Automatic login for ProxyAuth plugin, improved security documentation

plugins/proxy-auth/README.md

@@ -12,7 +12,7 @@ The following example is for Traefik with Authelia and Dovecot as mailserver.
 
 The following steps are require in SnappyMail:
 
-- To open SnappyMail through a reverse proxy server, make sure to enable the correct secfetch policies: ```mode=navigate,dest=document,site=cross-site,user=true``` in the admin panel -> Config -> Security -> secfetch_allow.
+- To open SnappyMail through a reverse proxy server (with redirect of authentication system), make sure to enable the correct secfetch policies: ```mode=navigate,dest=document,site=cross-site,user=true;mode=navigate,dest=document,site=same-site,user=true``` in the admin panel -> Config -> Security -> secfetch_allow.
 - Activate plugin in admin panel -> Extensions
 - Configure the plugin with the required data:
    - Master User Separator is dependent on Dovecot config (see below)
@@ -21,6 +21,7 @@ The following steps are require in SnappyMail:
    - Header Name is dependent on authentication solution. This is the header containing the name of currently logged in user. In case of Authelia, this is "Remote-User".
    - Check Proxy: Since this plugin partially bypasses authentication, it is important to only allow this access from well-defined hosts. It is highly recommended to activate this option!
    - When checking for reverse proxy, it is required to set the IP filter to either an IP address or a subnet.
+   - Automatic Login: Automatically logs in the user of user header is present (see below)
 
 This concludes the setup of SnappyMail.
 
@@ -50,12 +51,16 @@ passdb {
 
 You then need to create a master user in /etc/dovecot/master-users:
 ```
-admin:PASSWORD
+admin:PASSWORD::::::allow_nets=local,172.17.0.0/16
 ```
 where the encrypted password ```PASSWORD``` can be created from a cleartext password with ```doveadm pw -s CRYPT```.
 It should start with ```{CRYPT}```.
 Username and password need to configured in the SnappyMail ProxyAuth plugin (see above).
 
+You likely also want to limit the access by an IP address filter, e.g., to ```local,172.17.0.0/16```, if you are running Postfix (```local```) and within a default Docker environment (```172.17.0.0/16```).
+Otherwise, master user login (assuming password is known) is possible from every connectable system.
+This is an unnecessary security risk.
+
 Additionally, you need to set the master user separator in /etc/dovecot/conf.d/10-auth.conf, e.g., ```auth_master_user_separator = *```.
 The separator needs to be configured in the SnappyMail ProxyAuth plugin (see above).
 
@@ -64,3 +69,14 @@ The separator needs to be configured in the SnappyMail ProxyAuth plugin (see abo
 Once configured correctly, you should be able to access SnappyMail through your reverse proxy at ```https://snappymail.tld/?ProxyAuth```.
 If your reverse proxy provides the username in the configured header (e.g., Remote-User), you will automatically be logged in to your account.
 If not, you will be redirected to the login page.
+
+## Automatic Login
+
+By default, automatic login is activated.
+Behind the scenes, this checks for the existence of the configured user header (through ```/?UserHeaderSet```) and automatically redirects to ```https://snappymail.tld/?ProxyAuth```, trying to log in the user.
+Note that due to this implementation, logout is impossible, as once logged out, the user will automatically be logged in again.
+The user is always considered logged in, as authentication is handled through reverse proxy and authentication system.
+
+Auto login can be disabled in the plugin settings.
+You can also change the logout link in admin panel -> Config -> custom_logout_link to the one of your authentication system, e.g., ```https://auth.yourdomain.com/logout```.
+In this case, you can log out from your overall system via SnappyMail.

plugins/proxy-auth/index.php

@@ -15,7 +15,9 @@ class ProxyAuthPlugin extends \RainLoop\Plugins\AbstractPlugin
 
 	public function Init() : void
 	{
+		$this->addJs('js/auto-login.js');
 		$this->addPartHook('ProxyAuth', 'ServiceProxyAuth');
+		$this->addPartHook('UserHeaderSet', 'ServiceUserHeaderSet');
 		$this->addHook('login.credentials', 'MapEmailAddress');
 	}
 
@@ -140,6 +142,28 @@ public function ServiceProxyAuth() : bool
 		return true;
 	}
 
+	public function ServiceUserHeaderSet() : bool
+	{
+		$oActions = \RainLoop\Api::Actions();
+
+		$oLogger = $oActions->Logger();
+		$sLevel = LOG_DEBUG;
+		$sPrefix = "ProxyAuth";
+
+		$sHeaderName = \trim($this->Config()->getDecrypted('plugin', 'header_name', ''));
+
+		$sRemoteUser = $this->Manager()->Actions()->Http()->GetHeader($sHeaderName);
+		$sMsg = "Remote User: " . $sRemoteUser;
+		$oLogger->Write($sMsg, $sLevel, $sPrefix);
+
+		if (strlen($sRemoteUser) > 0) {
+			\MailSo\Base\Http::StatusHeader('200');
+		} else {
+			\MailSo\Base\Http::StatusHeader('401');
+		}
+		return true;
+	}
+
 	protected function configMapping() : array
 	{
 		return array(
@@ -178,7 +202,13 @@ protected function configMapping() : array
 				->SetType(\RainLoop\Enumerations\PluginPropertyType::STRING_TEXT)
 				->SetDescription('IP or Subnet of proxy, auth header will only be accepted from this address')
 				->SetDefaultValue('10.1.0.0/24')
-				->SetEncrypted()
+				->SetEncrypted(),
+			\RainLoop\Plugins\Property::NewInstance('auto_login')
+				->SetAllowedInJs(true)
+				->SetLabel('Activate automatic login')
+				->SetType(\RainLoop\Enumerations\PluginPropertyType::BOOL)
+				->SetDescription('Activates automatic login, if User Header is set (note: Use custom_logout_link to enable logout, see plugin README)')
+				->SetDefaultValue(true)
 		);
 	}
 }

plugins/proxy-auth/js/auto-login.js

@@ -0,0 +1,32 @@
+(rl => {
+
+    rl && addEventListener('rl-view-model', e => {
+        const id = e.detail.viewModelTemplateID;
+        if (e.detail && ('Login' === id)) {
+	    let
+		auto_login = window.rl.pluginSettingsGet('proxy-auth', 'auto_login');
+            ;
+
+            const
+                ForwardProxyAuth = () => {
+		    if (auto_login) {
+                        var xhr = new XMLHttpRequest();
+                        xhr.open("GET", "/?UserHeaderSet", true);
+
+                        xhr.onreadystatechange = function () {
+                            if (xhr.readyState == 4 && xhr.status == 200) {
+                                window.location.href = "/?ProxyAuth";
+                            }
+                        };
+
+                        xhr.send();
+                    }
+                };
+
+            window.ForwardProxyAuth = ForwardProxyAuth;
+
+            ForwardProxyAuth();
+        }
+    });
+})(window.rl);
+