Does it possible to create a wrapper loader for exe

Question

Does it possible to create a wrapper loader for exe

which will inject DLLs from memory before the program load (not from filesystem) so the exe inside the wrapper can use them freely?
Just like we static link things, but with shared libraries

0

09.01.2024

22 ответов

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Jacob Автор вопроса

void
this is how the most common wallhacks are loaded i...

Interesting. I want to use it for something good. To ship binary which depends on DLL without the DLLs

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09.01.2024

Manav | avoid unnecessary messaging me

But you'll need these to be present somewhere.

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09.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
But you'll need these to be present somewhere.

It has to be on the disk?

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
It has to be on the disk?

Oh i see, yeah you can do that. You mean to load the file then hook up the function pointers?

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09.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
Oh i see, yeah you can do that. You mean to load t...

Imagine a tool which easy to use as UPX you run it like that linkit.exe hello.exe hello.dll -o world.exe And it takes hello.dll and "Link" it so users can use world.exe without need hello.dll

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
Imagine a tool which easy to use as UPX you run it...

Why do that when you can have your app load the dll file and tie up the necessary functions itself.

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09.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
Why do that when you can have your app load the dl...

Because it's much simpler to ship single portable exe many times, And in terms of UX, it's easier for the user too. Download -> And open the exe

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
Because it's much simpler to ship single portable ...

You didn't get what i said

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
It has to be on the disk?

.

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09.01.2024

Jacob Автор вопроса

Jacob
Because it's much simpler to ship single portable ...

/help@thedevs_bot

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09.01.2024

Jacob Автор вопроса

Jacob
Because it's much simpler to ship single portable ...

.

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
.

You still don't get it what I meant. Whereever you choose to "put" your dll file, you embed it in your exe, just adding the contents at the end of your exe file or manually adding it following the elf format guidelines or shipping dll files together with yout app, you can use GetProcAddress() in windoes and dlsym in linux to get function pointers to exported functions

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09.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
You still don't get it what I meant. Whereever you...

Oh now I understand. Does it will work if I can't change the code of hello.exe? just wrap it?

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
Oh now I understand. Does it will work if I can't ...

Yeah since they are function pointers. What those exported functions need is a pointer. It could be pointing to anywhere in the memory

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09.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
Yeah since they are function pointers. What those ...

Interesting. I'm wondering if it should work in general on every exe in windows

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09.01.2024

Manav | avoid unnecessary messaging me

Jacob
Interesting. I'm wondering if it should work in ge...

here's the dumb way to do it :D, const uint8_t dll_data[] = { /* dump the raw dll file data here */ }; typedef int (*SquareFn)(int); int main() { // create a dll file from the above dll_data HANDLE hFile = CreateFileA("a.dll", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); DWORD written; BOOL writeResult = WriteFile(hFile, dll_data, sizeof(dll_data), &written, NULL); CloseHandle(hFile); HMODULE hModule = LoadLibraryA("a.dll"); SquareFn square = (SquareFn)GetProcAddress(hModule, "square"); int result = square(5); FreeLibrary(hModule); DeleteFileA("a.dll"); // Delete the temp file printf("Function result: %d\n", result); return 0; } the fun.c file which i create a dll out of, __declspec(dllexport) int square(int num) { return num * num; }

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10.01.2024

Manav | avoid unnecessary messaging me

Jacob
Interesting. I'm wondering if it should work in ge...

It should unless your shared library doesn't do something which depends on the specific version of windows

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10.01.2024

²

Manav | avoid unnecessary messaging me
here's the dumb way to do it :D, const uint8_t dl...

embedded thing?

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10.01.2024

Manav | avoid unnecessary messaging me

²
embedded thing?

Well it is kind of embedding it, but not quite right. I am just trying to avoid manual dll initialization. To do that you'll need to deal the executable format for the particular OS.

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10.01.2024

Jacob Автор вопроса

Manav | avoid unnecessary messaging me
Well it is kind of embedding it, but not quite rig...

Isn't there some c++ library for load dll from memory easily? Maybe even cross platform

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10.01.2024

Manav | avoid unnecessary messaging me

Jacob
Isn't there some c++ library for load dll from mem...

i don't think you'll find cross platform solutions but there's this which exists https://github.com/fancycode/MemoryModule

0

10.01.2024