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Commit bd31a7f5 authored by Jan Kiszka's avatar Jan Kiszka Committed by Marcelo Tosatti
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KVM: nVMX: Trap unconditionally if msr bitmap access fails 



This avoids basing decisions on uninitialized variables, potentially
leaking kernel data to the L1 guest.

Reviewed-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 908a7bdd

arch/x86/kvm/vmx.c

+2 −1
Original line number Diff line number Diff line
@@ -5985,7 +5985,8 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu, 
	/* Then read the msr_index'th bit from this bitmap: */

	if (msr_index < 1024*8) {

		unsigned char b;

		kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1);

		if (kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1))

			return 1;

		return 1 & (b >> (msr_index & 7));

	} else

		return 1; /* let L1 handle the wrong parameter */