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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-08-03 06:40:19 +0300
committerZhenyu Wang <zhenyuw@linux.intel.com>2018-08-14 10:26:49 +0300
commitde5372da605d3bca46e3102bab51b7e1c0e0a6f6 (patch)
tree8d187c054a300041da5f450f4c37dbfe4fcde471 /drivers/gpu
parent8d458ea0ec331adb4c829289e9a56c97d3c1e542 (diff)
downloadlinux-de5372da605d3bca46e3102bab51b7e1c0e0a6f6.tar.xz
drm/i915/kvmgt: Fix potential Spectre v1
info.index can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/gpu/drm/i915/gvt/kvmgt.c:1232 intel_vgpu_ioctl() warn: potential spectre issue 'vgpu->vdev.region' [r] Fix this by sanitizing info.index before indirectly using it to index vgpu->vdev.region Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/i915/gvt/kvmgt.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 31986c1c253e..9ba70826737a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -43,6 +43,8 @@
#include <linux/mdev.h>
#include <linux/debugfs.h>
+#include <linux/nospec.h>
+
#include "i915_drv.h"
#include "gvt.h"
@@ -1139,7 +1141,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
struct vfio_region_info info;
struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
- int i, ret;
+ unsigned int i;
+ int ret;
struct vfio_region_info_cap_sparse_mmap *sparse = NULL;
size_t size;
int nr_areas = 1;
@@ -1224,6 +1227,10 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
if (info.index >= VFIO_PCI_NUM_REGIONS +
vgpu->vdev.num_regions)
return -EINVAL;
+ info.index =
+ array_index_nospec(info.index,
+ VFIO_PCI_NUM_REGIONS +
+ vgpu->vdev.num_regions);
i = info.index - VFIO_PCI_NUM_REGIONS;