KVM: arm64: vgic-its: Validate the device table L1 entry

Checking that the device_id fits if the table, and we must make
sure that the associated memory is also accessible.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 268a0c7..4943d6a 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -693,8 +693,17 @@ static bool vgic_its_check_device_id(struct kvm *kvm, struct vgic_its *its,
        gfn_t gfn;
 
 
-       if (!(r & GITS_BASER_INDIRECT))
-               return device_id < (l1_tbl_size / GITS_BASER_ENTRY_SIZE(r));
+       if (!(r & GITS_BASER_INDIRECT)) {
+               phys_addr_t addr;
+
+               if (device_id >= (l1_tbl_size / GITS_BASER_ENTRY_SIZE(r)))
+                       return false;
+
+               addr = BASER_ADDRESS(r) + device_id * GITS_BASER_ENTRY_SIZE(r);
+               gfn = addr >> PAGE_SHIFT;
+
+               return kvm_is_visible_gfn(kvm, gfn);
+       }
 
        /* calculate and check the index into the 1st level */
        index = device_id / (SZ_64K / GITS_BASER_ENTRY_SIZE(r));