KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic

Otherwise kvm might attempt to dereference a NULL pointer.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 97f6f9565ac9..cd6fe0a5797f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1893,6 +1893,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 
         switch (ioctl) {
         case KVM_GET_LAPIC: {
+                r = -EINVAL;
+                if (!vcpu->arch.apic)
+                        goto out;
                 lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
 
                 r = -ENOMEM;
@@ -1908,6 +1911,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                 break;
         }
         case KVM_SET_LAPIC: {
+                r = -EINVAL;
+                if (!vcpu->arch.apic)
+                        goto out;
                 lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
                 r = -ENOMEM;
                 if (!lapic)