Re: [PATCH 06/19] nfsd: Check private request size before submitting a SCSI request

["bfields@fieldses.org" <bfields@fieldses.org>]

On Fri, May 26, 2017 at 08:10:03AM +0200, hch@lst.de wrote:
> On Thu, May 25, 2017 at 08:19:47PM +0000, Bart Van Assche wrote:
> > On Thu, 2017-05-25 at 14:48 -0400, J . Bruce Fields wrote:
> > > On Thu, May 25, 2017 at 11:43:14AM -0700, Bart Van Assche wrote:
> > > > Since using scsi_req() is only allowed against request queues for
> > > > which struct scsi_request is the first member of their private
> > > > request data, refuse to submit SCSI commands against a queue for
> > > > which this is not the case.
> > > 
> > > Is it possible we could catch this earlier and avoid giving out the
> > > layout in the first place?
> > 
> > Hello Christoph,
> > 
> > According to what I see in commit 8650b8a05850 you are the author of this
> > code? Can the blk_queue_scsi_pdu(q) test fail in nfsd4_scsi_identify_device()?
> 
> If the user explicitly asked for a scsi layout export of a non-scsi
> device it can.
> 
> > If so, can nfsd4_layout_verify() be modified in such a way that it prevents
> > that nfsd4_scsi_proc_getdeviceinfo() is ever called for a non-SCSI queue?
> > Can you recommend an approach?
> 
> Not easily.  The only thing we could do is an export time check, that
> would refuse the scsi layout export if the device is not capable.
> 
> I can look into that, but it will take some time so for now I think we
> should go ahead with your series.

Fine by me.--b.