Detect VirtualBox (Bios Brand & Bios Version Trick)

//http://waleedassar.blogspot.com (@waleedassar)
//Reading "SMBiosData" to extract Bios Brand and Bios Version strings from registry.
//If the Bios Brand string is "innotek GmbH" or Bios Version is "VirtualBox", then it is a sign that we are running in VirtualBox.
//You can also use WMI to extract the same info.
#include "stdafx.h"
#include "windows.h"
#include "stdio.h"


void AllToUpper(char* str,unsigned long len)
{
    for(unsigned long c=0;c<len;c++)
    {
        if(str[c]>='a' && str[c]<='z')
        {
            str[c]-=32;
        }
    }
}

unsigned char* ScanDataForString(unsigned char* data,unsigned long data_length,unsigned char* string2)
{
    unsigned long string_length=strlen((char*)string2);
    for(unsigned long i=0;i<=(data_length-string_length);i++)
    {
        if(strncmp((char*)(&data[i]),(char*)string2,string_length)==0) return &data[i];
    }
    return 0;
}

int main(int argc, char* argv[])
{
    HKEY hk=0;
    int ret=RegOpenKeyEx(HKEY_LOCAL_MACHINE,"SYSTEM\\CurrentControlSet\\Services\\mssmbios\\data",0,KEY_ALL_ACCESS,&hk);
    if(ret==ERROR_SUCCESS)
    {
        unsigned long type=0;
        unsigned long length=0;
        ret=RegQueryValueEx(hk,"SMBiosData",0,&type,0,&length);
        if(ret==ERROR_SUCCESS)
        {
            if(length)
            {
                char* p=(char*)LocalAlloc(LMEM_ZEROINIT,length);
                if(p)
                {
                    ret=RegQueryValueEx(hk,"SMBiosData",0,&type,(unsigned char*)p,&length);
                    if(ret==ERROR_SUCCESS)
                    {
                          AllToUpper(p,length);
                          unsigned char* x1=ScanDataForString((unsigned char*)p,length,(unsigned char*)"INNOTEK GMBH");
                          unsigned char* x2=ScanDataForString((unsigned char*)p,length,(unsigned char*)"VIRTUALBOX");
                          unsigned char* x3=ScanDataForString((unsigned char*)p,length,(unsigned char*)"SUN MICROSYSTEMS");
                          unsigned char* x4=ScanDataForString((unsigned char*)p,length,(unsigned char*)"VIRTUAL MACHINE");
                          unsigned char* x5=ScanDataForString((unsigned char*)p,length,(unsigned char*)"VBOXVER");
                          if(x1 || x2 || x3 || x4 || x5)
                          {
                              printf("VirtualBox detected\r\n");
                              printf("Some Strings found:\r\n");
                              if(x1) printf("%s\r\n",x1);
                              if(x2) printf("%s\r\n",x2);
                              if(x3) printf("%s\r\n",x3);
                              if(x4) printf("%s\r\n",x4);
                              if(x5) printf("%s\r\n",x5);
                          }
                    }
                    LocalFree(p);
                }
            }
        }
        RegCloseKey(hk);
    }
    return 0;
}