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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>,
	kevin.tian@intel.com, Stefano Stabellini <sstabellini@kernel.org>,
	mika.westerberg@linux.intel.com, ashok.raj@intel.com,
	Jonathan Corbet <corbet@lwn.net>,
	alan.cox@intel.com, Robin Murphy <robin.murphy@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	pengfei.xu@intel.com, Ingo Molnar <mingo@redhat.com>,
	jacob.jun.pan@intel.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v4 3/9] swiotlb: Zero out bounce buffer for untrusted device
Date: Mon, 10 Jun 2019 11:45:53 -0400	[thread overview]
Message-ID: <20190610154553.GT28796@char.us.oracle.com> (raw)
In-Reply-To: <20190603011620.31999-4-baolu.lu@linux.intel.com>

On Mon, Jun 03, 2019 at 09:16:14AM +0800, Lu Baolu wrote:
> This is necessary to avoid exposing valid kernel data to any
> milicious device.

malicious 

> 
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  kernel/dma/swiotlb.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index f956f785645a..ed41eb7f6131 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -35,6 +35,7 @@
>  #include <linux/scatterlist.h>
>  #include <linux/mem_encrypt.h>
>  #include <linux/set_memory.h>
> +#include <linux/pci.h>
>  #ifdef CONFIG_DEBUG_FS
>  #include <linux/debugfs.h>
>  #endif
> @@ -560,6 +561,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
>  	 */
>  	for (i = 0; i < nslots; i++)
>  		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
> +
> +	/* Zero out the bounce buffer if the consumer is untrusted. */
> +	if (dev_is_untrusted(hwdev))
> +		memset(phys_to_virt(tlb_addr), 0, alloc_size);

What if the alloc_size is less than a PAGE? Should this at least have ALIGN or such?

> +
>  	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
>  	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
>  		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
> -- 
> 2.17.1
> 
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
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WARNING: multiple messages have this Message-ID (diff)
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Joerg Roedel <joro@8bytes.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Christoph Hellwig <hch@lst.de>,
	ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com,
	kevin.tian@intel.com, mika.westerberg@linux.intel.com,
	Ingo Molnar <mingo@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	pengfei.xu@intel.com, Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 3/9] swiotlb: Zero out bounce buffer for untrusted device
Date: Mon, 10 Jun 2019 11:45:53 -0400	[thread overview]
Message-ID: <20190610154553.GT28796@char.us.oracle.com> (raw)
In-Reply-To: <20190603011620.31999-4-baolu.lu@linux.intel.com>

On Mon, Jun 03, 2019 at 09:16:14AM +0800, Lu Baolu wrote:
> This is necessary to avoid exposing valid kernel data to any
> milicious device.

malicious 

> 
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  kernel/dma/swiotlb.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index f956f785645a..ed41eb7f6131 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -35,6 +35,7 @@
>  #include <linux/scatterlist.h>
>  #include <linux/mem_encrypt.h>
>  #include <linux/set_memory.h>
> +#include <linux/pci.h>
>  #ifdef CONFIG_DEBUG_FS
>  #include <linux/debugfs.h>
>  #endif
> @@ -560,6 +561,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
>  	 */
>  	for (i = 0; i < nslots; i++)
>  		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
> +
> +	/* Zero out the bounce buffer if the consumer is untrusted. */
> +	if (dev_is_untrusted(hwdev))
> +		memset(phys_to_virt(tlb_addr), 0, alloc_size);

What if the alloc_size is less than a PAGE? Should this at least have ALIGN or such?

> +
>  	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
>  	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
>  		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
> -- 
> 2.17.1
> 

  reply	other threads:[~2019-06-10 15:46 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03  1:16 [PATCH v4 0/9] iommu: Bounce page for untrusted devices Lu Baolu
2019-06-03  1:16 ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 1/9] PCI: Add dev_is_untrusted helper Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 2/9] swiotlb: Split size parameter to map/unmap APIs Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 3/9] swiotlb: Zero out bounce buffer for untrusted device Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-10 15:45   ` Konrad Rzeszutek Wilk [this message]
2019-06-10 15:45     ` Konrad Rzeszutek Wilk
2019-06-12  0:43     ` Lu Baolu
2019-06-12  0:43       ` Lu Baolu
2019-06-12  1:05       ` Konrad Rzeszutek Wilk
2019-06-12  1:05         ` Konrad Rzeszutek Wilk
2019-06-12  3:08         ` Lu Baolu
2019-06-12  3:08           ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 4/9] iommu: Add bounce page APIs Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-10 15:56   ` Konrad Rzeszutek Wilk
2019-06-10 15:56     ` Konrad Rzeszutek Wilk
2019-06-12  0:45     ` Lu Baolu
2019-06-12  0:45       ` Lu Baolu
2019-06-11 12:10   ` Pavel Begunkov
2019-06-11 12:10     ` Pavel Begunkov
2019-06-12  0:52     ` Lu Baolu
2019-06-12  0:52       ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 5/9] iommu/vt-d: Don't switch off swiotlb if use direct dma Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-10 15:54   ` Konrad Rzeszutek Wilk
2019-06-10 15:54     ` Konrad Rzeszutek Wilk
2019-06-12  2:03     ` Lu Baolu
2019-06-12  2:03       ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 6/9] iommu/vt-d: Check whether device requires bounce buffer Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-10 16:08   ` Konrad Rzeszutek Wilk
2019-06-10 16:08     ` Konrad Rzeszutek Wilk
2019-06-12  2:22     ` Lu Baolu
2019-06-12  2:22       ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 7/9] iommu/vt-d: Add trace events for domain map/unmap Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-04  9:01   ` Steven Rostedt
2019-06-04  9:01     ` Steven Rostedt
2019-06-05  6:48     ` Lu Baolu
2019-06-05  6:48       ` Lu Baolu
2019-06-10 16:08   ` Konrad Rzeszutek Wilk
2019-06-10 16:08     ` Konrad Rzeszutek Wilk
2019-06-12  2:31     ` Lu Baolu
2019-06-12  2:31       ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 8/9] iommu/vt-d: Code refactoring for bounce map and unmap Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-03  1:16 ` [PATCH v4 9/9] iommu/vt-d: Use bounce buffer for untrusted devices Lu Baolu
2019-06-03  1:16   ` Lu Baolu
2019-06-10 15:42 ` [PATCH v4 0/9] iommu: Bounce page " Konrad Rzeszutek Wilk
2019-06-10 15:42   ` Konrad Rzeszutek Wilk
2019-06-12  3:00   ` Lu Baolu
2019-06-12  3:00     ` Lu Baolu
2019-06-12  6:22     ` Mika Westerberg
2019-06-12  6:22       ` Mika Westerberg
2019-06-10 16:10 ` Konrad Rzeszutek Wilk
2019-06-10 16:10   ` Konrad Rzeszutek Wilk
2019-06-12  3:04   ` Lu Baolu
2019-06-12  3:04     ` Lu Baolu

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