[PATCH 5.12 127/677] KVM: arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION read

[Greg Kroah-Hartman]

From: Eric Auger <eric.auger@xxxxxxxxxx>

commit 53b16dd6ba5cf64ed147ac3523ec34651d553cb0 upstream.

The doc says:
"The characteristics of a specific redistributor region can
 be read by presetting the index field in the attr data.
 Only valid for KVM_DEV_TYPE_ARM_VGIC_V3"

Unfortunately the existing code fails to read the input attr data.

Fixes: 04c110932225 ("KVM: arm/arm64: Implement KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION")
Cc: stable@xxxxxxxxxxxxxxx#v4.17+
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Reviewed-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210405163941.510258-3-eric.auger@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -226,6 +226,9 @@ static int vgic_get_common_attr(struct k
 		u64 addr;
 		unsigned long type = (unsigned long)attr->attr;
 
+		if (copy_from_user(&addr, uaddr, sizeof(addr)))
+			return -EFAULT;
+
 		r = kvm_vgic_addr(dev->kvm, type, &addr, false);
 		if (r)
 			return (r == -ENODEV) ? -ENXIO : r;