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Date:   Fri, 30 Nov 2018 14:55:38 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>, gedwards@ddn.com,
        joe@perches.com, lenaic@lhuard.fr, liang.z.li@intel.com,
        mhocko@kernel.org, mhocko@suse.com, stefanha@redhat.com,
        wei.w.wang@intel.com
Subject: Re: [PULL] vhost: cleanups and fixes
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On Fri, Nov 30, 2018 at 11:01:03AM -0800, Bijan Mottahedeh wrote:
> On 11/30/2018 5:44 AM, Michael S. Tsirkin wrote:
> > On Thu, Nov 01, 2018 at 04:06:19PM -0700, Linus Torvalds wrote:
> > > On Thu, Nov 1, 2018 at 4:00 PM Kees Cook <keescook@chromium.org> wrote:
> > > > +       memset(&rsp, 0, sizeof(rsp));
> > > > +       rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
> > > > +       resp = vq->iov[out].iov_base;
> > > > +       ret = __copy_to_user(resp, &rsp, sizeof(rsp));
> > > > 
> > > > Is it actually safe to trust that iov_base has passed an earlier
> > > > access_ok() check here? Why not just use copy_to_user() instead?
> > > Good point.
> > > 
> > > We really should have removed those double-underscore things ages ago.
> > > 
> > > Also, apart from the address, what about the size? Wouldn't it be
> > > better to use copy_to_iter() rather than implement it badly by hand?
> > > 
> > >                 Linus
> > Bijan can you respond please?
> > Are you going to look into this and convert code to copy_to_iter?
> > I don't think we should release Linux like this, so if you don't
> > have the time I'd rather revert for now and you can look
> > into reposting for the next release.
> > 
> > Thanks,
> > 
> 
> Sure, will do.? Can I send an individual patch for the fix to
> vhost_scsi_send_tmf_reject()?
> 
> Thanks.
> 
> --bijan

Please go ahead.

-- 
MST