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authorAlexey Kardashevskiy <aik@ozlabs.ru>2022-06-01 04:43:28 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2022-06-07 18:18:59 +0300
commite8bc2427018826e02add7b0ed0fc625a60390ae5 (patch)
tree52661a1814da48f885f74fe2db8696b43144657a /virt
parentffd1925a596ce68bed7d81c61cb64bc35f788a9d (diff)
downloadlinux-e8bc2427018826e02add7b0ed0fc625a60390ae5.tar.xz
KVM: Don't null dereference ops->destroy
A KVM device cleanup happens in either of two callbacks: 1) destroy() which is called when the VM is being destroyed; 2) release() which is called when a device fd is closed. Most KVM devices use 1) but Book3s's interrupt controller KVM devices (XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during the machine execution. The error handling in kvm_ioctl_create_device() assumes destroy() is always defined which leads to NULL dereference as discovered by Syzkaller. This adds a checks for destroy!=NULL and adds a missing release(). This is not changing kvm_destroy_devices() as devices with defined release() should have been removed from the KVM devices list by then. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 342043b30125..f2922ba3b7a8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4300,8 +4300,11 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
kvm_put_kvm_no_destroy(kvm);
mutex_lock(&kvm->lock);
list_del(&dev->vm_node);
+ if (ops->release)
+ ops->release(dev);
mutex_unlock(&kvm->lock);
- ops->destroy(dev);
+ if (ops->destroy)
+ ops->destroy(dev);
return ret;
}