crypto/tls: mark RSA KEX cipher suites insecure

Updates #63413

Change-Id: I31fc2f9728582524cac5d101d0011093dbd05ed3
Reviewed-on: https://go-review.googlesource.com/c/go/+/544336
Auto-Submit: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>

src/crypto/tls/cipher_suites.go

@@ -52,11 +52,6 @@ var (
 // and might not match those returned by this function.
 func CipherSuites() []*CipherSuite {
 	return []*CipherSuite{
-		{TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
-		{TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
-		{TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
-		{TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
-
 		{TLS_AES_128_GCM_SHA256, "TLS_AES_128_GCM_SHA256", supportedOnlyTLS13, false},
 		{TLS_AES_256_GCM_SHA384, "TLS_AES_256_GCM_SHA384", supportedOnlyTLS13, false},
 		{TLS_CHACHA20_POLY1305_SHA256, "TLS_CHACHA20_POLY1305_SHA256", supportedOnlyTLS13, false},
@@ -85,7 +80,11 @@ func InsecureCipherSuites() []*CipherSuite {
 	return []*CipherSuite{
 		{TLS_RSA_WITH_RC4_128_SHA, "TLS_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
 		{TLS_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
+		{TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, true},
+		{TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, true},
 		{TLS_RSA_WITH_AES_128_CBC_SHA256, "TLS_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
+		{TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, true},
+		{TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, true},
 		{TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
 		{TLS_ECDHE_RSA_WITH_RC4_128_SHA, "TLS_ECDHE_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
 		{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},

src/crypto/tls/tls_test.go

@@ -1490,16 +1490,21 @@ func TestCipherSuites(t *testing.T) {
 	if len(cipherSuitesPreferenceOrderNoAES) != len(cipherSuitesPreferenceOrder) {
 		t.Errorf("cipherSuitesPreferenceOrderNoAES is not the same size as cipherSuitesPreferenceOrder")
 	}
+	if len(defaultCipherSuites) >= len(defaultCipherSuitesWithRSAKex) {
+		t.Errorf("defaultCipherSuitesWithRSAKex should be longer than defaultCipherSuites")
+	}
 
 	// Check that disabled suites are marked insecure.
-	for id := range disabledCipherSuites {
-		c := CipherSuiteByID(id)
-		if c == nil {
-			t.Errorf("%#04x: no CipherSuite entry", id)
-			continue
-		}
-		if !c.Insecure {
-			t.Errorf("%#04x: disabled by default but not marked insecure", id)
+	for _, badSuites := range []map[uint16]bool{disabledCipherSuites, rsaKexCiphers} {
+		for id := range badSuites {
+			c := CipherSuiteByID(id)
+			if c == nil {
+				t.Errorf("%#04x: no CipherSuite entry", id)
+				continue
+			}
+			if !c.Insecure {
+				t.Errorf("%#04x: disabled by default but not marked insecure", id)
+			}
 		}
 	}