Re: [PATCH] SCSI: sanitize INQUIRY strings

["Philip R. Auld" <pauld@egenera.com>]

Hi,


Rumor has it that on Mon, Aug 21, 2006 at 11:35:46AM -0600 Matthew Wilcox said:
> On Mon, Aug 21, 2006 at 12:52:18PM -0400, Alan Stern wrote:
> > On Mon, 21 Aug 2006, Matthew Wilcox wrote:
> > 
> > > On Mon, Aug 21, 2006 at 12:03:21PM -0400, Alan Stern wrote:
> > > > This patch (as766) sanitizes the Vendor, Product, and Revision strings
> > > > contained in an INQUIRY result, by setting all non-graphic or
> > > > non-ASCII characters to ' '.  Since the standard disallows such
> > > > characters, this will affect only non-compliant devices.
> > > 
> > > I thiink you attached the wrong patch; it doesn't match the description
> > > at all.
> > 
> > No; it does match the description.  But you have to read it carefully, 
> > because the majority of the patch implements optimizations made possible 
> > by the small piece that does the actual sanitizing.
> 
> The description should have said that.  I don't know what you're trying
> to accomplish with pulling the length byte out of the inquiry data, for
> example.
> 
> In any case, you didn't address my point that a NUL byte is probably
> meant to terminate the string, not merely be treated equivalently to
> a space.  Of course, we can do anything here, the device is out of spec,
> but in terms of trying to ascertain the intention of the drug-crazed
> hobo^W^W^W^W engineer who wrote the firmware, I think your interpretation
> is less likely.

As far as I can tell Alan is not trying to "ascertain the intention"
of the firmware engineer, drug-crazed or otherwise. He is making sure
that the array of bytes is printable. You, I think, are trying to
get him to interepret the out-of-spec values. I think that's a
mistake. It's not a string so NUL byte termination does not 
apply. It's an array of what should be printable characters 
of the specified length.


Cheers,


Phil

-- 
Philip R. Auld, Ph.D.  	        	       Egenera, Inc.    
Software Architect                            165 Forest St.
(508) 858-2628                            Marlboro, MA 01752