Commit db80927e authored May 20, 2019 by Paolo Bonzini

KVM: nVMX: really fix the size checks on KVM_SET_NESTED_STATE



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 <pbonzini@redhat.com>

parent 6bff2a3d

arch/x86/kvm/vmx/nested.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5427,7 +5427,7 @@ 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,

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