Refactor login / ban authentication steps

Relates to https://github.com/shaarli/Shaarli/issues/324

Added:
- Add the `LoginManager` class to manage logins and bans

Changed:
- Refactor IP ban management
- Simplify logic
- Avoid using globals, inject dependencies

Fixed:
- Use `ban_duration` instead of `ban_after` when setting a new ban

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 134 insertions, 0 deletions

diff --git a/application/LoginManager.php b/application/LoginManager.php
new file mode 100644
index 00000000..397bc6e3
--- /dev/null
+++ b/application/LoginManager.php
@@ -0,0 +1,134 @@
+<?php
+namespace Shaarli;
+
+/**
+ * User login management
+ */
+class LoginManager
+{
+    protected $globals = [];
+    protected $configManager = null;
+    protected $banFile = '';
+
+    /**
+     * Constructor
+     *
+     * @param array         $globals       The $GLOBALS array (reference)
+     * @param ConfigManager $configManager Configuration Manager instance.
+     */
+    public function __construct(& $globals, $configManager)
+    {
+        $this->globals = &$globals;
+        $this->configManager = $configManager;
+        $this->banFile = $this->configManager->get('resource.ban_file', 'data/ipbans.php');
+        $this->readBanFile();
+    }
+
+    /**
+     * Read a file containing banned IPs
+     */
+    protected function readBanFile()
+    {
+        if (! file_exists($this->banFile)) {
+            return;
+        }
+        include $this->banFile;
+    }
+
+    /**
+     * Write the banned IPs to a file
+     */
+    protected function writeBanFile()
+    {
+        if (! array_key_exists('IPBANS', $this->globals)) {
+            return;
+        }
+        file_put_contents(
+            $this->banFile,
+            "<?php\n\$GLOBALS['IPBANS']=" . var_export($this->globals['IPBANS'], true) . ";\n?>"
+        );
+    }
+
+    /**
+     * Handle a failed login and ban the IP after too many failed attempts
+     *
+     * @param array $server The $_SERVER array
+     */
+    public function handleFailedLogin($server)
+    {
+        $ip = $server['REMOTE_ADDR'];
+        $trusted = $this->configManager->get('security.trusted_proxies', []);
+
+        if (in_array($ip, $trusted)) {
+            $ip = getIpAddressFromProxy($server, $trusted);
+            if (! $ip) {
+                // the IP is behind a trusted forward proxy, but is not forwarded
+                // in the HTTP headers, so we do nothing
+                return;
+            }
+        }
+
+        // increment the fail count for this IP
+        if (isset($this->globals['IPBANS']['FAILURES'][$ip])) {
+            $this->globals['IPBANS']['FAILURES'][$ip]++;
+        } else {
+            $this->globals['IPBANS']['FAILURES'][$ip] = 1;
+        }
+
+        if ($this->globals['IPBANS']['FAILURES'][$ip] >= $this->configManager->get('security.ban_after')) {
+            $this->globals['IPBANS']['BANS'][$ip] = time() + $this->configManager->get('security.ban_duration', 1800);
+            logm(
+                $this->configManager->get('resource.log'),
+                $server['REMOTE_ADDR'],
+                'IP address banned from login'
+            );
+        }
+        $this->writeBanFile();
+    }
+
+    /**
+     * Handle a successful login
+     *
+     * @param array $server The $_SERVER array
+     */
+    public function handleSuccessfulLogin($server)
+    {
+        $ip = $server['REMOTE_ADDR'];
+        // FIXME unban when behind a trusted proxy?
+
+        unset($this->globals['IPBANS']['FAILURES'][$ip]);
+        unset($this->globals['IPBANS']['BANS'][$ip]);
+
+        $this->writeBanFile();
+    }
+
+    /**
+     * Check if the user can login from this IP
+     *
+     * @param array $server The $_SERVER array
+     *
+     * @return bool true if the user is allowed to login
+     */
+    public function canLogin($server)
+    {
+        $ip = $server['REMOTE_ADDR'];
+
+        if (! isset($this->globals['IPBANS']['BANS'][$ip])) {
+            // the user is not banned
+            return true;
+        }
+
+        if ($this->globals['IPBANS']['BANS'][$ip] > time()) {
+            // the user is still banned
+            return false;
+        }
+
+        // the ban has expired, the user can attempt to log in again
+        logm($this->configManager->get('resource.log'), $server['REMOTE_ADDR'], 'Ban lifted.');
+        unset($this->globals['IPBANS']['FAILURES'][$ip]);
+        unset($this->globals['IPBANS']['BANS'][$ip]);
+
+        $this->writeBanFile();
+        return true;
+    }
+}