From aeaa5a1f5e57f63dd203db43fb6992ab1728c504 Mon Sep 17 00:00:00 2001 From: Pawel Wieczorek Date: Mon, 16 Sep 2019 17:51:39 +0200 Subject: k8s: Validate API server excluded admission plugins This patch verifies if CIS Kubernetes Benchmark v1.3.0 section regarding master node configuration is satisfied (1.1.10). However, CIS Kubernetes Benchmark v1.3.0 mismatches official documentation: Kubernetes 1.10+ already provides safe defaults from security standpoint [1] (ONAP Casablanca uses 1.11). Deprecated admission control plugin flag has also been validated since it was still available in Kubernetes provided by Rancher [2]. [1] https://kubernetes.io/docs/reference/access-authn-authz/admission-controllers/#is-there-a-recommended-set-of-admission-controllers-to-use [2] https://github.com/rancher/rancher/issues/15064 Issue-ID: SECCOM-235 Change-Id: I0e8fe9f885861f155cb8265df085fa93dbdff6d2 Signed-off-by: Pawel Wieczorek --- test/security/k8s/src/check/cmd/check/check.go | 2 ++ .../k8s/src/check/validators/master/api.go | 36 ++++++++++++++++++++++ .../k8s/src/check/validators/master/api_test.go | 15 +++++++++ 3 files changed, 53 insertions(+) (limited to 'test/security') diff --git a/test/security/k8s/src/check/cmd/check/check.go b/test/security/k8s/src/check/cmd/check/check.go index 3c005f77c..2ea180628 100644 --- a/test/security/k8s/src/check/cmd/check/check.go +++ b/test/security/k8s/src/check/cmd/check/check.go @@ -51,4 +51,6 @@ func main() { log.Printf("IsKubeletHTTPSAbsentOrEnabled: %t\n", master.IsKubeletHTTPSAbsentOrEnabled(k8sParams)) log.Printf("IsInsecureBindAddressAbsentOrLoopback: %t\n", master.IsInsecureBindAddressAbsentOrLoopback(k8sParams)) log.Printf("IsSecurePortAbsentOrValid: %t\n", master.IsSecurePortAbsentOrValid(k8sParams)) + + log.Printf("IsAlwaysAdmitAdmissionControlPluginExcluded: %t\n", master.IsAlwaysAdmitAdmissionControlPluginExcluded(k8sParams)) } diff --git a/test/security/k8s/src/check/validators/master/api.go b/test/security/k8s/src/check/validators/master/api.go index c91b77e30..58064ef10 100644 --- a/test/security/k8s/src/check/validators/master/api.go +++ b/test/security/k8s/src/check/validators/master/api.go @@ -126,3 +126,39 @@ func hasFlagValidPort(flag string, params []string) bool { } return true } + +// IsAlwaysAdmitAdmissionControlPluginExcluded validates AlwaysAdmit is excluded from admission control plugins. +func IsAlwaysAdmitAdmissionControlPluginExcluded(params []string) bool { + if isSingleFlagPresent("--enable-admission-plugins=", params) { + return !hasFlagArgumentIncluded("--enable-admission-plugins=", "AlwaysAdmit", params) + } + if isSingleFlagPresent("--admission-control=", params) { + return !hasFlagArgumentIncluded("--admission-control=", "AlwaysAdmit", params) + } + return false +} + +// isSingleFlagPresent checks presence of selected flag and whether it was used once. +func isSingleFlagPresent(flag string, params []string) bool { + found := filterFlags(params, flag) + if len(found) != 1 { + return false + } + return true +} + +// hasFlagArgumentIncluded checks whether selected flag includes requested argument. +func hasFlagArgumentIncluded(flag string, argument string, params []string) bool { + found := filterFlags(params, flag) + if len(found) != 1 { + return false + } + + _, values := splitKV(found[0], "=") + for _, v := range strings.Split(values, ",") { + if v == argument { + return true + } + } + return false +} diff --git a/test/security/k8s/src/check/validators/master/api_test.go b/test/security/k8s/src/check/validators/master/api_test.go index bee199519..f7c6daa52 100644 --- a/test/security/k8s/src/check/validators/master/api_test.go +++ b/test/security/k8s/src/check/validators/master/api_test.go @@ -18,6 +18,10 @@ var _ = Describe("Api", func() { "--profiling=false", "--repair-malformed-updates=false", "--service-account-lookup=true", + "--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount," + + "TaintNodesByCondition,Priority,DefaultTolerationSeconds,DefaultStorageClass," + + "PersistentVolumeClaimResize,MutatingAdmissionWebhook,ValidatingAdmissionWebhook," + + "ResourceQuota", } // kubeApiServerCasablanca was obtained from virtual environment for testing @@ -212,5 +216,16 @@ var _ = Describe("Api", func() { Entry("Should be set to true on CIS-compliant cluster", kubeApiServerCISCompliant, true), Entry("Should be set to true on Dublin cluster", kubeApiServerDublin, true), ) + + DescribeTable("AlwaysAdmit admission control plugin", + func(params []string, expected bool) { + Expect(IsAlwaysAdmitAdmissionControlPluginExcluded(params)).To(Equal(expected)) + }, + Entry("Is not absent on insecure cluster", []string{"--enable-admission-plugins=Foo,Bar,AlwaysAdmit,Baz,Quuz"}, false), + Entry("Is not absent on insecure deprecated cluster", []string{"--admission-control=Foo,Bar,AlwaysAdmit,Baz,Quuz"}, false), + Entry("Should be absent on CIS-compliant cluster", kubeApiServerCISCompliant, true), + Entry("Should be absent on Casablanca cluster", kubeApiServerCasablanca, true), + Entry("Should be absent on Dublin cluster", kubeApiServerDublin, true), + ) }) }) -- cgit 1.2.3-korg