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.rutl...@arm.com>
Cc: Christoffer Dall <cd...@kernel.org>
Cc: Marc Zyngier <marc.zyng...@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
---
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];
}
--
2.11.0
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