uninno

Introduction

uninno is a portable unpacking tool for Inno Setup (IS) installers.

It was originally conceived as a means to extract the data files from GOG.com (Good Old Games) installer packages. Back in 2008, when GOG was launched, only Microsoft Windows versions of older PC video games were offered. For many of these games, there exist emulators or engines rewrites that allow them to be played on other operating systems or CPU architectures.

To allow GOG customers to play these games without requiring a Windows system or Windows emulator, uninno was created. It is written in Perl and should run on any platform that has a moderately recent Perl interpreter available.

After initial success, uninno also became a bit of a research project for studying computer language parsing and automatic code generation.

When new InnoSetup versions are released, support for them will occasionally be added to uninno.

Usage

To just use uninno as a Inno Setup extractor, run the uninno.pl utility.

$ ./uninno.pl setup.exe

It will extract all files from the application part of the installer archvive and put them into ./app

Various Perl modules are required. You can either install them from CPAN or using your package manager (if available).

These are:

• Switch
• DateTime
• Digest::CRC
• IO::Uncompress::AnyInflate
• IO::Uncompress::Bunzip2
• Compress::Raw::Lzma
• Crypt::RC4

On Debian/Ubuntu Linux, use the following command to install all dependencies:

$ sudo apt install libswitch-perl libdatetime-perl libdigest-crc-perl libcompress-raw-lzma-perl libtext-glob-perl libio-stringy-perl libcrypt-rc4-perl

Code

uninno consists of a bunch of Perl packages that handle different stages of the analysis and extractiong process. Dissection of the installer executable is provided by Win::Exe, which has some submodules for each of the PE's parts. Setup::Inno provides a frontend for parsing the setup.0 (metadata) and setup.1 (compressed files) parts of the Inno Setup installer.

To improve code reuse and facilitate handling of all the installer versions, all version-specific code is represented by a class hierarchy, starting with a base class containing mostly stubs, continuing with support for the first open source Inno Setup release (2.0.8), and going up to the most recent version. Each class in the hierarchy has override points that implement headers, decompression and custom handling required for this version or its descendants.

Secondary to that is a set of data structure parsers for each exact Inno Setup version. These can be generated from the Inno source code, as outlined below.

Version numbers are coded in 4 digits: x.y.z -> xyzz. The last version part has two digits and is zero padded. Example: 2.0.8 -> 2008

Inno Setup has used many different compression algorithms in the course of its history, with varying degrees of compatibility with standard software. zlib, bzip2, LZMA and LZMA2 compression are supported by uninno, using corresponding Perl modules. LZMA compression uses a lot of memory currently and performance is poor, as the API of Compress::Raw::Lzma is very low-level and hard to use in a straight-forward way. A better implementation may be written in the future.

Starting with support for Inno Setup 5.5.0, a new approach is used to create the various structure parsers. Using a custom Delphi grammar based on an old edition of the Delphi Language Guide, Projects/Struct.pas from the Inno source code is processed and dissected. Then, a Perl module is generated that can parse binary data represented by the data structures in that file. The grammar can be found in DelphiGrammar.pm, the code for the generator is in ParserGenerator.pm.

To generate a new parser, you need the Perl module Marpa::R2. You also need the specific Inno Setup Struct.pas you would like to implement support for. The makeissrc.pl utility can clone the official git repository for you and optionally download and patch in older versions from their respective source files. It will put the repository into ./innosetup by default. The tool needs the tools wget, unzip and git to do its work.

makestruct.pl can then be used to access this repository and to generate a new parser for a specific Inno Setup version.

For example:

$ ./makestruct.pl --src ./innosetup --version 5.5.0u

Versions with a u at the end are Unicode versions, which means that all strings are interpreted as UTF-16. Non-Unicode installers used to have their strings stored in Windows code page 1252, but more recent installer may also specify the used code page in the data structures. Support for this has not been implemented yet. It is recommended to always generate Unicode and non-Unicode versions when creating a parser for a new version. Output will go to Struct5500u.pm in this case, which needs to be put into Setup/Inno/ to make Inno.pm find it.

Links

• Inno Setup: http://www.jrsoftware.org/isinfo.php
• innounp: http://innounp.sourceforge.net/
• Good Old Games: http://www.gog.com
• Object Pascal Language Guide for Delphi: http://tinyurl.com/nowcn6c

Copyright

uninno and all its components are

Copyright © 2012-2019 by Gregor Riepl <[email protected]>
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

    Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.
    
    Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The data extraction routines are generated based on the Inno Setup source code, while the rest of the software was developed independently. See http://www.jrsoftware.org/files/is/license.txt for the Inno Setup license.

No part of the project is affiliated with Inno Setup or its authors.