[patch 2/3] KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic

[Marcelo Tosatti]

Otherwise kvm might attempt to dereference a NULL pointer.

Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>

Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -1893,6 +1893,9 @@ long kvm_arch_vcpu_ioctl(struct file *fi
 
        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 *fi
                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)


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