[PATCH 29/35] KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic

[Avi Kivity]

From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

Otherwise kvm might attempt to dereference a NULL pointer.

Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 97f6f95..cd6fe0a 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)
-- 
1.6.5.2

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