5.10-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Upton oliver.upton@linux.dev
[ Upstream commit 6ddb4f372fc63210034b903d96ebbeb3c7195adb ]
vgic_v2_parse_attr() is responsible for finding the vCPU that matches the user-provided CPUID, which (of course) may not be valid. If the ID is invalid, kvm_get_vcpu_by_id() returns NULL, which isn't handled gracefully.
Similar to the GICv3 uaccess flow, check that kvm_get_vcpu_by_id() actually returns something and fail the ioctl if not.
Cc: stable@vger.kernel.org Fixes: 7d450e282171 ("KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers") Reported-by: Alexander Potapenko glider@google.com Tested-by: Alexander Potapenko glider@google.com Reviewed-by: Alexander Potapenko glider@google.com Reviewed-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20240424173959.3776798-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton oliver.upton@linux.dev Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/kvm/vgic/vgic-kvm-device.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c index 640cfa0c0f4cc..e80b638b78271 100644 --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c @@ -284,12 +284,12 @@ int kvm_register_vgic_device(unsigned long type) int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr, struct vgic_reg_attr *reg_attr) { - int cpuid; + int cpuid = FIELD_GET(KVM_DEV_ARM_VGIC_CPUID_MASK, attr->attr);
- cpuid = FIELD_GET(KVM_DEV_ARM_VGIC_CPUID_MASK, attr->attr); - - reg_attr->vcpu = kvm_get_vcpu_by_id(dev->kvm, cpuid); reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK; + reg_attr->vcpu = kvm_get_vcpu_by_id(dev->kvm, cpuid); + if (!reg_attr->vcpu) + return -EINVAL;
return 0; }