorf("invalid rule in ingress %s/%s: %s", ingress.Namespace, ingress.Name, err)
+			}
+		}
+	}
+
+	for _, tls := range ingress.Spec.TLS {
+		if err := CheckRegex(tls.SecretName); err != nil {
+			return fmt.Errorf("invalid secret in ingress %s/%s: %s", ingress.Namespace, ingress.Name, err)
+		}
+		for _, host := range tls.Hosts {
+			if err := CheckRegex(host); err != nil {
+				return fmt.Errorf("invalid host in ingress tls config %s/%s: %s", ingress.Namespace, ingress.Name, err)
+			}
+		}
+	}
+	return nil
+}
+
+func inspectIngressRule(httprule *networking.HTTPIngressRuleValue) error {
+	for _, path := range httprule.Paths {
+		if err := CheckRegex(path.Path); err != nil {
+			return fmt.Errorf("invalid http path: %s", err)
+		}
+	}
+	return nil
+}