Jail/chroot nginx process inside controller container (#8337)

* Initial work on chrooting nginx process

* More improvements in chroot

* Fix charts and some file locations

* Fix symlink on non chrooted container

* fix psp test

* Add e2e tests to chroot image

* Fix logger

* Add internal logger in controller

* Fix overlay for chrooted tests

* Fix tests

* fix boilerplates

* Fix unittest to point to the right pid

* Fix PR review

charts/ingress-nginx/README.md

@@ -306,6 +306,7 @@ Kubernetes: `>=1.19.0-0`
 | controller.hostPort.ports.https | int | `443` | 'hostPort' https port |
 | controller.hostname | object | `{}` | Optionally customize the pod hostname. |
 | controller.image.allowPrivilegeEscalation | bool | `true` |  |
+| controller.image.chroot | bool | `false` |  |
 | controller.image.digest | string | `"sha256:31f47c1e202b39fadecf822a9b76370bd4baed199a005b3e7d4d1455f4fd3fe2"` |  |
 | controller.image.image | string | `"ingress-nginx/controller"` |  |
 | controller.image.pullPolicy | string | `"IfNotPresent"` |  |

charts/ingress-nginx/templates/_helpers.tpl

@@ -43,11 +43,40 @@ capabilities:
   - ALL
   add:
   - NET_BIND_SERVICE
+  {{- if .Values.controller.image.chroot }}
+  - SYS_CHROOT
+  {{- end }}
 runAsUser: {{ .Values.controller.image.runAsUser }}
 allowPrivilegeEscalation: {{ .Values.controller.image.allowPrivilegeEscalation }}
 {{- end }}
 {{- end -}}
 
+{{/*
+Get specific image
+*/}}
+{{- define "ingress-nginx.image" -}}
+{{- if .chroot -}}
+{{- printf "%s-chroot" .image -}}
+{{- else -}}
+{{- printf "%s" .image -}}
+{{- end }}
+{{- end -}}
+
+{{/*
+Get specific image digest
+*/}}
+{{- define "ingress-nginx.imageDigest" -}}
+{{- if .chroot -}}
+{{- if .digestChroot -}}
+{{- printf "@%s" .digestChroot -}}
+{{- end }}
+{{- else -}}
+{{ if .digest -}}
+{{- printf "@%s" .digest -}}
+{{- end -}}
+{{- end -}}
+{{- end -}}
+
 {{/*
 Create a default fully qualified controller name.
 We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).

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

@@ -74,7 +74,7 @@ spec:
       containers:
         - name: {{ .Values.controller.containerName }}
           {{- with .Values.controller.image }}
-          image: "{{- if .repository -}}{{ .repository }}{{ else }}{{ .registry }}/{{ .image }}{{- end -}}:{{ .tag }}{{- if (.digest) -}} @{{.digest}} {{- end -}}"
+          image: "{{- if .repository -}}{{ .repository }}{{ else }}{{ .registry }}/{{ include "ingress-nginx.image" . }}{{- end -}}:{{ .tag }}{{ include "ingress-nginx.imageDigest" . }}"
           {{- end }}
           imagePullPolicy: {{ .Values.controller.image.pullPolicy }}
         {{- if .Values.controller.lifecycle }}

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

@@ -78,7 +78,7 @@ spec:
       containers:
         - name: {{ .Values.controller.containerName }}
           {{- with .Values.controller.image }}
-          image: "{{- if .repository -}}{{ .repository }}{{ else }}{{ .registry }}/{{ .image }}{{- end -}}:{{ .tag }}{{- if (.digest) -}} @{{.digest}} {{- end -}}"
+          image: "{{- if .repository -}}{{ .repository }}{{ else }}{{ .registry }}/{{ include "ingress-nginx.image" . }}{{- end -}}:{{ .tag }}{{ include "ingress-nginx.imageDigest" . }}"
           {{- end }}
           imagePullPolicy: {{ .Values.controller.image.pullPolicy }}
         {{- if .Values.controller.lifecycle }}

charts/ingress-nginx/values.yaml

@@ -16,6 +16,8 @@ commonLabels: {}
 controller:
   name: controller
   image:
+    ## Keep false as default for now!
+    chroot: false
     registry: k8s.gcr.io
     image: ingress-nginx/controller
     ## for backwards compatibility consider setting the full image url via the repository value below
@@ -23,6 +25,7 @@ controller:
     ## repository:
     tag: "v1.1.3"
     digest: sha256:31f47c1e202b39fadecf822a9b76370bd4baed199a005b3e7d4d1455f4fd3fe2
+    # digestChroot: "" # TODO: Fill when we have it
     pullPolicy: IfNotPresent
     # www-data -> uid 101
     runAsUser: 101