Add TLS support to socket_writer and socket_listener plugins (#4021)

internal/internal.go

@@ -112,9 +112,10 @@ func RandomString(n int) string {
 	return string(bytes)
 }
 
-// GetTLSConfig gets a tls.Config object from the given certs, key, and CA files.
-// you must give the full path to the files.
-// If all files are blank and InsecureSkipVerify=false, returns a nil pointer.
+// GetTLSConfig gets a tls.Config object from the given certs, key, and CA files
+// for use with a client.
+// The full path to each file must be provided.
+// Returns a nil pointer if all files are blank and InsecureSkipVerify=false.
 func GetTLSConfig(
 	SSLCert, SSLKey, SSLCA string,
 	InsecureSkipVerify bool,
@@ -155,6 +156,50 @@ func GetTLSConfig(
 	return t, nil
 }
 
+// GetServerTLSConfig gets a tls.Config object from the given certs, key, and one or more CA files
+// for use with a server.
+// The full path to each file must be provided.
+// Returns a nil pointer if all files are blank.
+func GetServerTLSConfig(
+	TLSCert, TLSKey string,
+	TLSAllowedCACerts []string,
+) (*tls.Config, error) {
+	if TLSCert == "" && TLSKey == "" && len(TLSAllowedCACerts) == 0 {
+		return nil, nil
+	}
+
+	t := &tls.Config{}
+
+	if len(TLSAllowedCACerts) != 0 {
+		caCertPool := x509.NewCertPool()
+		for _, cert := range TLSAllowedCACerts {
+			c, err := ioutil.ReadFile(cert)
+			if err != nil {
+				return nil, errors.New(fmt.Sprintf("Could not load TLS CA: %s",
+					err))
+			}
+			caCertPool.AppendCertsFromPEM(c)
+		}
+		t.ClientCAs = caCertPool
+		t.ClientAuth = tls.RequireAndVerifyClientCert
+	}
+
+	if TLSCert != "" && TLSKey != "" {
+		cert, err := tls.LoadX509KeyPair(TLSCert, TLSKey)
+		if err != nil {
+			return nil, errors.New(fmt.Sprintf(
+				"Could not load TLS client key/certificate from %s:%s: %s",
+				TLSKey, TLSCert, err))
+		}
+
+		t.Certificates = []tls.Certificate{cert}
+	}
+
+	t.BuildNameToCertificate()
+
+	return t, nil
+}
+
 // SnakeCase converts the given string to snake case following the Golang format:
 // acronyms are converted to lower-case and preceded by an underscore.
 func SnakeCase(in string) string {

plugins/inputs/socket_listener/README.md

@@ -35,6 +35,13 @@ This is a sample configuration for the plugin.
   ## 0 (default) is unlimited.
   # read_timeout = "30s"
 
+  ## Optional TLS configuration.
+  ## Only applies to stream sockets (e.g. TCP).
+  # tls_cert = "/etc/telegraf/cert.pem"
+  # tls_key  = "/etc/telegraf/key.pem"
+  ## Enables client authentication if set.
+  # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
+
   ## Maximum socket buffer size in bytes.
   ## For stream sockets, once the buffer fills up, the sender will start backing up.
   ## For datagram sockets, once the buffer fills up, metrics will start dropping.

plugins/inputs/socket_listener/socket_listener.go

@@ -12,6 +12,7 @@ import (
 
 	"time"
 
+	"crypto/tls"
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/inputs"
@@ -122,9 +123,9 @@ func (ssl *streamSocketListener) read(c net.Conn) {
 	}
 
 	if err := scnr.Err(); err != nil {
-		if err, ok := err.(net.Error); ok && err.Timeout() {
+		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
 			log.Printf("D! Timeout in plugin [input.socket_listener]: %s", err)
-		} else if !strings.HasSuffix(err.Error(), ": use of closed network connection") {
+		} else if netErr != nil && !strings.HasSuffix(err.Error(), ": use of closed network connection") {
 			ssl.AddError(err)
 		}
 	}
@@ -159,11 +160,14 @@ func (psl *packetSocketListener) listen() {
 }
 
 type SocketListener struct {
-	ServiceAddress  string
-	MaxConnections  int
-	ReadBufferSize  int
-	ReadTimeout     *internal.Duration
-	KeepAlivePeriod *internal.Duration
+	ServiceAddress    string             `toml:"service_address"`
+	MaxConnections    int                `toml:"max_connections"`
+	ReadBufferSize    int                `toml:"read_buffer_size"`
+	ReadTimeout       *internal.Duration `toml:"read_timeout"`
+	TLSAllowedCACerts []string           `toml:"tls_allowed_cacerts"`
+	TLSCert           string             `toml:"tls_cert"`
+	TLSKey            string             `toml:"tls_key"`
+	KeepAlivePeriod   *internal.Duration `toml:"keep_alive_period"`
 
 	parsers.Parser
 	telegraf.Accumulator
@@ -198,6 +202,13 @@ func (sl *SocketListener) SampleConfig() string {
   ## 0 (default) is unlimited.
   # read_timeout = "30s"
 
+  ## Optional TLS configuration.
+  ## Only applies to stream sockets (e.g. TCP).
+  # tls_cert = "/etc/telegraf/cert.pem"
+  # tls_key  = "/etc/telegraf/key.pem"
+  ## Enables client authentication if set.
+  # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
+
   ## Maximum socket buffer size in bytes.
   ## For stream sockets, once the buffer fills up, the sender will start backing up.
   ## For datagram sockets, once the buffer fills up, metrics will start dropping.
@@ -242,7 +253,21 @@ func (sl *SocketListener) Start(acc telegraf.Accumulator) error {
 
 	switch spl[0] {
 	case "tcp", "tcp4", "tcp6", "unix", "unixpacket":
-		l, err := net.Listen(spl[0], spl[1])
+		var (
+			err error
+			l   net.Listener
+		)
+
+		tlsCfg, err := internal.GetServerTLSConfig(sl.TLSCert, sl.TLSKey, sl.TLSAllowedCACerts)
+		if err != nil {
+			return nil
+		}
+
+		if tlsCfg == nil {
+			l, err = net.Listen(spl[0], spl[1])
+		} else {
+			l, err = tls.Listen(spl[0], spl[1], tlsCfg)
+		}
 		if err != nil {
 			return err
 		}
@@ -313,6 +338,14 @@ func (uc unixCloser) Close() error {
 	return err
 }
 
+func (uc unixCloser) Accept() (net.Conn, error) {
+	return uc.closer.(net.Listener).Accept()
+}
+
+func (uc unixCloser) Addr() net.Addr {
+	return uc.closer.(net.Listener).Addr()
+}
+
 func init() {
 	inputs.Add("socket_listener", func() telegraf.Input { return newSocketListener() })
 }

plugins/inputs/socket_listener/socket_listener_test.go

@@ -2,12 +2,14 @@ package socket_listener
 
 import (
 	"bytes"
+	"crypto/tls"
 	"log"
 	"net"
 	"os"
 	"testing"
 	"time"
 
+	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -25,6 +27,52 @@ func testEmptyLog(t *testing.T) func() {
 	}
 }
 
+func TestSocketListener_tcp_tls(t *testing.T) {
+	defer testEmptyLog(t)()
+
+	sl := newSocketListener()
+	sl.ServiceAddress = "tcp://127.0.0.1:0"
+	sl.TLSCert = "testdata/server.pem"
+	sl.TLSKey = "testdata/server.key"
+	sl.TLSAllowedCACerts = []string{"testdata/ca.pem"}
+
+	acc := &testutil.Accumulator{}
+	err := sl.Start(acc)
+	require.NoError(t, err)
+	defer sl.Stop()
+
+	tlsCfg, err := internal.GetTLSConfig("testdata/client.pem", "testdata/client.key", "testdata/ca.pem", true)
+	require.NoError(t, err)
+
+	secureClient, err := tls.Dial("tcp", sl.Closer.(net.Listener).Addr().String(), tlsCfg)
+	require.NoError(t, err)
+
+	testSocketListener(t, sl, secureClient)
+}
+
+func TestSocketListener_unix_tls(t *testing.T) {
+	defer testEmptyLog(t)()
+
+	sl := newSocketListener()
+	sl.ServiceAddress = "unix:///tmp/telegraf_test.sock"
+	sl.TLSCert = "testdata/server.pem"
+	sl.TLSKey = "testdata/server.key"
+	sl.TLSAllowedCACerts = []string{"testdata/ca.pem"}
+
+	acc := &testutil.Accumulator{}
+	err := sl.Start(acc)
+	require.NoError(t, err)
+	defer sl.Stop()
+
+	tlsCfg, err := internal.GetTLSConfig("testdata/client.pem", "testdata/client.key", "testdata/ca.pem", true)
+	require.NoError(t, err)
+
+	secureClient, err := tls.Dial("unix", "/tmp/telegraf_test.sock", tlsCfg)
+	require.NoError(t, err)
+
+	testSocketListener(t, sl, secureClient)
+}
+
 func TestSocketListener_tcp(t *testing.T) {
 	defer testEmptyLog(t)()
 

plugins/inputs/socket_listener/testdata/ca.pem

@@ -0,0 +1,31 @@
+-----BEGIN CERTIFICATE-----
+MIIFVTCCAz2gAwIBAgIJAOhLvwv6zUf+MA0GCSqGSIb3DQEBCwUAMEExCzAJBgNV
+BAYTAlVTMQswCQYDVQQIDAJDQTEWMBQGA1UEBwwNU2FuIEZyYW5jaXNjbzENMAsG
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+-----END CERTIFICATE-----

plugins/inputs/socket_listener/testdata/client.key

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
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+-----END RSA PRIVATE KEY-----

plugins/inputs/socket_listener/testdata/client.pem

@@ -0,0 +1,24 @@
+-----BEGIN CERTIFICATE-----
+MIIEEjCCAfoCCQCmcronmMSqXTANBgkqhkiG9w0BAQsFADBBMQswCQYDVQQGEwJV
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+-----END CERTIFICATE-----

plugins/inputs/socket_listener/testdata/server.key

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEowIBAAKCAQEAzkEDLijGOqXNQPAqUjOz5TLuM28SENauknLtcfIyEN/N6PwZ
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+BKAkUQN3D+XCN4pXdbKvbkOcfYRUHoD+pPBjRYH020OtPBUc6Wkl
+-----END RSA PRIVATE KEY-----

plugins/inputs/socket_listener/testdata/server.pem

@@ -0,0 +1,25 @@
+-----BEGIN CERTIFICATE-----
+MIIEJjCCAg4CCQCmcronmMSqXDANBgkqhkiG9w0BAQsFADBBMQswCQYDVQQGEwJV
+UzELMAkGA1UECAwCQ0ExFjAUBgNVBAcMDVNhbiBGcmFuY2lzY28xDTALBgNVBAoM
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+AL2l5T7JKU+XaWWeo+crV+AnGIJyqyh9Su/n97PEoZoEMGH4Kcl/n/w2Jms60+5s
+K0FK2OGNL42ddUfQiVL9CwYQQo70hydjsIo1x8S6+tSFLMAAysQEToSjfAA6qxDu
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+qwUyMg/oYWnwqw==
+-----END CERTIFICATE-----

plugins/outputs/socket_writer/README.md

@@ -19,6 +19,13 @@ It can output data in any of the [supported output formats](https://github.com/i
   # address = "unix:///tmp/telegraf.sock"
   # address = "unixgram:///tmp/telegraf.sock"
 
+  ## Optional SSL Config
+  # ssl_ca = "/etc/telegraf/ca.pem"
+  # ssl_cert = "/etc/telegraf/cert.pem"
+  # ssl_key = "/etc/telegraf/key.pem"
+  ## Use SSL but skip chain & host verification
+  # insecure_skip_verify = false
+
   ## Period between keep alive probes.
   ## Only applies to TCP sockets.
   ## 0 disables keep alive probes.