From 3b9c95a8a83db2436ef9bf0616c0213e2ecea51e Mon Sep 17 00:00:00 2001
From: Louis Lam <louislam@users.noreply.github.com>
Date: Sat, 8 Jul 2023 15:52:09 +0800
Subject: [PATCH] Prevent users from specifying an unexpected executable as
 Chromium (#3348)

---
 .../real-browser-monitor-type.js              | 84 +++++++++++++++----
 1 file changed, 68 insertions(+), 16 deletions(-)

diff --git a/server/monitor-types/real-browser-monitor-type.js b/server/monitor-types/real-browser-monitor-type.js
index 0a4f1f719..f3e5695f8 100644
--- a/server/monitor-types/real-browser-monitor-type.js
+++ b/server/monitor-types/real-browser-monitor-type.js
@@ -7,9 +7,60 @@ const childProcess = require("child_process");
 const path = require("path");
 const Database = require("../database");
 const jwt = require("jsonwebtoken");
+const config = require("../config");
 
 let browser = null;
 
+let allowedList = [];
+let lastAutoDetectChromeExecutable = null;
+
+if (process.platform === "win32") {
+    allowedList.push(process.env.LOCALAPPDATA + "\\Google\\Chrome\\Application\\chrome.exe");
+    allowedList.push(process.env.PROGRAMFILES + "\\Google\\Chrome\\Application\\chrome.exe");
+    allowedList.push(process.env["ProgramFiles(x86)"] + "\\Google\\Chrome\\Application\\chrome.exe");
+
+    // Allow Chromium too
+    allowedList.push(process.env.LOCALAPPDATA + "\\Chromium\\Application\\chrome.exe");
+    allowedList.push(process.env.PROGRAMFILES + "\\Chromium\\Application\\chrome.exe");
+    allowedList.push(process.env["ProgramFiles(x86)"] + "\\Chromium\\Application\\chrome.exe");
+
+    // For Loop A to Z
+    for (let i = 65; i <= 90; i++) {
+        let drive = String.fromCharCode(i);
+        allowedList.push(drive + ":\\Program Files\\Google\\Chrome\\Application\\chrome.exe");
+        allowedList.push(drive + ":\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe");
+    }
+
+} else if (process.platform === "linux") {
+    allowedList = [
+        "chromium",
+        "chromium-browser",
+        "google-chrome",
+
+        "/usr/bin/chromium",
+        "/usr/bin/chromium-browser",
+        "/usr/bin/google-chrome",
+    ];
+} else if (process.platform === "darwin") {
+    // TODO: Generated by GitHub Copilot, but not sure if it's correct
+    allowedList = [
+        "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
+        "/Applications/Chromium.app/Contents/MacOS/Chromium",
+    ];
+}
+
+log.debug("chrome", allowedList);
+
+async function isAllowedChromeExecutable(executablePath) {
+    console.log(config.args);
+    if (config.args["allow-all-chrome-exec"] || process.env.UPTIME_KUMA_ALLOW_ALL_CHROME_EXEC === "1") {
+        return true;
+    }
+
+    // Check if the executablePath is in the list of allowed executables
+    return allowedList.includes(executablePath);
+}
+
 async function getBrowser() {
     if (!browser) {
         let executablePath = await Settings.get("chromeExecutable");
@@ -27,6 +78,7 @@ async function getBrowser() {
 async function prepareChromeExecutable(executablePath) {
     // Special code for using the playwright_chromium
     if (typeof executablePath === "string" && executablePath.toLocaleLowerCase() === "#playwright_chromium") {
+        // Set to undefined = use playwright_chromium
         executablePath = undefined;
     } else if (!executablePath) {
         if (process.env.UPTIME_KUMA_IS_CONTAINER) {
@@ -56,30 +108,30 @@ async function prepareChromeExecutable(executablePath) {
                 });
             }
 
-        } else if (process.platform === "win32") {
-            executablePath = findChrome([
-                "C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe",
-                "C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe",
-                "D:\\Program Files\\Google\\Chrome\\Application\\chrome.exe",
-                "D:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe",
-                "E:\\Program Files\\Google\\Chrome\\Application\\chrome.exe",
-                "E:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe",
-            ]);
-        } else if (process.platform === "linux") {
-            executablePath = findChrome([
-                "chromium-browser",
-                "chromium",
-                "google-chrome",
-            ]);
+        } else {
+            executablePath = findChrome(allowedList);
+        }
+    } else {
+        // User specified a path
+        // Check if the executablePath is in the list of allowed
+        if (!await isAllowedChromeExecutable(executablePath)) {
+            throw new Error("This Chromium executable path is not allowed by default. If you are sure this is safe, please add an environment variable UPTIME_KUMA_ALLOW_ALL_CHROME_EXEC=1 to allow it.");
         }
-        // TODO: Mac??
     }
     return executablePath;
 }
 
 function findChrome(executables) {
+    // Use the last working executable, so we don't have to search for it again
+    if (lastAutoDetectChromeExecutable) {
+        if (commandExistsSync(lastAutoDetectChromeExecutable)) {
+            return lastAutoDetectChromeExecutable;
+        }
+    }
+
     for (let executable of executables) {
         if (commandExistsSync(executable)) {
+            lastAutoDetectChromeExecutable = executable;
             return executable;
         }
     }