From 8faaca0ea2d11cb8992e716b6ab78b5953f6bd2e Mon Sep 17 00:00:00 2001
From: Mark Nielsen <mark@moodlerooms.com>
Date: Wed, 30 Jul 2014 08:41:40 -0700
Subject: [PATCH] MDL-46536: OAuth signature fails with inconsistent new lines

When the LTI intro contains a single \n or
\r newline character then the OAuth signature
fails.  All newlines should be \r\n

Conflicts:
	mod/lti/tests/locallib_test.php
---
 mod/lti/locallib.php            | 13 +++++++--
 mod/lti/tests/locallib_test.php | 49 +++++++++++++++++++++++++++++++--
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/mod/lti/locallib.php b/mod/lti/locallib.php
index 1ec37750a74..74fa34b2491 100644
--- a/mod/lti/locallib.php
+++ b/mod/lti/locallib.php
@@ -227,7 +227,7 @@ function lti_build_sourcedid($instanceid, $userid, $launchid = null, $servicesal
  * This function builds the request that must be sent to the tool producer
  *
  * @param object    $instance       Basic LTI instance object
- * @param object    $typeconfig     Basic LTI tool configuration
+ * @param array     $typeconfig     Basic LTI tool configuration
  * @param object    $course         Course object
  *
  * @return array    $request        Request details
@@ -241,10 +241,19 @@ function lti_build_request($instance, $typeconfig, $course) {
 
     $role = lti_get_ims_role($USER, $instance->cmid, $instance->course);
 
+    $intro = '';
+    if (!empty($instance->cmid)) {
+        $intro = format_module_intro('lti', $instance, $instance->cmid);
+        $intro = html_to_text($intro, 0, false);
+
+        // This may look weird, but this is required for new lines
+        // so we generate the same OAuth signature as the tool provider.
+        $intro = str_replace("\n", "\r\n", $intro);
+    }
     $requestparams = array(
         'resource_link_id' => $instance->id,
         'resource_link_title' => $instance->name,
-        'resource_link_description' => $instance->intro,
+        'resource_link_description' => $intro,
         'user_id' => $USER->id,
         'roles' => $role,
         'context_id' => $course->id,
diff --git a/mod/lti/tests/locallib_test.php b/mod/lti/tests/locallib_test.php
index 33a21878bb7..9d3f050454b 100644
--- a/mod/lti/tests/locallib_test.php
+++ b/mod/lti/tests/locallib_test.php
@@ -53,8 +53,14 @@ global $CFG;
 require_once($CFG->dirroot . '/mod/lti/locallib.php');
 require_once($CFG->dirroot . '/mod/lti/servicelib.php');
 
-
-class mod_lti_locallib_testcase extends basic_testcase {
+/**
+ * Local library tests
+ *
+ * @package    mod_lti
+ * @copyright  Copyright (c) 2012 Moodlerooms Inc. (http://www.moodlerooms.com)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class mod_lti_locallib_testcase extends advanced_testcase {
 
     public function test_split_custom_parameters() {
         $this->assertEquals(lti_split_custom_parameters("x=1\ny=2"),
@@ -145,4 +151,43 @@ class mod_lti_locallib_testcase extends basic_testcase {
         $this->assertEquals('https://moodle.org', lti_ensure_url_is_https('moodle.org'));
         $this->assertEquals('https://moodle.org', lti_ensure_url_is_https('https://moodle.org'));
     }
+
+    /**
+     * Test lti_build_request's resource_link_description and ensure
+     * that the newlines in the description are correct.
+     */
+    public function test_lti_build_request_description() {
+        $this->resetAfterTest();
+
+        self::setUser($this->getDataGenerator()->create_user());
+        $course   = $this->getDataGenerator()->create_course();
+        $instance = $this->getDataGenerator()->create_module('lti', array(
+            'intro'       => "<p>This</p>\nhas\r\n<p>some</p>\nnew\n\rlines",
+            'introformat' => FORMAT_HTML,
+            'course'      => $course->id,
+        ));
+
+        $typeconfig = array(
+            'acceptgrades'     => 1,
+            'forcessl'         => 0,
+            'sendname'         => 2,
+            'sendemailaddr'    => 2,
+            'customparameters' => '',
+        );
+
+        $params = lti_build_request($instance, $typeconfig, $course, null);
+
+        $ncount = substr_count($params['resource_link_description'], "\n");
+        $this->assertGreaterThan(0, $ncount);
+
+        $rcount = substr_count($params['resource_link_description'], "\r");
+        $this->assertGreaterThan(0, $rcount);
+
+        $this->assertEquals($ncount, $rcount, 'The number of \n characters should be the same as the number of \r characters');
+
+        $rncount = substr_count($params['resource_link_description'], "\r\n");
+        $this->assertGreaterThan(0, $rncount);
+
+        $this->assertEquals($ncount, $rncount, 'All newline characters should be a combination of \r\n');
+    }
 }