Updating kube-proxy to trim space from loadBalancerSourceRanges

Before this fix, a Service with a loadBalancerSourceRange value that
included a space would cause kube-proxy to crashloop. This updates
kube-proxy to trim any space from that field.

pkg/proxy/iptables/proxier.go

@@ -1183,9 +1183,10 @@ func (proxier *Proxier) syncProxyRules() {
 						allowFromNode := false
 						for _, src := range svcInfo.LoadBalancerSourceRanges() {
 							writeLine(proxier.natRules, append(args, "-s", src, "-j", string(chosenChain))...)
-							// ignore error because it has been validated
-							_, cidr, _ := net.ParseCIDR(src)
-							if cidr.Contains(proxier.nodeIP) {
+							_, cidr, err := net.ParseCIDR(src)
+							if err != nil {
+								klog.Errorf("Error parsing %s CIDR in LoadBalancerSourceRanges, dropping: %v", cidr, err)
+							} else if cidr.Contains(proxier.nodeIP) {
 								allowFromNode = true
 							}
 						}

pkg/proxy/iptables/proxier_test.go

@@ -687,6 +687,10 @@ func TestLoadBalancer(t *testing.T) {
 			svc.Status.LoadBalancer.Ingress = []v1.LoadBalancerIngress{{
 				IP: svcLBIP,
 			}}
+			// Also ensure that invalid LoadBalancerSourceRanges will not result
+			// in a crash.
+			svc.Spec.ExternalIPs = []string{svcLBIP}
+			svc.Spec.LoadBalancerSourceRanges = []string{" 1.2.3.4/28"}
 		}),
 	)