resedit-js

resedit-js is a library that manipulates resouces contained by Windows Executable files. All implementations are written in JavaScript (TypeScript), without using any native binaries. resedit-js works in both Node.js environment and Web environment.

This library is not tested well for modifying and/or signing executables yet. Please be careful with the emitted binaries.

To use from command line, resedit-js-cli is suitable.

The demo page: resedit demo

- Install
- Usage
- Supported formats
- Parsing signed executables
- Signing executables with resedit-js
- Notes
- Examples
- License

Install

``
npm install resedit
`

Usage

- For detailed code using ResEdit namespace, see Examples.
- For more APIs, please see dist directory of the package. And, some test codes may help you for usages.

For ESM (ES Modules):

`js
//import * as PELibrary from 'pe-library';
import * as ResEdit from 'resedit';
`

For CJS (CommonJS modules including classic Node.js scripts):

`js
//const PELibrary = require('pe-library');
const ResEdit = require('resedit');
`

> If your Node.js version is prior to v20.19.5, require cannot be used for 'resedit' package and you must use 'resedit/cjs' package as described in Migrate from v1.x to v2.x (collapsed in Migration from prior resedit versions area).

Supported formats

- Windows Executables (PE Format, such as .exe and .dll), both 32-bit and 64-bit, are supported.
- Executables for 16-bit Windows is not supported.
- .res file is not supported now.
- PNG-based icon data is supported on require('resedit').Resource.IconGroupEntry class.

Parsing signed executables

- Parsing signed executables (by using Authenticode or etc.) is not allowed by default and an exception will be thrown if NtExecutable.from receives a signed binary.
- To parse signed, { ignoreCert: true } object must be passed to the second argument of NtExecutable.from.
- Although the base executable data is signed, NtExecutable.generate will generate unsigned executable binary. If you want to re-sign it, you must use generate-function with signing (see below) or any other signing tool such as Microsoft signtool.

Signing executables with resedit-js

resedit-js provides basic signing process generateExecutableWithSign function, which is based on Authenticode specification and related RFCs.

To keep resedit-js generic library, the followings are required to use signing process.

- Encryption / calculating hash (digest) process (e.g. Node.js built-in crypto module)
- A private key data is implicitly required to encrypt data.
- DER-format certificate binary (such as .cer file data or .p7b file data with DER-format), which is paired with the private key used by encryption process.
- (optional) Generating timestamp data, especially communicating with TSA server (e.g. HTTP/HTTPS API)

These requirements are represented as SignerObject. The caller of generateExecutableWithSign function must implement this object to sign executables.

An example code is here: signTest.mjs

Note that resedit-js only provides basic signing process, and provides as beta version. For example adding more attributes/informations to certificates are not supported now.

> Some digest algorithms, such as SHA3 algorithms, might not be supported by current Windows.

Notes

- It is not strongly recommended that the destination executable file is equal to the source executable file (which is not an intermediate data).

Examples

`js
import * as PELibrary from 'pe-library';
import * as ResEdit from 'resedit';
import * as fs from 'fs';

// load and parse data
const data = fs.readFileSync('MyApp.exe');
// (the Node.js Buffer instance can be specified directly to NtExecutable.from)
const exe = PELibrary.NtExecutable.from(data);
const res = PELibrary.NtExecutableResource.from(exe);

// rewrite resources
// - You can use helper classes as followings:
// - ResEdit.Resource.IconGroupEntry: access icon resource data
// - ResEdit.Resource.StringTable: access string resource data
// - ResEdit.Resource.VersionInfo: access version info data

// -- replace icons

// load icon data from file
// (you can use ResEdit.Data.IconFile to parse icon data)
const iconFile = ResEdit.Data.IconFile.from(fs.readFileSync('MyIcon.ico'));

ResEdit.Resource.IconGroupEntry.replaceIconsForResource(
// destEntries
res.entries,
// iconGroupID
// - This ID is originally defined in base executable file
// (the ID list can be retrieved by ResEdit.Resource.IconGroupEntry.fromEntries(res.entries).map((entry) => entry.id))
101,
// lang ('lang: 1033' means 'en-US')
1033,
// icons (map IconFileItem to IconItem/RawIconItem)
iconFile.icons.map((item) => item.data)
);

// -- replace version

const viList = ResEdit.Resource.VersionInfo.fromEntries(res.entries);
const vi = viList[0];
// setFileVersion will set vi.fixedInfo.fileVersionMS/fileVersionLS and 'FileVersion' string value
// ('1033' means 'en-US')
vi.setFileVersion(1, 0, 0, 0, 1033);
// ('lang: 1033' means 'en-US', 'codepage: 1200' is the default codepage)
vi.setStringValues(
{ lang: 1033, codepage: 1200 },
{
FileDescription: 'My application',
ProductName: 'My product',
}
);
vi.outputToResourceEntries(res.entries);

// write to another binary
res.outputResource(exe);
const newBinary = exe.generate();
fs.writeFileSync('MyApp_modified.exe', Buffer.from(newBinary));
``

License

MIT License