From 0157ea6276fd0eb838e71487f7b3bdc149153372 Mon Sep 17 00:00:00 2001
From: Tom Jason Schwanke <tom@catboys.cloud>
Date: Tue, 17 Sep 2024 21:23:35 +0200
Subject: [PATCH] Mqtt: add mTLS authentication using certificates to MQTT
 (#15563)

---
 assets/js/components/Config/MqttModal.vue     | 21 ++++++-
 .../components/Config/PropertyCertField.vue   | 55 +++++++++++++++++++
 cmd/configure/helper.go                       | 17 ++++--
 cmd/setup.go                                  |  2 +-
 i18n/de.toml                                  |  4 ++
 i18n/en.toml                                  |  4 ++
 provider/mqtt/client.go                       | 35 +++++++++---
 provider/mqtt/registry.go                     |  6 +-
 util/templates/includes/mqtt.tpl              |  9 +++
 9 files changed, 136 insertions(+), 17 deletions(-)
 create mode 100644 assets/js/components/Config/PropertyCertField.vue

diff --git a/assets/js/components/Config/MqttModal.vue b/assets/js/components/Config/MqttModal.vue
index ee22621aa..8949d5d52 100644
--- a/assets/js/components/Config/MqttModal.vue
+++ b/assets/js/components/Config/MqttModal.vue
@@ -63,6 +63,23 @@
 					</label>
 				</div>
 			</FormRow>
+			<PropertyCollapsible>
+				<template #advanced>
+					<FormRow id="mqttCaCert" :label="$t('config.mqtt.labelCaCert')" optional>
+						<PropertyCertField id="mqttCaCert" v-model="values.caCert" />
+					</FormRow>
+					<FormRow
+						id="mqttClientCert"
+						:label="$t('config.mqtt.labelClientCert')"
+						optional
+					>
+						<PropertyCertField id="mqttClientCert" v-model="values.clientCert" />
+					</FormRow>
+					<FormRow id="mqttClientKey" :label="$t('config.mqtt.labelClientKey')" optional>
+						<PropertyCertField id="mqttClientKey" v-model="values.clientKey" />
+					</FormRow>
+				</template>
+			</PropertyCollapsible>
 		</template>
 	</JsonModal>
 </template>
@@ -70,10 +87,12 @@
 <script>
 import JsonModal from "./JsonModal.vue";
 import FormRow from "./FormRow.vue";
+import PropertyCollapsible from "./PropertyCollapsible.vue";
+import PropertyCertField from "./PropertyCertField.vue";
 
 export default {
 	name: "MqttModal",
-	components: { FormRow, JsonModal },
+	components: { FormRow, JsonModal, PropertyCollapsible, PropertyCertField },
 	emits: ["changed"],
 };
 </script>
diff --git a/assets/js/components/Config/PropertyCertField.vue b/assets/js/components/Config/PropertyCertField.vue
new file mode 100644
index 000000000..9a470115c
--- /dev/null
+++ b/assets/js/components/Config/PropertyCertField.vue
@@ -0,0 +1,55 @@
+<template>
+	<div>
+		<textarea :id="id" v-model="value" class="form-control" rows="3" />
+		<div class="d-flex justify-content-end">
+			<button
+				type="button"
+				class="btn btn-link btn-sm text-muted pe-0"
+				@click="openFilePicker"
+			>
+				{{ $t("config.general.readFromFile") }}
+			</button>
+			<input
+				type="file"
+				ref="fileInput"
+				class="d-none"
+				@change="readFile"
+				accept=".crt,.pem,.cer,.csr,.key"
+			/>
+		</div>
+	</div>
+</template>
+
+<script>
+export default {
+	name: "PropertyCertField",
+	props: {
+		id: String,
+		modelValue: String,
+	},
+	emits: ["update:modelValue"],
+	computed: {
+		value: {
+			get() {
+				return this.modelValue;
+			},
+			set(value) {
+				this.$emit("update:modelValue", value);
+			},
+		},
+	},
+	methods: {
+		openFilePicker() {
+			this.$refs.fileInput.click();
+		},
+		readFile(event) {
+			const file = event.target.files[0];
+			const reader = new FileReader();
+			reader.onload = (e) => {
+				this.value = e.target.result;
+			};
+			reader.readAsText(file);
+		},
+	},
+};
+</script>
diff --git a/cmd/configure/helper.go b/cmd/configure/helper.go
index 8474df914..de356db2e 100644
--- a/cmd/configure/helper.go
+++ b/cmd/configure/helper.go
@@ -238,11 +238,17 @@ func (c *CmdConfigure) configureMQTT(_ templates.Template) (map[string]interface
 		_, paramPort := templates.ConfigDefaults.ParamByName("port")
 		_, paramUser := templates.ConfigDefaults.ParamByName("user")
 		_, paramPassword := templates.ConfigDefaults.ParamByName("password")
+		_, paramCaCert := templates.ConfigDefaults.ParamByName("caCert")
+		_, paramClientCert := templates.ConfigDefaults.ParamByName("clientCert")
+		_, paramClientKey := templates.ConfigDefaults.ParamByName("clientKey")
 
 		host := c.askParam(paramHost)
 		port := c.askParam(paramPort)
 		user := c.askParam(paramUser)
 		password := c.askParam(paramPassword)
+		caCert := c.askParam(paramCaCert)
+		clientCert := c.askParam(paramClientCert)
+		clientKey := c.askParam(paramClientKey)
 
 		fmt.Println()
 		fmt.Println("--------------------------------------------")
@@ -250,14 +256,17 @@ func (c *CmdConfigure) configureMQTT(_ templates.Template) (map[string]interface
 		broker := fmt.Sprintf("%s:%s", host, port)
 
 		mqttConfig := map[string]interface{}{
-			"broker":   broker,
-			"user":     user,
-			"password": password,
+			"broker":     broker,
+			"user":       user,
+			"password":   password,
+			"caCert":     caCert,
+			"clientCert": clientCert,
+			"clientKey":  clientKey,
 		}
 
 		log := util.NewLogger("mqtt")
 
-		if mqtt.Instance, err = mqtt.RegisteredClient(log, broker, user, password, "", 1, false); err == nil {
+		if mqtt.Instance, err = mqtt.RegisteredClient(log, broker, user, password, "", 1, false, caCert, clientCert, clientKey); err == nil {
 			return mqttConfig, nil
 		}
 
diff --git a/cmd/setup.go b/cmd/setup.go
index 96011aead..e09688280 100644
--- a/cmd/setup.go
+++ b/cmd/setup.go
@@ -597,7 +597,7 @@ func configureMqtt(conf *globalconfig.Mqtt) error {
 
 	log := util.NewLogger("mqtt")
 
-	instance, err := mqtt.RegisteredClient(log, conf.Broker, conf.User, conf.Password, conf.ClientID, 1, conf.Insecure, func(options *paho.ClientOptions) {
+	instance, err := mqtt.RegisteredClient(log, conf.Broker, conf.User, conf.Password, conf.ClientID, 1, conf.Insecure, conf.CaCert, conf.ClientCert, conf.ClientKey, func(options *paho.ClientOptions) {
 		topic := fmt.Sprintf("%s/status", strings.Trim(conf.Topic, "/"))
 		options.SetWill(topic, "offline", 1, true)
 
diff --git a/i18n/de.toml b/i18n/de.toml
index 4c3588721..5410fabbf 100644
--- a/i18n/de.toml
+++ b/i18n/de.toml
@@ -93,6 +93,7 @@ experimental = "Experimentell"
 off = "aus"
 on = "an"
 password = "Passwort"
+readFromFile = "Aus Datei lesen"
 remove = "Entfernen"
 save = "Speichern"
 telemetry = "Telemetrie"
@@ -155,8 +156,11 @@ description = "Verbinde evcc mit einem MQTT-Broker, um Daten mit anderen Systeme
 descriptionClientId = "Autor der Nachrichten. Wenn leer, wird `evcc-[rand]` verwendet."
 descriptionTopic = "Leer lassen, um das Publizieren zu deaktivieren."
 labelBroker = "Broker"
+labelCaCert = "Serverzertifikat (CA)"
 labelCheckInsecure = "Erlaube unsichere Verbindungen"
+labelClientCert = "Clientzertifikat"
 labelClientId = "Client ID"
+labelClientKey = "Client-Key"
 labelInsecure = "Zertifikatüberprüfung"
 labelPassword = "Passwort"
 labelTopic = "Thema"
diff --git a/i18n/en.toml b/i18n/en.toml
index 55d170fcc..5d9b81f56 100644
--- a/i18n/en.toml
+++ b/i18n/en.toml
@@ -93,6 +93,7 @@ experimental = "Experimental"
 off = "off"
 on = "on"
 password = "Password"
+readFromFile = "Read from file"
 remove = "Remove"
 save = "Save"
 telemetry = "Telemetry"
@@ -154,8 +155,11 @@ description = "Connect to an MQTT broker to exchange data with other systems on
 descriptionClientId = "Author of the messages. If empty `evcc-[rand]` is used."
 descriptionTopic = "Leave empty to disable publishing."
 labelBroker = "Broker"
+labelCaCert = "Server certificate (CA)"
 labelCheckInsecure = "Allow self-signed certificates"
+labelClientCert = "Client certificate"
 labelClientId = "Client ID"
+labelClientKey = "Client key"
 labelInsecure = "Certificate validation"
 labelPassword = "Password"
 labelTopic = "Topic"
diff --git a/provider/mqtt/client.go b/provider/mqtt/client.go
index c8b195739..35cb2d416 100644
--- a/provider/mqtt/client.go
+++ b/provider/mqtt/client.go
@@ -2,6 +2,7 @@ package mqtt
 
 import (
 	"crypto/tls"
+	"crypto/x509"
 	"fmt"
 	"math/rand/v2"
 	"strings"
@@ -25,11 +26,14 @@ func ClientID() string {
 
 // Config is the public configuration
 type Config struct {
-	Broker   string `json:"broker"`
-	User     string `json:"user"`
-	Password string `json:"password"`
-	ClientID string `json:"clientID"`
-	Insecure bool   `json:"insecure"`
+	Broker     string `json:"broker"`
+	User       string `json:"user"`
+	Password   string `json:"password"`
+	ClientID   string `json:"clientID"`
+	Insecure   bool   `json:"insecure"`
+	CaCert     string `json:"caCert"`
+	ClientCert string `json:"clientCert"`
+	ClientKey  string `json:"clientKey"`
 }
 
 // Client encapsulates mqtt publish/subscribe functions
@@ -48,7 +52,7 @@ type Option func(*paho.ClientOptions)
 const secure = "tls://"
 
 // NewClient creates new Mqtt publisher
-func NewClient(log *util.Logger, broker, user, password, clientID string, qos byte, insecure bool, opts ...Option) (*Client, error) {
+func NewClient(log *util.Logger, broker, user, password, clientID string, qos byte, insecure bool, caCert, clientCert, clientKey string, opts ...Option) (*Client, error) {
 	broker, isSecure := strings.CutPrefix(broker, secure)
 
 	// strip schema as it breaks net.SplitHostPort
@@ -74,9 +78,24 @@ func NewClient(log *util.Logger, broker, user, password, clientID string, qos by
 	options.SetConnectionLostHandler(mc.ConnectionLostHandler)
 	options.SetConnectTimeout(request.Timeout)
 
-	if insecure {
-		options.SetTLSConfig(&tls.Config{InsecureSkipVerify: true})
+	tlsConfig := &tls.Config{
+		InsecureSkipVerify: insecure,
 	}
+	if caCert != "" {
+		caCertPool := x509.NewCertPool()
+		if ok := caCertPool.AppendCertsFromPEM([]byte(caCert)); !ok {
+			return nil, fmt.Errorf("failed to add ca cert to cert pool")
+		}
+		tlsConfig.RootCAs = caCertPool
+	}
+	if clientCert != "" && clientKey != "" {
+		clientKeyPair, err := tls.X509KeyPair([]byte(clientCert), []byte(clientKey))
+		if err != nil {
+			return nil, fmt.Errorf("failed to add client cert: %w", err)
+		}
+		tlsConfig.Certificates = []tls.Certificate{clientKeyPair}
+	}
+	options.SetTLSConfig(tlsConfig)
 
 	// additional options
 	for _, o := range opts {
diff --git a/provider/mqtt/registry.go b/provider/mqtt/registry.go
index a24ff4452..fdb86cdce 100644
--- a/provider/mqtt/registry.go
+++ b/provider/mqtt/registry.go
@@ -31,7 +31,7 @@ var (
 )
 
 // RegisteredClient reuses an registered Mqtt publisher or creates a new one
-func RegisteredClient(log *util.Logger, broker, user, password, clientID string, qos byte, insecure bool, opts ...Option) (*Client, error) {
+func RegisteredClient(log *util.Logger, broker, user, password, clientID string, qos byte, insecure bool, caCert, clientCert, clientKey string, opts ...Option) (*Client, error) {
 	key := fmt.Sprintf("%s.%s:%s", broker, user, password)
 
 	mu.Lock()
@@ -42,7 +42,7 @@ func RegisteredClient(log *util.Logger, broker, user, password, clientID string,
 			clientID = ClientID()
 		}
 
-		if client, err = NewClient(log, broker, user, password, clientID, qos, insecure, opts...); err == nil {
+		if client, err = NewClient(log, broker, user, password, clientID, qos, insecure, caCert, clientCert, clientKey, opts...); err == nil {
 			registry.Add(key, client)
 		}
 	}
@@ -57,7 +57,7 @@ func RegisteredClientOrDefault(log *util.Logger, cc Config) (*Client, error) {
 
 	var err error
 	if cc.Broker != "" {
-		client, err = RegisteredClient(log, cc.Broker, cc.User, cc.Password, cc.ClientID, 1, cc.Insecure)
+		client, err = RegisteredClient(log, cc.Broker, cc.User, cc.Password, cc.ClientID, 1, cc.Insecure, cc.CaCert, cc.ClientCert, cc.ClientKey)
 	}
 
 	if client == nil && err == nil {
diff --git a/util/templates/includes/mqtt.tpl b/util/templates/includes/mqtt.tpl
index 35f091278..4200a544b 100644
--- a/util/templates/includes/mqtt.tpl
+++ b/util/templates/includes/mqtt.tpl
@@ -9,4 +9,13 @@ password: {{ .password }}
 {{- if ne .timeout "30s" }}
 timeout: {{ .timeout }}
 {{- end }}
+{{- if .caCert }}
+caCert: {{ .caCert }}
+{{- end }}
+{{- if .clientCert }}
+clientCert: {{ .clientCert }}
+{{- end }}
+{{- if .clientKey }}
+clientKey: {{ .clientKey }}
+{{- end }}
 {{- end }}