From: Gustavo A. R. Silva Date: Fri, 3 Aug 2018 03:40:19 +0000 (-0500) Subject: drm/i915/kvmgt: Fix potential Spectre v1 X-Git-Tag: v4.14.67~216 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b518e870f1f605536b544d81e52f4570bc9e340f;p=platform%2Fkernel%2Flinux-exynos.git drm/i915/kvmgt: Fix potential Spectre v1 commit de5372da605d3bca46e3102bab51b7e1c0e0a6f6 upstream. 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 Signed-off-by: Zhenyu Wang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 9bf4045..73c672f 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -42,6 +42,8 @@ #include #include +#include + #include "i915_drv.h" #include "gvt.h" @@ -953,7 +955,8 @@ 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; @@ -1030,6 +1033,10 @@ 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;