Avoid creating certs that violate Apple requirements for macOS 10.15 (#208)

* Prevent creating non-standards compliant certs.

Changes generated certificates to have a NotBefore based on either the
CA NotBefore or the current time. This prevents creation of certificates
that are valid for too long making them return errors on platforms like
MacOS.

* Add license header and add test cases

cert/cert.go

@@ -73,15 +73,15 @@ func NewPrivateKey() (*rsa.PrivateKey, error) {
 
 // NewSelfSignedCACert creates a CA certificate
 func NewSelfSignedCACert(cfg Config, key crypto.Signer) (*x509.Certificate, error) {
-	now := time.Now()
+	notBefore := CalculateNotBefore(nil)
 	tmpl := x509.Certificate{
 		SerialNumber: new(big.Int).SetInt64(0),
 		Subject: pkix.Name{
 			CommonName:   cfg.CommonName,
 			Organization: cfg.Organization,
 		},
-		NotBefore:             now.UTC(),
-		NotAfter:              now.Add(duration365d * 10).UTC(),
+		NotBefore:             notBefore,
+		NotAfter:              notBefore.Add(duration365d * 10),
 		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
 		BasicConstraintsValid: true,
 		IsCA:                  true,
@@ -125,6 +125,7 @@ func NewSignedCert(cfg Config, key crypto.Signer, caCert *x509.Certificate, caKe
 		}
 	}
 
+	notBefore := CalculateNotBefore(caCert)
 	certTmpl := x509.Certificate{
 		Subject: pkix.Name{
 			CommonName:   cfg.CommonName,
@@ -133,8 +134,8 @@ func NewSignedCert(cfg Config, key crypto.Signer, caCert *x509.Certificate, caKe
 		DNSNames:     cfg.AltNames.DNSNames,
 		IPAddresses:  cfg.AltNames.IPs,
 		SerialNumber: serial,
-		NotBefore:    caCert.NotBefore,
-		NotAfter:     time.Now().Add(expiresAt).UTC(),
+		NotBefore:    notBefore,
+		NotAfter:     notBefore.Add(expiresAt),
 		KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
 		ExtKeyUsage:  cfg.Usages,
 	}
@@ -186,8 +187,8 @@ func GenerateSelfSignedCertKey(host string, alternateIPs []net.IP, alternateDNS
 // <host>_<ip>-<ip>_<alternateDNS>-<alternateDNS>.key
 // Certs/keys not existing in that directory are created.
 func GenerateSelfSignedCertKeyWithFixtures(host string, alternateIPs []net.IP, alternateDNS []string, fixtureDirectory string) ([]byte, []byte, error) {
-	validFrom := time.Now().Add(-time.Hour) // valid an hour earlier to avoid flakes due to clock skew
-	maxAge := time.Hour * 24 * 365          // one year self-signed certs
+	notBefore := CalculateNotBefore(nil)
+	maxAge := time.Hour * 24 * 365 // one year self-signed certs
 
 	baseName := fmt.Sprintf("%s_%s_%s", host, strings.Join(ipsToStrings(alternateIPs), "-"), strings.Join(alternateDNS, "-"))
 	certFixturePath := filepath.Join(fixtureDirectory, baseName+".crt")
@@ -214,8 +215,8 @@ func GenerateSelfSignedCertKeyWithFixtures(host string, alternateIPs []net.IP, a
 		Subject: pkix.Name{
 			CommonName: fmt.Sprintf("%s-ca@%d", host, time.Now().Unix()),
 		},
-		NotBefore: validFrom,
-		NotAfter:  validFrom.Add(maxAge),
+		NotBefore: notBefore,
+		NotAfter:  notBefore.Add(maxAge),
 
 		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
 		BasicConstraintsValid: true,
@@ -242,8 +243,8 @@ func GenerateSelfSignedCertKeyWithFixtures(host string, alternateIPs []net.IP, a
 		Subject: pkix.Name{
 			CommonName: fmt.Sprintf("%s@%d", host, time.Now().Unix()),
 		},
-		NotBefore: validFrom,
-		NotAfter:  validFrom.Add(maxAge),
+		NotBefore: notBefore,
+		NotAfter:  notBefore.Add(maxAge),
 
 		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
 		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},

cert/validity.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2014 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 cert
+
+import (
+	"crypto/x509"
+	"time"
+
+	clockutil "k8s.io/utils/clock"
+)
+
+var clock clockutil.PassiveClock = &clockutil.RealClock{}
+
+// CalculateNotBefore calculates a NotBefore time of 1 hour in the past, or the
+// NotBefore time of the optionally provided *x509.Certificate, whichever is greater.
+func CalculateNotBefore(ca *x509.Certificate) time.Time {
+	// Subtract 1 hour for clock skew
+	now := clock.Now().UTC().Add(-time.Hour)
+
+	// It makes no sense to return a time before the CA itself is valid.
+	if ca != nil && now.Before(ca.NotBefore) {
+		return ca.NotBefore
+	}
+	return now
+}

cert/validity_test.go

@@ -0,0 +1,77 @@
+/*
+Copyright 2014 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 cert
+
+import (
+	"crypto/x509"
+	"testing"
+	"time"
+
+	clocktest "k8s.io/utils/clock/testing"
+)
+
+func TestCalculateNotBefore(t *testing.T) {
+	baseTime := time.Date(2025, 9, 29, 12, 0, 0, 0, time.UTC)
+
+	tests := []struct {
+		name     string
+		ca       *x509.Certificate
+		now      time.Time
+		expected time.Time
+	}{
+		{
+			name:     "nil CA returns 1h ago",
+			ca:       nil,
+			now:      baseTime,
+			expected: baseTime.Add(-time.Hour),
+		},
+		{
+			name: "CA notBefore before now returns 1h ago",
+			ca: &x509.Certificate{
+				NotBefore: baseTime.Add(-2 * time.Hour),
+			},
+			now:      baseTime,
+			expected: baseTime.Add(-time.Hour),
+		},
+		{
+			name: "CA notBefore after now returns CA.NotBefore",
+			ca: &x509.Certificate{
+				NotBefore: baseTime.Add(2 * time.Hour),
+			},
+			now:      baseTime,
+			expected: baseTime.Add(2 * time.Hour),
+		},
+		{
+			name: "CA notBefore equal to now returns now",
+			ca: &x509.Certificate{
+				NotBefore: baseTime,
+			},
+			now:      baseTime,
+			expected: baseTime,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			clock = clocktest.NewFakePassiveClock(tt.now)
+			result := CalculateNotBefore(tt.ca)
+			if !result.Equal(tt.expected) {
+				t.Errorf("Expected %v, got %v", tt.expected, result)
+			}
+		})
+	}
+}

factory/cert_utils.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/rancher/dynamiclistener/cert"
 	"github.com/sirupsen/logrus"
 )
 
@@ -24,13 +25,13 @@ const (
 )
 
 func NewSelfSignedCACert(key crypto.Signer, cn string, org ...string) (*x509.Certificate, error) {
-	now := time.Now()
+	notBefore := cert.CalculateNotBefore(nil)
 	tmpl := x509.Certificate{
 		BasicConstraintsValid: true,
 		IsCA:                  true,
 		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
-		NotAfter:              now.Add(time.Hour * 24 * 365 * 10).UTC(),
-		NotBefore:             now.UTC(),
+		NotBefore:             notBefore,
+		NotAfter:              notBefore.Add(time.Hour * 24 * 365 * 10),
 		SerialNumber:          new(big.Int).SetInt64(0),
 		Subject: pkix.Name{
 			CommonName:   cn,
@@ -55,11 +56,12 @@ func NewSignedClientCert(signer crypto.Signer, caCert *x509.Certificate, caKey c
 		return nil, err
 	}
 
+	notBefore := cert.CalculateNotBefore(caCert)
 	parent := x509.Certificate{
 		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
 		KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
-		NotAfter:     time.Now().Add(time.Hour * 24 * 365).UTC(),
-		NotBefore:    caCert.NotBefore,
+		NotBefore:    notBefore,
+		NotAfter:     notBefore.Add(time.Hour * 24 * 365),
 		SerialNumber: serialNumber,
 		Subject: pkix.Name{
 			CommonName: cn,
@@ -98,13 +100,14 @@ func NewSignedCert(signer crypto.Signer, caCert *x509.Certificate, caKey crypto.
 		}
 	}
 
+	notBefore := cert.CalculateNotBefore(caCert)
 	parent := x509.Certificate{
 		DNSNames:     domains,
 		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
 		IPAddresses:  ips,
 		KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
-		NotAfter:     time.Now().Add(time.Hour * 24 * time.Duration(expirationDays)).UTC(),
-		NotBefore:    caCert.NotBefore,
+		NotBefore:    notBefore,
+		NotAfter:     notBefore.Add(time.Hour * 24 * time.Duration(expirationDays)),
 		SerialNumber: serialNumber,
 		Subject: pkix.Name{
 			CommonName:   cn,

go.mod

@@ -10,6 +10,7 @@ require (
 	k8s.io/api v0.34.1
 	k8s.io/apimachinery v0.34.1
 	k8s.io/client-go v0.34.1
+	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4
 )
 
 require (
@@ -56,7 +57,6 @@ require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b // indirect
-	k8s.io/utils v0.0.0-20250604170112-4c0f3b243397 // indirect
 	sigs.k8s.io/json v0.0.0-20241014173422-cfa47c3a1cc8 // indirect
 	sigs.k8s.io/randfill v1.0.0 // indirect
 	sigs.k8s.io/structured-merge-diff/v6 v6.3.0 // indirect

go.sum

@@ -167,8 +167,8 @@ k8s.io/klog/v2 v2.130.1 h1:n9Xl7H1Xvksem4KFG4PYbdQCQxqc/tTUyrgXaOhHSzk=
 k8s.io/klog/v2 v2.130.1/go.mod h1:3Jpz1GvMt720eyJH1ckRHK1EDfpxISzJ7I9OYgaDtPE=
 k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b h1:MloQ9/bdJyIu9lb1PzujOPolHyvO06MXG5TUIj2mNAA=
 k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b/go.mod h1:UZ2yyWbFTpuhSbFhv24aGNOdoRdJZgsIObGBUaYVsts=
-k8s.io/utils v0.0.0-20250604170112-4c0f3b243397 h1:hwvWFiBzdWw1FhfY1FooPn3kzWuJ8tmbZBHi4zVsl1Y=
-k8s.io/utils v0.0.0-20250604170112-4c0f3b243397/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
+k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 h1:SjGebBtkBqHFOli+05xYbK8YF1Dzkbzn+gDM4X9T4Ck=
+k8s.io/utils v0.0.0-20251002143259-bc988d571ff4/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 sigs.k8s.io/json v0.0.0-20241014173422-cfa47c3a1cc8 h1:gBQPwqORJ8d8/YNZWEjoZs7npUVDpVXUUOFfW6CgAqE=
 sigs.k8s.io/json v0.0.0-20241014173422-cfa47c3a1cc8/go.mod h1:mdzfpAEoE6DHQEN0uh9ZbOCuHbLK5wOm7dK4ctXE9Tg=
 sigs.k8s.io/randfill v1.0.0 h1:JfjMILfT8A6RbawdsK2JXGBR5AQVfd+9TbzrlneTyrU=