Add settings for upshifting to encrypted gossip (#3079)

command/agent/agent.go

@@ -376,6 +376,14 @@ func (a *Agent) consulConfig() (*consul.Config, error) {
 	if a.config.ReconnectTimeoutWan != 0 {
 		base.SerfWANConfig.ReconnectTimeout = a.config.ReconnectTimeoutWan
 	}
+	if a.config.EncryptVerifyIncoming != nil {
+		base.SerfWANConfig.MemberlistConfig.GossipVerifyIncoming = *a.config.EncryptVerifyIncoming
+		base.SerfLANConfig.MemberlistConfig.GossipVerifyIncoming = *a.config.EncryptVerifyIncoming
+	}
+	if a.config.EncryptVerifyOutgoing != nil {
+		base.SerfWANConfig.MemberlistConfig.GossipVerifyOutgoing = *a.config.EncryptVerifyOutgoing
+		base.SerfLANConfig.MemberlistConfig.GossipVerifyOutgoing = *a.config.EncryptVerifyOutgoing
+	}
 	if a.config.AdvertiseAddrs.RPC != nil {
 		base.RPCAdvertise = a.config.AdvertiseAddrs.RPC
 	}

command/agent/config.go

@@ -365,6 +365,12 @@ type Config struct {
 	// Encryption key to use for the Serf communication
 	EncryptKey string `mapstructure:"encrypt" json:"-"`
 
+	// EncryptVerifyIncoming and EncryptVerifyOutgoing are used to enforce
+	// incoming/outgoing gossip encryption and can be used to upshift to
+	// encrypted gossip on a running cluster.
+	EncryptVerifyIncoming *bool `mapstructure:"encrypt_verify_incoming"`
+	EncryptVerifyOutgoing *bool `mapstructure:"encrypt_verify_outgoing"`
+
 	// LogLevel is the level of the logs to putout
 	LogLevel string `mapstructure:"log_level"`
 
@@ -864,6 +870,9 @@ func DefaultConfig() *Config {
 		RetryIntervalWan:   30 * time.Second,
 
 		TLSMinVersion: "tls10",
+
+		EncryptVerifyIncoming: Bool(true),
+		EncryptVerifyOutgoing: Bool(true),
 	}
 }
 
@@ -1477,6 +1486,12 @@ func MergeConfig(a, b *Config) *Config {
 	if b.EncryptKey != "" {
 		result.EncryptKey = b.EncryptKey
 	}
+	if b.EncryptVerifyIncoming != nil {
+		result.EncryptVerifyIncoming = b.EncryptVerifyIncoming
+	}
+	if b.EncryptVerifyOutgoing != nil {
+		result.EncryptVerifyOutgoing = b.EncryptVerifyOutgoing
+	}
 	if b.LogLevel != "" {
 		result.LogLevel = b.LogLevel
 	}

command/agent/config_test.go

@@ -123,6 +123,18 @@ func TestDecodeConfig(t *testing.T) {
 		t.Fatalf("bad: %#v", config)
 	}
 
+	input = `{"encrypt_verify_incoming":true, "encrypt_verify_outgoing":true}`
+	config, err = DecodeConfig(bytes.NewReader([]byte(input)))
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if config.EncryptVerifyIncoming == nil || !*config.EncryptVerifyIncoming {
+		t.Fatalf("bad: %#v", config)
+	}
+	if config.EncryptVerifyOutgoing == nil || !*config.EncryptVerifyOutgoing {
+		t.Fatalf("bad: %#v", config)
+	}
+
 	// DNS setup
 	input = `{"ports": {"dns": 8500}, "recursors": ["8.8.8.8","8.8.4.4"], "recursor":"127.0.0.1", "domain": "foobar"}`
 	config, err = DecodeConfig(bytes.NewReader([]byte(input)))

vendor/github.com/hashicorp/memberlist/config.go

@@ -141,6 +141,16 @@ type Config struct {
 	GossipNodes         int
 	GossipToTheDeadTime time.Duration
 
+	// GossipVerifyIncoming controls whether to enforce encryption for incoming
+	// gossip. It is used for upshifting from unencrypted to encrypted gossip on
+	// a running cluster.
+	GossipVerifyIncoming bool
+
+	// GossipVerifyOutgoing controls whether to enforce encryption for outgoing
+	// gossip. It is used for upshifting from unencrypted to encrypted gossip on
+	// a running cluster.
+	GossipVerifyOutgoing bool
+
 	// EnableCompression is used to control message compression. This can
 	// be used to reduce bandwidth usage at the cost of slightly more CPU
 	// utilization. This is only available starting at protocol version 1.
@@ -233,9 +243,11 @@ func DefaultLANConfig() *Config {
 		DisableTcpPings:         false,                  // TCP pings are safe, even with mixed versions
 		AwarenessMaxMultiplier:  8,                      // Probe interval backs off to 8 seconds
 
-		GossipNodes:         3,                      // Gossip to 3 nodes
-		GossipInterval:      200 * time.Millisecond, // Gossip more rapidly
-		GossipToTheDeadTime: 30 * time.Second,       // Same as push/pull
+		GossipNodes:          3,                      // Gossip to 3 nodes
+		GossipInterval:       200 * time.Millisecond, // Gossip more rapidly
+		GossipToTheDeadTime:  30 * time.Second,       // Same as push/pull
+		GossipVerifyIncoming: true,
+		GossipVerifyOutgoing: true,
 
 		EnableCompression: true, // Enable compression by default
 

vendor/github.com/hashicorp/memberlist/memberlist.go

@@ -334,7 +334,7 @@ func (m *Memberlist) setAlive() error {
 	addr, port, err := m.transport.FinalAdvertiseAddr(
 		m.config.AdvertiseAddr, m.config.AdvertisePort)
 	if err != nil {
-		return fmt.Errorf("Failed to get final advertise address: %v")
+		return fmt.Errorf("Failed to get final advertise address: %v", err)
 	}
 
 	// Check if this is a public address without encryption

vendor/github.com/hashicorp/memberlist/net.go

@@ -283,8 +283,13 @@ func (m *Memberlist) ingestPacket(buf []byte, from net.Addr, timestamp time.Time
 		// Decrypt the payload
 		plain, err := decryptPayload(m.config.Keyring.GetKeys(), buf, nil)
 		if err != nil {
-			m.logger.Printf("[ERR] memberlist: Decrypt packet failed: %v %s", err, LogAddress(from))
-			return
+			if !m.config.GossipVerifyIncoming {
+				// Treat the message as plaintext
+				plain = buf
+			} else {
+				m.logger.Printf("[ERR] memberlist: Decrypt packet failed: %v %s", err, LogAddress(from))
+				return
+			}
 		}
 
 		// Continue processing the plaintext buffer
@@ -557,7 +562,7 @@ func (m *Memberlist) encodeAndSendMsg(addr string, msgType messageType, msg inte
 func (m *Memberlist) sendMsg(addr string, msg []byte) error {
 	// Check if we can piggy back any messages
 	bytesAvail := m.config.UDPBufferSize - len(msg) - compoundHeaderOverhead
-	if m.config.EncryptionEnabled() {
+	if m.config.EncryptionEnabled() && m.config.GossipVerifyOutgoing {
 		bytesAvail -= encryptOverhead(m.encryptionVersion())
 	}
 	extra := m.getBroadcasts(compoundOverhead, bytesAvail)
@@ -621,7 +626,7 @@ func (m *Memberlist) rawSendMsgPacket(addr string, node *Node, msg []byte) error
 	}
 
 	// Check if we have encryption enabled
-	if m.config.EncryptionEnabled() {
+	if m.config.EncryptionEnabled() && m.config.GossipVerifyOutgoing {
 		// Encrypt the payload
 		var buf bytes.Buffer
 		primaryKey := m.config.Keyring.GetPrimaryKey()
@@ -652,7 +657,7 @@ func (m *Memberlist) rawSendMsgStream(conn net.Conn, sendBuf []byte) error {
 	}
 
 	// Check if encryption is enabled
-	if m.config.EncryptionEnabled() {
+	if m.config.EncryptionEnabled() && m.config.GossipVerifyOutgoing {
 		crypt, err := m.encryptLocalState(sendBuf)
 		if err != nil {
 			m.logger.Printf("[ERROR] memberlist: Failed to encrypt local state: %v", err)
@@ -876,7 +881,7 @@ func (m *Memberlist) readStream(conn net.Conn) (messageType, io.Reader, *codec.D
 		// Reset message type and bufConn
 		msgType = messageType(plain[0])
 		bufConn = bytes.NewReader(plain[1:])
-	} else if m.config.EncryptionEnabled() {
+	} else if m.config.EncryptionEnabled() && m.config.GossipVerifyIncoming {
 		return 0, nil, nil,
 			fmt.Errorf("Encryption is configured but remote state is not encrypted")
 	}

vendor/github.com/hashicorp/memberlist/state.go

@@ -40,6 +40,11 @@ func (n *Node) Address() string {
 	return joinHostPort(n.Addr.String(), n.Port)
 }
 
+// String returns the node name
+func (n *Node) String() string {
+	return n.Name
+}
+
 // NodeState is used to manage our state view of another node
 type nodeState struct {
 	Node

vendor/github.com/hashicorp/memberlist/tag.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -e
+
+# The version must be supplied from the environment. Do not include the
+# leading "v".
+if [ -z $VERSION ]; then
+    echo "Please specify a version."
+    exit 1
+fi
+
+# Generate the tag.
+echo "==> Tagging version $VERSION..."
+git commit --allow-empty -a --gpg-sign=348FFC4C -m "Release v$VERSION"
+git tag -a -m "Version $VERSION" -s -u 348FFC4C "v${VERSION}" master
+
+exit 0

vendor/vendor.json

@@ -642,10 +642,10 @@
 			"revisionTime": "2015-06-09T07:04:31Z"
 		},
 		{
-			"checksumSHA1": "JJsKjmgNTUTaEHEEAQgb9jCGGiM=",
+			"checksumSHA1": "AoIvQFHycqypYK57ZjiWzlQmdwk=",
 			"path": "github.com/hashicorp/memberlist",
-			"revision": "6cc6075ba9fba1915fa0416f00d2b4efa9dc2262",
-			"revisionTime": "2017-03-17T22:24:04Z"
+			"revision": "16fe34d996eba2b68f6f46f26c51c617c6bc1bf0",
+			"revisionTime": "2017-05-26T19:17:51Z"
 		},
 		{
 			"checksumSHA1": "qnlqWJYV81ENr61SZk9c65R1mDo=",

website/source/docs/agent/encryption.html.md

@@ -52,6 +52,24 @@ $ consul agent -data-dir=/tmp/consul -config-file=encrypt.json
 All nodes within a Consul cluster must share the same encryption key in
 order to send and receive cluster information.
 
+## Configuring Gossip Encryption on an existing cluster
+
+As of version 0.8.4, Consul supports upshifting to encrypted gossip on a running cluster
+through the following process.
+
+1. Generate an encryption key using [`consul keygen`](/docs/commands/keygen.html)
+2. Set the [`encrypt`](/docs/agent/options.html#_encrypt) key in the agent configuration and set
+[`encrypt_verify_incoming`](/docs/agent/options.html#encrypt_verify_incoming) and
+[`encrypt_verify_outgoing`](/docs/agent/options.html#encrypt_verify_outgoing) to `false`, doing a
+rolling update of the cluster with these new values. After this step, the agents will be able to
+decrypt gossip but will not yet be sending encrypted traffic.
+3. Remove the [`encrypt_verify_outgoing`](/docs/agent/options.html#encrypt_verify_outgoing) setting
+to change it back to false (the default) and perform another rolling update of the cluster. The
+agents will now be sending encrypted gossip but will still allow incoming unencrypted traffic.
+4. Remove the [`encrypt_verify_incoming`](/docs/agent/options.html#encrypt_verify_incoming) setting
+to change it back to false (the default) and perform a final rolling update of the cluster. All the
+agents will now be strictly enforcing encrypted gossip.
+
 ## RPC Encryption with TLS
 
 Consul supports using TLS to verify the authenticity of servers and clients. To enable this,

website/source/docs/agent/options.html.md

@@ -708,6 +708,18 @@ Consul will not enable TLS for the HTTP API unless the `https` port has been ass
 * <a name="encrypt"></a><a href="#encrypt">`encrypt`</a> Equivalent to the
   [`-encrypt` command-line flag](#_encrypt).
 
+* <a name="encrypt_verify_incoming"></a><a href="#encrypt_verify_incoming">`encrypt_verify_incoming`</a> -
+  This is an optional parameter that can be used to disable enforcing encryption for incoming gossip in order
+  to upshift from unencrypted to encrypted gossip on a running cluster. See [this section]
+  (/docs/agent/encryption.html#configuring-gossip-encryption-on-an-existing-cluster) for more information.
+  Defaults to true.
+
+* <a name="encrypt_verify_outgoing"></a><a href="#encrypt_verify_outgoing">`encrypt_verify_outgoing`</a> -
+  This is an optional parameter that can be used to disable enforcing encryption for outgoing gossip in order
+  to upshift from unencrypted to encrypted gossip on a running cluster. See [this section]
+  (/docs/agent/encryption.html#configuring-gossip-encryption-on-an-existing-cluster) for more information.
+  Defaults to true.
+
 * <a name="key_file"></a><a href="#key_file">`key_file`</a> This provides a the file path to a
   PEM-encoded private key. The key is used with the certificate to verify the agent's authenticity.
   This must be provided along with [`cert_file`](#cert_file).