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Message-Id: <20200213151955.343558256@linuxfoundation.org>
Date: Thu, 13 Feb 2020 07:19:51 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Nick Finco <nifi@...gle.com>,
Marios Pomonis <pomonis@...gle.com>,
Andrew Honig <ahonig@...gle.com>,
Jim Mattson <jmattson@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 4.14 088/173] KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() from Spectre-v1/L1TF attacks
From: Marios Pomonis <pomonis@...gle.com>
commit 25a5edea71b7c154b6a0b8cec14c711cafa31d26 upstream.
This fixes a Spectre-v1/L1TF vulnerability in fixed_msr_to_seg_unit().
This function contains index computations based on the
(attacker-controlled) MSR number.
Fixes: de9aef5e1ad6 ("KVM: MTRR: introduce fixed_mtrr_segment table")
Signed-off-by: Nick Finco <nifi@...gle.com>
Signed-off-by: Marios Pomonis <pomonis@...gle.com>
Reviewed-by: Andrew Honig <ahonig@...gle.com>
Cc: stable@...r.kernel.org
Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kvm/mtrr.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -202,11 +202,15 @@ static bool fixed_msr_to_seg_unit(u32 ms
break;
case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000:
*seg = 1;
- *unit = msr - MSR_MTRRfix16K_80000;
+ *unit = array_index_nospec(
+ msr - MSR_MTRRfix16K_80000,
+ MSR_MTRRfix16K_A0000 - MSR_MTRRfix16K_80000 + 1);
break;
case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000:
*seg = 2;
- *unit = msr - MSR_MTRRfix4K_C0000;
+ *unit = array_index_nospec(
+ msr - MSR_MTRRfix4K_C0000,
+ MSR_MTRRfix4K_F8000 - MSR_MTRRfix4K_C0000 + 1);
break;
default:
return false;
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