fix: avoid crash on big data URL source maps

Author: cap-Bernardito

package-lock.json

@@ -41,9 +41,11 @@
     "webpack": "^4.0.0 || ^5.0.0"
   },
   "dependencies": {
-    "neo-async": "^2.6.1",
+    "data-urls": "^2.0.0",
     "loader-utils": "^2.0.0",
-    "schema-utils": "^2.6.6"
+    "neo-async": "^2.6.1",
+    "schema-utils": "^2.6.6",
+    "whatwg-encoding": "^1.0.5"
   },
   "devDependencies": {
     "@babel/cli": "^7.8.4",

package.json

@@ -7,6 +7,8 @@ import path from 'path';
 
 import validateOptions from 'schema-utils';
 import async from 'neo-async';
+import parseDataURL from 'data-urls';
+import { labelToName, decode } from 'whatwg-encoding';
 import { getOptions, urlToRequest } from 'loader-utils';
 
 import schema from './options.json';
@@ -18,8 +20,6 @@ const baseRegex =
 const regex1 = new RegExp(`/\\*${baseRegex}\\s*\\*/`);
 // Matches // .... comments
 const regex2 = new RegExp(`//${baseRegex}($|\n|\r\n?)`);
-// Matches DataUrls
-const regexDataUrl = /data:[^;\n]+(?:;charset=[^;\n]+)?;base64,([a-zA-Z0-9+/]+={0,2})/;
 
 export default function loader(input, inputMap) {
   const options = getOptions(this);
@@ -39,20 +39,23 @@ export default function loader(input, inputMap) {
   }
 
   const [, url] = match;
-  const dataUrlMatch = regexDataUrl.exec(url);
-  const { context, resolve, addDependency, emitWarning } = this;
 
-  if (dataUrlMatch) {
-    const [, mapBase64] = dataUrlMatch;
-    const mapStr = new Buffer(mapBase64, 'base64').toString();
+  const dataURL = parseDataURL(url);
+
+  const { context, resolve, addDependency, emitWarning } = this;
 
+  if (dataURL) {
     let map;
 
     try {
-      map = JSON.parse(mapStr);
+      dataURL.encodingName =
+        labelToName(dataURL.mimeType.parameters.get('charset')) || 'UTF-8';
+
+      map = decode(dataURL.body, dataURL.encodingName);
+      map = JSON.parse(map);
     } catch (error) {
       emitWarning(
-        `Cannot parse inline SourceMap '${mapBase64.substr(0, 50)}': ${error}`
+        `Cannot parse inline SourceMap with Charset ${dataURL.encodingName}: ${error}`
       );
 
       callback(null, input, inputMap);
@@ -65,6 +68,14 @@ export default function loader(input, inputMap) {
     return;
   }
 
+  if (url.toLowerCase().indexOf('data:') === 0) {
+    emitWarning(`Cannot parse inline SourceMap: ${url}`);
+
+    callback(null, input, inputMap);
+
+    return;
+  }
+
   resolve(context, urlToRequest(url, true), (resolveError, result) => {
     if (resolveError) {
       emitWarning(`Cannot find SourceMap '${url}': ${resolveError}`);

src/index.js

@@ -181,7 +181,7 @@ describe('source-map-loader', () => {
         expect(map).toBeUndefined();
         expect(deps).toEqual([]);
         expect(warns).toEqual([
-          "Cannot parse inline SourceMap 'invalid/base64=': SyntaxError: Unexpected token � in JSON at position 0",
+          'Cannot parse inline SourceMap: data:application/source-map;base64,invalid/base64=',
         ]);
         done();
       }