Re: [Qemu-devel] [PATCH] Fix ATAPI GET_CONFIGURATION function

[Alexander Graf <agraf@suse.de>]

On May 25, 2008, at 12:38 PM, Carlo Marcelo Arenas Belon wrote:

> Alexander
>
> sorry if I wasn't clear enough.  I wasn't arguing about your patch  
> (which is
> correct) but was trying to explain why the old implementation was  
> done the way
> it was, in an (obviously excessive) effort to prevent a buffer  
> overflow for the
> response (which used to be hardcoded to 32 bytes regardless of the  
> size of the
> buffer) as shown by :
>
>  http://svn.savannah.gnu.org/viewvc/trunk/hw/ide.c?root=qemu&r1=3147&r2=3161
>
> a slightly modified version of your patch (which I'd been using  
> against kvm
> and validated correct with Linux and Solaris guests) attached.
>
> the only difference, is that it handles explicitly the empty buffer  
> case and
> cleans up the len calculation which shouldn't had been calculated
> conditionally as you pointed out.
>
> Carlo
> <kvm-69-qemu-ide-dvdrom.patch>


Hum ... it might be a good idea to inline patches so commenting on  
them is easier.
You don't need to check for max_len > 0, because if max_len == 0 the  
packet will be truncated back to 0 bytes by ide_atapi_cmd_reply(s,  
len, max_len).

Alex