From: Lu Baolu <baolu.lu@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>
Cc: baolu.lu@linux.intel.com, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Dan Williams <dan.j.williams@intel.com>,
rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
Cornelia Huck <cohuck@redhat.com>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Stuart Yoder <stuyoder@gmail.com>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Thierry Reding <thierry.reding@gmail.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Jonathan Hunter <jonathanh@nvidia.com>,
Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 00/18] Fix BUG_ON in vfio_iommu_group_notifier()
Date: Fri, 17 Dec 2021 14:41:24 +0800 [thread overview]
Message-ID: <acdb63ca-bb13-6688-0914-c1c979151d60@linux.intel.com> (raw)
In-Reply-To: <20211206015903.88687-1-baolu.lu@linux.intel.com>
On 12/6/21 9:58 AM, Lu Baolu wrote:
> Hi folks,
>
> The iommu group is the minimal isolation boundary for DMA. Devices in
> a group can access each other's MMIO registers via peer to peer DMA
> and also need share the same I/O address space.
>
> Once the I/O address space is assigned to user control it is no longer
> available to the dma_map* API, which effectively makes the DMA API
> non-working.
>
> Second, userspace can use DMA initiated by a device that it controls
> to access the MMIO spaces of other devices in the group. This allows
> userspace to indirectly attack any kernel owned device and it's driver.
>
> Therefore groups must either be entirely under kernel control or
> userspace control, never a mixture. Unfortunately some systems have
> problems with the granularity of groups and there are a couple of
> important exceptions:
>
> - pci_stub allows the admin to block driver binding on a device and
> make it permanently shared with userspace. Since PCI stub does not
> do DMA it is safe, however the admin must understand that using
> pci_stub allows userspace to attack whatever device it was bound
> it.
>
> - PCI bridges are sometimes included in groups. Typically PCI bridges
> do not use DMA, and generally do not have MMIO regions.
>
> Generally any device that does not have any MMIO registers is a
> possible candidate for an exception.
>
> Currently vfio adopts a workaround to detect violations of the above
> restrictions by monitoring the driver core BOUND event, and hardwiring
> the above exceptions. Since there is no way for vfio to reject driver
> binding at this point, BUG_ON() is triggered if a violation is
> captured (kernel driver BOUND event on a group which already has some
> devices assigned to userspace). Aside from the bad user experience
> this opens a way for root userspace to crash the kernel, even in high
> integrity configurations, by manipulating the module binding and
> triggering the BUG_ON.
>
> This series solves this problem by making the user/kernel ownership a
> core concept at the IOMMU layer. The driver core enforces kernel
> ownership while drivers are bound and violations now result in a error
> codes during probe, not BUG_ON failures.
>
> Patch partitions:
> [PATCH 1-9]: Detect DMA ownership conflicts during driver binding;
> [PATCH 10-13]: Add security context management for assigned devices;
> [PATCH 14-18]: Various cleanups.
>
> This is part one of three initial series for IOMMUFD:
> * Move IOMMU Group security into the iommu layer
> - Generic IOMMUFD implementation
> - VFIO ability to consume IOMMUFD
Thank you very much for reviewing my series. The v4 of this series has
been posted here:
https://lore.kernel.org/linux-iommu/20211217063708.1740334-1-baolu.lu@linux.intel.com/
Best regards,
baolu
prev parent reply other threads:[~2021-12-17 6:41 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-06 1:58 [PATCH v3 00/18] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2021-12-06 1:58 ` [PATCH v3 01/18] iommu: Add device dma ownership set/release interfaces Lu Baolu
2021-12-06 13:35 ` Joerg Roedel
2021-12-06 14:29 ` Christoph Hellwig
2021-12-06 15:01 ` Jason Gunthorpe
2021-12-07 1:52 ` Lu Baolu
2021-12-06 14:42 ` Christoph Hellwig
2021-12-07 2:07 ` Lu Baolu
2021-12-06 1:58 ` [PATCH v3 02/18] driver core: Add dma_cleanup callback in bus_type Lu Baolu
2021-12-06 1:58 ` [PATCH v3 03/18] driver core: platform: Rename platform_dma_configure() Lu Baolu
2021-12-06 7:53 ` Greg Kroah-Hartman
2021-12-06 14:13 ` Christoph Hellwig
2021-12-06 14:43 ` Greg Kroah-Hartman
2021-12-06 14:45 ` Jason Gunthorpe
2021-12-06 14:47 ` Christoph Hellwig
2021-12-06 15:04 ` Jason Gunthorpe
2021-12-07 1:21 ` Lu Baolu
2021-12-07 23:09 ` Dan Williams
2021-12-06 1:58 ` [PATCH v3 04/18] driver core: platform: Add driver dma ownership management Lu Baolu
2021-12-06 7:54 ` Greg Kroah-Hartman
2021-12-06 14:36 ` Christoph Hellwig
2021-12-06 15:06 ` Jason Gunthorpe
2021-12-07 2:57 ` Lu Baolu
2021-12-07 13:16 ` Jason Gunthorpe
2021-12-07 13:25 ` Christoph Hellwig
2021-12-07 13:30 ` Jason Gunthorpe
2021-12-09 1:20 ` Lu Baolu
2021-12-10 1:23 ` Lu Baolu
2021-12-13 0:50 ` Lu Baolu
2021-12-13 13:24 ` Jason Gunthorpe
2021-12-15 12:24 ` Lu Baolu
2021-12-14 16:35 ` Christoph Hellwig
2021-12-06 1:58 ` [PATCH v3 05/18] amba: " Lu Baolu
2021-12-06 1:58 ` [PATCH v3 06/18] bus: fsl-mc: " Lu Baolu
2021-12-06 1:58 ` [PATCH v3 07/18] PCI: " Lu Baolu
2021-12-06 1:58 ` [PATCH v3 08/18] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu
2021-12-06 1:58 ` [PATCH v3 09/18] PCI: portdrv: " Lu Baolu
2021-12-06 1:58 ` [PATCH v3 10/18] iommu: Add security context management for assigned devices Lu Baolu
2021-12-06 1:58 ` [PATCH v3 11/18] iommu: Expose group variants of dma ownership interfaces Lu Baolu
2021-12-06 1:58 ` [PATCH v3 12/18] iommu: Add iommu_at[de]tach_device_shared() for multi-device groups Lu Baolu
2021-12-06 14:43 ` Christoph Hellwig
2021-12-07 2:33 ` Lu Baolu
2021-12-06 1:58 ` [PATCH v3 13/18] vfio: Set DMA USER ownership for VFIO devices Lu Baolu
2021-12-06 1:58 ` [PATCH v3 14/18] vfio: Remove use of vfio_group_viable() Lu Baolu
2021-12-06 1:59 ` [PATCH v3 15/18] vfio: Delete the unbound_list Lu Baolu
2021-12-06 1:59 ` [PATCH v3 16/18] vfio: Remove iommu group notifier Lu Baolu
2021-12-06 1:59 ` [PATCH v3 17/18] iommu: Remove iommu group changes notifier Lu Baolu
2021-12-06 1:59 ` [PATCH v3 18/18] drm/tegra: Use the iommu dma_owner mechanism Lu Baolu
2021-12-06 12:40 ` Jason Gunthorpe
2021-12-07 2:34 ` Lu Baolu
2021-12-17 6:41 ` Lu Baolu [this message]
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