mirror of https://github.com/OpenRCT2/OpenRCT2.git
201 lines
5.3 KiB
C
201 lines
5.3 KiB
C
/*****************************************************************************
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* Copyright (c) 2014 Ted John
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* OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
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*
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* This file is part of OpenRCT2.
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*
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* OpenRCT2 is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*****************************************************************************/
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#include <windows.h>
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#include "hook.h"
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void* g_hooktableaddress = 0;
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int g_hooktableoffset = 0;
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int g_maxhooks = 1000;
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void hookfunc(int address, int newaddress, int stacksize, int registerargs[], int registersreturned)
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{
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int i = 0;
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char data[100];
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int registerssaved = 7;
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int n = registersreturned;
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for (; n; registerssaved--) {
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n &= n - 1;
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}
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int numrargs = 0;
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for (int j = 0; ; j++) {
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if (registerargs[j] != END) {
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numrargs++;
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} else {
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break;
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}
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}
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int rargssize = numrargs * 4;
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data[i++] = 0x50; // push eax
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// move stack down for possible existing arguments
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for (int j = 0; j < stacksize; j++) {
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data[i++] = 0x8B; // mov eax, [esp+x]
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data[i++] = 0x44;
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data[i++] = 0xE4;
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data[i++] = (signed char)((4 * (stacksize - j)) + 4);
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data[i++] = 0x89; // mov [esp+x], eax
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data[i++] = 0x44;
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data[i++] = 0xE4;
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data[i++] = (signed char)((4 * (stacksize - j)) - ((registerssaved + stacksize) * 4));
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}
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if (numrargs > 0) {
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// push the registers to be on the stack to access as arguments
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data[i++] = 0x83; // add esp, x
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data[i++] = 0xC4;
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data[i++] = -((registerssaved + stacksize) * 4) + 4;
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for (signed int j = numrargs - 1; j >= 0; j--) {
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switch (registerargs[j]) {
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case EAX: data[i++] = 0x50; break;
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case EBX: data[i++] = 0x53; break;
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case ECX: data[i++] = 0x51; break;
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case EDX: data[i++] = 0x52; break;
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case ESI: data[i++] = 0x56; break;
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case EDI: data[i++] = 0x57; break;
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case EBP: data[i++] = 0x55; break;
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}
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}
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data[i++] = 0x83; // add esp, x
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data[i++] = 0xC4;
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data[i++] = rargssize + ((registerssaved + stacksize) * 4) - 4;
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}
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data[i++] = 0xE8; // call
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data[i++] = 0x00;
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data[i++] = 0x00;
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data[i++] = 0x00;
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data[i++] = 0x00;
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int sizec = i;
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data[i++] = 0x8B; // push eax, [esp] - puts eip in eax
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data[i++] = 0x04;
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data[i++] = 0xE4;
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data[i++] = 0x83; // add eax, x
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data[i++] = 0xC0;
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int sizeoffset = i;
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data[i++] = 0; // set to returnlocation offset later
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data[i++] = 0x89; // mov [esp-20h], eax - put return address on stack
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data[i++] = 0x44;
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data[i++] = 0xE4;
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data[i++] = (signed char)(-(registerssaved * 4) - rargssize - (stacksize * 4)) + 4;
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data[i++] = 0x83; // add esp, x
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data[i++] = 0xC4;
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data[i++] = 4;
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data[i++] = 0x58; // pop eax
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if (!(registersreturned & EAX)) {
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data[i++] = 0x50; // push eax
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}
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if (!(registersreturned & EBX)) {
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data[i++] = 0x53; // push ebx
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}
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if (!(registersreturned & ECX)) {
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data[i++] = 0x51; // push ecx
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}
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if (!(registersreturned & EDX)) {
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data[i++] = 0x52; // push edx
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}
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if (!(registersreturned & EBP)) {
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data[i++] = 0x55; // push ebp
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}
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if (!(registersreturned & ESI)) {
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data[i++] = 0x56; // push esi
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}
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if (!(registersreturned & EDI)) {
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data[i++] = 0x57; // push edi
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}
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data[i++] = 0x83; // sub esp, x
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data[i++] = 0xEC;
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data[i++] = 4 + (stacksize * 4) + rargssize;
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data[i++] = 0xEA; // jmp
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*((int *)&data[i]) = newaddress; i += 4;
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data[i++] = 0x23;
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data[i++] = 0x00;
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data[sizeoffset] = i - sizec;
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// returnlocation:
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data[i++] = 0x83; // sub esp, x
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data[i++] = 0xEC;
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data[i++] = (signed char)(stacksize * -4) - rargssize;
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if (!(registersreturned & EDI)) {
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data[i++] = 0x5F; // pop edi
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}
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if (!(registersreturned & ESI)) {
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data[i++] = 0x5E; // pop esi
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}
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if (!(registersreturned & EBP)) {
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data[i++] = 0x5D; // pop ebp
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}
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if (!(registersreturned & EDX)) {
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data[i++] = 0x5A; // pop edx
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}
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if (!(registersreturned & ECX)) {
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data[i++] = 0x59; // pop ecx
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}
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if (!(registersreturned & EBX)) {
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data[i++] = 0x5B; // pop ebx
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}
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if (!(registersreturned & EAX)) {
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data[i++] = 0x58; // pop eax
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}
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data[i++] = 0xC3; // retn
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WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, i, 0);
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}
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void addhook(int address, int newaddress, int stacksize, int registerargs[], int registersreturned)
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{
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if (!g_hooktableaddress) {
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g_hooktableaddress = VirtualAllocEx(GetCurrentProcess(), NULL, g_maxhooks * 100, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
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}
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if (g_hooktableoffset > g_maxhooks) {
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return;
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}
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unsigned int hookaddress = (unsigned int)g_hooktableaddress + (g_hooktableoffset * 100);
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char data[9];
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int i = 0;
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data[i++] = 0xEA; // jmp
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*((int *)&data[i]) = hookaddress; i += 4;
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data[i++] = 0x23;
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data[i++] = 0x00;
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data[i++] = 0xC3; // retn
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WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, i, 0);
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hookfunc(hookaddress, newaddress, stacksize, registerargs, registersreturned);
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g_hooktableoffset++;
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} |