drm/i915/gvt: Fix mmap range check

This is to fix missed mmap range check on vGPU bar2 region
and only allow to map vGPU allocated GMADDR range, which means
user space should support sparse mmap to get proper offset for
mmap vGPU aperture. And this takes care of actual pgoff in mmap
request as original code always does from beginning of vGPU
aperture.

Fixes: 659643f7d814 ("drm/i915/gvt/kvmgt: add vfio/mdev support to KVMGT")
Cc: "Monroy, Rodrigo Axel" <rodrigo.axel.monroy@intel.com>
Cc: "Orrala Contreras, Alfredo" <alfredo.orrala.contreras@intel.com>
Cc: stable@vger.kernel.org # v4.10+
Reviewed-by: Hang Yuan <hang.yuan@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
CVE-2019-11085

(cherry picked from commit 51b00d8509dc69c98740da2ad07308b630d3eb7d)
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index f6c8fe9824ea842b7cd82d2326f859bd2861deb6..9d36a3c31062022bb5c920fd967beadec68e2bd6 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -819,7 +819,7 @@ static int intel_vgpu_mmap(struct mdev_device *mdev, struct vm_area_struct *vma)
 {
        unsigned int index;
        u64 virtaddr;
-       unsigned long req_size, pgoff = 0;
+       unsigned long req_size, pgoff, req_start;
        pgprot_t pg_prot;
        struct intel_vgpu *vgpu = mdev_get_drvdata(mdev);
 
@@ -837,7 +837,17 @@ static int intel_vgpu_mmap(struct mdev_device *mdev, struct vm_area_struct *vma)
        pg_prot = vma->vm_page_prot;
        virtaddr = vma->vm_start;
        req_size = vma->vm_end - vma->vm_start;
-       pgoff = vgpu_aperture_pa_base(vgpu) >> PAGE_SHIFT;
+       pgoff = vma->vm_pgoff &
+               ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
+       req_start = pgoff << PAGE_SHIFT;
+
+       if (!intel_vgpu_in_aperture(vgpu, req_start))
+               return -EINVAL;
+       if (req_start + req_size >
+           vgpu_aperture_offset(vgpu) + vgpu_aperture_sz(vgpu))
+               return -EINVAL;
+
+       pgoff = (gvt_aperture_pa_base(vgpu->gvt) >> PAGE_SHIFT) + pgoff;
 
        return remap_pfn_range(vma, virtaddr, pgoff, req_size, pg_prot);
 }