Add sysctl exemptions to controller PSP

I would like to be able to support this construction in my DaemonSet, I have coontrol over the host and this is the easiest way yo bump the socket properties.
```yaml
securityContext:
  sysctls:
    - name: net.core.somaxconn
      value: "8192"
```

charts/ingress-nginx/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: ingress-nginx
-version: 2.5.0
+version: 2.6.0
 appVersion: 0.33.0
 home: https://github.com/kubernetes/ingress-nginx
 description: Ingress controller for Kubernetes using NGINX as a reverse proxy and load balancer

charts/ingress-nginx/README.md

@@ -90,6 +90,7 @@ Parameter | Description | Default
 `controller.podAnnotations` | annotations to be added to pods | `{}`
 `controller.podLabels` | labels to add to the pod container metadata | `{}`
 `controller.podSecurityContext` | Security context policies to add to the controller pod | `{}`
+`controller.sysctls` | Map of optional sysctls to enable in the controller and in the PodSecurityPolicy | `{}`
 `controller.replicaCount` | desired number of controller pods | `1`
 `controller.minAvailable` | minimum number of available controller pods for PodDisruptionBudget | `1`
 `controller.resources` | controller pod resource requests & limits | `{}`

charts/ingress-nginx/templates/controller-daemonset.yaml

@@ -42,8 +42,18 @@ spec:
     {{- if .Values.controller.priorityClassName }}
       priorityClassName: {{ .Values.controller.priorityClassName }}
     {{- end }}
-    {{- if .Values.controller.podSecurityContext }}
-      securityContext: {{ toYaml .Values.controller.podSecurityContext | nindent 8 }}
+    {{- if or .Values.controller.podSecurityContext .Values.controller.sysctls }}
+      securityContext:
+    {{- end }}
+    {{- if .Values.controller.podSecurityContext  }}
+        {{- toYaml .Values.controller.podSecurityContext | nindent 8 }}
+    {{- end }}
+    {{- if .Values.controller.sysctls }}
+        sysctls:
+    {{- range $sysctl, $value := .Values.controller.sysctls }}
+        - name: {{ $sysctl }}
+          value: {{ $value }}
+    {{- end }}
     {{- end }}
       containers:
         - name: controller

charts/ingress-nginx/templates/controller-deployment.yaml

@@ -46,8 +46,18 @@ spec:
     {{- if .Values.controller.priorityClassName }}
       priorityClassName: {{ .Values.controller.priorityClassName }}
     {{- end }}
+    {{- if or .Values.controller.podSecurityContext .Values.controller.sysctls }}
+      securityContext:
+    {{- end }}
     {{- if .Values.controller.podSecurityContext }}
-      securityContext: {{ toYaml .Values.controller.podSecurityContext | nindent 8 }}
+        {{- toYaml .Values.controller.podSecurityContext | nindent 8 }}
+    {{- end }}
+    {{- if .Values.controller.sysctls }}
+        sysctls:
+    {{- range $sysctl, $value := .Values.controller.sysctls }}
+        - name: {{ $sysctl }}
+          value: {{ $value }}
+    {{- end }}
     {{- end }}
       containers:
         - name: controller

charts/ingress-nginx/templates/controller-psp.yaml

@@ -9,6 +9,12 @@ metadata:
 spec:
   allowedCapabilities:
     - NET_BIND_SERVICE
+{{- if .Values.controller.sysctls }}
+  allowedUnsafeSysctls:
+  {{- range $sysctl, $value := .Values.controller.sysctls }}
+  - {{ $sysctl }}
+  {{- end }}
+{{- end }}
   privileged: false
   allowPrivilegeEscalation: true
   # Allow core volume types.

charts/ingress-nginx/values.yaml

@@ -67,11 +67,16 @@ controller:
   #  key: value
 
   ## Security Context policies for controller pods
-  ## See https://kubernetes.io/docs/tasks/administer-cluster/sysctl-cluster/ for
-  ## notes on enabling and using sysctls
   ##
   podSecurityContext: {}
 
+  ## See https://kubernetes.io/docs/tasks/administer-cluster/sysctl-cluster/ for
+  ## notes on enabling and using sysctls
+  ###
+  sysctls: {}
+  # sysctls:
+  #   "net.core.somaxconn": "8192"
+
   ## Allows customization of the source of the IP address or FQDN to report
   ## in the ingress status field. By default, it reads the information provided
   ## by the service. If disable, the status field reports the IP address of the