Fixes security issue & Adds support to sent configuration via email (#83)

README.md

@@ -21,6 +21,18 @@ You can take a look at this example of [docker-compose.yml](https://github.com/n
 ```
 docker-compose up
 ```
+### Environment Variables
+
+
+Set the `SESSION_SECRET` environment variable to a random value.
+
+In order to sent the wireguard configuration to clients via email (using sendgrid api) set the following environment variables
+
+```
+SENDGRID_API_KEY: Your sendgrid api key
+EMAIL_FROM: the email address you registered on sendgrid
+EMAIL_FROM_NAME: the sender's email address
+```
 
 ### Using binary file
 

custom/js/helper.js

@@ -29,6 +29,9 @@ function renderClientList(data) {
                                 <div class="btn-group">
                                     <button onclick="location.href='/download?clientid=${obj.Client.id}'" type="button"
                                         class="btn btn-outline-success btn-sm">Download</button>
+                                    <button type="button" class="btn btn-outline-warning btn-sm" data-toggle="modal"
+                                        data-target="#modal_email_client" data-clientid="${obj.Client.id}"
+                                        data-clientname="${obj.Client.name}">Email</button>
                                     <button type="button" class="btn btn-outline-primary btn-sm" data-toggle="modal"
                                         data-target="#modal_edit_client" data-clientid="${obj.Client.id}"
                                         data-clientname="${obj.Client.name}">Edit</button>

docker-compose.yaml

@@ -2,8 +2,14 @@ version: '3'
 
 services:
   wg:
-    image: ngoduykhanh/wireguard-ui:latest
+    build: .
+    #image: ngoduykhanh/wireguard-ui:latest
     container_name: wgui
+    environment:
+      - SENDGRID_API_KEY
+      - EMAIL_FROM
+      - EMAIL_FROM_NAME
+      - SESSION_SECRET
     ports:
       - 5000:5000
     logging:

emailer/interface.go

@@ -0,0 +1,10 @@
+package emailer
+
+type Attachment struct {
+	Name string
+	Data []byte
+}
+
+type Emailer interface {
+	Send(toName string, to string, subject string, content string, attachments []Attachment) error
+}

emailer/sendgrid.go

@@ -0,0 +1,54 @@
+package emailer
+
+import (
+	"encoding/base64"
+
+	"github.com/sendgrid/sendgrid-go"
+	"github.com/sendgrid/sendgrid-go/helpers/mail"
+)
+
+type SendgridApiMail struct {
+	apiKey   string
+	fromName string
+	from     string
+}
+
+func NewSendgridApiMail(apiKey, fromName, from string) *SendgridApiMail {
+	ans := SendgridApiMail{apiKey: apiKey, fromName: fromName, from: from}
+	return &ans
+}
+
+func (o *SendgridApiMail) Send(toName string, to string, subject string, content string, attachments []Attachment) error {
+	m := mail.NewV3Mail()
+
+	mailFrom := mail.NewEmail(o.fromName, o.from)
+	mailContent := mail.NewContent("text/html", content)
+	mailTo := mail.NewEmail(toName, to)
+
+	m.SetFrom(mailFrom)
+	m.AddContent(mailContent)
+
+	personalization := mail.NewPersonalization()
+	personalization.AddTos(mailTo)
+	personalization.Subject = subject
+
+	m.AddPersonalizations(personalization)
+
+	toAdd := make([]*mail.Attachment, 0, len(attachments))
+	for i := range attachments {
+		var att mail.Attachment
+		encoded := base64.StdEncoding.EncodeToString(attachments[i].Data)
+		att.SetContent(encoded)
+		att.SetType("text/plain")
+		att.SetFilename(attachments[i].Name)
+		att.SetDisposition("attachment")
+		toAdd = append(toAdd, &att)
+	}
+
+	m.AddAttachment(toAdd...)
+	request := sendgrid.GetRequest(o.apiKey, "/v3/mail/send", "https://api.sendgrid.com")
+	request.Method = "POST"
+	request.Body = mail.GetRequestBody(m)
+	_, err := sendgrid.API(request)
+	return err
+}

go.mod

@@ -14,6 +14,8 @@ require (
 	github.com/leodido/go-urn v1.2.0 // indirect
 	github.com/rs/xid v1.2.1
 	github.com/sdomino/scribble v0.0.0-20191024200645-4116320640ba
+	github.com/sendgrid/rest v2.6.4+incompatible // indirect
+	github.com/sendgrid/sendgrid-go v3.10.0+incompatible
 	github.com/skip2/go-qrcode v0.0.0-20191027152451-9434209cb086
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20200324154536-ceff61240acf
 	gopkg.in/go-playground/assert.v1 v1.2.1 // indirect

go.sum

@@ -103,6 +103,10 @@ github.com/rs/xid v1.2.1 h1:mhH9Nq+C1fY2l1XIpgxIiUOfNpRBYH1kKcr+qfKgjRc=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/sdomino/scribble v0.0.0-20191024200645-4116320640ba h1:8QAc9wFAf2b/9cAXskm0wBylObZ0bTpRcaP7ThjLPVQ=
 github.com/sdomino/scribble v0.0.0-20191024200645-4116320640ba/go.mod h1:W6zxGUBCXRR5QugSd/nFcFVmwoGnvpjiNY/JwT03Wew=
+github.com/sendgrid/rest v2.6.4+incompatible h1:lq6gAQxLwVBf3mVyCCSHI6mgF+NfaJFJHjT0kl6SSo8=
+github.com/sendgrid/rest v2.6.4+incompatible/go.mod h1:kXX7q3jZtJXK5c5qK83bSGMdV6tsOE70KbHoqJls4lE=
+github.com/sendgrid/sendgrid-go v3.10.0+incompatible h1:aSYyurHxEZSDy7kxhvZ4fH0inNkEEmRssZNbAmETR2c=
+github.com/sendgrid/sendgrid-go v3.10.0+incompatible/go.mod h1:QRQt+LX/NmgVEvmdRw0VT/QgUn499+iza2FnDca9fg8=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/skip2/go-qrcode v0.0.0-20191027152451-9434209cb086 h1:RYiqpb2ii2Z6J4x0wxK46kvPBbFuZcdhS+CIztmYgZs=
 github.com/skip2/go-qrcode v0.0.0-20191027152451-9434209cb086/go.mod h1:PLPIyL7ikehBD1OAjmKKiOEhbvWyHGaNDjquXMcYABo=

handler/routes.go

@@ -1,6 +1,7 @@
 package handler
 
 import (
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -13,6 +14,7 @@ import (
 	"github.com/labstack/echo-contrib/session"
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/gommon/log"
+	"github.com/ngoduykhanh/wireguard-ui/emailer"
 	"github.com/ngoduykhanh/wireguard-ui/model"
 	"github.com/ngoduykhanh/wireguard-ui/util"
 	"github.com/rs/xid"
@@ -77,8 +79,6 @@ func Logout() echo.HandlerFunc {
 // WireGuardClients handler
 func WireGuardClients() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		clientDataList, err := util.GetClients(true)
 		if err != nil {
@@ -97,8 +97,6 @@ func WireGuardClients() echo.HandlerFunc {
 // GetClients handler return a list of Wireguard client data
 func GetClients() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		clientDataList, err := util.GetClients(true)
 		if err != nil {
@@ -114,8 +112,6 @@ func GetClients() echo.HandlerFunc {
 // GetClient handler return a of Wireguard client data
 func GetClient() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		clientID := c.Param("id")
 		clientData, err := util.GetClientByID(clientID, true)
@@ -130,8 +126,6 @@ func GetClient() echo.HandlerFunc {
 // NewClient handler
 func NewClient() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		client := new(model.Client)
 		c.Bind(client)
@@ -194,11 +188,53 @@ func NewClient() echo.HandlerFunc {
 	}
 }
 
+// EmailClient handler to sent the configuration via email
+func EmailClient(mailer emailer.Emailer, emailSubject, emailContent string) echo.HandlerFunc {
+	type clientIdEmailPayload struct {
+		ID    string `json:"id"`
+		Email string `json:"email"`
+	}
+
+	return func(c echo.Context) error {
+		var payload clientIdEmailPayload
+		c.Bind(&payload)
+		// TODO validate email
+
+		clientData, err := util.GetClientByID(payload.ID, true)
+		if err != nil {
+			log.Errorf("Cannot generate client id %s config file for downloading: %v", payload.ID, err)
+			return c.JSON(http.StatusNotFound, jsonHTTPResponse{false, "Client not found"})
+		}
+
+		// build config
+		server, _ := util.GetServer()
+		globalSettings, _ := util.GetGlobalSettings()
+		config := util.BuildClientConfig(*clientData.Client, server, globalSettings)
+
+		cfg_att := emailer.Attachment{"wg0.conf", []byte(config)}
+		qrdata, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(clientData.QRCode, "data:image/png;base64,"))
+		if err != nil {
+			return c.JSON(http.StatusInternalServerError, jsonHTTPResponse{false, "decoding: " + err.Error()})
+		}
+		qr_att := emailer.Attachment{"wg.png", qrdata}
+		err = mailer.Send(
+			clientData.Client.Name,
+			payload.Email,
+			emailSubject,
+			emailContent,
+			[]emailer.Attachment{cfg_att, qr_att},
+		)
+		if err != nil {
+			return c.JSON(http.StatusInternalServerError, jsonHTTPResponse{false, err.Error()})
+		}
+
+		return c.JSON(http.StatusOK, jsonHTTPResponse{true, "Email sent successfully"})
+	}
+}
+
 // UpdateClient handler to update client information
 func UpdateClient() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		_client := new(model.Client)
 		c.Bind(_client)
@@ -257,8 +293,6 @@ func UpdateClient() echo.HandlerFunc {
 // SetClientStatus handler to enable / disable a client
 func SetClientStatus() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		data := make(map[string]interface{})
 		err := json.NewDecoder(c.Request().Body).Decode(&data)
@@ -320,8 +354,6 @@ func DownloadClient() echo.HandlerFunc {
 // RemoveClient handler
 func RemoveClient() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		client := new(model.Client)
 		c.Bind(client)
@@ -346,8 +378,6 @@ func RemoveClient() echo.HandlerFunc {
 // WireGuardServer handler
 func WireGuardServer() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		server, err := util.GetServer()
 		if err != nil {
@@ -365,8 +395,6 @@ func WireGuardServer() echo.HandlerFunc {
 // WireGuardServerInterfaces handler
 func WireGuardServerInterfaces() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		serverInterface := new(model.ServerInterface)
 		c.Bind(serverInterface)
@@ -396,8 +424,6 @@ func WireGuardServerInterfaces() echo.HandlerFunc {
 // WireGuardServerKeyPair handler to generate private and public keys
 func WireGuardServerKeyPair() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		// gen Wireguard key pair
 		key, err := wgtypes.GeneratePrivateKey()
@@ -428,8 +454,6 @@ func WireGuardServerKeyPair() echo.HandlerFunc {
 // GlobalSettings handler
 func GlobalSettings() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		globalSettings, err := util.GetGlobalSettings()
 		if err != nil {
@@ -446,8 +470,6 @@ func GlobalSettings() echo.HandlerFunc {
 // GlobalSettingSubmit handler to update the global settings
 func GlobalSettingSubmit() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		globalSettings := new(model.GlobalSetting)
 		c.Bind(globalSettings)
@@ -477,8 +499,6 @@ func GlobalSettingSubmit() echo.HandlerFunc {
 // MachineIPAddresses handler to get local interface ip addresses
 func MachineIPAddresses() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		// get private ip addresses
 		interfaceList, err := util.GetInterfaceIPs()
@@ -503,8 +523,6 @@ func MachineIPAddresses() echo.HandlerFunc {
 // SuggestIPAllocation handler to get the list of ip address for client
 func SuggestIPAllocation() echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		server, err := util.GetServer()
 		if err != nil {
@@ -541,8 +559,6 @@ func SuggestIPAllocation() echo.HandlerFunc {
 // ApplyServerConfig handler to write config file and restart Wireguard server
 func ApplyServerConfig(tmplBox *rice.Box) echo.HandlerFunc {
 	return func(c echo.Context) error {
-		// access validation
-		validSession(c)
 
 		server, err := util.GetServer()
 		if err != nil {

handler/session.go

@@ -9,20 +9,30 @@ import (
 	"github.com/ngoduykhanh/wireguard-ui/util"
 )
 
-// validSession to redirect user to the login page if they are not authenticated or session expired.
+func ValidSession(next echo.HandlerFunc) echo.HandlerFunc {
-func validSession(c echo.Context) {
+	return func(c echo.Context) error {
-	if !util.DisableLogin {
+		if !isValidSession(c) {
+			nextURL := c.Request().URL
+			if nextURL != nil && c.Request().Method == http.MethodGet {
+				return c.Redirect(http.StatusTemporaryRedirect, fmt.Sprintf("/login?next=%s", c.Request().URL))
+			} else {
+				return c.Redirect(http.StatusTemporaryRedirect, "/login")
+			}
+		}
+		return next(c)
+	}
+}
+
+func isValidSession(c echo.Context) bool {
+	if util.DisableLogin {
+		return true
+	}
 	sess, _ := session.Get("session", c)
 	cookie, err := c.Cookie("session_token")
 	if err != nil || sess.Values["session_token"] != cookie.Value {
-			nextURL := c.Request().URL
+		return false
-			if nextURL != nil {
-				c.Redirect(http.StatusTemporaryRedirect, fmt.Sprintf("/login?next=%s", c.Request().URL))
-			} else {
-				c.Redirect(http.StatusTemporaryRedirect, "/login")
-			}
-		}
 	}
+	return true
 }
 
 // currentUser to get username of logged in user

main.go

@@ -4,10 +4,13 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
+	"os"
 	"time"
 
 	rice "github.com/GeertJohan/go.rice"
 	"github.com/labstack/echo/v4"
+
+	"github.com/ngoduykhanh/wireguard-ui/emailer"
 	"github.com/ngoduykhanh/wireguard-ui/handler"
 	"github.com/ngoduykhanh/wireguard-ui/router"
 	"github.com/ngoduykhanh/wireguard-ui/util"
@@ -21,6 +24,15 @@ var (
 	buildTime  = fmt.Sprintf(time.Now().UTC().Format("01-02-2006 15:04:05"))
 )
 
+const (
+	defaultEmailSubject = "Your wireguard configuration"
+	defaultEmailContent = `Hi,</br>
+<p>in this email you can file your personal configuration for our wireguard server.</p>
+
+<p>Best</p>
+`
+)
+
 func init() {
 	// command-line flags
 	flagDisableLogin := flag.Bool("disable-login", false, "Disable login page. Turn off authentication.")
@@ -30,6 +42,10 @@ func init() {
 	// update runtime config
 	util.DisableLogin = *flagDisableLogin
 	util.BindAddress = *flagBindAddress
+	util.SendgridApiKey = os.Getenv("SENDGRID_API_KEY")
+	util.EmailFrom = os.Getenv("EMAIL_FROM")
+	util.EmailFromName = os.Getenv("EMAIL_FROM_NAME")
+	util.SessionSecret = []byte(os.Getenv("SESSION_SECRET"))
 
 	// print app information
 	fmt.Println("Wireguard UI")
@@ -60,31 +76,34 @@ func main() {
 	assetHandler := http.FileServer(rice.MustFindBox("assets").HTTPBox())
 
 	// register routes
-	app := router.New(tmplBox, extraData)
+	app := router.New(tmplBox, extraData, util.SessionSecret)
 
-	app.GET("/", handler.WireGuardClients())
+	app.GET("/", handler.WireGuardClients(), handler.ValidSession)
 
 	if !util.DisableLogin {
 		app.GET("/login", handler.LoginPage())
 		app.POST("/login", handler.Login())
 	}
 
-	app.GET("/logout", handler.Logout())
+	sendmail := emailer.NewSendgridApiMail(util.SendgridApiKey, util.EmailFromName, util.EmailFrom)
-	app.POST("/new-client", handler.NewClient())
+
-	app.POST("/update-client", handler.UpdateClient())
+	app.GET("/logout", handler.Logout(), handler.ValidSession)
-	app.POST("/client/set-status", handler.SetClientStatus())
+	app.POST("/new-client", handler.NewClient(), handler.ValidSession)
-	app.POST("/remove-client", handler.RemoveClient())
+	app.POST("/update-client", handler.UpdateClient(), handler.ValidSession)
-	app.GET("/download", handler.DownloadClient())
+	app.POST("/email-client", handler.EmailClient(sendmail, defaultEmailSubject, defaultEmailContent), handler.ValidSession)
-	app.GET("/wg-server", handler.WireGuardServer())
+	app.POST("/client/set-status", handler.SetClientStatus(), handler.ValidSession)
-	app.POST("wg-server/interfaces", handler.WireGuardServerInterfaces())
+	app.POST("/remove-client", handler.RemoveClient(), handler.ValidSession)
-	app.POST("wg-server/keypair", handler.WireGuardServerKeyPair())
+	app.GET("/download", handler.DownloadClient(), handler.ValidSession)
-	app.GET("/global-settings", handler.GlobalSettings())
+	app.GET("/wg-server", handler.WireGuardServer(), handler.ValidSession)
-	app.POST("/global-settings", handler.GlobalSettingSubmit())
+	app.POST("wg-server/interfaces", handler.WireGuardServerInterfaces(), handler.ValidSession)
-	app.GET("/api/clients", handler.GetClients())
+	app.POST("wg-server/keypair", handler.WireGuardServerKeyPair(), handler.ValidSession)
-	app.GET("/api/client/:id", handler.GetClient())
+	app.GET("/global-settings", handler.GlobalSettings(), handler.ValidSession)
-	app.GET("/api/machine-ips", handler.MachineIPAddresses())
+	app.POST("/global-settings", handler.GlobalSettingSubmit(), handler.ValidSession)
-	app.GET("/api/suggest-client-ips", handler.SuggestIPAllocation())
+	app.GET("/api/clients", handler.GetClients(), handler.ValidSession)
-	app.GET("/api/apply-wg-config", handler.ApplyServerConfig(tmplBox))
+	app.GET("/api/client/:id", handler.GetClient(), handler.ValidSession)
+	app.GET("/api/machine-ips", handler.MachineIPAddresses(), handler.ValidSession)
+	app.GET("/api/suggest-client-ips", handler.SuggestIPAllocation(), handler.ValidSession)
+	app.GET("/api/apply-wg-config", handler.ApplyServerConfig(tmplBox), handler.ValidSession)
 
 	// servers other static files
 	app.GET("/static/*", echo.WrapHandler(http.StripPrefix("/static/", assetHandler)))

router/router.go

@@ -6,7 +6,7 @@ import (
 	"reflect"
 	"text/template"
 
-	"github.com/GeertJohan/go.rice"
+	rice "github.com/GeertJohan/go.rice"
 	"github.com/gorilla/sessions"
 	"github.com/labstack/echo-contrib/session"
 	"github.com/labstack/echo/v4"
@@ -44,9 +44,9 @@ func (t *TemplateRegistry) Render(w io.Writer, name string, data interface{}, c
 }
 
 // New function
-func New(tmplBox *rice.Box, extraData map[string]string) *echo.Echo {
+func New(tmplBox *rice.Box, extraData map[string]string, secret []byte) *echo.Echo {
 	e := echo.New()
-	e.Use(session.Middleware(sessions.NewCookieStore([]byte("secret"))))
+	e.Use(session.Middleware(sessions.NewCookieStore(secret)))
 
 	// read html template file to string
 	tmplBaseString, err := tmplBox.String("base.html")

templates/clients.html

@@ -30,6 +30,34 @@ Wireguard Clients
     </div>
 </section>
 
+<div class="modal fade" id="modal_email_client">
+    <div class="modal-dialog">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h4 class="modal-title">Email Configuration</h4>
+                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
+                    <span aria-hidden="true">&times;</span>
+                </button>
+            </div>
+            <form name="frm_email_client" id="frm_email_client">
+                <div class="modal-body">
+                    <input type="hidden" id="_client_id" name="_client_id">
+                    <div class="form-group">
+                        <label for="_client_email" class="control-label">Email</label>
+                        <input type="text" class="form-control" id="_client_email" name="client_email">
+                    </div>
+                </div>
+                <div class="modal-footer justify-content-between">
+                    <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
+                    <button type="submit" class="btn btn-success">Send</button>
+                </div>
+            </form>
+        </div>
+        <!-- /.modal-content -->
+    </div>
+    <!-- /.modal-dialog -->
+</div>
+
 <div class="modal fade" id="modal_edit_client">
     <div class="modal-dialog">
         <div class="modal-content">
@@ -243,6 +271,8 @@ Wireguard Clients
             });
         });
 
+
+
         // Edit client modal event
         $(document).ready(function () {
             $("#modal_edit_client").on('shown.bs.modal', function (event) {
@@ -308,6 +338,31 @@ Wireguard Clients
             });
         });
 
+        // submitEmailClient function for sending an email to the client with the configuration
+        function submitEmailClient() {
+            const client_id = $("#_client_id").val();
+            const email = $("#_client_email").val();
+            const data = {"id": client_id, "email": email};
+            $.ajax({
+                cache: false,
+                method: 'POST',
+                url: '/email-client',
+                dataType: 'json',
+                contentType: "application/json",
+                data: JSON.stringify(data),
+                success: function(resp) {
+                    $("#modal_email_client").modal('hide');
+                    toastr.success('Sent email to client successfully');
+                     // Refresh the home page (clients page) after sending email successfully
+                    location.reload();
+                },
+                error: function(jqXHR, exception) {
+                    const responseJson = jQuery.parseJSON(jqXHR.responseText);
+                    toastr.error(responseJson['message']);
+                }
+            });
+        }
+
         // submitEditClient function for updating an existing client
         function submitEditClient() {
             const client_id = $("#_client_id").val();
@@ -350,13 +405,48 @@ Wireguard Clients
             });
         }
 
-        // Edit client form validation
+        // submitHandler
-        $(document).ready(function () {
+        function submitHandler(form) {
-            $.validator.setDefaults({
+            const formId = $(form).attr('id');
-                submitHandler: function () {
+            if (formId === "frm_edit_client") {
                 submitEditClient();
+            }else if (formId === "frm_email_client") {
+                submitEmailClient();
+            }
+        }
+
+        $("#modal_email_client").on('shown.bs.modal', function (event) {
+            let modal = $(this);
+            const button = $(event.relatedTarget);
+            const client_id = button.data('clientid');
+            $.ajax({
+                cache: false,
+                method: 'GET',
+                url: '/api/client/' + client_id,
+                dataType: 'json',
+                contentType: "application/json",
+                success: function (resp) {
+                    const client = resp.Client;
+
+                    modal.find(".modal-title").text("Email Client " + client.name);
+                    modal.find("#_client_id").val(client.id);
+                    modal.find("#_client_email").val(client.email);
+                },
+                error: function (jqXHR, exception) {
+                    const responseJson = jQuery.parseJSON(jqXHR.responseText);
+                    toastr.error(responseJson['message']);
                 }
             });
+        });
+
+        $(document).ready(function () {
+            $.validator.setDefaults({
+                submitHandler: function (form) {
+                    //submitEditClient();
+                    submitHandler(form);
+                }
+            });
+            // Edit client form validation
                 $("#frm_edit_client").validate({
                     rules: {
                         client_name: {
@@ -388,6 +478,33 @@ Wireguard Clients
                         $(element).removeClass('is-invalid');
                     }
                 });
+
+                // Email client form validation
+                $("#frm_email_client").validate({
+                rules: {
+                    client_email: {
+                        required: true,
+                        email: true,
+                    },
+                },
+                messages: {
+                    client_email: {
+                        required: "Please enter an email address",
+                        email: "Please enter a valid email address"
+                    },
+                },
+                errorElement: 'span',
+                errorPlacement: function (error, element) {
+                    error.addClass('invalid-feedback');
+                    element.closest('.form-group').append(error);
+                },
+                highlight: function (element, errorClass, validClass) {
+                    $(element).addClass('is-invalid');
+                },
+                unhighlight: function (element, errorClass, validClass) {
+                    $(element).removeClass('is-invalid');
+                }
+            });
         });
     </script>
 {{end}}

util/config.go

@@ -4,4 +4,10 @@ package util
 var (
 	DisableLogin   bool
 	BindAddress    string
+	SendgridApiKey string
+	EmailFrom      string
+	EmailFromName  string
+	EmailSubject   string
+	EmailContent   string
+	SessionSecret  []byte
 )