Secure kubelet public api

Secure kubelet public api, add authentication for https port 10250 and close http port 10255. Please refer to kubernetes/kubernetes#7965, kubernetes/kubernetes#59666 for reasons and docker/for-linux#324, [Backdooring through kubelet](https://medium.com/handy-tech/analysis-of-a-kubernetes-hack-backdooring-through-kubelet-823be5c3d67c) for hacking examples.
microsoft · Aug 30, 2018 · 0204d84 · 0204d84
1 parent 85686d9
commit 0204d84
Show file tree

Hide file tree

Showing 5 changed files with 96 additions and 1 deletion.
diff --git a/pai-management/k8sPaiLibrary/maintainconf/deploy.yaml b/pai-management/k8sPaiLibrary/maintainconf/deploy.yaml
@@ -39,6 +39,10 @@ master-deployment:
       src: k8sPaiLibrary/template/kubelet.sh.template
       dst: master-deployment
 
+    - name: certs.sh
+      src: k8sPaiLibrary/template/certs.sh.template
+      dst: master-deployment
+
     - name: config
       src: k8sPaiLibrary/template/config.template
       dst: master-deployment/etc/kubernetes

diff --git a/pai-management/k8sPaiLibrary/maintaintool/kubelet-start.sh b/pai-management/k8sPaiLibrary/maintaintool/kubelet-start.sh
@@ -42,5 +42,9 @@ if [ ! -d "$manifestpath" ]; then
 fi
 
 
+# generate certs for kubelet
+chmod u+x $scriptPath/certs.sh
+./$scriptPath/certs.sh
+
 chmod u+x $scriptPath/kubelet.sh
 ./$scriptPath/kubelet.sh
diff --git a/pai-management/k8sPaiLibrary/template/apiserver.yaml.template b/pai-management/k8sPaiLibrary/template/apiserver.yaml.template
@@ -41,3 +41,14 @@ spec:
     - --anonymous-auth=true
     - --cors-allowed-origins
     - .*
+    - --kubelet-client-certificate
+    - /certs/apiserver.crt
+    - --kubelet-client-key
+    - /certs/apiserver.key
+    volumeMounts:
+    - mountPath: /certs
+      name: certs
+  volumes:
+  - hostPath:
+    path: /etc/pai.certs
+    name: certs
diff --git a/pai-management/k8sPaiLibrary/template/certs.sh.template b/pai-management/k8sPaiLibrary/template/certs.sh.template
@@ -0,0 +1,71 @@
+#!/bin/sh
+
+# Copyright (c) Microsoft Corporation
+# All rights reserved.
+#
+# MIT License
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
+# to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+# The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+# BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+hostip="{{ hostcofig['hostip'] }}"
+
+# Put CAs, certs and keys in /etc/pai.certs
+certspath="/etc/pai.certs"
+mkdir -p ${certspath}
+
+# Certificate signing request configuration
+# from https://kubernetes.io/docs/concepts/cluster-administration/certificates/#openssl
+cat > ${certspath}/csr.conf << EOL
+[ req ]
+default_bits = 4096
+prompt = no
+default_md = sha256
+req_extensions = req_ext
+distinguished_name = dn
+
+[ dn ]
+C = CN
+L = PEK
+O = OpenPAI
+CN = ${hostip}
+
+[ req_ext ]
+subjectAltName = @alt_names
+
+[ alt_names ]
+IP.1 = ${hostip}
+IP.2 = ${hostip}
+
+[ v3_ext ]
+authorityKeyIdentifier=keyid,issuer:always
+basicConstraints=CA:FALSE
+keyUsage=keyEncipherment,dataEncipherment
+extendedKeyUsage=serverAuth,clientAuth
+subjectAltName=@alt_names
+EOL
+
+
+# Authentication for apiserver -> kubelet
+openssl genrsa -out ${certspath}/kubelet.ca.key 4096
+openssl req -x509 -new -nodes -key ${certspath}/kubelet.ca.key \
+  -out ${certspath}/kubelet.ca.crt -subj "/CN=${hostip}" -days 365
+openssl genrsa -out ${certspath}/apiserver.key 4096
+openssl req -new -key ${certspath}/apiserver.key \
+  -out ${certspath}/apiserver.csr -config ${certspath}/csr.conf
+openssl x509 -req -in ${certspath}/apiserver.csr \
+  -CA ${certspath}/kubelet.ca.crt -CAkey ${certspath}/kubelet.ca.key -CAcreateserial \
+  -out ${certspath}/apiserver.crt -days 365 -extensions v3_ext -extfile ${certspath}/csr.conf
+
+cp ${certspath}/kubelet.ca.crt /var/lib/kubelet/ca.crt
+
diff --git a/pai-management/k8sPaiLibrary/template/kubelet.sh.template b/pai-management/k8sPaiLibrary/template/kubelet.sh.template
@@ -36,7 +36,12 @@ docker run \
     --privileged=true \
     -d \
     {{ clusterconfig['dockerregistry'] }}/hyperkube:{{ clusterconfig['hyperkubeversion'] }} \
-    /hyperkube kubelet --fail-swap-on=false --address={{ hostcofig['hostip'] }} \
+    /hyperkube kubelet --address={{ hostcofig['hostip'] }} \
+  --anonymous-auth=false \
+  --authentication-token-webhook \
+  --client-ca-file=/var/lib/kubelet/ca.crt \
+  --fail-swap-on=false \
+  --read-only-port=0 \
   --register-node=true \
   --kubeconfig=/etc/kubernetes/config \
   --require-kubeconfig \