From eec61f52891822de524c14c76662c2e302deca6c Mon Sep 17 00:00:00 2001
From: Scott Nonnenberg <scott@signal.org>
Date: Fri, 25 May 2018 14:11:26 -0700
Subject: [PATCH] Fine-tune file protocol filter

---
 app/protocol_filter.js           | 39 ++++++++++++++++++++------------
 main.js                          |  1 +
 test/app/protocol_filter_test.js | 14 ++++++++++--
 3 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/app/protocol_filter.js b/app/protocol_filter.js
index f0e33cc89e6..121117f5b19 100644
--- a/app/protocol_filter.js
+++ b/app/protocol_filter.js
@@ -1,23 +1,29 @@
 const path = require('path');
 
-const FILE_SCHEME = /^file:\/\//;
-const WINDOWS_PREFIX = /^\/[A-Z]:/;
-function _urlToPath(targetUrl) {
-  let withoutScheme = targetUrl.replace(FILE_SCHEME, '');
-  if (WINDOWS_PREFIX.test(withoutScheme)) {
-    withoutScheme = withoutScheme.slice(1);
+function _eliminateAllAfterCharacter(string, character) {
+  const index = string.indexOf(character);
+  if (index < 0) {
+    return string;
   }
 
-  const withoutQuerystring = withoutScheme.replace(/\?.*$/, '');
-  const withoutHash = withoutQuerystring.replace(/#.*$/, '');
-
-  return decodeURIComponent(withoutHash);
+  return string.slice(0, index);
 }
 
-function _createFileHandler({ userDataPath, installPath }) {
+function _urlToPath(targetUrl, options = {}) {
+  const { isWindows } = options;
+
+  const decoded = decodeURIComponent(targetUrl);
+  const withoutScheme = decoded.slice(isWindows ? 8 : 7);
+  const withoutQuerystring = _eliminateAllAfterCharacter(withoutScheme, '?');
+  const withoutHash = _eliminateAllAfterCharacter(withoutQuerystring, '#');
+
+  return withoutHash;
+}
+
+function _createFileHandler({ userDataPath, installPath, isWindows }) {
   return (request, callback) => {
     // normalize() is primarily useful here for switching / to \ on windows
-    const target = path.normalize(_urlToPath(request.url));
+    const target = path.normalize(_urlToPath(request.url, { isWindows }));
 
     if (!path.isAbsolute(target)) {
       return callback();
@@ -34,10 +40,15 @@ function _createFileHandler({ userDataPath, installPath }) {
   };
 }
 
-function installFileHandler({ protocol, userDataPath, installPath }) {
+function installFileHandler({
+  protocol,
+  userDataPath,
+  installPath,
+  isWindows,
+}) {
   protocol.interceptFileProtocol(
     'file',
-    _createFileHandler({ userDataPath, installPath })
+    _createFileHandler({ userDataPath, installPath, isWindows })
   );
 }
 
diff --git a/main.js b/main.js
index 64bca6edb65..81dd73eedef 100644
--- a/main.js
+++ b/main.js
@@ -452,6 +452,7 @@ app.on('ready', () => {
       protocol: electronProtocol,
       userDataPath,
       installPath,
+      isWindows: process.platform === 'win32',
     });
   }
 
diff --git a/test/app/protocol_filter_test.js b/test/app/protocol_filter_test.js
index 11411431d52..11964224591 100644
--- a/test/app/protocol_filter_test.js
+++ b/test/app/protocol_filter_test.js
@@ -34,12 +34,13 @@ describe('Protocol Filter', () => {
       expect(actual).to.equal(expected);
     });
 
-    it('returns proper file path for windows style file URI', () => {
+    it('returns proper file path for file URI on windows', () => {
       const path =
         'file:///C:/Users/Someone/dev/desktop/background.html?name=Signal&locale=en&version=2.4.0';
       const expected = 'C:/Users/Someone/dev/desktop/background.html';
+      const isWindows = true;
 
-      const actual = _urlToPath(path, { isWindows: true });
+      const actual = _urlToPath(path, { isWindows });
       expect(actual).to.equal(expected);
     });
 
@@ -72,6 +73,15 @@ describe('Protocol Filter', () => {
       expect(actual).to.equal(expected);
     });
 
+    it('handles SMB share path on windows', () => {
+      const path = 'file://relative/path';
+      const expected = 'elative/path';
+      const isWindows = true;
+
+      const actual = _urlToPath(path, { isWindows });
+      expect(actual).to.equal(expected);
+    });
+
     it('hands back a path with .. in it', () => {
       const path = 'file://../../..';
       const expected = '../../..';