integrate cert-source lib, add listener CLR file and cert rotation

Author: everesio

cmd/kafka-proxy/server.go

@@ -103,10 +103,12 @@ func initFlags() {
 	Server.Flags().DurationVar(&c.Proxy.ListenerKeepAlive, "proxy-listener-keep-alive", 60*time.Second, "Keep alive period for an active network connection. If zero, keep-alives are disabled")
 
 	Server.Flags().BoolVar(&c.Proxy.TLS.Enable, "proxy-listener-tls-enable", false, "Whether or not to use TLS listener")
+	Server.Flags().DurationVar(&c.Proxy.TLS.Refresh, "proxy-listener-tls-refresh", 0*time.Second, "Interval for refreshing server TLS certificates. If set to zero, the refresh watch is disabled")
 	Server.Flags().StringVar(&c.Proxy.TLS.ListenerCertFile, "proxy-listener-cert-file", "", "PEM encoded file with server certificate")
 	Server.Flags().StringVar(&c.Proxy.TLS.ListenerKeyFile, "proxy-listener-key-file", "", "PEM encoded file with private key for the server certificate")
 	Server.Flags().StringVar(&c.Proxy.TLS.ListenerKeyPassword, "proxy-listener-key-password", os.Getenv("PROXY_LISTENER_KEY_PASSWORD"), "Password to decrypt rsa private key")
-	Server.Flags().StringVar(&c.Proxy.TLS.CAChainCertFile, "proxy-listener-ca-chain-cert-file", "", "PEM encoded CA's certificate file. If provided, client certificate is required and verified")
+	Server.Flags().StringVar(&c.Proxy.TLS.ListenerCAChainCertFile, "proxy-listener-ca-chain-cert-file", "", "PEM encoded CA's certificate file. If provided, client certificate is required and verified")
+	Server.Flags().StringVar(&c.Proxy.TLS.ListenerCRLFile, "proxy-listener-crl-file", "", "PEM encoded X509 CRLs file")
 	Server.Flags().StringSliceVar(&c.Proxy.TLS.ListenerCipherSuites, "proxy-listener-cipher-suites", []string{}, "List of supported cipher suites")
 	Server.Flags().StringSliceVar(&c.Proxy.TLS.ListenerCurvePreferences, "proxy-listener-curve-preferences", []string{}, "List of curve preferences")
 
@@ -153,6 +155,7 @@ func initFlags() {
 
 	// TLS
 	Server.Flags().BoolVar(&c.Kafka.TLS.Enable, "tls-enable", false, "Whether or not to use TLS when connecting to the broker")
+	Server.Flags().DurationVar(&c.Kafka.TLS.Refresh, "tls-refresh", 0*time.Second, "Interval for refreshing client TLS certificates. If set to zero, the refresh watch is disabled")
 	Server.Flags().BoolVar(&c.Kafka.TLS.InsecureSkipVerify, "tls-insecure-skip-verify", false, "It controls whether a client verifies the server's certificate chain and host name")
 	Server.Flags().StringVar(&c.Kafka.TLS.ClientCertFile, "tls-client-cert-file", "", "PEM encoded file with client certificate")
 	Server.Flags().StringVar(&c.Kafka.TLS.ClientKeyFile, "tls-client-key-file", "", "PEM encoded file with private key for the client certificate")

config/config.go

@@ -88,10 +88,12 @@ type Config struct {
 
 		TLS struct {
 			Enable                   bool
+			Refresh                  time.Duration
 			ListenerCertFile         string
 			ListenerKeyFile          string
 			ListenerKeyPassword      string
-			CAChainCertFile          string
+			ListenerCAChainCertFile  string
+			ListenerCRLFile          string
 			ListenerCipherSuites     []string
 			ListenerCurvePreferences []string
 			ClientCert               struct {
@@ -145,6 +147,7 @@ type Config struct {
 
 		TLS struct {
 			Enable               bool
+			Refresh              time.Duration
 			InsecureSkipVerify   bool
 			ClientCertFile       string
 			ClientKeyFile        string

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/go-ldap/ldap/v3 v3.2.3
 	github.com/google/uuid v1.6.0
+	github.com/grepplabs/cert-source v0.0.7
 	github.com/hashicorp/go-hclog v1.6.3
 	github.com/hashicorp/go-multierror v0.0.0-20171204182908-b7773ae21874
 	github.com/hashicorp/go-plugin v1.6.3
@@ -26,7 +27,7 @@ require (
 	github.com/spf13/viper v1.0.2
 	github.com/stretchr/testify v1.10.0
 	github.com/xdg/scram v0.0.0-20180814205039-7eeb5667e42c
-	github.com/youmark/pkcs8 v0.0.0-20240424034433-3c2c7870ae76
+	github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78
 	golang.org/x/net v0.34.0
 	golang.org/x/oauth2 v0.24.0
 	google.golang.org/api v0.126.0

go.sum

@@ -137,6 +137,8 @@ github.com/googleapis/gax-go/v2 v2.11.0 h1:9V9PWXEsWnPpQhu/PeQIkS4eGzMlTLGgt80cU
 github.com/googleapis/gax-go/v2 v2.11.0/go.mod h1:DxmR61SGKkGLa2xigwuZIQpkCI2S5iydzRfb3peWZJI=
 github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
 github.com/gorilla/sessions v1.2.1/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
+github.com/grepplabs/cert-source v0.0.7 h1:wzgPHho7YbBJ/eYiNBPfzkxUd9cZwsxYap/uqgueo2A=
+github.com/grepplabs/cert-source v0.0.7/go.mod h1:gs3IoykME1cFfZ6/h6hch8yg8ktUInsR9OY2xSHA2r4=
 github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/hashicorp/errwrap v0.0.0-20141028054710-7554cd9344ce h1:prjrVgOk2Yg6w+PflHoszQNLTUh4kaByUcEWM/9uin4=
 github.com/hashicorp/errwrap v0.0.0-20141028054710-7554cd9344ce/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
@@ -281,8 +283,8 @@ github.com/xdg/scram v0.0.0-20180814205039-7eeb5667e42c h1:u40Z8hqBAAQyv+vATcGgV
 github.com/xdg/scram v0.0.0-20180814205039-7eeb5667e42c/go.mod h1:lB8K/P019DLNhemzwFU4jHLhdvlE6uDZjXFejJXr49I=
 github.com/xdg/stringprep v1.0.0 h1:d9X0esnoa3dFsV0FG35rAT0RIhYFlPq7MiP+DW89La0=
 github.com/xdg/stringprep v1.0.0/go.mod h1:Jhud4/sHMO4oL310DaZAKk9ZaJ08SJfe+sJh0HrGL1Y=
-github.com/youmark/pkcs8 v0.0.0-20240424034433-3c2c7870ae76 h1:tBiBTKHnIjovYoLX/TPkcf+OjqqKGQrPtGT3Foz+Pgo=
-github.com/youmark/pkcs8 v0.0.0-20240424034433-3c2c7870ae76/go.mod h1:SQliXeA7Dhkt//vS29v3zpbEwoa+zb2Cn5xj5uO4K5U=
+github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 h1:ilQV1hzziu+LLM3zUTJ0trRztfwgjqKnBWNtSRkbmwM=
+github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78/go.mod h1:aL8wCCfTfSfmXjznFBSZNN13rSJjlIOI1fUNAtF7rmI=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=

proxy/client.go

@@ -1,7 +1,6 @@
 package proxy
 
 import (
-	"crypto/tls"
 	"crypto/x509"
 	"fmt"
 	"net"
@@ -46,7 +45,7 @@ type Client struct {
 }
 
 func NewClient(conns *ConnSet, c *config.Config, netAddressMappingFunc config.NetAddressMappingFunc, localPasswordAuthenticator apis.PasswordAuthenticator, localTokenAuthenticator apis.TokenInfo, saslTokenProvider apis.TokenProvider, gatewayTokenProvider apis.TokenProvider, gatewayTokenInfo apis.TokenInfo) (*Client, error) {
-	tlsConfig, err := newTLSClientConfig(c)
+	tlsConfigFunc, err := newTLSClientConfig(c)
 	if err != nil {
 		return nil, err
 	}
@@ -59,7 +58,7 @@ func NewClient(conns *ConnSet, c *config.Config, netAddressMappingFunc config.Ne
 		}
 	}
 
-	dialer, err := newDialer(c, tlsConfig)
+	dialer, err := newDialer(c, tlsConfigFunc)
 	if err != nil {
 		return nil, err
 	}
@@ -195,7 +194,7 @@ func getAddressToDialAddressMapping(cfg *config.Config) (map[string]config.DialA
 	return addressToDialAddressMapping, nil
 }
 
-func newDialer(c *config.Config, tlsConfig *tls.Config) (Dialer, error) {
+func newDialer(c *config.Config, tlsConfigFunc TLSConfigFunc) (Dialer, error) {
 	directDialer := directDialer{
 		dialTimeout: c.Kafka.DialTimeout,
 		keepAlive:   c.Kafka.KeepAlive,
@@ -230,13 +229,13 @@ func newDialer(c *config.Config, tlsConfig *tls.Config) (Dialer, error) {
 		rawDialer = directDialer
 	}
 	if c.Kafka.TLS.Enable {
-		if tlsConfig == nil {
-			return nil, errors.New("tlsConfig must not be nil")
+		if tlsConfigFunc == nil || tlsConfigFunc() == nil {
+			return nil, errors.New("tlsConfigFunc must not be nil")
 		}
 		tlsDialer := tlsDialer{
-			timeout:   c.Kafka.DialTimeout,
-			rawDialer: rawDialer,
-			config:    tlsConfig,
+			timeout:    c.Kafka.DialTimeout,
+			rawDialer:  rawDialer,
+			configFunc: tlsConfigFunc,
 		}
 		return tlsDialer, nil
 	}

proxy/dial.go

@@ -69,14 +69,15 @@ func (d socks5Dialer) Dial(network, addr string) (net.Conn, error) {
 }
 
 type tlsDialer struct {
-	timeout   time.Duration
-	rawDialer Dialer
-	config    *tls.Config
+	timeout    time.Duration
+	rawDialer  Dialer
+	configFunc TLSConfigFunc
 }
 
 // see tls.DialWithDialer
 func (d tlsDialer) Dial(network, addr string) (net.Conn, error) {
-	if d.config == nil {
+	config := d.configFunc()
+	if config == nil {
 		return nil, errors.New("tlsConfig must not be nil")
 	}
 	if d.rawDialer == nil {
@@ -106,8 +107,6 @@ func (d tlsDialer) Dial(network, addr string) (net.Conn, error) {
 	}
 	hostname := addr[:colonPos]
 
-	config := d.config
-
 	// If no ServerName is set, infer the ServerName
 	// from the hostname we're connecting to.
 	if config.ServerName == "" {

proxy/tls.go

@@ -8,12 +8,17 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
+	"log/slog"
 	"net"
 	"os"
 	"reflect"
 	"strings"
 	"time"
 
+	tlsconfig "github.com/grepplabs/cert-source/config"
+	tlsclientconfig "github.com/grepplabs/cert-source/tls/client/config"
+	tlsserver "github.com/grepplabs/cert-source/tls/server"
+	tlsserverconfig "github.com/grepplabs/cert-source/tls/server/config"
 	"github.com/grepplabs/kafka-proxy/config"
 	"github.com/pkg/errors"
 	"github.com/youmark/pkcs8"
@@ -59,25 +64,6 @@ var (
 func newTLSListenerConfig(conf *config.Config) (*tls.Config, error) {
 	opts := conf.Proxy.TLS
 
-	if opts.ListenerKeyFile == "" || opts.ListenerCertFile == "" {
-		return nil, errors.New("Listener key and cert files must not be empty")
-	}
-	certPEMBlock, err := os.ReadFile(opts.ListenerCertFile)
-	if err != nil {
-		return nil, err
-	}
-	keyPEMBlock, err := os.ReadFile(opts.ListenerKeyFile)
-	if err != nil {
-		return nil, err
-	}
-	keyPEMBlock, err = decryptPEM(keyPEMBlock, opts.ListenerKeyPassword)
-	if err != nil {
-		return nil, err
-	}
-	cert, err := tls.X509KeyPair(certPEMBlock, keyPEMBlock)
-	if err != nil {
-		return nil, err
-	}
 	cipherSuites, err := getCipherSuites(opts.ListenerCipherSuites)
 	if err != nil {
 		return nil, err
@@ -86,35 +72,27 @@ func newTLSListenerConfig(conf *config.Config) (*tls.Config, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	cfg := &tls.Config{
-		Certificates:             []tls.Certificate{cert},
-		ClientAuth:               tls.NoClientCert,
-		PreferServerCipherSuites: true,
-		MinVersion:               tls.VersionTLS12,
-		CurvePreferences:         curvePreferences,
-		CipherSuites:             cipherSuites,
-	}
-	if opts.CAChainCertFile != "" {
-		caCertPEMBlock, err := os.ReadFile(opts.CAChainCertFile)
-		if err != nil {
-			return nil, err
-		}
-		clientCAs := x509.NewCertPool()
-		if ok := clientCAs.AppendCertsFromPEM(caCertPEMBlock); !ok {
-			return nil, errors.New("Failed to parse listener root certificate")
-		}
-		cfg.ClientCAs = clientCAs
-		cfg.ClientAuth = tls.RequireAndVerifyClientCert
-	}
-
 	tlsValidateFunc, err := tlsClientCertVerificationFunc(conf)
 	if err != nil {
 		return nil, err
 	}
-	cfg.VerifyPeerCertificate = tlsValidateFunc
-
-	return cfg, nil
+	tlsConfig, err := tlsserverconfig.GetServerTLSConfig(slog.Default(),
+		&tlsconfig.TLSServerConfig{
+			Enable:      true,
+			Refresh:     opts.Refresh,
+			KeyPassword: opts.ListenerKeyPassword,
+			File: tlsconfig.TLSServerFiles{
+				Key:       opts.ListenerKeyFile,
+				Cert:      opts.ListenerCertFile,
+				ClientCAs: opts.ListenerCAChainCertFile,
+				ClientCRL: opts.ListenerCRLFile,
+			},
+		},
+		tlsserver.WithTLSServerVerifyPeerCertificate(tlsValidateFunc),
+		tlsserver.WithTLSServerCipherSuites(cipherSuites),
+		tlsserver.WithTLSServerCurvePreferences(curvePreferences),
+	)
+	return tlsConfig, nil
 }
 
 func getCipherSuites(enabledCipherSuites []string) ([]uint16, error) {
@@ -147,45 +125,28 @@ func getCurvePreferences(enabledCurvePreferences []string) ([]tls.CurveID, error
 	return curvePreferences, nil
 }
 
-func newTLSClientConfig(conf *config.Config) (*tls.Config, error) {
+type TLSConfigFunc func() *tls.Config
+
+func newTLSClientConfig(conf *config.Config) (TLSConfigFunc, error) {
 	// https://blog.cloudflare.com/exposing-go-on-the-internet/
 	opts := conf.Kafka.TLS
-
-	cfg := &tls.Config{InsecureSkipVerify: opts.InsecureSkipVerify}
-
-	if opts.ClientCertFile != "" && opts.ClientKeyFile != "" {
-		certPEMBlock, err := os.ReadFile(opts.ClientCertFile)
-		if err != nil {
-			return nil, err
-		}
-		keyPEMBlock, err := os.ReadFile(opts.ClientKeyFile)
-		if err != nil {
-			return nil, err
-		}
-		keyPEMBlock, err = decryptPEM(keyPEMBlock, opts.ClientKeyPassword)
-		if err != nil {
-			return nil, err
-		}
-		cert, err := tls.X509KeyPair(certPEMBlock, keyPEMBlock)
-		if err != nil {
-			return nil, err
-		}
-		cfg.Certificates = []tls.Certificate{cert}
-	}
-
-	if opts.CAChainCertFile != "" {
-		caCertPEMBlock, err := os.ReadFile(opts.CAChainCertFile)
-		if err != nil {
-			return nil, err
-		}
-		rootCAs := x509.NewCertPool()
-		if ok := rootCAs.AppendCertsFromPEM(caCertPEMBlock); !ok {
-			return nil, errors.New("Failed to parse client root certificate")
-		}
-
-		cfg.RootCAs = rootCAs
+	tlsConfigFunc, err := tlsclientconfig.GetTLSClientConfigFunc(slog.Default(), &tlsconfig.TLSClientConfig{
+		Enable:             true,
+		Refresh:            opts.Refresh,
+		InsecureSkipVerify: opts.InsecureSkipVerify,
+		KeyPassword:        opts.ClientKeyPassword,
+		File: tlsconfig.TLSClientFiles{
+			Key:     opts.ClientKeyFile,
+			Cert:    opts.ClientCertFile,
+			RootCAs: opts.CAChainCertFile,
+		},
+	})
+	if err != nil {
+		return nil, err
 	}
-	return cfg, nil
+	return func() *tls.Config {
+		return tlsConfigFunc()
+	}, err
 }
 
 func decryptPEM(pemData []byte, password string) ([]byte, error) {