C/C++内存遍历与KMP特征搜索

内存遍历，枚举数据，实现特征码扫描。

内存遍历: 每次读入4096字节，然后每16个字符换一次行，遍历内存 0x00401000 - 0x7FFFFFFF。

#include <stdio.h>  
#include <stdlib.h>  
#include <windows.h>  

VOID ScanAddress(HANDLE process)
{
	const DWORD beginAddr = 0x00401000;
	const DWORD endAddr = 0x7FFFFFFF;
	const DWORD pageSize = 4096;

	BOOL _break = FALSE;
	BYTE page[pageSize];
	DWORD tmpAddr = beginAddr;
	while (tmpAddr <= endAddr)
	{
		::ReadProcessMemory(process, (LPCVOID)tmpAddr, &page, pageSize, 0);

		for (int x = 0; x < 4096; x++)
		{
			
			if (x % 16 != 0)
			{
				DWORD ch = page[x];

				if (ch >= 0 && ch <= 15)
				{
					printf("0%x ", ch);
				}
				else
				{
					printf("%x ", ch);
				}
			}
			else
				printf(" | %x \n", tmpAddr);
		}
		tmpAddr += pageSize;
	}
}

int main(int argc, char* argv[])
{
	HANDLE process = ::OpenProcess(PROCESS_ALL_ACCESS, false, 4748);
	ScanAddress(process);
	::CloseHandle(process);

	system("pause");
	return 0;
}

过程：

#include <stdio.h>  
#include <stdlib.h>  
#include <windows.h>  

VOID ScanAddress(HANDLE Process)
{
	const DWORD beginAddr = 0x00401000;
	const DWORD endAddr = 0x7FFFFFFF;

	unsigned char shell[5] = {0x55,0x8b,0xec,0x6a,0xff};
	unsigned char *read = new unsigned char[5];


	for (int x = 0; x < beginAddr; x++)
	{
		DWORD addr = beginAddr + x;
		ReadProcessMemory(Process, (LPVOID)addr, read, 5, 0);
		printf("%x :", addr);
		for (int y = 0; y < 5; y++)
			printf("%02x ",read[y]);
		printf("\n");
	}
}

int main(int argc, char* argv[])
{
	HANDLE process = ::OpenProcess(PROCESS_ALL_ACCESS, false, 1772);
	ScanAddress(process);
	/*
	unsigned char set[] = { 4,41,55 };
	unsigned char aa[] = { 4, 41, 55 };
	int ret = memcmp(set, aa, 3);
	printf("%d \n", ret);
	*/
	//ScanAddress(process);
	//::CloseHandle(process);
	system("pause");
	return 0;
}

寻找开始

#include <stdio.h>  
#include <stdlib.h>  
#include <windows.h>  

VOID ScanAddress(HANDLE Process)
{
	const DWORD beginAddr = 0x00401000;
	const DWORD endAddr = 0x7FFFFFFF;

	unsigned char shell[6] = {0xff,0x75,0x10,0xff,0x75,0x0c};
	
	unsigned char *read = new unsigned char[6];

	for (int x = 0; x < 684032; x++)
	{
		DWORD addr = beginAddr + x;
		ReadProcessMemory(Process, (LPVOID)addr, read, 6, 0);
		int a = memcmp(read, shell, 6);

		if (a == 0)
		{
			printf("%x :", addr);

			for (int y = 0; y < 6; y++)
			{
				printf("%02x ", read[y]);
			}

			printf(" \n");
		}
	}
}
int main(int argc, char* argv[])
{
	HANDLE process = ::OpenProcess(PROCESS_ALL_ACCESS, false, 1772);
	ScanAddress(process);
	system("pause");
	return 0;
}

KMP算法搜索特征码： KMP算法每次在4096字节中寻找特征，成功返回位置，失败返回-1

#include <iostream>
#include <string>

using namespace std;

/* P 为模式串，下标从 0 开始 */
void GetNextval(string SubString, int nextval[])
{
	int SubStringLen = SubString.size();
	int i = 0;
	int j = -1;
	nextval[0] = -1;

	while (i < SubStringLen)
	{
		if (j == -1 || SubString[i] == SubString[j])
		{
			i++; j++;
			if (SubString[i] != SubString[j])
				nextval[i] = j;
			else
				nextval[i] = nextval[j];
		}
		else
		{
			j = nextval[j];
		}
	}
}

/* 在 MainString 中找到 SubString 第一次出现的位置 下标从0开始*/
int KMPSearchString(string MainString, string SubString, int next[])
{
	GetNextval(SubString, next);

	int MainStringIndex = 0;                 // 存储主字符串下标
	int SubStringIndex = 0;                  // 存储子字符串下标
	int MainStringLen = MainString.size();   // 主字符串大小
	int SubStringLen = SubString.size();     // 子字符串大小

	// 循环遍历字符串,因为末尾 '\0' 的存在，所以不会越界
	while (MainStringIndex < MainStringLen && SubStringIndex < SubStringLen)
	{
		// MainString 的第一个字符不匹配或 MainString[] == SubString[]
		if (SubStringIndex == -1 || MainString[MainStringIndex] == SubString[SubStringIndex])
		{
			MainStringIndex++; SubStringIndex++;
		}
		else   // 当字符串匹配失败则跳转
		{
			SubStringIndex = next[SubStringIndex];
		}
	}
	// 最后匹配成功直接返回位置
	if (SubStringIndex == SubStringLen)
		return MainStringIndex - SubStringIndex;
	return -1;
}

int main(int argc, char *argv[])
{
	int next[100] = { 0 };

	char *Str = "e5 8d 64 24 fc ba ff ff ff ff 92 f0 0f c1";
	char *Search = "ba ff ff ff ff 92 f0";

	// 在Str字符串中找Search子串,找到后返回位置
	int ret = KMPSearchString(Str, Search,next);

	printf("%d \n", ret);


	system("pause");
	return 0;
}

将上方代码整合，可实现根据特征码动态打补丁：

int main(int argc, char* argv[])
{
	HANDLE Process = OpenProcess(PROCESS_ALL_ACCESS, false, 2876);

	// 搜索指定特征码的地址数据.
	unsigned char FindCode[6] = { 0xff, 0x75, 0x10, 0xff, 0x75, 0x0c };
	DWORD ret = ScanAddress(Process, FindCode, 6);
	printf("特征地址: %x \n", ret);

	// 给指定位置动态打补丁
	unsigned char Pack[6] = { 0x90, 0x90, 0x90, 0x90, 0x90, 0x90 };
	WriteProcessMemory(Process, (LPVOID)ret, Pack, 6, 0);

	system("pause");
	return 0;
}