[PATCH 2/4] KVM: arm64: vgic: Add more checks when restoring ITS tables

[Ricardo Koller <ricarkol@google.com>]

Restoring corrupted ITS tables could lead to a misbehaving ITS, and
possibly a failed ITS save as the save performs more checks than the
restore. Add sanity checks when restoring DTEs and ITEs.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 arch/arm64/kvm/vgic/vgic-its.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index d7c1a3a01af4..dfd73fa1ed43 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -2209,6 +2209,12 @@ static int vgic_its_restore_ite(struct vgic_its *its, u32 event_id,
 	if (!collection)
 		return -EINVAL;
 
+	if (find_ite(its, dev->device_id, event_id))
+		return -EINVAL;
+
+	if (!vgic_its_check_ite(its, dev, event_id))
+		return -EINVAL;
+
 	ite = vgic_its_alloc_ite(dev, collection, event_id);
 	if (IS_ERR(ite))
 		return PTR_ERR(ite);
@@ -2330,6 +2336,7 @@ static int vgic_its_restore_dte(struct vgic_its *its, u32 id,
 				void *ptr, void *opaque)
 {
 	struct its_device *dev;
+	u64 baser = its->baser_device_table;
 	gpa_t itt_addr;
 	u8 num_eventid_bits;
 	u64 entry = *(u64 *)ptr;
@@ -2350,6 +2357,12 @@ static int vgic_its_restore_dte(struct vgic_its *its, u32 id,
 	/* dte entry is valid */
 	offset = (entry & KVM_ITS_DTE_NEXT_MASK) >> KVM_ITS_DTE_NEXT_SHIFT;
 
+	if (find_its_device(its, id))
+		return -EINVAL;
+
+	if (!vgic_its_check_id(its, baser, id, NULL))
+		return -EINVAL;
+
 	dev = vgic_its_alloc_device(its, id, itt_addr, num_eventid_bits);
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
-- 
2.36.0.rc2.479.g8af0fa9b8e-goog