Backport of Prevent serving TLS via ports.grpc into release/1.14.x (#15342)

This pull request was automerged via backport-assistant

.changelog/15339.txt

@@ -2,5 +2,5 @@
 config: Add new `ports.grpc_tls` configuration option.
 Introduce a new port to better separate TLS config from the existing `ports.grpc` config.
 The new `ports.grpc_tls` only supports TLS encrypted communication.
-The existing `ports.grpc` currently supports both plain-text and tls communication, but tls support will be removed in a future release.
+The existing `ports.grpc` now only supports plain-text communication.
 ```

agent/agent.go

@@ -887,16 +887,9 @@ func (a *Agent) listenAndServeGRPC() error {
 		return nil
 	}
 
-	// The original grpc port may spawn in either plain-text or TLS mode (for backwards compatibility).
-	// TODO: Simplify this block to only spawn plain-text after 1.14 when deprecated TLS support is removed.
+	// Only allow grpc to spawn with a plain-text listener.
 	if a.config.GRPCPort > 0 {
-		// Only allow the grpc port to spawn TLS connections if the other grpc_tls port is NOT defined.
-		protocol := middleware.ProtocolPlaintext
-		if a.config.GRPCTLSPort <= 0 && a.tlsConfigurator.GRPCServerUseTLS() {
-			a.logger.Warn("deprecated gRPC TLS configuration detected. Consider using `ports.grpc_tls` instead")
-			protocol = middleware.ProtocolTLS
-		}
-		if err := start("grpc", a.config.GRPCAddrs, protocol); err != nil {
+		if err := start("grpc", a.config.GRPCAddrs, middleware.ProtocolPlaintext); err != nil {
 			closeListeners(listeners)
 			return err
 		}

agent/config/builder.go

@@ -1090,6 +1090,16 @@ func (b *builder) build() (rt RuntimeConfig, err error) {
 		return RuntimeConfig{}, err
 	}
 
+	// `ports.grpc` previously supported TLS, but this was changed for Consul 1.14.
+	// This check is done to warn users that a config change is mandatory.
+	if rt.TLS.GRPC.CertFile != "" || (rt.TLS.AutoTLS && rt.TLS.GRPC.UseAutoCert) {
+		// If only `ports.grpc` is enabled, and the gRPC TLS port is not explicitly defined by the user,
+		// check the grpc TLS settings for incompatibilities.
+		if rt.GRPCPort > 0 && c.Ports.GRPCTLS == nil {
+			return RuntimeConfig{}, fmt.Errorf("the `ports.grpc` listener no longer supports TLS. Use `ports.grpc_tls` instead. This message is appearing because GRPC is configured to use TLS, but `ports.grpc_tls` is not defined")
+		}
+	}
+
 	rt.UseStreamingBackend = boolValWithDefault(c.UseStreamingBackend, true)
 
 	if c.RaftBoltDBConfig != nil {

agent/config/builder_test.go

@@ -366,6 +366,90 @@ func TestBuilder_tlsVersion(t *testing.T) {
 	require.Contains(t, b.err.Error(), invalidTLSVersion)
 }
 
+func TestBuilder_WarnGRPCTLS(t *testing.T) {
+	tests := []struct {
+		name      string
+		hcl       string
+		expectErr bool
+	}{
+		{
+			name:      "success",
+			hcl:       ``,
+			expectErr: false,
+		},
+		{
+			name: "grpc_tls is disabled but explicitly defined",
+			hcl: `
+			ports { grpc_tls = -1 }
+			tls { grpc { cert_file = "defined" }}
+			`,
+			// This behavior is a little strange, but it allows users
+			// to setup TLS and disable the port if they wish.
+			expectErr: false,
+		},
+		{
+			name: "grpc is disabled",
+			hcl: `
+			ports { grpc = -1 }
+			tls { grpc { cert_file = "defined" }}
+			`,
+			expectErr: false,
+		},
+		{
+			name: "grpc_tls is undefined with default manual cert",
+			hcl: `
+			tls { defaults { cert_file = "defined" }}
+			`,
+			expectErr: true,
+		},
+		{
+			name: "grpc_tls is undefined with manual cert",
+			hcl: `
+			tls { grpc { cert_file = "defined" }}
+			`,
+			expectErr: true,
+		},
+		{
+			name: "grpc_tls is undefined with auto encrypt",
+			hcl: `
+			auto_encrypt { tls = true }
+			tls { grpc { use_auto_cert = true }}
+			`,
+			expectErr: true,
+		},
+		{
+			name: "grpc_tls is undefined with auto config",
+			hcl: `
+			auto_config { enabled = true }
+			tls { grpc { use_auto_cert = true }}
+			`,
+			expectErr: true,
+		},
+	}
+	for _, tc := range tests {
+		// using dev mode skips the need for a data dir
+		// and enables both grpc ports by default.
+		devMode := true
+		builderOpts := LoadOpts{
+			DevMode: &devMode,
+			Overrides: []Source{
+				FileSource{
+					Name:   "overrides",
+					Format: "hcl",
+					Data:   tc.hcl,
+				},
+			},
+		}
+		_, err := Load(builderOpts)
+		if tc.expectErr {
+			require.Error(t, err)
+			require.Contains(t, err.Error(), "listener no longer supports TLS")
+		} else {
+			require.NoError(t, err)
+		}
+	}
+}
+
 func TestBuilder_tlsCipherSuites(t *testing.T) {
 	b := builder{}
 

website/content/docs/agent/config/config-files.mdx

@@ -607,14 +607,12 @@ Valid time units are 'ns', 'us' (or 'µs'), 'ms', 's', 'm', 'h'."
   - `grpc` ((#grpc_port)) - The gRPC API, -1 to disable. Default -1 (disabled).
     **We recommend using `8502` for `grpc`** as your conventional gRPC port number, as it allows some
     tools to work automatically. This parameter is set to `8502` by default when the agent runs
-    in `-dev` mode. The `grpc` port currently supports either plaintext or TLS traffic for
-    backwards-compatibility, but TLS support is deprecated and will be removed in a future
-    release. Refer to `grpc_tls` for more information on configuring a TLS-enabled port.
+    in `-dev` mode. The `grpc` port only supports plaintext traffic starting in Consul 1.14.
+    Refer to `grpc_tls` for more information on configuring a TLS-enabled port.
   - `grpc_tls` ((#grpc_tls_port)) - The gRPC API with TLS connections, -1 to disable. gRPC_TLS is enabled by default on port 8503 for Consul servers.
     **We recommend using `8503` for `grpc_tls`** as your conventional gRPC port number, as it allows some
     tools to work automatically. `grpc_tls` is always guaranteed to be encrypted. Both `grpc` and `grpc_tls`
-    can be configured at the same time, but they may not utilize the same port number. If both `grpc` and
-    `grpc_tls` are defined, then `grpc` will always be plaintext. This field was added in Consul 1.14.
+    can be configured at the same time, but they may not utilize the same port number. This field was added in Consul 1.14.
   - `serf_lan` ((#serf_lan_port)) - The Serf LAN port. Default 8301. TCP
     and UDP. Equivalent to the [`-serf-lan-port` command line flag](/docs/agent/config/cli-flags#_serf_lan_port).
   - `serf_wan` ((#serf_wan_port)) - The Serf WAN port. Default 8302.

website/content/docs/upgrading/upgrade-specific.mdx

@@ -26,22 +26,21 @@ A breaking change was made in Consul 1.14 that:
 
 #### Changes to gRPC TLS configuration
 
-**Make configuration changes** if using sidecar proxies or gateways that include any of the following configuration file values:
-1. [`ports.https`](/docs/agent/config/config-files#https_port) - Encrypts gRPC in Consul 1.12 and prior
-1. [`auto_encrypt`](/docs/agent/config/config-files#auto_encrypt) - Encrypts gRPC in Consul 1.13 and prior
-1. [`auto_config`](/docs/agent/config/config-files#auto_config) - Encrypts gRPC in Consul 1.13 and prior
+**Make configuration changes** if using [`ports.grpc`](/docs/agent/config/config-files#grpc_port) in conjunction with any of the following settings that enables encryption:
+1. [`tls.grpc`](/docs/agent/config/config-files#tls_grpc)
+1. [`tls.defaults`](/docs/agent/config/config-files#tls_defaults)
+1. [`auto_encrypt`](/docs/agent/config/config-files#auto_encrypt)
+1. [`auto_config`](/docs/agent/config/config-files#auto_config)
 
 Prior to Consul 1.14, it was possible to encrypt communication between Consul and Envoy over `ports.grpc` using these settings.
 
 Consul 1.14 introduces [`ports.grpc_tls`](/docs/agent/config/config-files#grpc_tls_port), a new configuration
 for encrypting communication over gRPC. The existing [`ports.grpc`](/docs/agent/config/config-
-files#grpc_port) configuration **will stop supporting encryption in a future release**. As of version 1.14,
-[`ports.grpc_tls`](/docs/agent/config/config-files#grpc_tls_port) is the recommended configuration to encrypt gRPC traffic.
-The default value for gRPC TLS port is 8503 for Consul servers. To disable the gRPC TLS port, use value -1.
+files#grpc_port) configuration **no longer supports encryption**. As of version 1.14,
+[`ports.grpc_tls`](/docs/agent/config/config-files#grpc_tls_port) is the only port that serves encrypted gRPC traffic.
+The default value for the gRPC TLS port is 8503 for Consul servers. To disable the gRPC TLS port, use value -1.
 
-For most environments, the Envoy communication to Consul is loop-back only and does not benefit from encryption.
-
-If you already use gRPC encryption, change the existing `ports.grpc` to `ports.grpc_tls` in your configuration to ensure compatibility with future releases.
+If you already use gRPC encryption, change the existing `ports.grpc` to `ports.grpc_tls` in your configuration to ensure compatibility.
 
 #### Changes to peering