From 5e1ca5e23b167987d5b6d8b08f2d5b7dd2d13f49 Mon Sep 17 00:00:00 2001 From: Mark Rutland <mark.rutland@arm.com> Date: Wed, 25 Apr 2018 17:13:42 +0100 Subject: [PATCH] KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_mmio_read_apr() 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> --- virt/kvm/arm/vgic/vgic-mmio-v2.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c index e21e2f49b005..ffc587bf4742 100644 --- 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(struct kvm_vcpu *vcpu, 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]; } -- GitLab