On 26/06/06 11:44, Ian Abbott wrote:
> From: Ian Abbott <[EMAIL PROTECTED]>
> 
> The anti user-DoS mechanism in the USB serial 'visor' driver can fail in
> the following way:
> 
> visor_open: priv->outstanding_urbs = 0
> visor_write: ++priv->outstanding_urbs
> visor_close:
> visor_open: priv->outstanding_urbs = 0
> visor_write_bulk_callback: --priv->outstanding_urbs
> 
> So priv->outstanding_urbs ends up as (unsigned long)(-1).  Not good!

Actually, it's not quite as bad as that, as priv->outstanding_urbs is an
int in visor.c. (It was an unsigned long in the ftdi_sio patch I was
testing.)  So in the case of the visor driver the only effect of the bug
is that it will allow slightly more outstanding URBs (in theory up to
twice as many) before the limiter kicks in.

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <[EMAIL PROTECTED]>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-

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