From e3c7f03aaa7cbba88fa7a99d8727655fc3e72e85 Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Sat, 25 Nov 2017 17:19:40 -0500
Subject: [PATCH] Avoid generating a CA keypair on-demand

Instead we must explicitly create it; this avoids races where we are
reading the private key and creating CA certs.

Issue #3875
---
 upup/pkg/fi/clientset_castore.go    | 10 ++-----
 upup/pkg/fi/fitasks/BUILD.bazel     | 11 +++++++-
 upup/pkg/fi/fitasks/keypair_test.go | 44 +++++++++++++++++++++++++++++
 upup/pkg/fi/vfs_castore.go          | 11 ++++----
 4 files changed, 62 insertions(+), 14 deletions(-)
 create mode 100644 upup/pkg/fi/fitasks/keypair_test.go

diff --git a/upup/pkg/fi/clientset_castore.go b/upup/pkg/fi/clientset_castore.go
index 0344d21d2c..72bea46aa4 100644
--- a/upup/pkg/fi/clientset_castore.go
+++ b/upup/pkg/fi/clientset_castore.go
@@ -62,7 +62,8 @@ func NewClientsetCAStore(cluster *kops.Cluster, clientset kopsinternalversion.Ko
 	return c
 }
 
-// readCAKeypairs retrieves the CA keypair, generating a new keypair if not found
+// readCAKeypairs retrieves the CA keypair.
+// (No longer generates a keypair if not found.)
 func (c *ClientsetCAStore) readCAKeypairs(id string) (*keyset, error) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
@@ -78,14 +79,9 @@ func (c *ClientsetCAStore) readCAKeypairs(id string) (*keyset, error) {
 	}
 
 	if keyset == nil {
-		keyset, err = c.generateCACertificate(id)
-		if err != nil {
-			return nil, err
-		}
-
+		return nil, nil
 	}
 	c.cachedCaKeysets[id] = keyset
-
 	return keyset, nil
 }
 
diff --git a/upup/pkg/fi/fitasks/BUILD.bazel b/upup/pkg/fi/fitasks/BUILD.bazel
index 3c4cf84b5f..a1c492607d 100644
--- a/upup/pkg/fi/fitasks/BUILD.bazel
+++ b/upup/pkg/fi/fitasks/BUILD.bazel
@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
@@ -27,3 +27,12 @@ go_library(
         "//vendor/k8s.io/apimachinery/pkg/util/validation/field:go_default_library",
     ],
 )
+
+go_test(
+    name = "go_default_test",
+    size = "small",
+    srcs = ["keypair_test.go"],
+    importpath = "k8s.io/kops/upup/pkg/fi/fitasks",
+    library = ":go_default_library",
+    deps = ["//upup/pkg/fi:go_default_library"],
+)
diff --git a/upup/pkg/fi/fitasks/keypair_test.go b/upup/pkg/fi/fitasks/keypair_test.go
new file mode 100644
index 0000000000..871c33043c
--- /dev/null
+++ b/upup/pkg/fi/fitasks/keypair_test.go
@@ -0,0 +1,44 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fitasks
+
+import (
+	"k8s.io/kops/upup/pkg/fi"
+	"strings"
+	"testing"
+)
+
+func TestKeypairDeps(t *testing.T) {
+	ca := &Keypair{}
+	cert := &Keypair{
+		Signer: ca,
+	}
+
+	tasks := make(map[string]fi.Task)
+	tasks["ca"] = ca
+	tasks["cert"] = cert
+
+	deps := fi.FindTaskDependencies(tasks)
+
+	if strings.Join(deps["ca"], ",") != "" {
+		t.Errorf("unexpected dependencies for ca: %v", deps["ca"])
+	}
+
+	if strings.Join(deps["cert"], ",") != "ca" {
+		t.Errorf("unexpected dependencies for cert: %v", deps["cert"])
+	}
+}
diff --git a/upup/pkg/fi/vfs_castore.go b/upup/pkg/fi/vfs_castore.go
index df3fb6413e..fc83dd1651 100644
--- a/upup/pkg/fi/vfs_castore.go
+++ b/upup/pkg/fi/vfs_castore.go
@@ -68,7 +68,7 @@ func (s *VFSCAStore) VFSPath() vfs.Path {
 	return s.basedir
 }
 
-// Retrieves the CA keypair, generating a new keypair if not found
+// Retrieves the CA keypair.  No longer generates keypairs if not found.
 func (s *VFSCAStore) readCAKeypairs(id string) (*certificates, *privateKeys, error) {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
@@ -98,16 +98,15 @@ func (s *VFSCAStore) readCAKeypairs(id string) (*certificates, *privateKeys, err
 	}
 
 	if caPrivateKeys == nil {
-		caCertificates, caPrivateKeys, err = s.generateCACertificate(id)
-		if err != nil {
-			return nil, nil, err
-		}
-
+		// We no longer generate CA certificates automatically - too race-prone
+		return caCertificates, caPrivateKeys, nil
 	}
+
 	cached = &cachedEntry{certificates: caCertificates, privateKeys: caPrivateKeys}
 	s.cachedCAs[id] = cached
 
 	return cached.certificates, cached.privateKeys, nil
+
 }
 
 func BuildCAX509Template() *x509.Certificate {