lkml.org 
[lkml]   [2019]   [Jul]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 06/10] swiotlb: Zero out bounce buffer for untrusted device
Date
This is necessary to avoid exposing valid kernel data to any
malicious device.

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 43c88626a1f3..edc84a00b9f9 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
@@ -562,6 +563,11 @@ 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
\
 
 \ /
  Last update: 2019-07-25 05:19    [W:0.125 / U:0.556 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site