forked from hashicorp/vault
/
tls.go
241 lines (205 loc) · 6.59 KB
/
tls.go
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package pluginutil
import (
"context"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/base64"
"errors"
"net/url"
"os"
"time"
"github.com/SermoDigital/jose/jws"
"github.com/hashicorp/errwrap"
uuid "github.com/hashicorp/go-uuid"
"github.com/hashicorp/vault/api"
"github.com/hashicorp/vault/helper/certutil"
)
var (
// PluginUnwrapTokenEnv is the ENV name used to pass unwrap tokens to the
// plugin.
PluginUnwrapTokenEnv = "VAULT_UNWRAP_TOKEN"
// PluginCACertPEMEnv is an ENV name used for holding a CA PEM-encoded
// string. Used for testing.
PluginCACertPEMEnv = "VAULT_TESTING_PLUGIN_CA_PEM"
)
// generateCert is used internally to create certificates for the plugin
// client and server.
func generateCert() ([]byte, *ecdsa.PrivateKey, error) {
key, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
return nil, nil, err
}
host, err := uuid.GenerateUUID()
if err != nil {
return nil, nil, err
}
sn, err := certutil.GenerateSerialNumber()
if err != nil {
return nil, nil, err
}
template := &x509.Certificate{
Subject: pkix.Name{
CommonName: host,
},
DNSNames: []string{host},
ExtKeyUsage: []x509.ExtKeyUsage{
x509.ExtKeyUsageClientAuth,
x509.ExtKeyUsageServerAuth,
},
KeyUsage: x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment | x509.KeyUsageKeyAgreement,
SerialNumber: sn,
NotBefore: time.Now().Add(-30 * time.Second),
NotAfter: time.Now().Add(262980 * time.Hour),
IsCA: true,
}
certBytes, err := x509.CreateCertificate(rand.Reader, template, template, key.Public(), key)
if err != nil {
return nil, nil, errwrap.Wrapf("unable to generate client certificate: {{err}}", err)
}
return certBytes, key, nil
}
// createClientTLSConfig creates a signed certificate and returns a configured
// TLS config.
func createClientTLSConfig(certBytes []byte, key *ecdsa.PrivateKey) (*tls.Config, error) {
clientCert, err := x509.ParseCertificate(certBytes)
if err != nil {
return nil, errwrap.Wrapf("error parsing generated plugin certificate: {{err}}", err)
}
cert := tls.Certificate{
Certificate: [][]byte{certBytes},
PrivateKey: key,
Leaf: clientCert,
}
clientCertPool := x509.NewCertPool()
clientCertPool.AddCert(clientCert)
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{cert},
RootCAs: clientCertPool,
ClientCAs: clientCertPool,
ClientAuth: tls.RequireAndVerifyClientCert,
ServerName: clientCert.Subject.CommonName,
MinVersion: tls.VersionTLS12,
}
tlsConfig.BuildNameToCertificate()
return tlsConfig, nil
}
// wrapServerConfig is used to create a server certificate and private key, then
// wrap them in an unwrap token for later retrieval by the plugin.
func wrapServerConfig(ctx context.Context, sys RunnerUtil, certBytes []byte, key *ecdsa.PrivateKey) (string, error) {
rawKey, err := x509.MarshalECPrivateKey(key)
if err != nil {
return "", err
}
wrapInfo, err := sys.ResponseWrapData(ctx, map[string]interface{}{
"ServerCert": certBytes,
"ServerKey": rawKey,
}, time.Second*60, true)
if err != nil {
return "", err
}
return wrapInfo.Token, nil
}
// VaultPluginTLSProvider is run inside a plugin and retrieves the response
// wrapped TLS certificate from vault. It returns a configured TLS Config.
func VaultPluginTLSProvider(apiTLSConfig *api.TLSConfig) func() (*tls.Config, error) {
if os.Getenv(PluginMetadataModeEnv) == "true" {
return nil
}
return func() (*tls.Config, error) {
unwrapToken := os.Getenv(PluginUnwrapTokenEnv)
// Parse the JWT and retrieve the vault address
wt, err := jws.ParseJWT([]byte(unwrapToken))
if err != nil {
return nil, errwrap.Wrapf("error decoding token: {{err}}", err)
}
if wt == nil {
return nil, errors.New("nil decoded token")
}
addrRaw := wt.Claims().Get("addr")
if addrRaw == nil {
return nil, errors.New("decoded token does not contain the active node's api_addr")
}
vaultAddr, ok := addrRaw.(string)
if !ok {
return nil, errors.New("decoded token's api_addr not valid")
}
if vaultAddr == "" {
return nil, errors.New(`no vault api_addr found`)
}
// Sanity check the value
if _, err := url.Parse(vaultAddr); err != nil {
return nil, errwrap.Wrapf("error parsing the vault api_addr: {{err}}", err)
}
// Unwrap the token
clientConf := api.DefaultConfig()
clientConf.Address = vaultAddr
if apiTLSConfig != nil {
err := clientConf.ConfigureTLS(apiTLSConfig)
if err != nil {
return nil, errwrap.Wrapf("error configuring api client {{err}}", err)
}
}
client, err := api.NewClient(clientConf)
if err != nil {
return nil, errwrap.Wrapf("error during api client creation: {{err}}", err)
}
secret, err := client.Logical().Unwrap(unwrapToken)
if err != nil {
return nil, errwrap.Wrapf("error during token unwrap request: {{err}}", err)
}
if secret == nil {
return nil, errors.New("error during token unwrap request: secret is nil")
}
// Retrieve and parse the server's certificate
serverCertBytesRaw, ok := secret.Data["ServerCert"].(string)
if !ok {
return nil, errors.New("error unmarshalling certificate")
}
serverCertBytes, err := base64.StdEncoding.DecodeString(serverCertBytesRaw)
if err != nil {
return nil, errwrap.Wrapf("error parsing certificate: {{err}}", err)
}
serverCert, err := x509.ParseCertificate(serverCertBytes)
if err != nil {
return nil, errwrap.Wrapf("error parsing certificate: {{err}}", err)
}
// Retrieve and parse the server's private key
serverKeyB64, ok := secret.Data["ServerKey"].(string)
if !ok {
return nil, errors.New("error unmarshalling certificate")
}
serverKeyRaw, err := base64.StdEncoding.DecodeString(serverKeyB64)
if err != nil {
return nil, errwrap.Wrapf("error parsing certificate: {{err}}", err)
}
serverKey, err := x509.ParseECPrivateKey(serverKeyRaw)
if err != nil {
return nil, errwrap.Wrapf("error parsing certificate: {{err}}", err)
}
// Add CA cert to the cert pool
caCertPool := x509.NewCertPool()
caCertPool.AddCert(serverCert)
// Build a certificate object out of the server's cert and private key.
cert := tls.Certificate{
Certificate: [][]byte{serverCertBytes},
PrivateKey: serverKey,
Leaf: serverCert,
}
// Setup TLS config
tlsConfig := &tls.Config{
ClientCAs: caCertPool,
RootCAs: caCertPool,
ClientAuth: tls.RequireAndVerifyClientCert,
// TLS 1.2 minimum
MinVersion: tls.VersionTLS12,
Certificates: []tls.Certificate{cert},
ServerName: serverCert.Subject.CommonName,
}
tlsConfig.BuildNameToCertificate()
return tlsConfig, nil
}
}