/src/utils/sourcelua/sigscan.cpp

#include <stdio.h>



#ifdef WIN32

	#define WIN32_LEAN_AND_MEAN

	#include <windows.h>

#else

	#include <dlfcn.h>

	#include <sys/types.h>

	#include <sys/stat.h> 

#endif



#include "sigscan.h"



/* There is no ANSI ustrncpy */

unsigned char* ustrncpy(unsigned char *dest, const unsigned char *src, int len) {

	while(len--)

		dest[len] = src[len];



	return dest;

}



/* //////////////////////////////////////

    CSigScan Class

    ////////////////////////////////////// */

unsigned char* CSigScan::base_addr;

size_t CSigScan::base_len;

void *(*CSigScan::sigscan_dllfunc)(const char *pName, int *pReturnCode);



/* Initialize the Signature Object */

void CSigScan::Init(unsigned char *sig, char *mask, size_t len) {

	is_set = 0;



	sig_len = len;

	sig_str = new unsigned char[sig_len];

	ustrncpy(sig_str, sig, sig_len);



	sig_mask = new char[sig_len+1];

	strncpy(sig_mask, mask, sig_len);

	sig_mask[sig_len+1] = 0;



	if(!base_addr)

		return ; // GetDllMemInfo() Failed



	if((sig_addr = FindSignature()) == NULL)

		return ; // FindSignature() Failed



	is_set = 1;

	// SigScan Successful!

}



/* Destructor frees sig-string allocated memory */

CSigScan::~CSigScan(void) {

	delete[] sig_str;

	delete[] sig_mask;

}



/* Get base address of the server module (base_addr) and get its ending offset (base_len) */

bool CSigScan::GetDllMemInfo(void) {

	void *pAddr = (void*)sigscan_dllfunc;

	base_addr = 0;

	base_len = 0;



	#ifdef WIN32

	MEMORY_BASIC_INFORMATION mem;



	if(!pAddr)

		return false; // GetDllMemInfo failed: !pAddr



	if(!VirtualQuery(pAddr, &mem, sizeof(mem)))

		return false;



	base_addr = (unsigned char*)mem.AllocationBase;



	IMAGE_DOS_HEADER *dos = (IMAGE_DOS_HEADER*)mem.AllocationBase;

	IMAGE_NT_HEADERS *pe = (IMAGE_NT_HEADERS*)((unsigned long)dos+(unsigned long)dos->e_lfanew);



	if(pe->Signature != IMAGE_NT_SIGNATURE) {

		base_addr = 0;

		return false; // GetDllMemInfo failed: pe points to a bad location

	}



	base_len = (size_t)pe->OptionalHeader.SizeOfImage;



	#else



	Dl_info info;

	struct stat buf;

	

	if(!dladdr(pAddr, &info))

		return false;

	

	if(!info.dli_fbase || !info.dli_fname)

		return false;

	

	if(stat(info.dli_fname, &buf) != 0)

		return false;

	

	base_addr = (unsigned char*)info.dli_fbase;

	base_len = buf.st_size;

	#endif



	return true;

}



/* Scan for the signature in memory then return the starting position's address */

void* CSigScan::FindSignature(void) {

	unsigned char *pBasePtr = base_addr;

	unsigned char *pEndPtr = base_addr+base_len;

	size_t i;



	while(pBasePtr < pEndPtr) {

		for(i = 0;i < sig_len;i++) {

			if((sig_mask[i] != '?') && (sig_str[i] != pBasePtr[i]))

				break;

		}



		// If 'i' reached the end, we know we have a match!

		if(i == sig_len)

			return (void*)pBasePtr;



		pBasePtr++;

	}



	return NULL;

}