[PATCH 49/55] KVM: arm64: vgic-its: Validate the device table L1 entry

Marc Zyngier
2016-07-22T17:29:06Z

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>
---
virt/kvm/arm/vgic/vgic-its.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 268a0c7..4943d6a 100644
--- 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));
--
2.8.1