Implement mail functioning / handling and sending from golang via API

2026-04-11 13:47:05 +02:00 · 2025-01-30 11:00:14 +01:00
parent ed95571b39
commit 77e6e8cf9d
4 changed files with 342 additions and 108 deletions
--- a/internal/config/settings.go
+++ b/internal/config/settings.go
@@ -28,22 +28,32 @@ import (
 	"sync"
 )

-// AppSettings holds both the UI settings (like language) and
-// relevant Fail2ban jail/local config options.
-type AppSettings struct {
-	Language       string   `json:"language"`
-	Debug          bool     `json:"debug"`
-	ReloadNeeded   bool     `json:"reloadNeeded"`
-	AlertCountries []string `json:"alertCountries"`
+// SMTPSettings holds the SMTP server configuration for sending alert emails
+type SMTPSettings struct {
+	Host     string `json:"host"`
+	Port     int    `json:"port"`
+	Username string `json:"username"`
+	Password string `json:"password"`
+	From     string `json:"from"`
+	UseTLS   bool   `json:"useTLS"`
+}

-	// These mirror some Fail2ban [DEFAULT] section parameters from jail.local
+// AppSettings holds the main UI settings and Fail2ban configuration
+type AppSettings struct {
+	Language       string       `json:"language"`
+	Debug          bool         `json:"debug"`
+	ReloadNeeded   bool         `json:"reloadNeeded"`
+	AlertCountries []string     `json:"alertCountries"`
+	SMTP           SMTPSettings `json:"smtp"`
+
+	// Fail2Ban [DEFAULT] section values from jail.local
 	BantimeIncrement bool   `json:"bantimeIncrement"`
 	IgnoreIP         string `json:"ignoreip"`
 	Bantime          string `json:"bantime"`
 	Findtime         string `json:"findtime"`
 	Maxretry         int    `json:"maxretry"`
 	Destemail        string `json:"destemail"`
-	Sender           string `json:"sender"`
+	//Sender           string `json:"sender"`
 }

 // init paths to key-files
@@ -88,7 +98,7 @@ func setDefaults() {
 		currentSettings.Language = "en"
 	}
 	if currentSettings.AlertCountries == nil {
-		currentSettings.AlertCountries = []string{"all"}
+		currentSettings.AlertCountries = []string{"ALL"}
 	}
 	if currentSettings.Bantime == "" {
 		currentSettings.Bantime = "48h"
@@ -100,10 +110,25 @@ func setDefaults() {
 		currentSettings.Maxretry = 3
 	}
 	if currentSettings.Destemail == "" {
-		currentSettings.Destemail = "alerts@swissmakers.ch"
+		currentSettings.Destemail = "alerts@example.com"
 	}
-	if currentSettings.Sender == "" {
-		currentSettings.Sender = "noreply@swissmakers.ch"
+	if currentSettings.SMTP.Host == "" {
+		currentSettings.SMTP.Host = "smtp.office365.com"
+	}
+	if currentSettings.SMTP.Port == 0 {
+		currentSettings.SMTP.Port = 587
+	}
+	if currentSettings.SMTP.Username == "" {
+		currentSettings.SMTP.Username = "noreply@swissmakers.ch"
+	}
+	if currentSettings.SMTP.Password == "" {
+		currentSettings.SMTP.Password = "password"
+	}
+	if currentSettings.SMTP.From == "" {
+		currentSettings.SMTP.From = "noreply@swissmakers.ch"
+	}
+	if !currentSettings.SMTP.UseTLS {
+		currentSettings.SMTP.UseTLS = true
 	}
 	if currentSettings.IgnoreIP == "" {
 		currentSettings.IgnoreIP = "127.0.0.1/8 ::1"
@@ -151,9 +176,9 @@ func initializeFromJailFile() error {
 	if val, ok := settings["destemail"]; ok {
 		currentSettings.Destemail = val
 	}
-	if val, ok := settings["sender"]; ok {
+	/*if val, ok := settings["sender"]; ok {
 		currentSettings.Sender = val
-	}
+	}*/

 	return nil
 }
@@ -379,9 +404,10 @@ func UpdateSettings(new AppSettings) (AppSettings, error) {
 		old.IgnoreIP != new.IgnoreIP ||
 		old.Bantime != new.Bantime ||
 		old.Findtime != new.Findtime ||
-		old.Maxretry != new.Maxretry ||
+		//old.Maxretry != new.Maxretry ||
 		old.Destemail != new.Destemail ||
-		old.Sender != new.Sender {
+		//old.Sender != new.Sender {
+		old.Maxretry != new.Maxretry {
 		new.ReloadNeeded = true
 	} else {
 		// preserve previous ReloadNeeded if it was already true
--- a/pkg/web/handlers.go
+++ b/pkg/web/handlers.go
@@ -17,13 +17,14 @@
 package web

 import (
-	"bytes"
+	"crypto/tls"
+	"errors"
 	"fmt"
 	"log"
 	"net"
 	"net/http"
+	"net/smtp"
 	"os"
-	"os/exec"
 	"strings"
 	"time"

@@ -195,40 +196,6 @@ func shouldAlertForCountry(country string, alertCountries []string) bool {
 	return false
 }

-// sendBanAlert sends an email notification for a banned IP.
-func sendBanAlert(ip, jail, hostname, failures, whois, logs, country string, settings config.AppSettings) error {
-	// Construct email content
-	emailBody := fmt.Sprintf(`Subject: [Fail2Ban] %s: banned %s from %s
-Date: `+"`LC_ALL=C date +\"%%a, %%d %%h %%Y %%T %%z\"`"+`
-From: %s <%s>
-To: %s
-
-Hi,
-
-The IP %s has just been banned by Fail2Ban after %s attempts against %s.
-
-📍 Country: %s
-🔍 Whois Info: 
-%s
-
-📄 Log Entries:
-%s
-
-Best Regards,
-Fail2Ban
-`, jail, ip, hostname, settings.Sender, settings.Sender, settings.Destemail, ip, failures, jail, country, whois, logs)
-
-	// Use msmtp or sendmail to send email
-	cmd := exec.Command("/usr/sbin/sendmail", "-f", settings.Sender, settings.Destemail)
-	cmd.Stdin = bytes.NewBufferString(emailBody)
-
-	if err := cmd.Run(); err != nil {
-		return fmt.Errorf("failed to send email: %w", err)
-	}
-
-	return nil
-}
-
 func sortByTimeDesc(events []fail2ban.BanEvent) {
 	for i := 0; i < len(events); i++ {
 		for j := i + 1; j < len(events); j++ {
@@ -395,7 +362,7 @@ func ApplyFail2banSettings(jailLocalPath string) error {
 		fmt.Sprintf("findtime = %s", s.Findtime),
 		fmt.Sprintf("maxretry = %d", s.Maxretry),
 		fmt.Sprintf("destemail = %s", s.Destemail),
-		fmt.Sprintf("sender = %s", s.Sender),
+		//fmt.Sprintf("sender = %s", s.Sender),
 		"",
 	}
 	content := strings.Join(newLines, "\n")
@@ -427,3 +394,200 @@ func ReloadFail2banHandler(c *gin.Context) {
 	}
 	c.JSON(http.StatusOK, gin.H{"message": "Fail2ban reloaded successfully"})
 }
+
+// *******************************************************************
+// *                 Unified Email Sending Function :                *
+// *******************************************************************
+func sendEmail(to, subject, body string, settings config.AppSettings) error {
+	// Validate SMTP settings
+	if settings.SMTP.Host == "" || settings.SMTP.Username == "" || settings.SMTP.Password == "" || settings.SMTP.From == "" {
+		return errors.New("SMTP settings are incomplete. Please configure all required fields")
+	}
+
+	// Format message with **correct HTML headers**
+	message := fmt.Sprintf("From: %s\nTo: %s\nSubject: %s\n"+
+		"MIME-Version: 1.0\nContent-Type: text/html; charset=\"UTF-8\"\n\n%s",
+		settings.SMTP.From, to, subject, body)
+	msg := []byte(message)
+
+	// SMTP Connection Config
+	smtpHost := settings.SMTP.Host
+	smtpPort := settings.SMTP.Port
+	auth := LoginAuth(settings.SMTP.Username, settings.SMTP.Password)
+	smtpAddr := fmt.Sprintf("%s:%d", smtpHost, smtpPort)
+
+	// **Choose Connection Type**
+	if smtpPort == 465 {
+		// SMTPS (Implicit TLS) - Not supported at the moment.
+		tlsConfig := &tls.Config{ServerName: smtpHost}
+		conn, err := tls.Dial("tcp", smtpAddr, tlsConfig)
+		if err != nil {
+			return fmt.Errorf("failed to connect via TLS: %w", err)
+		}
+		defer conn.Close()
+
+		client, err := smtp.NewClient(conn, smtpHost)
+		if err != nil {
+			return fmt.Errorf("failed to create SMTP client: %w", err)
+		}
+		defer client.Quit()
+
+		if err := client.Auth(auth); err != nil {
+			return fmt.Errorf("SMTP authentication failed: %w", err)
+		}
+
+		return sendSMTPMessage(client, settings.SMTP.From, to, msg)
+
+	} else if smtpPort == 587 {
+		// STARTTLS (Explicit TLS)
+		conn, err := net.Dial("tcp", smtpAddr)
+		if err != nil {
+			return fmt.Errorf("failed to connect to SMTP server: %w", err)
+		}
+		defer conn.Close()
+
+		client, err := smtp.NewClient(conn, smtpHost)
+		if err != nil {
+			return fmt.Errorf("failed to create SMTP client: %w", err)
+		}
+		defer client.Quit()
+
+		// Start TLS Upgrade
+		tlsConfig := &tls.Config{ServerName: smtpHost}
+		if err := client.StartTLS(tlsConfig); err != nil {
+			return fmt.Errorf("failed to start TLS: %w", err)
+		}
+
+		if err := client.Auth(auth); err != nil {
+			return fmt.Errorf("SMTP authentication failed: %w", err)
+		}
+
+		return sendSMTPMessage(client, settings.SMTP.From, to, msg)
+	}
+
+	return errors.New("unsupported SMTP port. Use 587 (STARTTLS) or 465 (SMTPS)")
+}
+
+// Helper Function to Send SMTP Message
+func sendSMTPMessage(client *smtp.Client, from, to string, msg []byte) error {
+	// Set sender & recipient
+	if err := client.Mail(from); err != nil {
+		return fmt.Errorf("failed to set sender: %w", err)
+	}
+	if err := client.Rcpt(to); err != nil {
+		return fmt.Errorf("failed to set recipient: %w", err)
+	}
+
+	// Send email body
+	wc, err := client.Data()
+	if err != nil {
+		return fmt.Errorf("failed to start data command: %w", err)
+	}
+	defer wc.Close()
+
+	if _, err = wc.Write(msg); err != nil {
+		return fmt.Errorf("failed to write email content: %w", err)
+	}
+
+	// Close connection
+	client.Quit()
+	return nil
+}
+
+// *******************************************************************
+// *                      sendBanAlert Function :                    *
+// *******************************************************************
+func sendBanAlert(ip, jail, hostname, failures, whois, logs, country string, settings config.AppSettings) error {
+	subject := fmt.Sprintf("[Fail2Ban] %s: banned %s from %s", jail, ip, hostname)
+
+	// Ensure HTML email format
+	body := fmt.Sprintf(`<!DOCTYPE html>
+	<html>
+	<head>
+	<meta charset="UTF-8">
+	<title>Fail2Ban Alert</title>
+	<style>
+		body { font-family: Arial, sans-serif; background-color: #f4f4f4; margin: 0; padding: 0; }
+		.container { max-width: 600px; margin: 20px auto; background: #ffffff; padding: 20px; border-radius: 8px; box-shadow: 0px 2px 4px rgba(0,0,0,0.1); }
+		h2 { color: #d9534f; }
+		.details { background: #f9f9f9; padding: 15px; border-left: 4px solid #d9534f; margin-bottom: 10px; }
+		.footer { text-align: center; color: #888; font-size: 12px; padding-top: 10px; border-top: 1px solid #ddd; }
+		.label { font-weight: bold; color: #333; }
+		pre { background: #eee; padding: 10px; border-radius: 5px; overflow-x: auto; }
+	</style>
+	</head>
+	<body>
+		<div class="container">
+			<h2>🚨 Fail2Ban Alert</h2>
+			<p>A new IP has been banned due to excessive failed login attempts.</p>
+			<div class="details">
+				<p><span class="label">📌 Banned IP:</span> %s</p>
+				<p><span class="label">🛡️ Jail Name:</span> %s</p>
+				<p><span class="label">🏠 Hostname:</span> %s</p>
+				<p><span class="label">🚫 Failed Attempts:</span> %s</p>
+				<p><span class="label">🌍 Country:</span> %s</p>
+			</div>
+			<h3>🔍 Whois Information:</h3>
+			<pre>%s</pre>
+			<h3>📄 Log Entries:</h3>
+			<pre>%s</pre>
+			<p class="footer">This email was generated automatically by Fail2Ban. If you believe this was a mistake, please review your security settings.</p>
+		</div>
+	</body>
+	</html>`, ip, jail, hostname, failures, country, whois, logs)
+
+	// Send the email
+	return sendEmail(settings.Destemail, subject, body, settings)
+}
+
+// *******************************************************************
+// *               TestEmailHandler to send test-mail :              *
+// *******************************************************************
+func TestEmailHandler(c *gin.Context) {
+	settings := config.GetSettings()
+
+	err := sendEmail(
+		settings.Destemail,
+		"Test Email from Fail2Ban UI",
+		"This is a test email sent from the Fail2Ban UI to verify SMTP settings.",
+		settings,
+	)
+
+	if err != nil {
+		log.Printf("❌ Test email failed: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to send test email: " + err.Error()})
+		return
+	}
+
+	log.Println("✅ Test email sent successfully!")
+	c.JSON(http.StatusOK, gin.H{"message": "Test email sent successfully!"})
+}
+
+// *******************************************************************
+// *                 Office365 LOGIN Authentication :                *
+// *******************************************************************
+type loginAuth struct {
+	username, password string
+}
+
+func LoginAuth(username, password string) smtp.Auth {
+	return &loginAuth{username, password}
+}
+
+func (a *loginAuth) Start(server *smtp.ServerInfo) (string, []byte, error) {
+	return "LOGIN", []byte(a.username), nil
+}
+
+func (a *loginAuth) Next(fromServer []byte, more bool) ([]byte, error) {
+	if more {
+		switch string(fromServer) {
+		case "Username:":
+			return []byte(a.username), nil
+		case "Password:":
+			return []byte(a.password), nil
+		default:
+			return nil, errors.New("unexpected server challenge")
+		}
+	}
+	return nil, nil
+}
--- a/pkg/web/routes.go
+++ b/pkg/web/routes.go
@@ -37,6 +37,7 @@ func RegisterRoutes(r *gin.Engine) {
 		// settings
 		api.GET("/settings", GetSettingsHandler)
 		api.POST("/settings", UpdateSettingsHandler)
+		api.POST("/settings/test-email", TestEmailHandler)

 		// filter debugger
 		api.GET("/filters", ListFiltersHandler)
--- a/pkg/web/templates/index.html
+++ b/pkg/web/templates/index.html
@@ -143,21 +143,13 @@
    <!-- Alert Settings Group -->
    <fieldset class="border p-3 rounded mb-4">
      <legend class="w-auto px-2">Alert Settings</legend>
-
-      <!-- Source Email -->
      <div class="mb-3">
-        <label for="sourceEmail" class="form-label">Source Email - Emails are sent from this address.</label>
-        <input type="email" class="form-control" id="sourceEmail"/>
+        <label for="destEmail" class="form-label">Destination Email (Alerts Receiver)</label>
+        <input type="email" class="form-control" id="destEmail" placeholder="alerts@swissmakers.ch" />
      </div>
-      <!-- Destination Email -->
      <div class="mb-3">
-        <label for="destEmail" class="form-label">Destination Email - Where to sent the alert messages?</label>
-        <input type="email" class="form-control" id="destEmail" placeholder="e.g., alerts@swissmakers.ch" />
-      </div>
-      <!-- Alert Countries -->
-      <div class="mb-3">
-        <label for="alertCountries" class="form-label">Select alert Countries</label>
-        <p class="text-muted">Choose which country IP blocks should trigger an email. You can select multiple with CTRL.</p>
+        <label for="alertCountries" class="form-label">Select Alert Countries</label>
+        <p class="text-muted">Choose which country IP blocks should trigger an email (hold CTRL for multiple).</p>
        <select id="alertCountries" class="form-select" multiple size="7">
          <option value="ALL">ALL (Every Country)</option>
          <option value="CH">Switzerland (CH)</option>
@@ -171,6 +163,37 @@
      </div>
    </fieldset>

+    <!-- SMTP Configuration Group -->
+    <fieldset class="border p-3 rounded mb-4">
+      <legend class="w-auto px-2">SMTP Configuration</legend>
+      <div class="mb-3">
+        <label for="smtpHost" class="form-label">SMTP Host</label>
+        <input type="text" class="form-control" id="smtpHost" placeholder="e.g., smtp.gmail.com" required />
+      </div>
+      <label for="smtpPort">SMTP Port</label>
+      <select id="smtpPort" class="form-select">
+          <option value="587" selected>587 (Recommended - STARTTLS)</option>
+          <option value="465" disabled>465 (Not Supported)</option>
+      </select>
+      <div class="mb-3">
+        <label for="smtpUsername" class="form-label">SMTP Username</label>
+        <input type="text" class="form-control" id="smtpUsername" placeholder="e.g., user@example.com" required />
+      </div>
+      <div class="mb-3">
+        <label for="smtpPassword" class="form-label">SMTP Password</label>
+        <input type="password" class="form-control" id="smtpPassword" placeholder="Enter SMTP Password" required />
+      </div>
+      <div class="mb-3">
+        <label for="smtpFrom" class="form-label">Sender Email</label>
+        <input type="email" class="form-control" id="smtpFrom" placeholder="noreply@swissmakers.ch" required />
+      </div>
+      <div class="mb-3 form-check">
+        <input type="checkbox" class="form-check-input" id="smtpUseTLS">
+        <label for="smtpUseTLS" class="form-check-label">Use TLS (Recommended)</label>
+      </div>
+      <button type="button" class="btn btn-secondary mt-2" onclick="sendTestEmail()">Send Test Email</button>
+    </fieldset>
+
    <!-- Fail2Ban Configuration Group -->
    <fieldset class="border p-3 rounded mb-4">
      <legend class="w-auto px-2">Fail2Ban Configuration</legend>
@@ -198,9 +221,9 @@
      <!-- Ignore IPs -->
      <div class="mb-3">
        <label for="ignoreIP" class="form-label">Ignore IPs</label>
-        <textarea class="form-control" id="ignoreIP" rows="2" placeholder="Enter IPs to ignore, separated by spaces"></textarea>
+        <textarea class="form-control" id="ignoreIP" rows="2" placeholder="IPs to ignore, separated by spaces"></textarea>
      </div>
-    </fieldset>  
+    </fieldset>
    <button type="submit" class="btn btn-primary">Save</button>
  </form>
 </div>
@@ -589,12 +612,11 @@ function loadSettings() {
      document.getElementById('languageSelect').value = data.language || 'en';
      document.getElementById('debugMode').checked = data.debug || false;

-      // Get current alert settings
-      document.getElementById('sourceEmail').value = data.sender || '';
+      // Get Alert settings
      document.getElementById('destEmail').value = data.destemail || '';
-      // alertCountries multi
+
+      // Get Alert countries selection
      const select = document.getElementById('alertCountries');
-      // clear selection
      for (let i = 0; i < select.options.length; i++) {
        select.options[i].selected = false;
      }
@@ -611,7 +633,17 @@ function loadSettings() {
        }
      }

-      // Get current Fail2Ban Configuration
+      // Get SMTP settings
+      if (data.smtp) {
+        document.getElementById('smtpHost').value = data.smtp.host || '';
+        document.getElementById('smtpPort').value = data.smtp.port || 587;
+        document.getElementById('smtpUsername').value = data.smtp.username || '';
+        document.getElementById('smtpPassword').value = data.smtp.password || '';
+        document.getElementById('smtpFrom').value = data.smtp.from || '';
+        document.getElementById('smtpUseTLS').checked = data.smtp.useTLS || false;
+      }
+
+      // Get current Fail2Ban settings
      document.getElementById('bantimeIncrement').checked = data.bantimeIncrement || false;
      document.getElementById('banTime').value = data.bantime || '';
      document.getElementById('findTime').value = data.findtime || '';
@@ -625,57 +657,49 @@ function loadSettings() {
 }

 // Save settings when hit the save button
-function saveSettings(e) {
-  e.preventDefault(); // prevent form submission
+function saveSettings(event) {
+  event.preventDefault(); // prevent form submission

  showLoading(true);
-  const lang = document.getElementById('languageSelect').value;
-  const debugMode = document.getElementById("debugMode").checked;
-  const srcmail = document.getElementById('sourceEmail').value;
-  const destmail = document.getElementById('destEmail').value;
+  
+  // Gather form values
+  const smtpSettings = {
+    host: document.getElementById('smtpHost').value.trim(),
+    port: parseInt(document.getElementById('smtpPort').value, 10) || 587,
+    username: document.getElementById('smtpUsername').value.trim(),
+    password: document.getElementById('smtpPassword').value.trim(),
+    from: document.getElementById('smtpFrom').value.trim(),
+    useTLS: document.getElementById('smtpUseTLS').checked,
+  };

-  const select = document.getElementById('alertCountries');
-  let chosenCountries = [];
-  for (let i = 0; i < select.options.length; i++) {
-    if (select.options[i].selected) {
-      chosenCountries.push(select.options[i].value);
-    }
-  }
-  // If user selected "ALL", we override everything
-  if (chosenCountries.includes("ALL")) {
-    chosenCountries = ["all"];
-  }
+  const selectedCountries = Array.from(document.getElementById('alertCountries').selectedOptions).map(opt => opt.value);

-  const bantimeinc = document.getElementById('bantimeIncrement').checked;
-  const bant = document.getElementById('banTime').value;
-  const findt = document.getElementById('findTime').value;
-  const maxre = parseInt(document.getElementById('maxRetry').value, 10) || 1; // Default to 1 (if parsing fails)
-  const ignip = document.getElementById('ignoreIP').value;
+  const settingsData = {
+    language: document.getElementById('languageSelect').value,
+    debug: document.getElementById('debugMode').checked,
+    destemail: document.getElementById('destEmail').value.trim(),
+    alertCountries: selectedCountries.length > 0 ? selectedCountries : ["ALL"],
+    
+    bantimeIncrement: document.getElementById('bantimeIncrement').checked,
+    bantime: document.getElementById('banTime').value.trim(),
+    findtime: document.getElementById('findTime').value.trim(),
+    
+    maxretry: parseInt(document.getElementById('maxRetry').value, 10) || 3,
+    ignoreip: document.getElementById('ignoreIP').value.trim(),

-  const body = {
-    language: lang,
-    debug: debugMode,
-    sender: srcmail,
-    destemail: destmail,
-    alertCountries: chosenCountries,
-    bantimeIncrement: bantimeinc,
-    bantime: bant,
-    findtime: findt,
-    maxretry: maxre,
-    ignoreip: ignip
+    smtp: smtpSettings // (Includes SMTP settings)
  };

  fetch('/api/settings', {
    method: 'POST',
    headers: {'Content-Type': 'application/json'},
-    body: JSON.stringify(body)
+    body: JSON.stringify(settingsData),
  })
    .then(res => res.json())
    .then(data => {
      if (data.error) {
        alert('Error saving settings: ' + data.error + data.details);
      } else {
-        //alert(data.message || 'Settings saved');
        console.log("Settings saved successfully. Reload needed? " + data.reloadNeeded);
        if (data.reloadNeeded) {
          document.getElementById('reloadBanner').style.display = 'block';
@@ -719,6 +743,25 @@ function loadFilters() {
    .finally(() => showLoading(false));
 }

+function sendTestEmail() {
+  showLoading(true);
+
+  fetch('/api/settings/test-email', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' }
+  })
+    .then(res => res.json())
+    .then(data => {
+      if (data.error) {
+        alert('Error sending test email: ' + data.error);
+      } else {
+        alert('Test email sent successfully!');
+      }
+    })
+    .catch(error => alert('Error: ' + error))
+    .finally(() => showLoading(false));
+}
+
 // Called when clicking "Test Filter" button
 function testSelectedFilter() {
  const filterName = document.getElementById('filterSelect').value;