From: Dave Chinner <david@fromorbit.com>
To: James Gowans <jgowans@amazon.com>
Cc: linux-kernel@vger.kernel.org,
Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.org, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
iommu@lists.linux.dev, Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
kvm@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Alexander Graf <graf@amazon.com>,
David Woodhouse <dwmw@amazon.co.uk>,
"Jan H . Schoenherr" <jschoenh@amazon.de>,
Usama Arif <usama.arif@bytedance.com>,
Anthony Yznaga <anthony.yznaga@oracle.com>,
Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>,
madvenka@linux.microsoft.com, steven.sistare@oracle.com,
yuleixzhang@tencent.com
Subject: Re: [RFC 05/18] pkernfs: add file mmap callback
Date: Tue, 6 Feb 2024 10:34:46 +1100 [thread overview]
Message-ID: <ZcFwlu9+LQQWWOz4@dread.disaster.area> (raw)
In-Reply-To: <20240205120203.60312-6-jgowans@amazon.com>
On Mon, Feb 05, 2024 at 12:01:50PM +0000, James Gowans wrote:
> Make the file data useable to userspace by adding mmap. That's all that
> QEMU needs for guest RAM, so that's all be bother implementing for now.
>
> When mmaping the file the VMA is marked as PFNMAP to indicate that there
> are no struct pages for the memory in this VMA. Remap_pfn_range() is
> used to actually populate the page tables. All PTEs are pre-faulted into
> the pgtables at mmap time so that the pgtables are useable when this
> virtual address range is given to VFIO's MAP_DMA.
And so what happens when this file is truncated whilst it is mmap()d
by an application? Ain't that just a great big UAF waiting to be
exploited?
-Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2024-02-05 23:34 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 12:01 [RFC 00/18] Pkernfs: Support persistence for live update James Gowans
2024-02-05 12:01 ` [RFC 01/18] pkernfs: Introduce filesystem skeleton James Gowans
2024-02-05 12:01 ` [RFC 02/18] pkernfs: Add persistent inodes hooked into directies James Gowans
2024-02-05 12:01 ` [RFC 03/18] pkernfs: Define an allocator for persistent pages James Gowans
2024-02-05 12:01 ` [RFC 04/18] pkernfs: support file truncation James Gowans
2024-02-05 12:01 ` [RFC 05/18] pkernfs: add file mmap callback James Gowans
2024-02-05 23:34 ` Dave Chinner [this message]
2024-02-05 12:01 ` [RFC 06/18] init: Add liveupdate cmdline param James Gowans
2024-02-05 12:01 ` [RFC 07/18] pkernfs: Add file type for IOMMU root pgtables James Gowans
2024-02-05 12:01 ` [RFC 08/18] iommu: Add allocator for pgtables from persistent region James Gowans
2024-02-05 12:01 ` [RFC 09/18] intel-iommu: Use pkernfs for root/context pgtable pages James Gowans
2024-02-05 12:01 ` [RFC 10/18] iommu/intel: zap context table entries on kexec James Gowans
2024-02-05 12:01 ` [RFC 11/18] dma-iommu: Always enable deferred attaches for liveupdate James Gowans
2024-02-05 17:45 ` Jason Gunthorpe
2024-02-05 12:01 ` [RFC 12/18] pkernfs: Add IOMMU domain pgtables file James Gowans
2024-02-05 12:01 ` [RFC 13/18] vfio: add ioctl to define persistent pgtables on container James Gowans
2024-02-05 17:08 ` Jason Gunthorpe
2024-02-05 12:01 ` [RFC 14/18] intel-iommu: Allocate domain pgtable pages from pkernfs James Gowans
2024-02-05 17:12 ` Jason Gunthorpe
2024-02-05 12:02 ` [RFC 15/18] pkernfs: register device memory for IOMMU domain pgtables James Gowans
2024-02-05 12:02 ` [RFC 16/18] vfio: support not mapping IOMMU pgtables on live-update James Gowans
2024-02-05 12:02 ` [RFC 17/18] pci: Don't clear bus master is persistence enabled James Gowans
2024-02-05 12:02 ` [RFC 18/18] vfio-pci: Assume device working after liveupdate James Gowans
2024-02-05 17:10 ` [RFC 00/18] Pkernfs: Support persistence for live update Alex Williamson
2024-02-07 14:56 ` Gowans, James
2024-02-07 15:28 ` Jason Gunthorpe
2024-02-05 17:42 ` Jason Gunthorpe
2024-02-07 14:45 ` Gowans, James
2024-02-07 15:22 ` Jason Gunthorpe
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