From: Will Deacon <will@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>,
mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
Frank Rowand <frowand.list@gmail.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
boris.ostrovsky@oracle.com, jgross@suse.com,
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Marek Szyprowski <m.szyprowski@samsung.com>,
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"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
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Thierry Reding <treding@nvidia.com>,
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Greg KH <gregkh@linuxfoundation.org>,
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Subject: Re: [PATCH v12 00/12] Restricted DMA
Date: Wed, 16 Jun 2021 13:08:38 +0100 [thread overview]
Message-ID: <20210616120837.GA22783@willie-the-truck> (raw)
In-Reply-To: <20210616062157.953777-1-tientzu@chromium.org>
Hi Claire,
On Wed, Jun 16, 2021 at 02:21:45PM +0800, Claire Chang wrote:
> This series implements mitigations for lack of DMA access control on
> systems without an IOMMU, which could result in the DMA accessing the
> system memory at unexpected times and/or unexpected addresses, possibly
> leading to data leakage or corruption.
>
> For example, we plan to use the PCI-e bus for Wi-Fi and that PCI-e bus is
> not behind an IOMMU. As PCI-e, by design, gives the device full access to
> system memory, a vulnerability in the Wi-Fi firmware could easily escalate
> to a full system exploit (remote wifi exploits: [1a], [1b] that shows a
> full chain of exploits; [2], [3]).
>
> To mitigate the security concerns, we introduce restricted DMA. Restricted
> DMA utilizes the existing swiotlb to bounce streaming DMA in and out of a
> specially allocated region and does memory allocation from the same region.
> The feature on its own provides a basic level of protection against the DMA
> overwriting buffer contents at unexpected times. However, to protect
> against general data leakage and system memory corruption, the system needs
> to provide a way to restrict the DMA to a predefined memory region (this is
> usually done at firmware level, e.g. MPU in ATF on some ARM platforms [4]).
>
> [1a] https://googleprojectzero.blogspot.com/2017/04/over-air-exploiting-broadcoms-wi-fi_4.html
> [1b] https://googleprojectzero.blogspot.com/2017/04/over-air-exploiting-broadcoms-wi-fi_11.html
> [2] https://blade.tencent.com/en/advisories/qualpwn/
> [3] https://www.bleepingcomputer.com/news/security/vulnerabilities-found-in-highly-popular-firmware-for-wifi-chips/
> [4] https://github.com/ARM-software/arm-trusted-firmware/blob/master/plat/mediatek/mt8183/drivers/emi_mpu/emi_mpu.c#L132
>
> v12:
> Split is_dev_swiotlb_force into is_swiotlb_force_bounce (patch 06/12) and
> is_swiotlb_for_alloc (patch 09/12)
I took this for a spin in an arm64 KVM guest with virtio devices using the
DMA API and it works as expected on top of swiotlb devel/for-linus-5.14, so:
Tested-by: Will Deacon <will@kernel.org>
Thanks!
Will
next prev parent reply other threads:[~2021-06-16 12:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 6:21 [PATCH v12 00/12] Restricted DMA Claire Chang
2021-06-16 6:21 ` [PATCH v12 01/12] swiotlb: Refactor swiotlb init functions Claire Chang
2021-06-16 6:21 ` [PATCH v12 02/12] swiotlb: Refactor swiotlb_create_debugfs Claire Chang
2021-06-16 6:21 ` [PATCH v12 03/12] swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used Claire Chang
2021-06-16 6:21 ` [PATCH v12 04/12] swiotlb: Update is_swiotlb_buffer to add a struct device argument Claire Chang
2021-06-16 6:21 ` [PATCH v12 05/12] swiotlb: Update is_swiotlb_active " Claire Chang
2021-06-16 6:21 ` [PATCH v12 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing Claire Chang
2021-06-16 7:39 ` Christoph Hellwig
2021-06-17 0:47 ` Stefano Stabellini
2021-06-16 6:21 ` [PATCH v12 07/12] swiotlb: Move alloc_size to swiotlb_find_slots Claire Chang
2021-06-16 6:21 ` [PATCH v12 08/12] swiotlb: Refactor swiotlb_tbl_unmap_single Claire Chang
2021-06-16 6:21 ` [PATCH v12 09/12] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-06-16 7:39 ` Christoph Hellwig
2021-06-16 6:21 ` [PATCH v12 10/12] swiotlb: Add restricted DMA pool initialization Claire Chang
2021-06-16 6:21 ` [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-06-17 0:09 ` Stefano Stabellini
2021-06-16 6:21 ` [PATCH v12 12/12] of: Add plumbing for " Claire Chang
2021-06-16 12:08 ` Will Deacon [this message]
2021-06-17 6:40 ` [PATCH v12 00/12] Restricted DMA Claire Chang
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