Commit 86187937 authored by Marios Pomonis's avatar Marios Pomonis Committed by Paolo Bonzini
Browse files

KVM: x86: Protect kvm_hv_msr_[get|set]_crash_data() from Spectre-v1/L1TF attacks 



This fixes Spectre-v1/L1TF vulnerabilities in kvm_hv_msr_get_crash_data()
and kvm_hv_msr_set_crash_data().
These functions contain index computations that use the
(attacker-controlled) MSR number.

Fixes: e7d9513b ("kvm/x86: added hyper-v crash msrs into kvm hyperv context")

Signed-off-by: default avatarNick Finco <nifi@google.com>
Signed-off-by: default avatarMarios Pomonis <pomonis@google.com>
Reviewed-by: default avatarAndrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3c9053a2

arch/x86/kvm/hyperv.c

+6 −4
Original line number Diff line number Diff line
@@ -810,11 +810,12 @@ static int kvm_hv_msr_get_crash_data(struct kvm_vcpu *vcpu, 
				     u32 index, u64 *pdata)

{

	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	size_t size = ARRAY_SIZE(hv->hv_crash_param);



	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))

	if (WARN_ON_ONCE(index >= size))

		return -EINVAL;



	*pdata = hv->hv_crash_param[index];

	*pdata = hv->hv_crash_param[array_index_nospec(index, size)];

	return 0;

}
@@ -853,11 +854,12 @@ static int kvm_hv_msr_set_crash_data(struct kvm_vcpu *vcpu, 
				     u32 index, u64 data)

{

	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	size_t size = ARRAY_SIZE(hv->hv_crash_param);



	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))

	if (WARN_ON_ONCE(index >= size))

		return -EINVAL;



	hv->hv_crash_param[index] = data;

	hv->hv_crash_param[array_index_nospec(index, size)] = data;

	return 0;

}