Commit 3dc24108 authored by Roland Shoemaker's avatar Roland Shoemaker
Browse files

crypto/tls: change default minimum version to 1.2 

Updates the default from 1.0 -> 1.2 for servers, bringing it in line
with clients. Add a GODEBUG setting, tls10server, which lets users
revert this change.

Fixes #62459

Change-Id: I2b82f85b1c2d527df1f9afefae4ab30a8f0ceb41
Reviewed-on: https://go-review.googlesource.com/c/go/+/541516


LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: default avatarDamien Neil <dneil@google.com>
parent 59d4a9c7

common.go

+13 −10
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ import ( 
	"crypto/x509"

	"errors"

	"fmt"

	"internal/godebug"

	"io"

	"net"

	"strings"
@@ -732,14 +733,11 @@ type Config struct { 


	// MinVersion contains the minimum TLS version that is acceptable.

	//

	// By default, TLS 1.2 is currently used as the minimum when acting as a

	// client, and TLS 1.0 when acting as a server. TLS 1.0 is the minimum

	// supported by this package, both as a client and as a server.

	// By default, TLS 1.2 is currently used as the minimum. TLS 1.0 is the

	// minimum supported by this package.

	//

	// The client-side default can temporarily be reverted to TLS 1.0 by

	// including the value "x509sha1=1" in the GODEBUG environment variable.

	// Note that this option will be removed in Go 1.19 (but it will still be

	// possible to set this field to VersionTLS10 explicitly).

	// The server-side default can be reverted to TLS 1.0 by including the value

	// "tls10server=1" in the GODEBUG environment variable.

	MinVersion uint16



	// MaxVersion contains the maximum TLS version that is acceptable.
@@ -1028,16 +1026,21 @@ var supportedVersions = []uint16{ 
const roleClient = true

const roleServer = false



var tls10godebug = godebug.New("tls10server")



func (c *Config) supportedVersions(isClient bool) []uint16 {

	versions := make([]uint16, 0, len(supportedVersions))

	for _, v := range supportedVersions {

		if needFIPS() && (v < fipsMinVersion(c) || v > fipsMaxVersion(c)) {

			continue

		}

		if (c == nil || c.MinVersion == 0) &&

			isClient && v < VersionTLS12 {

		if (c == nil || c.MinVersion == 0) && v < VersionTLS12 {

			if !isClient && tls10godebug.Value() == "1" {

				tls10godebug.IncNonDefault()

			} else {

				continue

			}

		}

		if c != nil && c.MinVersion != 0 && v < c.MinVersion {

			continue

		}

handshake_server_test.go

+12 −10
Original line number Diff line number Diff line
@@ -389,21 +389,22 @@ func TestClose(t *testing.T) { 
func TestVersion(t *testing.T) {

	serverConfig := &Config{

		Certificates: testConfig.Certificates,

		MaxVersion:   VersionTLS11,

		MaxVersion:   VersionTLS13,

	}

	clientConfig := &Config{

		InsecureSkipVerify: true,

		MinVersion:         VersionTLS10,

		MinVersion:         VersionTLS12,

	}

	state, _, err := testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)

	}

	if state.Version != VersionTLS11 {

	if state.Version != VersionTLS13 {

		t.Fatalf("incorrect version %x, should be %x", state.Version, VersionTLS11)

	}



	clientConfig.MinVersion = 0

	serverConfig.MaxVersion = VersionTLS11

	_, _, err = testHandshake(t, clientConfig, serverConfig)

	if err == nil {

		t.Fatalf("expected failure to connect with TLS 1.0/1.1")
@@ -487,17 +488,17 @@ func testCrossVersionResume(t *testing.T, version uint16) { 
		InsecureSkipVerify: true,

		ClientSessionCache: NewLRUClientSessionCache(1),

		ServerName:         "servername",

		MinVersion:         VersionTLS10,

		MinVersion:         VersionTLS12,

	}



	// Establish a session at TLS 1.1.

	clientConfig.MaxVersion = VersionTLS11

	// Establish a session at TLS 1.3.

	clientConfig.MaxVersion = VersionTLS13

	_, _, err := testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)

	}



	// The client session cache now contains a TLS 1.1 session.

	// The client session cache now contains a TLS 1.3 session.

	state, _, err := testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)
@@ -507,7 +508,7 @@ func testCrossVersionResume(t *testing.T, version uint16) { 
	}



	// Test that the server will decline to resume at a lower version.

	clientConfig.MaxVersion = VersionTLS10

	clientConfig.MaxVersion = VersionTLS12

	state, _, err = testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)
@@ -516,7 +517,7 @@ func testCrossVersionResume(t *testing.T, version uint16) { 
		t.Fatalf("handshake resumed at a lower version")

	}



	// The client session cache now contains a TLS 1.0 session.

	// The client session cache now contains a TLS 1.2 session.

	state, _, err = testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)
@@ -526,7 +527,7 @@ func testCrossVersionResume(t *testing.T, version uint16) { 
	}



	// Test that the server will decline to resume at a higher version.

	clientConfig.MaxVersion = VersionTLS11

	clientConfig.MaxVersion = VersionTLS13

	state, _, err = testHandshake(t, clientConfig, serverConfig)

	if err != nil {

		t.Fatalf("handshake failed: %s", err)
@@ -1170,6 +1171,7 @@ func TestServerResumptionDisabled(t *testing.T) { 
func TestFallbackSCSV(t *testing.T) {

	serverConfig := Config{

		Certificates: testConfig.Certificates,

		MinVersion:   VersionTLS11,

	}

	test := &serverTest{

		name:   "FallbackSCSV",

tls_test.go

+2 −0
Original line number Diff line number Diff line
@@ -1365,6 +1365,7 @@ func TestClientHelloInfo_SupportsCertificate(t *testing.T) { 
			SupportedPoints:   []uint8{pointFormatUncompressed},

			SignatureSchemes:  []SignatureScheme{Ed25519},

			SupportedVersions: []uint16{VersionTLS10},

			config:            &Config{MinVersion: VersionTLS10},

		}, "doesn't support Ed25519"},

		{ed25519Cert, &ClientHelloInfo{

			CipherSuites:      []uint16{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
@@ -1379,6 +1380,7 @@ func TestClientHelloInfo_SupportsCertificate(t *testing.T) { 
			SupportedCurves:   []CurveID{CurveP256}, // only relevant for ECDHE support

			SupportedPoints:   []uint8{pointFormatUncompressed},

			SupportedVersions: []uint16{VersionTLS10},

			config:            &Config{MinVersion: VersionTLS10},

		}, ""},

		{rsaCert, &ClientHelloInfo{

			CipherSuites:      []uint16{TLS_RSA_WITH_AES_128_GCM_SHA256},