From: Christoph Hellwig <hch@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux.dev
Subject: Re: lack of permission checking with intel-iommu?
Date: Tue, 2 Jul 2024 01:02:51 -0700 [thread overview]
Message-ID: <ZoO0KxkU_JNO0av4@infradead.org> (raw)
In-Reply-To: <ZoOwc7O5W0PUeja5@infradead.org>
On Tue, Jul 02, 2024 at 12:46:59AM -0700, Christoph Hellwig wrote:
> Hi all,
>
> we've recently had an interesting case where a device unexpectedly
> modified a dma buffer passed to it. On AMD systems this caused iommu
> faults because the buffer was mapped read only (DMA_FROM_DEVICE), but
> on an Intel system everything worked fine as the IOMMU did not trip up
> on the device writes to that buffer. Any idea why that could sneak
> through?
Sorry if this was confusing, the permission checking is of course about
the device reading from a buffer mapped read-only for the device
(as that is what DMA_FROM_DEVICE is), which on intel still allows it
to read.
next prev parent reply other threads:[~2024-07-02 8:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-02 7:46 lack of permission checking with intel-iommu? Christoph Hellwig
2024-07-02 8:02 ` Christoph Hellwig [this message]
2024-07-02 8:22 ` Baolu Lu
2024-07-02 8:25 ` Christoph Hellwig
2024-07-02 9:12 ` Baolu Lu
2024-07-02 11:42 ` Christoph Hellwig
2024-07-03 0:56 ` Tian, Kevin
2024-07-03 2:28 ` Baolu Lu
2024-07-02 8:47 ` Yi Liu
2024-07-02 9:07 ` Baolu Lu
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