Re: [PATCH] USB Pegasus driver - avoid a potential NULL pointer dereference.

Forget this :-)

All my problem came from the usage of a buffer inialized by usb-serial.c that is too small for my module.. So I was writing or reading outside the memory allocation dedicated to the urb structure....


Alain

-----Message d'origine-----
De : Oliver Neukum [mailto:[email protected]] 
Envoyé : dimanche 29 juillet 2007 21:42
À : [email protected]
Cc : [email protected]
Objet : Re: [linux-usb-devel] [PATCH] USB Pegasus driver - avoid a potential NULL pointer dereference.

Am Sonntag 29 Juli 2007 schrieb [email protected]:
> I have the same problem in my development..
> 
> Somewhere  in my code:
> 
>         unsigned char *data = urb->transfer_buffer ;
> ....
>         if ( data == NULL )
>                         dbg("%s - data is NULL !!!",__FUNCTION__ );
> 
>         if ( urb->actual_length == 1  && data != NULL )
>                 len = (int) data[0];
> 
> 
> If I don’t do this check in a usb callback function, I have kernel panic
> deference to null pointer !
> But the fun stuff in this story is that I never see the debug " data is NULL
> !!! " so This never happen if I do this check....

urb->transfer_buffer is set by the caller. Usbcore should never change
it. What do you set it to?

	Regards
		Oliver



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