FIX Privilege escalation through Group hierarchy setting (SS-2013-003)

See http://www.silverstripe.org/ss-2013-003-privilege-escalation-through-group-hierarchy-setting/

docs/en/changelogs/2.4.12.md

@@ -0,0 +1,15 @@
+# 2.4.12
+
+## Overview
+
+### Security: Privilege escalation through Group hierarchy setting (SS-2013-003)
+
+See [announcement](http://www.silverstripe.org/ss-2013-003-privilege-escalation-through-group-hierarchy-setting/)
+
+### Security: Privilege escalation through Group and Member CSV upload (SS-2013-004)
+
+See [announcement](http://www.silverstripe.org/ss-2013-004-privilege-escalation-through-group-and-member-csv-upload/)
+
+### Security: Privilege escalation through APPLY_ROLES assignment (SS-2013-005)
+
+See [announcement](http://www.silverstripe.org/ss-2013-005-privilege-escalation-through-apply-roles-assignment/)

security/Group.php

@@ -319,6 +319,33 @@ class Group extends DataObject {
 		$this->setField("Code",SiteTree::generateURLSegment($val));
 	}
 
+	public function validate() {
+		$result = parent::validate();
+
+		// Check if the new group hierarchy would add certain "privileged permissions",
+		// and require an admin to perform this change in case it does. 
+		// This prevents "sub-admin" users with group editing permissions to increase their privileges.
+		if($this->ParentID && !Permission::check('ADMIN')) {
+			$ancestorIds = $this->Parent()->collateAncestorIDs();
+			$inheritedPermissions = DataObject::get(
+				'Permission',
+				sprintf('"GroupID" IN (%s)', implode(',', array_map('intval', $ancestorIds)))
+			);
+			$inheritedCodes = $inheritedPermissions ? $inheritedPermissions->column('Code') : array();
+			if(array_intersect($inheritedCodes, Permission::$privileged_permissions)) {
+				$result->error(sprintf(
+					_t(
+						'Group.HierarchyPermsError',
+						'Can\'t assign parent group "%s" with privileged permissions (requires ADMIN access)'
+					),
+					$this->Parent()->Title
+				));
+			}
+		}
+
+		return $result;
+	}
+	
 	function onBeforeWrite() {
 		parent::onBeforeWrite();
 		

security/Permission.php

@@ -90,6 +90,17 @@ class Permission extends DataObject {
 	 */
 	static $hidden_permissions = array();
 
+	/**
+	 * @config These permissions can only be applied by ADMIN users, to prevent
+	 * privilege escalation on group assignments and inheritance.
+	 * @var array
+	 */
+	static $privileged_permissions = array(
+		'ADMIN', 
+		'APPLY_ROLES',
+		'EDIT_PERMISSIONS'
+	);
+
 	/**
 	 * Check that the current member has the given permission.
 	 * 

tests/security/GroupTest.php

@@ -86,6 +86,54 @@ class GroupTest extends FunctionalTest {
 		$this->assertNull(DataObject::get('Group', "\"ID\"={$adminGroup->ID}"), 'Group is removed');
 		$this->assertNull(DataObject::get('Permission',"\"GroupID\"={$adminGroup->ID}"), 'Permissions removed along with the group');
 	}
+
+	public function testValidatesPrivilegeLevelOfParent() {
+		if(!class_exists('ReflectionMethod')) {
+			$this->markTestSkipped('Test requires PHP 5.3 Reflection API');
+		}
+
+		$nonAdminUser = $this->objFromFixture('GroupTest_Member', 'childgroupuser');
+		$adminUser = $this->objFromFixture('GroupTest_Member', 'admin');
+		$nonAdminGroup = $this->objFromFixture('Group', 'childgroup');
+		$adminGroup = $this->objFromFixture('Group', 'admingroup');
+
+		$nonAdminValidateMethod = new ReflectionMethod($nonAdminGroup, 'validate');
+		$nonAdminValidateMethod->setAccessible(true);
+
+		// Making admin group parent of a non-admin group, effectively expanding is privileges
+		$nonAdminGroup->ParentID = $adminGroup->ID;
+
+		$this->logInWithPermission('APPLY_ROLES');
+		$result = $nonAdminValidateMethod->invoke($nonAdminGroup);
+		$this->assertFalse(
+			$result->valid(),
+			'Members with only APPLY_ROLES can\'t assign parent groups with direct ADMIN permissions'
+		);
+
+		$this->logInWithPermission('ADMIN');
+		$result = $nonAdminValidateMethod->invoke($nonAdminGroup);
+		$this->assertTrue(
+			$result->valid(),
+			'Members with ADMIN can assign parent groups with direct ADMIN permissions'
+		);
+		$nonAdminGroup->write();
+		$newlyAdminGroup = $nonAdminGroup;
+
+		$this->logInWithPermission('ADMIN');
+		$inheritedAdminGroup = $this->objFromFixture('Group', 'group1');
+		$inheritedAdminMethod = new ReflectionMethod($inheritedAdminGroup, 'validate');
+		$inheritedAdminMethod->setAccessible(true);
+		$inheritedAdminGroup->ParentID = $adminGroup->ID;
+		$inheritedAdminGroup->write(); // only works with ADMIN login
+
+		$this->logInWithPermission('APPLY_ROLES');
+		$result = $inheritedAdminMethod->invoke($nonAdminGroup);
+		$this->assertFalse(
+			$result->valid(),
+			'Members with only APPLY_ROLES can\'t assign parent groups with inherited ADMIN permission'
+		);
+	}
+
 }
 
 class GroupTest_Member extends Member implements TestOnly {