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Completed the hook.

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Jazzinghen 2020-05-23 23:24:59 +09:00 committed by Akash Mozumdar
parent 51b217169e
commit ae35f82199
1 changed files with 83 additions and 26 deletions
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75
texthook/engine/engine.cc
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@ -6623,10 +6623,36 @@ bool InsertNitroplusHook()
*
* Hook code: HS-14*8@B5420:TokyoNecro.exe
*
* -
* Debug method:
* Found memory location where the text was written, then used hardware break on write.
* After that found the function that writes the text in, found that the memory pointed
* contains more than just the text. Followed the call stack "upwards" until a function
* that handles only the text copy is found.
*
* Disassembled code:
*
* TokyoNecro.exe+B53F7 - 51 - push ecx
* TokyoNecro.exe+B53F8 - E8 3DC80B00 - call TokyoNecro.exe+171C3A
* TokyoNecro.exe+B53FD - 83 C4 04 - add esp,04
* TokyoNecro.exe+B5400 - 8B 4D F4 - mov ecx,[ebp-0C]
* TokyoNecro.exe+B5403 - 33 C0 - xor eax,eax
* TokyoNecro.exe+B5405 - 64 89 0D 00000000 - mov fs:[00000000],ecx
* TokyoNecro.exe+B540C - 8B E5 - mov esp,ebp
* TokyoNecro.exe+B540E - 5D - pop ebp
* TokyoNecro.exe+B540F - C2 0400 - ret 0004
* TokyoNecro.exe+B5412 - CC - int 3
* TokyoNecro.exe+B5413 - CC - int 3
* TokyoNecro.exe+B5414 - CC - int 3
* TokyoNecro.exe+B5415 - CC - int 3
* TokyoNecro.exe+B5416 - CC - int 3
* TokyoNecro.exe+B5417 - CC - int 3
* TokyoNecro.exe+B5418 - CC - int 3
* TokyoNecro.exe+B5419 - CC - int 3
* TokyoNecro.exe+B541A - CC - int 3
* TokyoNecro.exe+B541B - CC - int 3
* TokyoNecro.exe+B541C - CC - int 3
* TokyoNecro.exe+B541D - CC - int 3
* TokyoNecro.exe+B541E - CC - int 3
* TokyoNecro.exe+B541F - CC - int 3
* TokyoNecro.exe+B5420 - 55 - push ebp ; place to hook
* TokyoNecro.exe+B5421 - 8B EC - mov ebp,esp
* TokyoNecro.exe+B5423 - 6A FF - push -01
@ -6646,20 +6672,47 @@ bool InsertNitroplusHook()
*
* Notes:
*
* The text is contained into the memory location at [ebp+08].
* There's more data above due to the fact that the start of the function is very
* common and it was hooking a wrong function.
*
* The text is contained into the memory location at [esp+04] when hooking the
* code at TokyoNecro.exe+B5420
*
* If the game is hooked right at the main menu it will also catch the real time clock
* rendered there.
*
* There's a second hook that seems to be capturing the game encyclopedia plus
* extra garbage (only when it is brought to screen): /HS4@B5380:tokyonecro.exe
* https://wiki.anime-sharing.com/hgames/index.php?title=AGTH/H-Codes#More_H-Codes.5B74.5D
*
* I can confirm that that function is called consistently at every call of the
* encyclopedia but I don't know what memory location is a positive number in the hook
* code.
* encyclopedia but I don't know what memory location is a positive number in
* the hook code.
*/
bool InsertTokyoNecroHook() {
const BYTE bytecodes[] = {
0x8b, 0x4d, 0xf4, // 8B 4D F4 - mov ecx,[ebp-0C]
0x33, 0xc0, // 33 C0 - xor eax,eax
0x64, 0x89, 0x0d, XX4, // 64 89 0D 00000000 - mov fs:[00000000],ecx
0x8b, 0xe5, // 8B E5 - mov esp,ebp
0x5d, // 5D - pop ebp
0xc2, XX2, // C2 0400 - ret 0004
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0xcc, // CC - int 3
0x55, // 55 - push ebp
0x8b, 0xec, // 8B EC - mov ebp,esp
0x6a, 0xff, // 6A FF - push -01
@ -6675,14 +6728,14 @@ bool InsertTokyoNecroHook() {
0x57, // 57 - push edi
0x8b, 0xd9, // 8B D9 - mov ebx,ecx
0xc7, 0x45, 0xec, XX4, // C7 45 EC 0F000000 - mov [ebp-14],0000000F
0xc7, 0x45, 0xe8, XX4 // C7 45 E8 00000000 - mov [ebp-18],00000000
0xc7, 0x45, 0xe8, XX4 // C7 45 E8 00000000 - mov [ebp-18],00000000 //
};
ULONG range = min(processStopAddress - processStartAddress, MAX_REL_ADDR);
ULONG addr =
MemDbg::findBytes(bytecodes, sizeof(bytecodes), processStartAddress,
processStartAddress + range);
enum {
addr_offset = 0
addr_offset = 32
}; // distance to the beginning of the function
if (addr == 0ull) {
@ -6706,8 +6759,12 @@ bool InsertTokyoNecroHook() {
HookParam hp = {};
hp.address = addr;
hp.offset = -0x14;
hp.index = 8;
// The memory address is held at [ebp+08] at TokyoNecro.exe+B543B, meaning that at
// the start of the function it's right above the stack pointer. Since there's no
// way to do an operation on the value of a register BEFORE dereferencing (e.g.
// (void*)(esp+4) instead of ((void*)esp)+4) we have to go up the stack instead of
// using the data in the registers
hp.offset = 0x4;
hp.type = USING_STRING;
ConsoleOutput("vnreng: INSERT TokyoNecro");