JonathanDotCel / KingstVisFontPatcher

Patches the KingstVis logic analyser font (qt's qwindows.dll) so "8" and "B" are more distinct.

KingstVis Font Size Patcher

What

Patch to make 8's and B's more distinct in the KingstVis Logic Analyser

How

Patches qwindows.dll's calls to CreateFontIndirectW

But like...

I'm under no illusion that such a direct binary patch without wildcard searches will hold up, but between the source and the info below, it should be relatively easy to recreate it.

Is it that bad?

Before: Is it an 8 or a B? God himself could not help you here.

After: Awww yeah. Look at that. It's hideous. But legible.

Steps:

• Start spooky bug (X64DBG) and open KingstVis.exe
• At the first sys breakpoint open the Symbols page, select gdi32.dll on the left and breakpoint on CreateFontIndirectW on the right (F2)
• Let it run.
• The first few return addresses to qwindows.dll from the BP will be the same. Ignore those until it changes. ( in my case the first 4 BPs return to an address ending in A2, then switch to BE on 5 )
• Follow this one, we'll code cave it
• RAX/EAX is pretty much always 0 so we'll cram that value into the font struct via code cave ( https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-logfonta )
• @ Drop a JMP instr over call qword ptr ds:[<&CreateFontIndirectw>] to the int3s at the end of the function
• RCX has the logfont struct so mov dword ptr ds:[rcx], eax gives us a 4 byte write instruction in 2 bytes
• Pop in call qword ptr ds:[<&CreateFontIndirectw>]
• And jump back jmp 0x00007FFA545767BE or something similar (E9 DE F8 FF FF)