* [PATCH 4.16 107/279] KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_mmio_read_apr()
[not found] <20180618080608.851973560@linuxfoundation.org>
@ 2018-06-18 8:11 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2018-06-18 8:11 UTC (permalink / raw)
To: linux-kernel
Cc: Greg Kroah-Hartman, stable, Mark Rutland, Christoffer Dall,
Marc Zyngier, kvmarm, Will Deacon, Sasha Levin
4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mark Rutland <mark.rutland@arm.com>
[ Upstream commit 5e1ca5e23b167987d5b6d8b08f2d5b7dd2d13f49 ]
It's possible for userspace to control n. Sanitize n when using it as an
array index.
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@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
virt/kvm/arm/vgic/vgic-mmio-v2.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -14,6 +14,8 @@
#include <linux/irqchip/arm-gic.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <linux/nospec.h>
+
#include <kvm/iodev.h>
#include <kvm/arm_vgic.h>
@@ -324,6 +326,9 @@ static unsigned long vgic_mmio_read_apr(
if (n > vgic_v3_max_apr_idx(vcpu))
return 0;
+
+ n = array_index_nospec(n, 4);
+
/* GICv3 only uses ICH_AP1Rn for memory mapped (GICv2) guests */
return vgicv3->vgic_ap1r[n];
}
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