Re: [PATCH 06/20] staging/lustre: fix comparison between signed and unsigned

[Greg Kroah-Hartman]

On Mon, Feb 02, 2015 at 04:02:31PM +0300, Dan Carpenter wrote:
> On Sun, Feb 01, 2015 at 09:52:05PM -0500, green@xxxxxxxxxxxxxx wrote:
> > From: Dmitry Eremin <dmitry.eremin@xxxxxxxxx>
> > 
> > Expression if (size != (ssize_t)size) is always false.
> > Therefore no bounds check errors detected.
> 
> The original code actually worked as designed.  The integer overflow
> could only happen on 32 bit systems and the test only was true for 32
> bit systems.
> 
> > -	if (size != (ssize_t)size)
> > +	if (size > ~((size_t)0)>>1)
> >  		return -1;
> 
> The problem is that the code was unclear.  I think the new code is even
> more complicated to look at.

I agree, I don't even understand what the new code is doing.

What is this code supposed to be protecting from?  And -1?  That should
never be a return value...

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/