Protect asar archive files from extraction
npm install asarmorasar extract).---
> Maintenance of this project is made possible by all the lovely contributors and sponsors.
If you'd like to sponsor this project and have your avatar or company logo appear in this section, click here. 💖
Unfortunately, at the time of writing, most of the 'old school' patches have been patched (pun not intended) by the asar project itself. For that reason I strongly recommend enabling encryption as well.
Installation:
npm install -g asarmor
Usage:
``
Usage: asarmor [options]
Options:
-V, --version output the version number
-a, --archive
-o, --output
Examples:
$ asarmor -a app.asar -o asarmor.asar --backup --bloat 1000
$ asarmor -a plaintext.asar -o encrypted.asar --encryption
`
Installation:
npm install --save-dev asarmor
Usage:
`javascript
const asarmor = require('asarmor');
(async () => {
// Encrypt the JavaScript file contents stored within the asar file.
await asarmor.encrypt({
src: './app.asar', // target asar file to encrypt
dst: './encrypted.asar', // output asar file
});
// Read & parse the (optionally encrypted) asar file.
// This can take a while depending on the size of your file.
const archive = await asarmor.open('encrypted.asar');
// Create a backup, which can be restored at any point in time through CLI or code.
await archive.createBackup({backupPath: '~/Documents/backups/encrypted.asar.backup'});
// Apply customized bloat patch.
// The bloat patch by itself will write randomness to disk on extraction attempt.
archive.patch(asarmor.createBloatPatch(50)); // adds 50 GB of bloat in total
// Write changes back to disk.
const outputPath = await archive.write('app.asar');
console.log('successfully wrote changes to ' + outputPath);
})();
`
javascript
const asarmor = require('asarmor');
const { join } = require("path");exports.default = async ({ appOutDir, packager }) => {
try {
const asarPath = join(packager.getResourcesDir(appOutDir), 'app.asar');
console.log(
asarmor is applying patches to ${asarPath});
const archive = await asarmor.open(asarPath);
archive.patch(); // apply default patches
await archive.write(asarPath);
} catch (err) {
console.error(err);
}
};
`There's a few more steps involved to get encryption working. See example/electron-builder if you'd like to skip ahead to the code.
Steps:
1. Update afterPack.js:
js
exports.default = async ({ appOutDir, packager }) => {
try {
const asarPath = join(packager.getResourcesDir(appOutDir), 'app.asar'); console.log(
\x1B34m•\x1B[0m asarmor encrypting contents of ${asarPath}
);
await encrypt({
src: asarPath,
dst: asarPath,
}); // then patch the header
console.log(
);
const archive = await asarmor.open(asarPath);
archive.patch(); // apply default patches
await archive.write(asarPath);
} catch (err) {
console.error(err);
}
};
`2. Create [beforePack.js
js
const { join } = require('path');
const { copyFile } = require('fs/promises');exports.default = async (context) => {
try {
console.log('copying native dependencies');
const release = join(__dirname, '..', 'node_modules', 'asarmor', 'build', 'Release');
// copy main.node from asarmor to our dist/build/release folder; this will become the entrypoint later on.
await copyFile(
join(release, 'main.node'),
join(
context.packager.info.projectDir,
'release',
'app',
'dist',
'main',
'main.node'
)
);
// copy renderer.node to our dist/build/release folder; the render process will be bootstrapped from the main process later on.
await copyFile(
join(release, 'renderer.node'),
join(
context.packager.info.projectDir,
'release',
'app',
'dist',
'renderer',
'renderer.node'
)
);
} catch (err) {
console.error(err);
}
};
`Don't forget to update
as well:
`diff
"afterPack": "./afterPack.js",
+ "beforePack": "./beforePack.js",
`3. Update your project's package.json entrypoint:
diff
+ "main": "./dist/main/main.node",
- "main": "./dist/main/main.js",
`4. Optional: load configuration hooks at the start of the main process file:
ts
// main.ts
import { allowUnencrypted } from 'asarmor';allowUnencrypted(['node_modules']); // enables resolution of non-encrypted dependencies from
node_modules.asar
5. Update your
configuration settings:
`ts
const mainWindow = new BrowserWindow({
// ...
webPreferences: {
nodeIntegration: true, // MUST BE ENABLED
contextIsolation: false, // MUST BE DISABLED
},
});
`6. Bootstrap the render process:
ts
await mainWindow.webContents.executeJavaScript(!function () {);
`7. Export a default function in the main process, accepting the decryption key as a parameter.
ts
module.exports = function bootstrap(k: Uint8Array) {
// sanity check
if (!Array.isArray(k) || k.length === 0) {
throw new Error('Failed to bootstrap application.');
} // key should be valid at this point, but you can access it here to perform additional checks.
console.log('decryption key: ' + k);
// start the app
if (!process.env.ELECTRON_RUN_AS_NODE) {
app
.whenReady()
.then(() => {
createWindow();
app.on('activate', () => {
if (mainWindow === null) createWindow();
});
})
.catch(console.log);
} else {
console.error('failed to bootstrap main process');
}
};
`$3
The instructions below assume you're using the Vite + TypeScript configuration. You may need to adjust the instructions according to your setup.You can easily include asarmor in your packaging process using a postPackage hook:
ts
import * as asarmor from 'asarmor';const config = {
// ...
hooks: {
// ...
postPackage: async (forgeConfig, buildPath) => {
const asarPath =
${buildPath.outputPaths[0]}/resources/app.asar;
console.log(
asarmor is encrypting all JavaScript files stored in ${asarPath}
);
await asarmor.encrypt({
src: asarPath,
dst: asarPath,
});
console.log();
const archive = await asarmor.open(asarPath);
archive.patch();
await archive.write(asarPath);
},
},
};
`There's a few more steps involved to get encryption working. See example/electron-forge if you'd like to skip ahead to the code.
Steps:
1. Add the following hooks to your
:
`ts
import { join } from 'path';
import { copyFile } from "fs/promises";
import * as asarmor from "asarmor";const config = {
// ...
hooks: {
// ...
packageAfterCopy: async (forgeConfig, buildPath) => {
try {
console.log('copying native asarmor dependencies');
const release = join(__dirname, 'node_modules', 'asarmor', 'build', 'Release');
// copy main.node from asarmor to our build folder; this will become the entrypoint later on.
await copyFile(
join(release, 'main.node'),
join(
buildPath,
'.vite', // change this if you're not using Vite
'build',
'main.node'
)
);
// copy renderer.node to our build folder; the render process will be bootstrapped from the main process later on.
await copyFile(
join(release, 'renderer.node'),
join(
buildPath,
'.vite', // change this if you're not using Vite
'renderer',
'main_window',
'renderer.node'
)
);
// uncomment the line below to copy the final build directory for debugging purposes.
// await cp(buildPath, './tmp', {recursive: true, force: true});
} catch (err) {
console.error(err);
}
},
postPackage: async (forgeConfig, buildPath) => {
const asarPath =
${buildPath.outputPaths[0]}/resources/app.asar;
console.log(
asarmor is encrypting all JavaScript files stored in ${asarPath}
);
await asarmor.encrypt({
src: asarPath,
dst: asarPath,
});
console.log();
const archive = await asarmor.open(asarPath);
archive.patch();
await archive.write(asarPath);
},
},
};
`2. Update your project's package.json entrypoint:
diff
+ "main": ".vite/build/main.node",
- "main": ".vite/build/main.js",
`3. Optional: disable chunk splitting of renderer assets. This is recommended to ensure the renderer assets can be bootstrapped correctly from the main process.
You may choose to skip this step or handle it differently. Whatever you do, make sure you know the import paths as you'll need them in step
. See below for more information.`ts
// vite.renderer.config.ts
return {
// ...
build: {
// ...
// Add the following rollup configuration:
rollupOptions: {
output: {
// Disable chunk splitting.
inlineDynamicImports: true,
entryFileNames: 'assets/[name].js',
chunkFileNames: 'assets/[name].js',
assetFileNames: 'assets/[name].[ext]',
},
},
},
};
`4. Update your
configuration settings:
`ts
const mainWindow = new BrowserWindow({
// ...
webPreferences: {
// preload: path.join(__dirname, 'preload.js'), // MUST BE DISABLED (preload scripts are not supported, see #40)
nodeIntegration: true, // MUST BE ENABLED
contextIsolation: false, // MUST BE DISABLED
},
});
`5. Bootstrap the render process:
ts
await mainWindow.webContents.executeJavaScript(!function () {);
`If you deviated from the default instructions in step
, replace ./assets/index.js with the path to your renderer asset.6. Export a default function in the main process, accepting the decryption key as a parameter.
`ts
export default function bootstrap(k: Uint8Array) {
// sanity check
if (!Array.isArray(k) || k.length === 0) {
throw new Error('Failed to bootstrap application.');
} // key should be valid at this point, but you can access it here to perform additional checks.
console.log('decryption key: ' + k);
// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', createWindow);
// Quit when all windows are closed, except on macOS. There, it's common
// for applications and their menu bar to stay active until the user quits
// explicitly with Cmd + Q.
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
app.quit();
}
});
app.on('activate', () => {
// On OS X it's common to re-create a window in the app when the
// dock icon is clicked and there are no other windows open.
if (BrowserWindow.getAllWindows().length === 0) {
createWindow();
}
});
}
``