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Message-Id: <20190603011620.31999-4-baolu.lu@linux.intel.com>
Date: Mon, 3 Jun 2019 09:16:14 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: David Woodhouse <dwmw2@...radead.org>,
Joerg Roedel <joro@...tes.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Christoph Hellwig <hch@....de>
Cc: ashok.raj@...el.com, jacob.jun.pan@...el.com, alan.cox@...el.com,
kevin.tian@...el.com, mika.westerberg@...ux.intel.com,
Ingo Molnar <mingo@...hat.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
pengfei.xu@...el.com,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Robin Murphy <robin.murphy@....com>,
Jonathan Corbet <corbet@....net>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>,
Stefano Stabellini <sstabellini@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v4 3/9] swiotlb: Zero out bounce buffer for untrusted device
This is necessary to avoid exposing valid kernel data to any
milicious device.
Suggested-by: Christoph Hellwig <hch@....de>
Signed-off-by: Lu Baolu <baolu.lu@...ux.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);
+
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
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