From: Claire Chang <tientzu@chromium.org>
To: robh+dt@kernel.org, frowand.list@gmail.com, hch@lst.de,
m.szyprowski@samsung.com, robin.murphy@arm.com
Cc: devicetree@vger.kernel.org, heikki.krogerus@linux.intel.com,
saravanak@google.com, suzuki.poulose@arm.com,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
bgolaszewski@baylibre.com, iommu@lists.linux-foundation.org,
drinkcat@chromium.org, tientzu@chromium.org,
dan.j.williams@intel.com, treding@nvidia.com
Subject: [RFC v2 0/5] Restricted DMA
Date: Tue, 28 Jul 2020 13:01:35 +0800 [thread overview]
Message-ID: <20200728050140.996974-1-tientzu@chromium.org> (raw)
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 on one MTK platform 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. The
restricted DMA is implemented by per-device swiotlb and coherent memory
pools. 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. in ATF on some ARM
platforms).
[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/
Claire Chang (5):
swiotlb: Add io_tlb_mem struct
swiotlb: Add device swiotlb pool
swiotlb: Use device swiotlb pool if available
dt-bindings: of: Add plumbing for restricted DMA pool
of: Add plumbing for restricted DMA pool
.../reserved-memory/reserved-memory.txt | 35 ++
drivers/iommu/intel/iommu.c | 8 +-
drivers/of/address.c | 39 ++
drivers/of/device.c | 3 +
drivers/of/of_private.h | 6 +
drivers/xen/swiotlb-xen.c | 4 +-
include/linux/device.h | 4 +
include/linux/dma-direct.h | 8 +-
include/linux/swiotlb.h | 49 +-
kernel/dma/direct.c | 8 +-
kernel/dma/swiotlb.c | 418 +++++++++++-------
11 files changed, 393 insertions(+), 189 deletions(-)
--
v1: https://lore.kernel.org/patchwork/cover/1271660/
Changes in v2:
- build on top of swiotlb
2.28.0.rc0.142.g3c755180ce-goog
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next reply other threads:[~2020-07-28 5:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 5:01 Claire Chang [this message]
2020-07-28 5:01 ` [RFC v2 1/5] swiotlb: Add io_tlb_mem struct Claire Chang
2020-07-28 5:01 ` [RFC v2 2/5] swiotlb: Add device swiotlb pool Claire Chang
2020-07-28 5:01 ` [RFC v2 3/5] swiotlb: Use device swiotlb pool if available Claire Chang
2020-07-28 5:01 ` [RFC v2 4/5] dt-bindings: of: Add plumbing for restricted DMA pool Claire Chang
2020-07-31 20:58 ` Rob Herring
2020-08-03 14:26 ` Claire Chang
2020-08-03 15:15 ` Tomasz Figa
2020-08-11 9:15 ` Tomasz Figa
2020-08-24 17:24 ` Tomasz Figa
2020-09-08 9:49 ` Claire Chang
2020-07-28 5:01 ` [RFC v2 5/5] " Claire Chang
2020-07-28 11:59 ` [RFC v2 0/5] Restricted DMA Claire Chang
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