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| author | Mark Rutland <mark.rutland@arm.com> | 2018-07-10 19:01:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-26 08:38:02 +0200 |
| commit | 737066efec608045559ce62abda4210962526349 (patch) | |
| tree | 80a3d5b7f3883aa04493f6e3ea26320c4be866a1 /virt | |
| parent | 3cb3868f98f53468160eb732d30ef29aaf046ae3 (diff) | |
| download | linux-rt-737066efec608045559ce62abda4210962526349.tar.gz | |
KVM: arm/arm64: vgic: Fix possible spectre-v1 write in vgic_mmio_write_apr()
[ 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@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/arm/vgic/vgic-mmio-v2.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c index af003268bf3e..7ea5928244fa 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c @@ -348,6 +348,9 @@ static void vgic_mmio_write_apr(struct kvm_vcpu *vcpu, 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; } |