Open source decompressors for many "old" amiga compressors

[AmigaBoy]

Originally Posted by temisu

Googling password protected dms-files lead to me for searching amiga format subscriber disks. But I only found 1 of those

Amiga Format subscriber disks are/were probably the main password protected DMS source. They're available on the AF cover CDs, if you have access to them.

Galaxy once created a thread where he uploaded the disks to the zone. They might be on the FTP. In that thread, Codetapper mentions he's also written a password brute forcer, so he could be useful if you have questions.

Great project btw!

[retrogamer]

How do I use this?

[Genju]

I'm getting the following errors when trying to build the latest git revision in Msys2 x86-64 mode, any idea what could be the problem?

clang++ -Os -Wall -Wsign-compare -Wshorten-64-to-32 -Wno-error=multichar -Wno-multichar -Isrc -std=c++14 -fno-rtti -o DMSDecompressor.o -c src/DMSDecompressor.cpp
src/DMSDecompressor.cpp:201:21: error: no member named 'memset' in the global namespace
        if (clearBuffer) ::memset(rawData.data(),0,_rawSize);
                         ~~^
src/DMSDecompressor.cpp:313:30: error: no member named 'memset' in the global namespace
                        if (_contextBufferSize) ::memset(contextBuffer.data(),0,_contextBufferSize);
                                                ~~^
src/DMSDecompressor.cpp:648:9: error: no member named 'memset' in the global namespace
                                                ::memset(dest+rawChunkLength-missingNo,ch,missingNo);
                                                ~~^
3 errors generated.
make: *** [Makefile:28: DMSDecompressor.o] Error 1

[acd2001]

in DMSDecompressor.cpp add

#include <cstring>

[Genju]

That seems to have done the trick, thanks!

[Leffmann]

Here's a Windows executable if anyone else needs it:

[temisu]

Originally Posted by acd2001

in DMSDecompressor.cpp add

#include <cstring>

I'm currently doing a big cleanup. I'll add this one there as well (or rather <string.h>). but thank you, it helps

In my madness I also wanted to add legacy zip decompressors (easy) as well as all lha/lzh modes but LH2 is giving me serious headache. (The dynamic huffmann tree needs to be constructed exactly as in reference)

I also managed to gather good collection of different stone cracker versions. So that is coming at some point as well, when I get there.

When I have some free moment I'll take a second look to SASC/SHSC stuff as well. The preprocessor there is kinky

In any case, don't lose hope yet. updates are coming.

[chip]

Hi Temisu

The exe you put in the zone, it doesn't work

Indeed it asks for a file (.DLL) which i don't have

Can you please rebuild the exe so that no external library is needed ?

[temisu]

Originally Posted by chip

Hi Temisu

The exe you put in the zone, it doesn't work

Indeed it asks for a file (.DLL) which i don't have

Can you please rebuild the exe so that no external library is needed ?

Yeah, my bad. I edited debug-conf to be static but then I built release. facepalm...

Should be fine now, new upload in the zone.

This is for the brave, since I did not run the usual test suite (just some files) and I made changes to make it compile for MSVC. I'm sure you'll let me know if it is broken.

[chip]

Thanks temisu, i got the new build

I will let you know something as soon as i will find some files to test it

[chip]

Already tested a little

Well, i guess it's better to know what kind of decrunchers "ancient" is able to decompress

Indeed all the ones i tried till now are not recognized

[temisu]

You can find the list here what is supported: https://github.com/temisu/ancient_fo...ster/README.md

If you find out something that is not supported but should be, put files to zone and I can take a look. Funny if no files are supported.

[chip]

Ok, we can do in this way

I will test the decompression another little and i will keep a file for each of the ones not supported

Then i will put a zip in the zone with ALL the files i found till now

Sorry temisu, but at the moment, 3 files tried and 3 format not supported

[chip]

Ok, test finished

This is the list of unsupported formats found

StoneCracker 3.0 (exe)
MasterCruncher 3.0 Addr (exe)
ByteKiller 1.3 (exe)
PowerPacker 4.0 (exe)
StoneCracker4.04 Data (data)
Imploder (exe)

In the zone one file for each of the above

[malko]

The following is displayed when ran from a Win7 (x86) console :

Cette version de ancient.exe n’est pas compatible avec la version de Windows actuellement exécutée. Vérifiez dans les informations système de votre ordinateur si une version x86 (32 bits) ou x64 (64 bits) du programme est requise, puis contactez l’éditeur de logiciel.

-- deepl.com

This version of ancient.exe is not compatible with the currently running version of Windows. Check your computer's system information to see if an x86 (32-bit) or x64 (64-bit) version of the program is required, then contact the software publisher.

[jbl007]

Hi,
My compiler complains about "no member named 'reallocf' in the global namespace". I replaced it with realloc in src/common/MemoryBuffer.cpp as suggested, and now it builds fine.

$ clang++ --version
clang version 7.0.1 (tags/RELEASE_701/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

I tested a bunch of DMS files: different versions, compression types, encryption etc. They all decompressed successfully.

Originally Posted by temisu

I even added plaintext attack to it: if it is bootable image i.e. starting with 'DOS' the password bypassing is lightning fast. (if not, it is just fast)

It looks like plain text attack does not kick in if compression type is NONE. At least it takes a little longer to decompress...

Support for Titanics Cruncher would be nice to have. Source code is not available unfortunately.

[temisu]

Originally Posted by chip

Ok, test finished

This is the list of unsupported formats found

Thanks for uploading examples. Those are indeed unsupported files. Basically

Originally Posted by chip

StoneCracker4.04 Data (data)

This will be supported at some point. (it is in my plans right after SHSC, ARTM, MMCMP)

Originally Posted by chip

StoneCracker 3.0 (exe)
MasterCruncher 3.0 Addr (exe)
ByteKiller 1.3 (exe)
PowerPacker 4.0 (exe)
Imploder (exe)

These are not necessarily feasible to support. I think we already touched this topic earlier but lets go into more detail...

Executables have multiple parts (typically) and part of the executable is the relocation information which the (de)compressor needs to deal with (or use static address). It could be that the executable does not need relocation but this is rare. Also there could be multiple segments which are joined by the compressor or there are flags (for FAST/SLOW memory) which are most likely embedded in either the data compressed or in the decompressor itself. Executable without no instruction how to load it is of very little use.

Further complication is that f.e. powerpacker, imploder executable compressors do not use the same header formats as the data files when embedding to the executable thus finding the bitstream is extra complication.

This means putting this kind of toothpaste back to the tube is rather hard. the "correct" decompression for these files would be to produce uncompressed executable, but this is most likely not possible in the common case. (there are obviously exceptions to the rule). Maybe when everything else is finished I can think of these things, but for now there are many other things to achieve first.

Originally Posted by malko

The following is displayed when ran from a Win7 (x86) console

You are still having 32-bit windows I suppose? If so I can build you another version...

Originally Posted by jbl007

I tested a bunch of DMS files: different versions, compression types, encryption etc. They all decompressed successfully.

This is good news...

Originally Posted by jbl007

It looks like plain text attack does not kick in if compression type is NONE. At least it takes a little longer to decompress...

... and this is not so good news. Care to share the file in zone? Probably fix is simple

Originally Posted by jbl007

Support for Titanics Cruncher would be nice to have. Source code is not available unfortunately.

I'm not afraid of the no-source part. I've already implemented many decompressors just using disassembled code as a reference.

It is again the part of exe-decompression that is hard.

[jbl007]

Zoned uncompressed encrypted dms test image.

[chip]

Thanks for reply temisu

So, summarizing, main goal of ancient is to decompress crunched data, not crunched exe ?

[malko]

Originally Posted by temisu

[...] You are still having 32-bit windows I suppose? If so I can build you another version... [...]

please, yes You can add it in the archive.