Add possibility to setting up tls security levels

internal/tls/config.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"fmt"
 	"io/ioutil"
+	"strings"
 )
 
 // ClientConfig represents the standard client TLS config.
@@ -25,6 +26,9 @@ type ServerConfig struct {
 	TLSCert           string   `toml:"tls_cert"`
 	TLSKey            string   `toml:"tls_key"`
 	TLSAllowedCACerts []string `toml:"tls_allowed_cacerts"`
+	TLSCipherSuites   []string `toml:"tls_cipher_suites"`
+	TLSMinVersion     string   `toml:"tls_min_version"`
+	TLSMaxVersion     string   `toml:"tls_max_version"`
 }
 
 // TLSConfig returns a tls.Config, may be nil without error if TLS is not
@@ -97,6 +101,38 @@ func (c *ServerConfig) TLSConfig() (*tls.Config, error) {
 		}
 	}
 
+	if len(c.TLSCipherSuites) != 0 {
+		cipherSuites, err := ParseCiphers(c.TLSCipherSuites)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"could not parse server cipher suites %s: %v", strings.Join(c.TLSCipherSuites, ","), err)
+		}
+		tlsConfig.CipherSuites = cipherSuites
+	}
+
+	if c.TLSMaxVersion != "" {
+		version, err := ParseTLSVersion(c.TLSMaxVersion)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"could not parse tls max version %q: %v", c.TLSMaxVersion, err)
+		}
+		tlsConfig.MaxVersion = version
+	}
+
+	if c.TLSMinVersion != "" {
+		version, err := ParseTLSVersion(c.TLSMinVersion)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"could not parse tls min version %q: %v", c.TLSMinVersion, err)
+		}
+		tlsConfig.MinVersion = version
+	}
+
+	if tlsConfig.MinVersion != 0 && tlsConfig.MaxVersion != 0 && tlsConfig.MinVersion > tlsConfig.MaxVersion {
+		return nil, fmt.Errorf(
+			"tls min version %q can't be greater then tls max version %q", tlsConfig.MinVersion, tlsConfig.MaxVersion)
+	}
+
 	return tlsConfig, nil
 }
 

internal/tls/config_test.go

@@ -123,6 +123,47 @@ func TestServerConfig(t *testing.T) {
 				TLSCert:           pki.ServerCertPath(),
 				TLSKey:            pki.ServerKeyPath(),
 				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
+				TLSMinVersion:     pki.TLSMinVersion(),
+				TLSMaxVersion:     pki.TLSMaxVersion(),
+			},
+		},
+		{
+			name: "missing tls cipher suites is okay",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
+			},
+		},
+		{
+			name: "missing tls max version is okay",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
+				TLSMaxVersion:     pki.TLSMaxVersion(),
+			},
+		},
+		{
+			name: "missing tls min version is okay",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
+				TLSMinVersion:     pki.TLSMinVersion(),
+			},
+		},
+		{
+			name: "missing tls min/max versions is okay",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
 			},
 		},
 		{
@@ -172,6 +213,56 @@ func TestServerConfig(t *testing.T) {
 			expNil: true,
 			expErr: true,
 		},
+		{
+			name: "invalid cipher suites",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CACertPath()},
+			},
+			expNil: true,
+			expErr: true,
+		},
+		{
+			name: "TLS Max Version less then TLS Min version",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CACertPath()},
+				TLSMinVersion:     pki.TLSMaxVersion(),
+				TLSMaxVersion:     pki.TLSMinVersion(),
+			},
+			expNil: true,
+			expErr: true,
+		},
+		{
+			name: "invalid tls min version",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CipherSuite()},
+				TLSMinVersion:     pki.ServerKeyPath(),
+				TLSMaxVersion:     pki.TLSMaxVersion(),
+			},
+			expNil: true,
+			expErr: true,
+		},
+		{
+			name: "invalid tls max version",
+			server: tls.ServerConfig{
+				TLSCert:           pki.ServerCertPath(),
+				TLSKey:            pki.ServerKeyPath(),
+				TLSAllowedCACerts: []string{pki.CACertPath()},
+				TLSCipherSuites:   []string{pki.CACertPath()},
+				TLSMinVersion:     pki.TLSMinVersion(),
+				TLSMaxVersion:     pki.ServerCertPath(),
+			},
+			expNil: true,
+			expErr: true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

internal/tls/utils.go

@@ -0,0 +1,59 @@
+package tls
+
+import (
+	"crypto/tls"
+	"fmt"
+)
+
+func ParseCiphers(ciphers []string) ([]uint16, error) {
+	suites := []uint16{}
+
+	cipherMap := map[string]uint16{
+		"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305":    tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+		"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305":  tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+		"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256":   tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+		"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+		"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384":   tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+		"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+		"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256":   tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+		"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA":      tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+		"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
+		"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA":    tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+		"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA":      tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+		"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA":    tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+		"TLS_RSA_WITH_AES_128_GCM_SHA256":         tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
+		"TLS_RSA_WITH_AES_256_GCM_SHA384":         tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
+		"TLS_RSA_WITH_AES_128_CBC_SHA256":         tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
+		"TLS_RSA_WITH_AES_128_CBC_SHA":            tls.TLS_RSA_WITH_AES_128_CBC_SHA,
+		"TLS_RSA_WITH_AES_256_CBC_SHA":            tls.TLS_RSA_WITH_AES_256_CBC_SHA,
+		"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA":     tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+		"TLS_RSA_WITH_3DES_EDE_CBC_SHA":           tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+		"TLS_RSA_WITH_RC4_128_SHA":                tls.TLS_RSA_WITH_RC4_128_SHA,
+		"TLS_ECDHE_RSA_WITH_RC4_128_SHA":          tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+		"TLS_ECDHE_ECDSA_WITH_RC4_128_SHA":        tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
+	}
+	for _, cipher := range ciphers {
+		if v, ok := cipherMap[cipher]; ok {
+			suites = append(suites, v)
+		} else {
+			return suites, fmt.Errorf("unsupported cipher %q", cipher)
+		}
+	}
+
+	return suites, nil
+}
+
+func ParseTLSVersion(version string) (uint16, error) {
+	versionMap := map[string]uint16{
+		"SSL30": tls.VersionSSL30,
+		"TLS10": tls.VersionTLS10,
+		"TLS11": tls.VersionTLS11,
+		"TLS12": tls.VersionTLS12,
+		// for go >= 1.12
+		//"TLS13": tls.VersionTLS13,
+	}
+	if v, ok := versionMap[version]; ok {
+		return v, nil
+	}
+	return 0, fmt.Errorf("unsupported version %q", version)
+}

plugins/outputs/prometheus_client/README.md

@@ -40,6 +40,42 @@ This plugin starts a [Prometheus](https://prometheus.io/) Client, it exposes all
   ## enable mutually authenticated TLS connections
   # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
 
+  ## Use only tls ciphers defined in this list
+  ## Possible values:
+  ## TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305
+  ## TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305
+  ## TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
+  ## TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
+  ## TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
+  ## TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
+  ## TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
+  ## TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
+  ## TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
+  ## TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
+  ## TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
+  ## TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
+  ## TLS_RSA_WITH_AES_128_GCM_SHA256
+  ## TLS_RSA_WITH_AES_256_GCM_SHA384
+  ## TLS_RSA_WITH_AES_128_CBC_SHA256
+  ## TLS_RSA_WITH_AES_128_CBC_SHA
+  ## TLS_RSA_WITH_AES_256_CBC_SHA
+  ## TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
+  ## TLS_RSA_WITH_3DES_EDE_CBC_SHA
+  ## TLS_RSA_WITH_RC4_128_SHA
+  ## TLS_ECDHE_RSA_WITH_RC4_128_SHA
+  ## TLS_ECDHE_ECDSA_WITH_RC4_128_SHA
+  ## If value wasn't defined default will be used
+  # tls_cipher_suites = ["TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305", "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", "TLS_RSA_WITH_AES_128_GCM_SHA256", "TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_CBC_SHA256", "TLS_RSA_WITH_AES_128_CBC_SHA", "TLS_RSA_WITH_AES_256_CBC_SHA"]
+
+  ## contains the minimum SSL/TLS version that is acceptable.
+  ## If not set, then TLS 1.0 is taken as the minimum.
+  # tls_min_version = "TLS11"
+
+  ## contains the maximum SSL/TLS version that is acceptable.
+  ## If not set, then the maximum version supported by this package is used,
+  ## which is currently TLS 1.2 (for go < 1.12) or TLS 1.3 (for go >= 1.12).
+  # tls_max_version = "TLS12"
+
   ## Export metric collection time.
   # export_timestamp = false
 ```

plugins/outputs/prometheus_client/prometheus_client.go

@@ -117,6 +117,8 @@ var sampleConfig = `
   ## enable mutually authenticated TLS connections
   # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
 
+  # tls_cipher_suites = ["TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305", "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", "TLS_RSA_WITH_AES_128_GCM_SHA256", "TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_CBC_SHA256", "TLS_RSA_WITH_AES_128_CBC_SHA", "TLS_RSA_WITH_AES_256_CBC_SHA"]
+
   ## Export metric collection time.
   # export_timestamp = false
 `

plugins/outputs/prometheus_client/prometheus_client_tls_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"testing"
 
+	inttls "github.com/influxdata/telegraf/internal/tls"
 	"github.com/influxdata/telegraf/plugins/outputs/prometheus_client"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/influxdata/toml"
@@ -19,7 +20,9 @@ var configWithTLS = fmt.Sprintf(`
  tls_allowed_cacerts = ["%s"]
  tls_cert = "%s"
  tls_key = "%s"
-`, pki.TLSServerConfig().TLSAllowedCACerts[0], pki.TLSServerConfig().TLSCert, pki.TLSServerConfig().TLSKey)
+ tls_cipher_suites = ["%s"]
+ tls_min_version = "%s"
+`, pki.TLSServerConfig().TLSAllowedCACerts[0], pki.TLSServerConfig().TLSCert, pki.TLSServerConfig().TLSKey, pki.CipherSuite(), pki.TLSMaxVersion())
 
 var configWithoutTLS = `
   listen = "127.0.0.1:0"
@@ -50,12 +53,22 @@ func TestWorksWithTLS(t *testing.T) {
 	require.NoError(t, err)
 	defer tc.Output.Close()
 
+	serverCiphers, err := inttls.ParseCiphers(tc.Output.ServerConfig.TLSCipherSuites)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(serverCiphers))
+
+	tlsVersion, err := inttls.ParseTLSVersion(tc.Output.ServerConfig.TLSMinVersion)
+	require.NoError(t, err)
+
 	response, err := tc.Client.Get(tc.Output.URL())
 	require.NoError(t, err)
 
 	require.NoError(t, err)
 	require.Equal(t, response.StatusCode, http.StatusOK)
 
+	require.Equal(t, response.TLS.CipherSuite, serverCiphers[0])
+	require.Equal(t, response.TLS.Version, tlsVersion)
+
 	tr := &http.Transport{
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}

testutil/tls.go

@@ -30,6 +30,9 @@ func (p *pki) TLSServerConfig() *tls.ServerConfig {
 		TLSAllowedCACerts: []string{p.CACertPath()},
 		TLSCert:           p.ServerCertPath(),
 		TLSKey:            p.ServerKeyPath(),
+		TLSCipherSuites:   []string{p.CipherSuite()},
+		TLSMinVersion:     p.TLSMinVersion(),
+		TLSMaxVersion:     p.TLSMaxVersion(),
 	}
 }
 
@@ -41,6 +44,18 @@ func (p *pki) CACertPath() string {
 	return path.Join(p.path, "cacert.pem")
 }
 
+func (p *pki) CipherSuite() string {
+	return "TLS_RSA_WITH_3DES_EDE_CBC_SHA"
+}
+
+func (p *pki) TLSMinVersion() string {
+	return "TLS11"
+}
+
+func (p *pki) TLSMaxVersion() string {
+	return "TLS12"
+}
+
 func (p *pki) ReadClientCert() string {
 	return readCertificate(p.ClientCertPath())
 }