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authorMark Rutland <mark.rutland@arm.com>2018-04-25 17:13:42 +0100
committerWill Deacon <will.deacon@arm.com>2018-04-26 17:06:00 +0100
commit5e1ca5e23b167987d5b6d8b08f2d5b7dd2d13f49 (patch)
tree9a0111967f01a664c3be094fc9b0b895b1110cf6
parent41b87599c74300027f305d7b34368ec558978ff2 (diff)
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>
-rw-r--r--virt/kvm/arm/vgic/vgic-mmio-v2.c5
1 files changed, 5 insertions, 0 deletions
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];
}