kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)

[platform/kernel/linux-exynos.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bbc34e8..9b79818 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2912,8 +2912,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
        if (ops->init)
                ops->init(dev);
 
+       kvm_get_kvm(kvm);
        ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
        if (ret < 0) {
+               kvm_put_kvm(kvm);
                mutex_lock(&kvm->lock);
                list_del(&dev->vm_node);
                mutex_unlock(&kvm->lock);
@@ -2921,7 +2923,6 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
                return ret;
        }
 
-       kvm_get_kvm(kvm);
        cd->fd = ret;
        return 0;
 }