From df1bf4a883248e5bbfd024e883ca0dabe11bb7d2 Mon Sep 17 00:00:00 2001
From: Weston Ruter <westonruter@git.wordpress.org>
Date: Mon, 18 Sep 2017 23:03:06 +0000
Subject: [PATCH] Customize: Add `wp_is_uuid()` validation function with
 optional second `$version=4` parameter to enforce v4 random UUIDs.

Props jonathanbardo.
Fixes #39778.


git-svn-id: https://develop.svn.wordpress.org/trunk@41388 602fd350-edb4-49c9-b593-d223f7449a82
---
 .../class-wp-customize-manager.php            |  2 +-
 src/wp-includes/functions.php                 | 28 ++++++++++
 tests/phpunit/tests/functions.php             | 52 ++++++++++++++++++-
 3 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-customize-manager.php b/src/wp-includes/class-wp-customize-manager.php
index cead2d0ce9..7bd1489543 100644
--- a/src/wp-includes/class-wp-customize-manager.php
+++ b/src/wp-includes/class-wp-customize-manager.php
@@ -488,7 +488,7 @@ final class WP_Customize_Manager {
 			return;
 		}
 
-		if ( ! preg_match( '/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/', $this->_changeset_uuid ) ) {
+		if ( ! wp_is_uuid( $this->_changeset_uuid ) ) {
 			$this->wp_die( -1, __( 'Invalid changeset UUID' ) );
 		}
 
diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index bab1f7463b..2559613fbc 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -5704,6 +5704,34 @@ function wp_generate_uuid4() {
 	);
 }
 
+/**
+ * Validates that a UUID is valid.
+ *
+ * @since 4.9.0
+ *
+ * @param mixed $uuid    UUID to check.
+ * @param int   $version Specify which version of UUID to check against. Default is none, to accept any UUID version. Otherwise, only version allowed is `4`.
+ * @return bool The string is a valid UUID or false on failure.
+ */
+function wp_is_uuid( $uuid, $version = null ) {
+
+	if ( ! is_string( $uuid ) ) {
+		return false;
+	}
+
+	if ( is_numeric( $version ) ) {
+		if ( 4 !== (int) $version ) {
+			_doing_it_wrong( __FUNCTION__, __( 'Only UUID V4 is supported at this time.' ), '4.9.0' );
+			return false;
+		}
+		$regex = '/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/';
+	} else {
+		$regex = '/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/';
+	}
+
+	return (bool) preg_match( $regex, $uuid );
+}
+
 /**
  * Get last changed date for the specified cache group.
  *
diff --git a/tests/phpunit/tests/functions.php b/tests/phpunit/tests/functions.php
index 252d890bbb..3fa9fbcc74 100644
--- a/tests/phpunit/tests/functions.php
+++ b/tests/phpunit/tests/functions.php
@@ -901,7 +901,7 @@ class Tests_Functions extends WP_UnitTestCase {
 		$uuids = array();
 		for ( $i = 0; $i < 20; $i += 1 ) {
 			$uuid = wp_generate_uuid4();
-			$this->assertRegExp( '/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/', $uuid );
+			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
 			$uuids[] = $uuid;
 		}
 
@@ -909,6 +909,56 @@ class Tests_Functions extends WP_UnitTestCase {
 		$this->assertEquals( $uuids, $unique_uuids );
 	}
 
+	/**
+	 * Tests wp_is_uuid().
+	 *
+	 * @covers ::wp_is_uuid
+	 * @ticket 39778
+	 */
+	function test_wp_is_valid_uuid() {
+		$uuids_v4 = array(
+			'27fe2421-780c-44c5-b39b-fff753092b55',
+			'b7c7713a-4ee9-45a1-87ed-944a90390fc7',
+			'fbedbe35-7bf5-49cc-a5ac-0343bd94360a',
+			'4c58e67e-123b-4290-a41c-5eeb6970fa3e',
+			'f54f5b78-e414-4637-84a9-a6cdc94a1beb',
+			'd1c533ac-abcf-44b6-9b0e-6477d2c91b09',
+			'7fcd683f-e5fd-454a-a8b9-ed15068830da',
+			'7962c750-e58c-470a-af0d-ec1eae453ff2',
+			'a59878ce-9a67-4493-8ca0-a756b52804b3',
+			'6faa519d-1e13-4415-bd6f-905ae3689d1d',
+		);
+
+		foreach ( $uuids_v4 as $uuid ) {
+			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
+		}
+
+		$uuids = array(
+			'00000000-0000-0000-0000-000000000000', // Nil.
+			'9e3a0460-d72d-11e4-a631-c8e0eb141dab', // Version 1.
+			'2c1d43b8-e6d7-376e-af7f-d4bde997cc3f', // Version 3.
+			'39888f87-fb62-5988-a425-b2ea63f5b81e', // Version 5.
+		);
+
+		foreach ( $uuids as $uuid ) {
+			$this->assertTrue( wp_is_uuid( $uuid ) );
+			$this->assertFalse( wp_is_uuid( $uuid, 4 ) );
+		}
+
+		$invalid_uuids = array(
+			'a19d5192-ea41-41e6-b006',
+			'this-is-not-valid',
+			1234,
+			true,
+			array(),
+		);
+
+		foreach ( $invalid_uuids as $invalid_uuid ) {
+			$this->assertFalse( wp_is_uuid( $invalid_uuid, 4 ) );
+			$this->assertFalse( wp_is_uuid( $invalid_uuid ) );
+		}
+	}
+
 	/**
 	 * @ticket 40017
 	 * @dataProvider _wp_get_image_mime