import KernelEx-4.5.2

vxd/patch.cpp

@@ -0,0 +1,223 @@
+/*
+ *  KernelEx
+ *  Copyright (C) 2010-2011, Xeno86
+ *
+ *  This file is part of KernelEx source code.
+ *
+ *  KernelEx is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published
+ *  by the Free Software Foundation; version 2 of the License.
+ *
+ *  KernelEx is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GNU Make; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <windows.h>
+#include <cassert>
+#include "patch.h"
+#include "debug.h"
+
+extern "C" {
+#define WANTVXDWRAPS
+#include <vmm.h>
+#include <vxdwraps.h>
+};
+
+#ifdef _DEBUG
+
+const struct
+{
+	MessageID id;
+	const char* desc;
+}
+MessageText[] =
+{
+    IDS_NOPAT,               "ERROR: %s: pattern not found",
+    IDS_MULPAT,              "ERROR: %s: multiple pattern matches",
+    IDS_FAILSEC,             "ERROR: Failed to allocate %s section memory",
+    IDS_ERRCHECK,            "ERROR: Checksum error",
+    IDS_WINVER,              "Incompatible Windows version",
+    IDS_DOWNGRADE,           "Can't downgrade. Please uninstall currently installed version of KernelEx before continuing.",
+};
+
+#endif
+
+void Patch::ShowError(MessageID id, ...)
+{
+#ifdef _DEBUG
+	const char* format = NULL;
+	char out[512];
+	va_list vargs;
+	
+	va_start(vargs, id);
+	for (int i = 0 ; i < sizeof(MessageText) / sizeof(MessageText[0]) ; i++)
+	{
+		if (MessageText[i].id == id)
+		{
+			format = MessageText[i].desc;
+			break;
+		}
+	}
+
+	assert(format != NULL);
+
+	_Vsprintf(out, const_cast<char*>(format), vargs);
+	va_end(vargs);
+	strcat(out, "\n");
+	debug_printf(out);
+#endif
+	abort();
+}
+
+int Patch::find_pattern(DWORD offset, int size, const short* pattern, 
+						int pat_len, DWORD* found_loc)
+{
+	DWORD end_offset = offset + size - pat_len;
+	int found = 0;
+
+	for (DWORD i = offset ; i <= end_offset ; i++)
+	{
+		if (pattern[0] < 0 || *(unsigned char*)i == pattern[0])
+		{
+			int j;
+			for (j = 1 ; j < pat_len ; j++)
+			{
+				if (pattern[j] >= 0 && *(unsigned char*)(i + j) != pattern[j]) 
+					break;
+			}
+			if (j == pat_len) //pattern found
+			{
+				*found_loc = i;
+				found++;
+			}
+		}
+	}
+	return found;
+}
+
+void Patch::set_pattern(DWORD loc, const short* new_pattern, int pat_len)
+{
+	unsigned char* offset = (unsigned char*) loc;
+	const short* pat_ptr = new_pattern;
+
+	while (pat_len--)
+	{
+		if (*pat_ptr != -1)
+			*offset = *pat_ptr & 0xff;
+		offset++;
+		pat_ptr++;
+	}
+
+	pagelock(loc, pat_len);
+}
+
+DWORD Patch::decode_call(DWORD addr, int len)
+{
+	unsigned char* code = (unsigned char*)addr;
+
+	/* CALL rel32 */
+	if (code[0] == 0xe8)
+	{
+		if (len && len == 5 || !len)
+		return (DWORD)((DWORD)code + 5 + *(INT32*)(code + 1));
+	}
+	/* CALL imm32 */
+	else if (code[0] == 0xff && code[1] == 0x15)
+	{
+		if (len && len == 6 || !len)
+		return *(DWORD*)(code + 2);
+	}
+	/* unmatched */
+	return 0;
+}
+
+DWORD Patch::decode_jmp(DWORD addr, int len)
+{
+	unsigned char* code = (unsigned char*)addr;
+
+	/* JMP rel8 */
+	if (code[0] == 0xeb)
+	{
+		if (len && len == 2 || !len)
+		return (DWORD)((DWORD)code + 2 + *(INT8*)(code + 1));
+	}
+	/* JMP rel32 */
+	else if (code[0] == 0xe9)
+	{
+		if (len && len == 5 || !len)
+		return (DWORD)((DWORD)code + 5 + *(INT32*)(code + 1));
+	}
+	/* JMP imm32 */
+	else if (code[0] == 0xff && code[1] == 0x25)
+	{
+		if (len && len == 6 || !len)
+		return *(DWORD*)(code + 2);
+	}
+	/* Jxx rel8 */
+	else if (code[0] >= 0x70 && code[0] < 0x7f || code[0] == 0xe3)
+	{
+		if (len && len == 2 || !len)
+		return (DWORD)((DWORD)code + 2 + *(INT8*)(code + 1));
+	}
+	/* Jxx rel32 */
+	else if (code[0] == 0x0f && code[1] >= 0x80 && code[1] <= 0x8f)
+	{
+		if (len && len == 6 || !len)
+		return (DWORD)((DWORD)code + 6 + *(INT32*)(code + 2));
+	}
+	/* unmatched */
+	return 0;
+}
+
+bool Patch::is_call_ref(DWORD loc, DWORD target)
+{
+	DWORD addr = decode_call(loc, 5); // size of call imm32 opcode
+	if (addr == target)
+		return true;
+	return false;
+}
+
+// Both addresses have to be from the same section!
+void Patch::set_call_ref(DWORD loc, DWORD target)
+{
+	DWORD rel;
+
+	assert(*(BYTE*) loc == 0xe8);
+
+	rel = target - (loc + 5);
+	*(DWORD*)(loc + 1) = rel;
+	pagelock(loc + 1, sizeof(DWORD));
+}
+
+// Both addresses have to be from the same section!
+void Patch::set_jmp_ref(DWORD loc, DWORD target)
+{
+	DWORD rel;
+	unsigned char* code = (unsigned char*)loc;
+
+	if (code[0] == 0xe9)
+	{
+		rel = target - (loc + 5);
+		*(DWORD*)(loc + 1) = rel;
+		pagelock(loc + 1, sizeof(DWORD));
+	}
+	else if (code[0] == 0x0f && code[1] >= 0x80 && code[1] <= 0x8f)
+	{
+		rel = target - (loc + 6);
+		*(DWORD*)(loc + 2) = rel;
+		pagelock(loc + 2, sizeof(DWORD));
+	}
+	else assert(false);
+}
+
+void Patch::pagelock(DWORD addr, DWORD count)
+{
+	_LinPageLock(PAGE(addr), NPAGES((addr & PAGEMASK) + count), 0);
+}