linux-kernel - Re: [RFT][PATCH v1 5/6] vfio/ccw: Add kmap_local

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20220620153956.GB5502@nvidia.com>
Date:   Mon, 20 Jun 2022 12:39:56 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Nicolin Chen <nicolinc@...dia.com>, kwankhede@...dia.com,
        corbet@....net, hca@...ux.ibm.com, gor@...ux.ibm.com,
        agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
        svens@...ux.ibm.com, zhenyuw@...ux.intel.com, zhi.a.wang@...el.com,
        jani.nikula@...ux.intel.com, joonas.lahtinen@...ux.intel.com,
        rodrigo.vivi@...el.com, tvrtko.ursulin@...ux.intel.com,
        airlied@...ux.ie, daniel@...ll.ch, farman@...ux.ibm.com,
        mjrosato@...ux.ibm.com, pasic@...ux.ibm.com, vneethv@...ux.ibm.com,
        oberpar@...ux.ibm.com, freude@...ux.ibm.com,
        akrowiak@...ux.ibm.com, jjherne@...ux.ibm.com,
        alex.williamson@...hat.com, cohuck@...hat.com,
        kevin.tian@...el.com, jchrist@...ux.ibm.com, kvm@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-s390@...r.kernel.org, intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org
Subject: Re: [RFT][PATCH v1 5/6] vfio/ccw: Add kmap_local_page() for memcpy

On Sun, Jun 19, 2022 at 11:32:07PM -0700, Christoph Hellwig wrote:

> > This helps because we now block io memory from ever getting into these
> > call paths. I'm pretty sure this is a serious security bug, but would
> > let the IBM folks remark as I don't know it all that well..
> 
> Prevent as in crash when trying to convert it to a page?

That or when calling memcpy() on an IO memory PFN that the guest
passed into the dma s/g list the ccw driver is processing.

Jason