Patch-mainline: v5.6-rc1

Git-commit: 8618793750071d66028584a83ed0b4fa7eb4f607

From: Marios Pomonis <pomonis@google.com>

Date: Wed, 11 Dec 2019 12:47:42 -0800

Subject: [PATCH] KVM: x86: Protect kvm_hv_msr_[get|set]_crash_data() from

 Spectre-v1/L1TF attacks

References: bsc#1164712

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: e7d9513b60e8 ("kvm/x86: added hyper-v crash msrs into kvm hyperv context")

Signed-off-by: Nick Finco <nifi@google.com>

Signed-off-by: Marios Pomonis <pomonis@google.com>

Reviewed-by: Andrew Honig <ahonig@google.com>

Cc: stable@vger.kernel.org

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Juergen Gross <jgross@suse.com>

---

 arch/x86/kvm/hyperv.c | 10 ++++++----

 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c

index b255b9e865e5..4df1c965bf1a 100644

--- a/arch/x86/kvm/hyperv.c

+++ b/arch/x86/kvm/hyperv.c

@@ -753,11 +753,12 @@ 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;

 }

@@ -796,11 +797,12 @@ 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;

 }

-- 

2.16.4