This is a note to let you know that I've just added the patch titled
KVM: arm/arm64: vgic: Fix possible spectre-v1 write in vgic_mmio_write_apr()
to the 4.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm-arm64-vgic-fix-possible-spectre-v1-write-in-vgic_mmio_write_apr.patch
and it can be found in the queue-4.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Sep 21 10:21:24 CEST 2018
From: Mark Rutland <mark.rutland@xxxxxxx>
Date: Tue, 10 Jul 2018 19:01:23 +0100
Subject: KVM: arm/arm64: vgic: Fix possible spectre-v1 write in vgic_mmio_write_apr()
From: Mark Rutland <mark.rutland@xxxxxxx>
[ Upstream commit 6b8b9a48545e08345b8ff77c9fd51b1aebdbefb3 ]
It's possible for userspace to control n. Sanitize n when using it as an
array index, to inhibit the potential spectre-v1 write gadget.
Note that while it appears that n must be bound to the interval [0,3]
due to the way it is extracted from addr, we cannot guarantee that
compiler transformations (and/or future refactoring) will ensure this is
the case, and given this is a slow path it's better to always perform
the masking.
Found by smatch.
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
virt/kvm/arm/vgic/vgic-mmio-v2.c | 3 +++
1 file changed, 3 insertions(+)
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -352,6 +352,9 @@ static void vgic_mmio_write_apr(struct k
if (n > vgic_v3_max_apr_idx(vcpu))
return;
+
+ n = array_index_nospec(n, 4);
+
/* GICv3 only uses ICH_AP1Rn for memory mapped (GICv2) guests */
vgicv3->vgic_ap1r[n] = val;
}
Patches currently in stable-queue which might be from mark.rutland@xxxxxxx are
queue-4.18/arm64-fix-possible-spectre-v1-write-in-ptrace_hbp_set_event.patch
queue-4.18/kvm-arm-arm64-vgic-fix-possible-spectre-v1-write-in-vgic_mmio_write_apr.patch
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