diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-08-02 22:40:19 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-24 13:04:49 +0200 |
| commit | d8a1aecababa4baaa9eeb892f531c9ac4930d09f (patch) | |
| tree | c1d675e26e87ac189c3ec4ede17a8bb4404b201f | |
| parent | 5b6ea348768d5b26adeeef384971820e24710ad0 (diff) | |
| download | linux-d8a1aecababa4baaa9eeb892f531c9ac4930d09f.tar.gz | |
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 <gustavo@embeddedor.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/i915/gvt/kvmgt.c | 9 |
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 df4e4a07db3d68..14dce5c201d5e3 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" @@ -1084,7 +1086,8 @@ 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; @@ -1169,6 +1172,10 @@ 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; |