[ Upstream commit db80927ea1977a845230a161df643b48fd1e1ea4 ] The offset for reading the shadow VMCS is sizeof(*kvm_state)+VMCS12_SIZE, so the correct size must be that plus sizeof(*vmcs12). This could lead to KVM reading garbage data from userspace and not reporting an error, but is otherwise not sensitive.
Signed-off-by: Paolo Bonzini <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 8f6f69c26c35..5fa0c17d0b41 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5467,7 +5467,7 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, vmcs12->vmcs_link_pointer != -1ull) { struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu); - if (kvm_state->size < sizeof(*kvm_state) + 2 * sizeof(*vmcs12)) + if (kvm_state->size < sizeof(*kvm_state) + VMCS12_SIZE + sizeof(*vmcs12)) return -EINVAL; if (copy_from_user(shadow_vmcs12, -- 2.20.1
