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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 v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier()
Date: Fri, 18 Feb 2022 09:07:51 +0800	[thread overview]
Message-ID: <cbfa96be-74a7-92f5-620a-2d820c7f55d8@linux.intel.com> (raw)
In-Reply-To: <20220104015644.2294354-1-baolu.lu@linux.intel.com>

On 1/4/22 9:56 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 1-7]: Detect DMA ownership conflicts during driver binding;
>    [PATCH 8-10]: Add security context management for assigned devices;
>    [PATCH 11-14]: Various cleanups.
> 
> This is also 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 your comments. A new version of this series has
been posted here:

https://lore.kernel.org/linux-iommu/20220218005521.172832-1-baolu.lu@linux.intel.com/

Best regards,
baolu

WARNING: multiple messages have this Message-ID (diff)
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: kvm@vger.kernel.org, rafael@kernel.org,
	David Airlie <airlied@linux.ie>,
	linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
	Stuart Yoder <stuyoder@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier()
Date: Fri, 18 Feb 2022 09:07:51 +0800	[thread overview]
Message-ID: <cbfa96be-74a7-92f5-620a-2d820c7f55d8@linux.intel.com> (raw)
In-Reply-To: <20220104015644.2294354-1-baolu.lu@linux.intel.com>

On 1/4/22 9:56 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 1-7]: Detect DMA ownership conflicts during driver binding;
>    [PATCH 8-10]: Add security context management for assigned devices;
>    [PATCH 11-14]: Various cleanups.
> 
> This is also 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 your comments. A new version of this series has
been posted here:

https://lore.kernel.org/linux-iommu/20220218005521.172832-1-baolu.lu@linux.intel.com/

Best regards,
baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  parent reply	other threads:[~2022-02-18  1:09 UTC|newest]

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-04  1:56 [PATCH v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2022-01-04  1:56 ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 01/14] iommu: Add dma ownership management interfaces Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 10:08   ` Christoph Hellwig
2022-01-04 10:08     ` Christoph Hellwig
2022-01-04 16:41     ` Bjorn Helgaas
2022-01-04 16:41       ` Bjorn Helgaas
2022-01-04 19:23       ` Jason Gunthorpe
2022-01-04 19:23         ` Jason Gunthorpe via iommu
2022-01-06  3:18         ` Lu Baolu
2022-01-06  3:18           ` Lu Baolu
2022-01-06  3:54         ` Lu Baolu
2022-01-06  3:54           ` Lu Baolu
2022-01-06 15:46           ` Jason Gunthorpe
2022-01-06 15:46             ` Jason Gunthorpe via iommu
2022-01-07  1:50             ` Lu Baolu
2022-01-07  1:50               ` Lu Baolu
2022-01-06  3:43       ` Lu Baolu
2022-01-06  3:43         ` Lu Baolu
2022-01-06  3:47       ` Lu Baolu
2022-01-06  3:47         ` Lu Baolu
2022-01-06  3:51       ` Lu Baolu
2022-01-06  3:51         ` Lu Baolu
2022-01-05  6:57     ` Lu Baolu
2022-01-05  6:57       ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 02/14] driver core: Add dma_cleanup callback in bus_type Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 10:08   ` Christoph Hellwig
2022-01-04 10:08     ` Christoph Hellwig
2022-01-04 12:39     ` Jason Gunthorpe
2022-01-04 12:39       ` Jason Gunthorpe via iommu
2022-01-04 13:04       ` Greg Kroah-Hartman
2022-01-04 13:04         ` Greg Kroah-Hartman
2022-02-08  5:55         ` Lu Baolu
2022-02-08  5:55           ` Lu Baolu
2022-02-08 11:35           ` Greg Kroah-Hartman
2022-02-08 11:35             ` Greg Kroah-Hartman
2022-02-14 10:01     ` Greg Kroah-Hartman
2022-02-14 10:01       ` Greg Kroah-Hartman
2022-02-14 10:02   ` Greg Kroah-Hartman
2022-02-14 10:02     ` Greg Kroah-Hartman
2022-01-04  1:56 ` [PATCH v5 03/14] amba: Stop sharing platform_dma_configure() Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 04/14] driver core: platform: Add driver dma ownership management Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-02-14  9:59   ` Greg Kroah-Hartman
2022-02-14  9:59     ` Greg Kroah-Hartman
2022-02-14 13:18     ` Jason Gunthorpe
2022-02-14 13:18       ` Jason Gunthorpe via iommu
2022-02-14 13:37       ` Greg Kroah-Hartman
2022-02-14 13:37         ` Greg Kroah-Hartman
2022-02-14 13:43         ` Jason Gunthorpe
2022-02-14 13:43           ` Jason Gunthorpe via iommu
2022-01-04  1:56 ` [PATCH v5 05/14] amba: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 06/14] bus: fsl-mc: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 07/14] PCI: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-02-14 10:03   ` Greg Kroah-Hartman
2022-02-14 10:03     ` Greg Kroah-Hartman
2022-02-14 12:38     ` Jason Gunthorpe
2022-02-14 12:38       ` Jason Gunthorpe via iommu
2022-02-14 12:51       ` Greg Kroah-Hartman
2022-02-14 12:51         ` Greg Kroah-Hartman
2022-02-14 13:11         ` Jason Gunthorpe
2022-02-14 13:11           ` Jason Gunthorpe via iommu
2022-02-14 13:39           ` Greg Kroah-Hartman
2022-02-14 13:39             ` Greg Kroah-Hartman
2022-02-14 13:43             ` Jason Gunthorpe
2022-02-14 13:43               ` Jason Gunthorpe via iommu
2022-02-15  3:06               ` Lu Baolu
2022-02-15  3:06                 ` Lu Baolu
2022-02-23 18:00   ` Bjorn Helgaas
2022-02-23 18:00     ` Bjorn Helgaas
2022-02-23 18:07     ` Jason Gunthorpe
2022-02-23 18:07       ` Jason Gunthorpe via iommu
2022-01-04  1:56 ` [PATCH v5 08/14] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 09/14] PCI: portdrv: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 17:06   ` Bjorn Helgaas
2022-01-04 17:06     ` Bjorn Helgaas
2022-01-04 19:26     ` Jason Gunthorpe
2022-01-04 19:26       ` Jason Gunthorpe via iommu
2022-01-04 19:51       ` Bjorn Helgaas
2022-01-04 19:51         ` Bjorn Helgaas
2022-01-05  0:35         ` Jason Gunthorpe
2022-01-05  0:35           ` Jason Gunthorpe via iommu
2022-01-06  4:12     ` Lu Baolu
2022-01-06  4:12       ` Lu Baolu
2022-01-06 18:32       ` Bjorn Helgaas
2022-01-06 18:32         ` Bjorn Helgaas
2022-01-07  1:53         ` Lu Baolu
2022-01-07  1:53           ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 10/14] vfio: Set DMA ownership for VFIO devices Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 11/14] vfio: Remove use of vfio_group_viable() Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 12/14] vfio: Delete the unbound_list Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 13/14] vfio: Remove iommu group notifier Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 14/14] iommu: Remove iommu group changes notifier Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 12:48 ` [PATCH v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier() Jason Gunthorpe
2022-01-04 12:48   ` Jason Gunthorpe via iommu
2022-01-05  6:52   ` Lu Baolu
2022-01-05  6:52     ` Lu Baolu
2022-02-18  1:07 ` Lu Baolu [this message]
2022-02-18  1:07   ` Lu Baolu

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