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security.go
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security.go
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// Copyright DataStax, Inc.
// Please see the included license file for details.
package httphelper
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"net/http"
"strings"
api "github.com/datastax/cass-operator/operator/pkg/apis/cassandra/v1beta1"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/types"
"sigs.k8s.io/controller-runtime/pkg/client"
)
// API for Node Management mAuth Config
func GetManagementApiProtocol(dc *api.CassandraDatacenter) (string, error) {
provider, err := BuildManagmenetApiSecurityProvider(dc)
if err != nil {
return "", err
}
return provider.GetProtocol(), nil
}
func BuildManagementApiHttpClient(dc *api.CassandraDatacenter, client client.Client, ctx context.Context) (HttpClient, error) {
provider, err := BuildManagmenetApiSecurityProvider(dc)
if err != nil {
return nil, err
}
return provider.BuildHttpClient(client, ctx)
}
func AddManagementApiServerSecurity(dc *api.CassandraDatacenter, pod *corev1.PodTemplateSpec) error {
provider, err := BuildManagmenetApiSecurityProvider(dc)
if err != nil {
return err
}
return provider.AddServerSecurity(pod)
}
func BuildManagmenetApiSecurityProvider(dc *api.CassandraDatacenter) (ManagementApiSecurityProvider, error) {
options := []func(*api.CassandraDatacenter) (ManagementApiSecurityProvider, error){
buildManualApiSecurityProvider,
buildInsecureManagementApiSecurityProvider,
}
var selectedProvider ManagementApiSecurityProvider = nil
for _, builder := range options {
provider, err := builder(dc)
if err != nil {
return nil, err
}
if provider != nil && selectedProvider != nil {
return nil, fmt.Errorf("Multiple options specified for 'managementApiAuth', but expected exactly one.")
}
if provider != nil {
selectedProvider = provider
}
}
if selectedProvider == nil {
return nil, fmt.Errorf("No security strategy specified for 'managementApiAuth'.")
}
return selectedProvider, nil
}
func ValidateManagementApiConfig(dc *api.CassandraDatacenter, client client.Client, ctx context.Context) []error {
provider, err := BuildManagmenetApiSecurityProvider(dc)
if err != nil {
return []error{err}
}
return provider.ValidateConfig(client, ctx)
}
// SPI for adding new mechanisms for securing the management API
type ManagementApiSecurityProvider interface {
BuildHttpClient(client client.Client, ctx context.Context) (HttpClient, error)
AddServerSecurity(pod *corev1.PodTemplateSpec) error
GetProtocol() string
ValidateConfig(client client.Client, ctx context.Context) []error
}
type InsecureManagementApiSecurityProvider struct {
}
func buildInsecureManagementApiSecurityProvider(dc *api.CassandraDatacenter) (ManagementApiSecurityProvider, error) {
if dc.Spec.ManagementApiAuth.Insecure != nil {
return &InsecureManagementApiSecurityProvider{}, nil
}
return nil, nil
}
func (provider *InsecureManagementApiSecurityProvider) GetProtocol() string {
return "http"
}
func (provider *InsecureManagementApiSecurityProvider) BuildHttpClient(client client.Client, ctx context.Context) (HttpClient, error) {
return http.DefaultClient, nil
}
func (provider *InsecureManagementApiSecurityProvider) AddServerSecurity(pod *corev1.PodTemplateSpec) error {
return nil
}
func (provider *InsecureManagementApiSecurityProvider) ValidateConfig(client client.Client, ctx context.Context) []error {
return []error{}
}
type ManualManagementApiSecurityProvider struct {
Namespace string
Config *api.ManagementApiAuthManualConfig
}
func buildManualApiSecurityProvider(dc *api.CassandraDatacenter) (ManagementApiSecurityProvider, error) {
if dc.Spec.ManagementApiAuth.Manual != nil {
provider := &ManualManagementApiSecurityProvider{}
provider.Config = dc.Spec.ManagementApiAuth.Manual
provider.Namespace = dc.ObjectMeta.Namespace
return provider, nil
}
return nil, nil
}
func (provider *ManualManagementApiSecurityProvider) GetProtocol() string {
return "https"
}
func (provider *ManualManagementApiSecurityProvider) AddServerSecurity(pod *corev1.PodTemplateSpec) error {
caCertPath := "/management-api-certs/ca.crt"
tlsCrt := "/management-api-certs/tls.crt"
tlsKey := "/management-api-certs/tls.key"
// find the container
var container *corev1.Container = nil
for i := range pod.Spec.Containers {
if pod.Spec.Containers[i].Name == "cassandra" {
container = &pod.Spec.Containers[i]
}
}
if container == nil {
return fmt.Errorf("Could not find cassandra container")
}
// Add volume containing certificates
secretVolumeName := "management-api-server-certs-volume"
secretVolume := corev1.Volume{
Name: secretVolumeName,
VolumeSource: corev1.VolumeSource{
Secret: &corev1.SecretVolumeSource{
SecretName: provider.Config.ServerSecretName,
},
},
}
if pod.Spec.Volumes == nil {
pod.Spec.Volumes = []corev1.Volume{}
}
pod.Spec.Volumes = append(pod.Spec.Volumes, secretVolume)
// Mount certificates volume in container
secretVolumeMount := corev1.VolumeMount{
Name: secretVolumeName,
ReadOnly: true,
MountPath: "/management-api-certs",
}
if container.VolumeMounts == nil {
container.VolumeMounts = []corev1.VolumeMount{}
}
container.VolumeMounts = append(container.VolumeMounts, secretVolumeMount)
// Configure Management API to use certificates
envVars := []corev1.EnvVar{
{
Name: "MGMT_API_TLS_CA_CERT_FILE",
Value: caCertPath,
},
{
Name: "MGMT_API_TLS_CERT_FILE",
Value: tlsCrt,
},
{
Name: "MGMT_API_TLS_KEY_FILE",
Value: tlsKey,
},
// TODO remove the below stuff post 1.0
{
Name: "DSE_MGMT_TLS_CA_CERT_FILE",
Value: caCertPath,
},
{
Name: "DSE_MGMT_TLS_CERT_FILE",
Value: tlsCrt,
},
{
Name: "DSE_MGMT_TLS_KEY_FILE",
Value: tlsKey,
},
}
if container.Env == nil {
container.Env = []corev1.EnvVar{}
}
container.Env = append(envVars, container.Env...)
// Update Liveness probe to account for mutual auth (can't just use HTTP probe now)
// TODO: Get endpoint from configured HTTPGet probe
livenessEndpoint := "https://localhost:8080/api/v0/probes/liveness"
if container.LivenessProbe == nil {
container.LivenessProbe = &corev1.Probe{
Handler: corev1.Handler{},
}
}
container.LivenessProbe.Handler.HTTPGet = nil
container.LivenessProbe.Handler.TCPSocket = nil
container.LivenessProbe.Handler.Exec = &corev1.ExecAction{
Command: []string{
"wget",
"--output-document", "/dev/null",
"--no-check-certificate",
"--certificate", tlsCrt,
"--private-key", tlsKey,
"--ca-certificate", caCertPath,
livenessEndpoint,
},
}
// Update Readiness probe to account for mutual auth (can't just use HTTP probe now)
// TODO: Get endpoint from configured HTTPGet probe
readinessEndpoint := "https://localhost:8080/api/v0/probes/readiness"
if container.ReadinessProbe == nil {
container.ReadinessProbe = &corev1.Probe{
Handler: corev1.Handler{},
}
}
container.ReadinessProbe.Handler.HTTPGet = nil
container.ReadinessProbe.Handler.TCPSocket = nil
container.ReadinessProbe.Handler.Exec = &corev1.ExecAction{
Command: []string{
"wget",
"--output-document", "/dev/null",
"--no-check-certificate",
"--certificate", tlsCrt,
"--private-key", tlsKey,
"--ca-certificate", caCertPath,
readinessEndpoint,
},
}
return nil
}
func validatePrivateKey(data []byte) []error {
const privateKeyExpect = "Private key should be unencrypted PKCS#8 format using PEM encoding with preamble 'PRIVATE KEY'"
var validationErrors []error
var block *pem.Block
var rest []byte = data
foundBlocks := false
for {
block, rest = pem.Decode(rest)
if block == nil {
break
}
foundBlocks = true
if block.Type != "PRIVATE KEY" {
if block.Type == "RSA PRIVATE KEY" {
validationErrors = append(
validationErrors,
fmt.Errorf("%s, but found PKCS#1 format using preamble '%s'.", privateKeyExpect, block.Type))
} else if block.Type == "CERTIFICATE" {
validationErrors = append(
validationErrors,
fmt.Errorf("%s, but found certificate using preamble '%s'.", privateKeyExpect, block.Type))
} else if strings.Contains(block.Type, "ENCRYPTED") {
validationErrors = append(
validationErrors,
fmt.Errorf("%s, but found certificate using preamble '%s'.", privateKeyExpect, block.Type))
} else {
validationErrors = append(
validationErrors,
fmt.Errorf("%s, but found preamble '%s'", privateKeyExpect, block.Type))
}
} else { // block.Type == "PRIVATE_KEY"
// but is it _really_ a PKCS#8 key?
_, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
validationErrors = append(
validationErrors,
// TODO: Switch %v to %w when golang version updated
fmt.Errorf("%s, correct preamble was found but does not appear to be in PKCS#8 format. %w", privateKeyExpect, err))
}
}
}
if !foundBlocks {
validationErrors = append(
validationErrors,
fmt.Errorf("%s, but provided key does not appear to be PEM encoded.", privateKeyExpect))
}
return validationErrors
}
func validateCertificate(data []byte) []error {
var validationErrors []error
foundBlocks := false
for rest := data; ; {
var block *pem.Block
block, rest = pem.Decode(rest)
if block == nil {
break
}
foundBlocks = true
if block.Type != "CERTIFICATE" {
validationErrors = append(
validationErrors,
fmt.Errorf("Certificate should be PEM encoded with preamble 'CERTIFICATE', but found preamble '%s'.", block.Type))
} else {
_, err := x509.ParseCertificates(block.Bytes)
if err != nil {
validationErrors = append(
validationErrors,
fmt.Errorf("Found PEM block with correct preamble of 'CERTIFICATE', but content does not appear to be a valid certificate. %w", err))
}
}
}
if !foundBlocks {
validationErrors = append(
validationErrors,
fmt.Errorf("Did not find any certificates."))
}
return validationErrors
}
func validateKeyAndCertificate(certificate, privateKey, caCertificate []byte) []error {
var validationErrors []error
privateKeyValidationErrors := validatePrivateKey(privateKey)
certificateValidationErrors := validateCertificate(certificate)
caValidationErrors := validateCertificate(caCertificate)
validationErrors = append(
validationErrors,
privateKeyValidationErrors...)
validationErrors = append(
validationErrors,
certificateValidationErrors...)
validationErrors = append(
validationErrors,
caValidationErrors...)
// This will catch errors with the certificate and check whether it matches
// the private key.
_, err := tls.X509KeyPair(
certificate,
privateKey)
if err != nil {
validationErrors = append(
validationErrors,
fmt.Errorf("Could not load x509 key pair. %w", err))
}
return validationErrors
}
func pemToCertificateChain(certificate []byte) ([]*x509.Certificate, error) {
certs := []*x509.Certificate{}
rest := certificate
var block *pem.Block
for {
block, rest = pem.Decode(rest)
if block == nil {
break
}
if block.Type == "CERTIFICATE" {
parsedCerts, err := x509.ParseCertificates(block.Bytes)
if err != nil {
return nil, err
}
certs = append(certs, parsedCerts...)
}
}
return certs, nil
}
func validateCertificateChain(chain []*x509.Certificate) error {
for i := 0; i < len(chain)-1; i = i + 1 {
certificateA := chain[i]
certificateB := chain[i+1]
err := certificateA.CheckSignatureFrom(certificateB)
if err != nil {
return fmt.Errorf(
"Failed to validate chain, certificate %s not signed by certificate %s. %w",
certificateA.Subject.CommonName, certificateB.Subject.CommonName, err)
}
}
return nil
}
func validatePeerACertificateSignedByPeerBCa(peerACertificate, peerACa, peerBCa []byte) error {
// In order for the certificate of peer A (`peerACertificate`) to be
// properly signed, it must be possible to construct a chain of trust from
// peer A's certificate and peer A's CA (`peerACA`) to peer B's CA
// (`peerBCa`).
// Load the certificate chain for peerA
peerACertificateChain, err := pemToCertificateChain(peerACertificate)
if err != nil {
return err
}
// Make sure the certificate chain is valid (i.e. that it is a sequence of
// certificates for which each certificate in chain has signed the one
// preceeding it)
err = validateCertificateChain(peerACertificateChain)
if err != nil {
return err
}
// Now we need to construct candidate chains to test against peer B's CA
// pool
candidateChains := [][]*x509.Certificate{}
// One such chain is peer A's certificate chain as it may have all that is
// needed for to tie it to one of peer B's CAs
candidateChains = append(candidateChains, peerACertificateChain)
// It might be the case that there are some intermediate CAs in peer A's CA
// pool, so we find all such chains.
peerACaCertPool := x509.NewCertPool()
peerACaCertPool.AppendCertsFromPEM(peerACa)
chainsUsingPeerACAs, err := verifyPeerCertificateNoHostCheck(peerACertificateChain, peerACaCertPool)
if err == nil {
// we found some chains, add them to our candidates
candidateChains = append(candidateChains, chainsUsingPeerACAs...)
}
// Now we see if any of our candidate chains will work with peer B's CA
// pool.
peerBCaCertPool := x509.NewCertPool()
peerBCaCertPool.AppendCertsFromPEM(peerBCa)
var lastVerifyCertificateError error = nil
for _, candidateChain := range candidateChains {
_, lastVerifyCertificateError = verifyPeerCertificateNoHostCheck(candidateChain, peerBCaCertPool)
if lastVerifyCertificateError == nil {
// We found a valid chain, success!
return nil
}
}
if lastVerifyCertificateError == nil {
// This should not ever happen because we will always have at least one
// chain to test which means we should either return above or have an
// error here. But it would cause an insidious bug if the logic above
// was broken and we didn't do this check.
lastVerifyCertificateError = errors.New("No candidate chains found to check.")
}
return lastVerifyCertificateError
}
func validateSecretStructure(secret *corev1.Secret) error {
secretNamespacedName := types.NamespacedName{
Name: secret.ObjectMeta.Name,
Namespace: secret.ObjectMeta.Namespace,
}
// Check secret type
if secret.Type != "kubernetes.io/tls" {
// Not the right type
err := fmt.Errorf("Expected Secret %s to have type 'kubernetes.io/tls' but was '%s'",
secretNamespacedName.String(),
secret.Type)
return err
}
// Ensure all keys are present
for _, key := range []string{"ca.crt", "tls.crt", "tls.key"} {
if _, ok := secret.Data[key]; !ok {
err := fmt.Errorf("Expected Secret %s to have data key '%s' but was not found",
secretNamespacedName.String(),
key)
return err
}
}
return nil
}
func loadSecret(client client.Client, ctx context.Context, namespace, name string) (*corev1.Secret, error) {
secretNamespacedName := types.NamespacedName{
Name: name,
Namespace: namespace,
}
secret := &corev1.Secret{}
err := client.Get(
ctx,
secretNamespacedName,
secret)
if err != nil {
// Couldn't get the secret
return nil, err
}
return secret, nil
}
func validateSecret(secret *corev1.Secret) []error {
var validationErrors []error
err := validateSecretStructure(secret)
if err != nil {
validationErrors = append(
validationErrors,
err)
return validationErrors
}
keyAndCertificateErrors := validateKeyAndCertificate(secret.Data["tls.crt"], secret.Data["tls.key"], secret.Data["ca.crt"])
validationErrors = append(validationErrors, keyAndCertificateErrors...)
return validationErrors
}
func (provider *ManualManagementApiSecurityProvider) ValidateConfig(client client.Client, ctx context.Context) []error {
var validationErrors []error
if provider.Config.SkipSecretValidation {
return validationErrors
}
var clientSecret *corev1.Secret
var serverSecret *corev1.Secret
clientSecretName := provider.Config.ClientSecretName
serverSecretName := provider.Config.ServerSecretName
secretChecks := []struct {
secretName string
secretPtrPtr **corev1.Secret // everyone likes a pointer to a pointer
configKey string
}{
{
secretName: clientSecretName,
secretPtrPtr: &clientSecret,
configKey: ".managementApiAuth.manual.clientSecretName",
},
{
secretName: serverSecretName,
secretPtrPtr: &serverSecret,
configKey: ".managementApiAuth.manual.serverSecretName",
},
}
for _, check := range secretChecks {
var err error
*check.secretPtrPtr, err = loadSecret(client, ctx, provider.Namespace, check.secretName)
if err != nil {
validationErrors = append(
validationErrors,
fmt.Errorf("Failed to load Management API secret specified at %s with value '%s'. %w",
check.configKey, check.secretName, err))
return validationErrors
}
errs := validateSecret(*check.secretPtrPtr)
for _, err := range errs {
validationErrors = append(
validationErrors,
fmt.Errorf("Loaded Management API secret specified at %s with value '%s' is not valid. %w",
check.configKey, check.secretName, err))
}
}
certificateSigningChecks := []struct {
peerAsecret *corev1.Secret
peerBsecret *corev1.Secret
configKey string
}{
{
peerAsecret: clientSecret,
peerBsecret: serverSecret,
configKey: ".managementApiAuth.manual.clientSecretName",
},
{
peerAsecret: serverSecret,
peerBsecret: clientSecret,
configKey: ".managementApiAuth.manual.serverSecretName",
},
}
for _, check := range certificateSigningChecks {
var err error
secretName := check.peerAsecret.ObjectMeta.Name
err = validatePeerACertificateSignedByPeerBCa(check.peerAsecret.Data["tls.crt"], check.peerAsecret.Data["ca.crt"], check.peerBsecret.Data["ca.crt"])
if err != nil {
validationErrors = append(
validationErrors,
fmt.Errorf("Loaded Management API client secret specified at %s with value '%s' is not properly signed. %w", check.configKey, secretName, err))
}
}
return validationErrors
}
func (provider *ManualManagementApiSecurityProvider) BuildHttpClient(client client.Client, ctx context.Context) (HttpClient, error) {
// Get the client Secret
secretNamespacedName := types.NamespacedName{
Name: provider.Config.ClientSecretName,
Namespace: provider.Namespace,
}
secret := &corev1.Secret{}
err := client.Get(
ctx,
secretNamespacedName,
secret)
if err != nil {
// Couldn't get the secret
return nil, err
}
err = validateSecretStructure(secret)
if err != nil {
// Secret didn't look the way we expect
return nil, err
}
// Create the CA certificate pool
caCertPool := x509.NewCertPool()
ok := caCertPool.AppendCertsFromPEM(secret.Data["ca.crt"])
if !ok {
err = fmt.Errorf("No certificates found in %s when parsing 'ca.crt' value: %v",
secretNamespacedName.String(),
secret.Data["ca.crt"])
return nil, err
}
// Load client key pair
cert, err := tls.X509KeyPair(secret.Data["tls.crt"], secret.Data["tls.key"])
if err != nil {
return nil, err
}
// Build the client
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{cert},
RootCAs: caCertPool,
// TODO: ...we should probably verify something here...
InsecureSkipVerify: true,
VerifyPeerCertificate: buildVerifyPeerCertificateNoHostCheck(caCertPool),
}
tlsConfig.BuildNameToCertificate()
transport := &http.Transport{TLSClientConfig: tlsConfig}
httpClient := &http.Client{Transport: transport}
return httpClient, nil
}
// Below implementation modified from:
//
// https://go-review.googlesource.com/c/go/+/193620/5/src/crypto/tls/example_test.go#210
//
func buildVerifyPeerCertificateNoHostCheck(rootCAs *x509.CertPool) func([][]byte, [][]*x509.Certificate) error {
f := func(certificates [][]byte, _ [][]*x509.Certificate) error {
certs := make([]*x509.Certificate, len(certificates))
for i, asn1Data := range certificates {
cert, err := x509.ParseCertificate(asn1Data)
if err != nil {
return err
}
certs[i] = cert
}
_, err := verifyPeerCertificateNoHostCheck(certs, rootCAs)
return err
}
return f
}
func verifyPeerCertificateNoHostCheck(certificates []*x509.Certificate, rootCAs *x509.CertPool) ([][]*x509.Certificate, error) {
opts := x509.VerifyOptions{
Roots: rootCAs,
// Setting the DNSName to the empty string will cause
// Certificate.Verify() to skip hostname checking
DNSName: "",
Intermediates: x509.NewCertPool(),
}
for _, cert := range certificates[1:] {
opts.Intermediates.AddCert(cert)
}
chains, err := certificates[0].Verify(opts)
return chains, err
}