WriteFile writing filename to file

Question

I'm getting quite a strange problem.

I'm hooking to the Winsock function on the Xbox 360, send. This function is called a-lot in the application I'm trying to dump the Http Request information from.

First I will show the code and explain my issue:

WritetoFile function.

BOOL WritetoFile(char* filename, char* buffer, DWORD len)
{

 // Setup expansion 
 doMountPath("Hdd:", "\\Device\\Harddisk0\\Partition1");    

 //print
 printf("Creating %s\n", filename);

 //create our file
 HANDLE fileHandle = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_WRITE, NULL, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);

 //does file exist?
 if(fileHandle!=INVALID_HANDLE_VALUE)
 {
     //print
     printf("Writing to file... \n");

     //bytes written parameter
     DWORD wfbr;

     //write to our file
     if(WriteFile(fileHandle, (void*)&buffer, len, &wfbr, NULL))
     {
         printf("File written! (Bytes Written:%u) \n", wfbr);
     } else {
         printf("Error writing to file: (Error:%u)\n", GetLastError());
     }

    //close our file handle
    CloseHandle(fileHandle);
  } else {
      printf("Error creating file: (Error:%u)\n", GetLastError());
 }

 return true;
}

Winsock hook

INT WINSOCK_SEND_HOOK(SOCKET s,const char FAR *buf,int len,int flags) 
{
memcpy(SocketData.SendData, buf, len);

if(len>40)
{
    WINSOCK_SEND_COUNT +=1;

    char Filename[40];
    sprintf(Filename, "Hdd:\\Dump\\Send\\Winsock_Send_%d.txt", WINSOCK_SEND_COUNT);
    WritetoFile(Filename, SocketData.SendData, len);


} else { printf("Winsock skipped\n"); }
memset(SocketData.SendData, 0, 0x1388);

return send(s, buf, len, flags);
}

The problem is pretty difficult to explain. So the first time I ran my .dll to hook onto this function it worked fine up until tries to create 'Winsock_Send_85.txt'. It prints this:

  `Creating b0ZEK0EwSDBwSXR2RW5EdXd5ZXFnN1IrLzFQYno4RmN0ZnI2MnNnWWQwb2JXMGlYbEdQRkxGOXFkdHJabiszb1I2MG1vUFlkSjBJVW0xcFB4UzZxWEtqZEVYSjEvQmJtOHhmMUdVMDlZaHA2SUtWZTJjb0ZVU1RsUTlvYXJhc0NDOHJNUitlUDBaQmVSOTNUWVM1TU1hLzB0NlhGZmQ2dE1CVDRKVTRxdzliRUtlRmVvVGgvaVdoMUFBczBpNzhkcXNlVUYwaTlQT3B5ekdyeU9ZTzU0QWYyVXpUSXZiTDMzRWl4SXhzOUJOZDZxaWtDQUlNQmZkNHRYVTNaS2pKZngxRmd3dXE2QnRIYmkySlgxcE9vUjFyVlRpci9iZHdTZTZEOTJDSXFqNkNqM0lSaDY1N3VKUzhOQ3VxaFZpclhTUnZMZlJCN21mTS9aV2dCRUJNWHBVeUdZcGxqOVNGUÿÿexception code=0xc0000005 thread=0xf9000044 address=0x910d0a00 read=0x910d0a00 firstxbWatson: Xbox is restarting`

And crashes. After restarting the console I then run it again and it works fine and doesnt crash but it's now writing the incorrect data to the files which is all the same repetitive data even though the buffer points to different data. This is what it writes to file:

‘ÀÛ(       W              
 ÿÿÿÿÿÿÿÿ      ÿÿÿÿ‘Á  Hdd:\Dump\Send\Winsock_Send_87.txt   ‚i夀…Ü                  H>

I then discovered a way to stop this from happening which was to unplug the console entirely from all power but then it goes back to the first issue.

Please ignore what you may think be un-necessary uses of memcpy.

Answer 1

The problem was solved pretty quickly (embarrassing) and I cant believe I was struggling with this for 1 hour, silly mistake.

I wasn't checking the size of the buffer therefore I wasn't allocating enough memory.