KVM: arm/arm64: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()

In kvm_vgic_dist_init() called from kvm_vgic_map_resources(), if
dist->vgic_model is invalid, dist->spis will be freed without set
dist->spis = NULL. And in vgicv2 resources clean up path,
__kvm_vgic_destroy() will be called to free allocated resources.
And dist->spis will be freed again in clean up chain because we
forget to set dist->spis = NULL in kvm_vgic_dist_init() failed
path. So double free would happen.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/1574923128-19956-1-git-send-email-linmiaohe@huawei.com

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index b3c5de4..7c58112 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -177,6 +177,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
                        break;
                default:
                        kfree(dist->spis);
+                       dist->spis = NULL;
                        return -EINVAL;
                }
        }