From 285262b6c668b4f367f8222880ceb01be39fd3ac Mon Sep 17 00:00:00 2001
From: Florian Pritz <bluewind@xinu.at>
Date: Thu, 29 Aug 2013 17:55:52 +0200
Subject: Add CSRF protection

Signed-off-by: Florian Pritz <bluewind@xinu.at>
---
 application/core/MY_Controller.php | 46 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

(limited to 'application/core/MY_Controller.php')

diff --git a/application/core/MY_Controller.php b/application/core/MY_Controller.php
index 3ee63424a..09b813b71 100644
--- a/application/core/MY_Controller.php
+++ b/application/core/MY_Controller.php
@@ -19,6 +19,7 @@ class MY_Controller extends CI_Controller {
 		parent::__construct();
 
 		$this->var = new StdClass();
+		$csrf_protection = true;
 
 		$this->load->library('migration');
 		if ( ! $this->migration->current()) {
@@ -41,6 +42,51 @@ class MY_Controller extends CI_Controller {
 			show_error("Function not JSON enabled");
 		}
 
+		if ($this->input->post("apikey") !== false) {
+			/* This relies on the authentication code always verifying the supplied
+			 * apikey. If the key is not verified/logged in an attacker could simply
+			 * add an empty "apikey" field to the CSRF form to circumvent the
+			 * protection. If we always log in if a key is supplied we can ensure
+			 * that an attacker (and the victim since they get a cookie) can only
+			 * access the attacker's account.
+			 */
+			$csrf_protection = false;
+		}
+
+		$uri_start = $this->uri->rsegment(1)."/".$this->uri->rsegment(2);
+		$csrf_whitelisted_handlers = array(
+			"always" => array(
+				/* Whitelist the upload pages because they don't cause harm and a user
+				 * might keep the upload page open for more than csrf_expire seconds
+				 * and we don't want to annoy them when they upload a big file and the
+				 * CSRF check fails.
+				 */
+				"file/do_upload",
+				"file/do_paste",
+			),
+			"cli_client" => array(
+				"file/do_delete",
+				"file/delete",
+				"file/upload_history",
+			),
+		);
+		if (in_array($uri_start, $csrf_whitelisted_handlers["always"])) {
+			$csrf_protection = false;
+		}
+
+		// TODO: replace cli client with request_type("plain")?
+		if (is_cli_client() && in_array($uri_start, $csrf_whitelisted_handlers["cli_client"])) {
+			$csrf_protection = false;
+		}
+
+		if ($csrf_protection) {
+			// 2 functions for accessing config options, really?
+			$this->config->set_item('csrf_protection', true);
+			config_item("csrf_protection", true);
+			$this->security->__construct();
+			$this->security->csrf_verify();
+		}
+
 		$this->data['title'] = "FileBin";
 	}
 }
-- 
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