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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>
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1 changed files with 8 additions and 1 deletions
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@ -43,6 +43,8 @@
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#include <linux/mdev.h>
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#include <linux/debugfs.h>
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#include <linux/nospec.h>
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#include "i915_drv.h"
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#include "gvt.h"
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@ -1139,7 +1141,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
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} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
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struct vfio_region_info info;
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struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
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int i, ret;
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unsigned int i;
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int ret;
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struct vfio_region_info_cap_sparse_mmap *sparse = NULL;
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size_t size;
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int nr_areas = 1;
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@ -1224,6 +1227,10 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
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if (info.index >= VFIO_PCI_NUM_REGIONS +
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vgpu->vdev.num_regions)
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return -EINVAL;
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info.index =
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array_index_nospec(info.index,
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VFIO_PCI_NUM_REGIONS +
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vgpu->vdev.num_regions);
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i = info.index - VFIO_PCI_NUM_REGIONS;
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