From 624b2144818bfad876d7a36f5fb0878e654b8848 Mon Sep 17 00:00:00 2001
From: Ben Hu <bensea@google.com>
Date: Wed, 6 Jan 2021 00:31:39 +0000
Subject: [PATCH] Configure --tls-cipher-suites on kube-apiserver.

---
 cluster/gce/config-default.sh              | 3 +++
 cluster/gce/config-test.sh                 | 3 +++
 cluster/gce/gci/configure-kubeapiserver.sh | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/cluster/gce/config-default.sh b/cluster/gce/config-default.sh
index 308d5ab83eb..6f8a590e567 100755
--- a/cluster/gce/config-default.sh
+++ b/cluster/gce/config-default.sh
@@ -559,3 +559,6 @@ export ETCD_PROGRESS_NOTIFY_INTERVAL="${ETCD_PROGRESS_NOTIFY_INTERVAL:-10m}"
 # It improves container image pull performance since most time is spent
 # unzipping the image layers to disk.
 export WINDOWS_ENABLE_PIGZ="${WINDOWS_ENABLE_PIGZ:-true}"
+
+# TLS_CIPHER_SUITES defines cipher suites allowed to be used by kube-apiserver. If this variable is unset or empty, kube-apiserver is allowed to use any cipher it supports.
+export TLS_CIPHER_SUITES=""
diff --git a/cluster/gce/config-test.sh b/cluster/gce/config-test.sh
index 7a7b28a7d66..538dad29879 100755
--- a/cluster/gce/config-test.sh
+++ b/cluster/gce/config-test.sh
@@ -595,3 +595,6 @@ export ETCD_PROGRESS_NOTIFY_INTERVAL="${ETCD_PROGRESS_NOTIFY_INTERVAL:-10m}"
 # It improves container image pull performance since most time is spent
 # unzipping the image layers to disk.
 export WINDOWS_ENABLE_PIGZ="${WINDOWS_ENABLE_PIGZ:-true}"
+
+# TLS_CIPHER_SUITES defines cipher suites allowed to be used by kube-apiserver. If this variable is unset or empty, kube-apiserver is allowed to use any cipher it supports.
+export TLS_CIPHER_SUITES=""
diff --git a/cluster/gce/gci/configure-kubeapiserver.sh b/cluster/gce/gci/configure-kubeapiserver.sh
index 045ea62b587..eab6932e6d2 100644
--- a/cluster/gce/gci/configure-kubeapiserver.sh
+++ b/cluster/gce/gci/configure-kubeapiserver.sh
@@ -92,6 +92,9 @@ function start-kube-apiserver {
     fi
     params+=" --tls-sni-cert-key=${OLD_MASTER_CERT_PATH},${OLD_MASTER_KEY_PATH}:${old_ips}"
   fi
+  if [[ -n "${TLS_CIPHER_SUITES:-}" ]]; then
+    params+=" --tls-cipher-suites=${TLS_CIPHER_SUITES}"
+  fi
   params+=" --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname"
   if [[ -s "${REQUESTHEADER_CA_CERT_PATH:-}" ]]; then
     params+=" --requestheader-client-ca-file=${REQUESTHEADER_CA_CERT_PATH}"