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VirtualAllocEx Problems

 
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muse4665
How do I cheat?
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Joined: 18 Feb 2018
Posts: 4

PostPosted: Mon Feb 19, 2018 10:25 am    Post subject: VirtualAllocEx Problems Reply with quote

Hello,

I'm trying to alloc memory in c# in a similar manner that cheats engine does. My current goal is to use VirtualAllocEx to allocate 4096 bytes of memory at the base address of the game - 0x10000. I will then write to this memory for an injection/hook(I'm kinda new, don't quite know the terminology yet).

So here is what I have been doing.

1) use cheat engine to alloc() memory that I can use in step 2
2) Write memory to 2 places to do desired function.

here is the auto assembly I have been using for step 1.
Code:

[ENABLE]
 
alloc(newmem,$1000,"theHunterCotW_F . exe")
 
newmem:
 
 
[DISABLE]
 
dealloc(newmem)


Cheat engine puts that newly allocated memory at (the base address of the game - 0x10000)

Here is the c# code that writes to the memory
Code:

        // Every thing in here works as intended
        private void button2_Click(object sender, EventArgs e)
        {
            // part that finds a pattern and replaces some stuff
            PatternScanner patternscanner = new PatternScanner(hProcess);
            patternscanner . SelectModule(gameProcess . MainModule);
            long timetookms;
            ulong offset = patternscanner . FindPattern("F3 0F 11 84 8B 68 05 00 00 F3 41 0F 10 00 0F 2F C2", out timetookms); // The pattern scanner works good and finds correct place
            WriteByteArray((IntPtr)offset, new byte[] { 0xE9, 0xE9, 0xDB, 0xBB, 0xFF, 0x90, 0x90, 0x90, 0x90 }); // The memory class works too
 
            // part that writes to the blank memory from cheat engine
            IntPtr lpAddress = baseaddress - 0x10000;
            WriteByteArray(lpAddress, new byte[] { 0xC7, 0x84, 0x8B, 0x68, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE9, 0x0B, 0x24, 0x44, 0x00, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90 });
        }


This whole dance above works a treat, but I don't want to use cheat engine to allocate this memory.

So I tried not doing step 1 with cheat engine but rather doing it with VirtualAllocEx.

Here is the code I used for that




Code:
                // Alloc doesn't work
        private void withVirtAlloc()
        {
            // part that finds a pattern and replaces some stuff
            PatternScanner patternscanner = new PatternScanner(hProcess);
            patternscanner . SelectModule(gameProcess.MainModule);
            long timetookms;
            ulong offset = patternscanner . FindPattern("F3 0F 11 84 8B 68 05 00 00 F3 41 0F 10 00 0F 2F C2", out timetookms); // The pattern scanner works good and finds correct place
            WriteByteArray((IntPtr)offset, new byte[] { 0xE9, 0xE9, 0xDB, 0xBB, 0xFF, 0x90, 0x90, 0x90, 0x90 }); // The memory class works too
 
            // part that writes to the blank memory from cheat engine
            IntPtr lpAddress = baseaddress - 0x10000;
            // AllocationType . Commit = 0x1000; VirtualMemoryProtection . PAGE_EXECUTE_READWRITE = 0x40
            IntPtr thing = VirtualAllocEx(hProcess, lpAddress, 4096, (uint)AllocationType . Commit, (uint)VirtualMemoryProtection . PAGE_EXECUTE_READWRITE);
            MessageBox . Show(thing . ToString() + " | " + Marshal . GetLastWin32Error()); // Show 0 | 487
            WriteByteArray(lpAddress, new byte[] { 0xC7, 0x84, 0x8B, 0x68, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE9, 0x0B, 0x24, 0x44, 0x00, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90 });
        }


This code doesn't work because of the VirtualAllocEx's 487 error. From what i've read the 487 could mean invaild address, but I set a breakpoint and the address is the same place where cheat engine would have put it.

I've been stuck on this one for the past couple of days and I would love some advice on where to go from here. Maybe I have to use a VirtualProtectEx.

I had to put spaces betweeen all the periods
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Dark Byte
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Joined: 09 May 2003
Posts: 25262
Location: The netherlands

PostPosted: Mon Feb 19, 2018 11:29 am    Post subject: Reply with quote

try (uint)AllocationType.Commit | (uint)AllocationType.Reserve

also, I assume baseaddress is correct? Because it doesn't seem to get set

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muse4665
How do I cheat?
Reputation: 0

Joined: 18 Feb 2018
Posts: 4

PostPosted: Mon Feb 19, 2018 12:01 pm    Post subject: Reply with quote

Quote:
try (uint)AllocationType . Commit | (uint)AllocationType . Reserve


That did it, thank you soooooo much.
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