* FAILED: patch "[PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF" failed to apply to 4.4-stable tree
@ 2020-02-09 11:58 gregkh
2020-02-09 19:00 ` Sasha Levin
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2020-02-09 11:58 UTC (permalink / raw)
To: pomonis, ahonig, jmattson, nifi, pbonzini; +Cc: stable
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4bf79cb089f6b1c6c632492c0271054ce52ad766 Mon Sep 17 00:00:00 2001
From: Marios Pomonis <pomonis@google.com>
Date: Wed, 11 Dec 2019 12:47:46 -0800
Subject: [PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF
attacks
This fixes a Spectre-v1/L1TF vulnerability in kvm_lapic_reg_write().
This function contains index computations based on the
(attacker-controlled) MSR number.
Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic")
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
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 88c3c0c6d1e3..865edce27a6a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1960,15 +1960,20 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
case APIC_LVTTHMR:
case APIC_LVTPC:
case APIC_LVT1:
- case APIC_LVTERR:
+ case APIC_LVTERR: {
/* TODO: Check vector */
+ size_t size;
+ u32 index;
+
if (!kvm_apic_sw_enabled(apic))
val |= APIC_LVT_MASKED;
-
- val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4];
+ size = ARRAY_SIZE(apic_lvt_mask);
+ index = array_index_nospec(
+ (reg - APIC_LVTT) >> 4, size);
+ val &= apic_lvt_mask[index];
kvm_lapic_set_reg(apic, reg, val);
-
break;
+ }
case APIC_LVTT:
if (!kvm_apic_sw_enabled(apic))
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: FAILED: patch "[PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF" failed to apply to 4.4-stable tree
2020-02-09 11:58 FAILED: patch "[PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF" failed to apply to 4.4-stable tree gregkh
@ 2020-02-09 19:00 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-02-09 19:00 UTC (permalink / raw)
To: gregkh; +Cc: pomonis, ahonig, jmattson, nifi, pbonzini, stable
On Sun, Feb 09, 2020 at 12:58:06PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.4-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 4bf79cb089f6b1c6c632492c0271054ce52ad766 Mon Sep 17 00:00:00 2001
>From: Marios Pomonis <pomonis@google.com>
>Date: Wed, 11 Dec 2019 12:47:46 -0800
>Subject: [PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF
> attacks
>
>This fixes a Spectre-v1/L1TF vulnerability in kvm_lapic_reg_write().
>This function contains index computations based on the
>(attacker-controlled) MSR number.
>
>Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic")
>
>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
>Reviewed-by: Jim Mattson <jmattson@google.com>
>Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We didn't have 1e6e2755b635 ("KVM: x86: Misc LAPIC changes to expose
helper functions") in 4.4. I've fixed it and queued this patch for 4.4.
--
Thanks,
Sasha
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-02-09 11:58 FAILED: patch "[PATCH] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF" failed to apply to 4.4-stable tree gregkh
2020-02-09 19:00 ` Sasha Levin
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