[Flopik]

Is there a way to allow debug mode with Skype?
It froze the machine when launching in this mode.(I dont like that kind of protection , I still dont know how the crash the os )

[EreTIk]

Connect the kernel-mode debugger: Skype generates debug exceptions in its process

[Flopik]

And why this is crashing the os?

[EreTIk]

And why this is crashing the os?

Сrash or freezing?

It froze the machine when launching in this mode

[newgre]

Skype still has softice protection code.
Apart from that: why do you think you need a kernel debugger anyway? I'd simply use Olly or IDA together with one of the usual debugger hiding plugins and you're done.

[Flopik]

Froze, maybe i didnt wait enough. I like to be able to have Windbg in local kernel mode.

[r2nwcnydc]

What OS are you using? If you are on Vista or windows 7 try using bcdedit with /dbgsettings /start DISABLE. From there you can use the kdbgctrl utilty to enable the kernel debugger once the system has started. This should bypass the startup exceptions and still allow you to do local kernel debugging

http://msdn.microsoft.com/en-us/library ... s.85).aspx

[EreTIk]

F.e. try execute code:

Code: Select all

  bool bDebuggerPresent;
  __try
  {
    __debugbreak();
    bDebuggerPresent = true;
  }
  __except(EXCEPTION_EXECUTE_HANDLER)
  {
    bDebuggerPresent = false;
  }

Without DEBUG mode - normal, with DEBUG mode - hang.
This simple construction is used in some products (for detect debugger), including in Skype. Solution: kernel mode debugger or user mode debugging of target process (as described above)

[aionescu]

You simply need to boot with /noumex and it will no longer freeze.

[r2nwcnydc]

You simply need to boot with /noumex and it will no longer freeze.

This only valid for windows vista and later OSes.. So if he is trying this on XP, /noumex will not work.