From 31950e91b9178f85cf91946f67db3ec79d406a3b Mon Sep 17 00:00:00 2001
From: Johannes Rieken <johannes.rieken@gmail.com>
Date: Fri, 11 Mar 2016 10:51:50 +0100
Subject: [PATCH] don't get stuck in _wordenize, don't allow evil regexp as
 word definition, fixes #3963

---
 src/vs/editor/common/services/editorSimpleWorker.ts | 4 ++++
 src/vs/workbench/api/node/extHost.api.impl.ts       | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/src/vs/editor/common/services/editorSimpleWorker.ts b/src/vs/editor/common/services/editorSimpleWorker.ts
index d3f19c25956..e8d071e30cf 100644
--- a/src/vs/editor/common/services/editorSimpleWorker.ts
+++ b/src/vs/editor/common/services/editorSimpleWorker.ts
@@ -96,6 +96,10 @@ class MirrorModel extends MirrorModel2 {
 		var result:editorCommon.IWordRange[] = [];
 		var match:RegExpExecArray;
 		while (match = wordDefinition.exec(content)) {
+			if (match[0].length === 0) {
+				// it did match the empty string
+				break;
+			}
 			result.push({ start: match.index, end: match.index + match[0].length });
 		}
 		return result;
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index dd7a094f04f..138eba0c406 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -6,6 +6,7 @@
 
 import {Emitter} from 'vs/base/common/event';
 import {score} from 'vs/editor/common/modes/languageSelector';
+import {regExpLeadsToEndlessLoop} from 'vs/base/common/strings';
 import {Remotable, IThreadService} from 'vs/platform/thread/common/thread';
 import * as errors from 'vs/base/common/errors';
 import {ExtHostFileSystemEventService} from 'vs/workbench/api/node/extHostFileSystemEventService';
@@ -398,6 +399,11 @@ export class ExtHostAPIImplementation {
 
 		let {wordPattern} = configuration;
 
+		// check for a valid word pattern
+		if (wordPattern && regExpLeadsToEndlessLoop(wordPattern)) {
+			throw new Error(`Invalid language configuration: wordPattern '${wordPattern}' is not allowed to match the empty string.`);
+		}
+
 		// word definition
 		if (wordPattern) {
 			setWordDefinitionFor(modeId, wordPattern);