diff mbox

KVM: use after free in kvm_ioctl_create_device()

Message ID 20161130192105.GC28180@mwanda (mailing list archive)
State New, archived
Headers show

Commit Message

Dan Carpenter Nov. 30, 2016, 7:21 p.m. UTC 
We should move the ops->destroy(dev) after the list_del(&dev->vm_node)
so that we don't use "dev" after freeing it.

Fixes: a28ebea2adc4 ("KVM: Protect device ops->create and list_add with kvm->lock")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

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Comments

David Hildenbrand Dec. 1, 2016, 12:20 p.m. UTC | #1 
Am 30.11.2016 um 20:21 schrieb Dan Carpenter:
> We should move the ops->destroy(dev) after the list_del(&dev->vm_node)
> so that we don't use "dev" after freeing it.
>
> Fixes: a28ebea2adc4 ("KVM: Protect device ops->create and list_add with kvm->lock")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 69a1247..de102ca 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2899,10 +2899,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm,

Looks sane to me! This also matches kvm_destroy_devices().

Reviewed-by: David Hildenbrand <david@redhat.com>
Radim Krčmář Dec. 1, 2016, 3:14 p.m. UTC | #2 
2016-11-30 22:21+0300, Dan Carpenter:
> We should move the ops->destroy(dev) after the list_del(&dev->vm_node)
> so that we don't use "dev" after freeing it.
> 
> Fixes: a28ebea2adc4 ("KVM: Protect device ops->create and list_add with kvm->lock")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Applied to kvm/master, thanks.
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diff mbox

Patch

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 69a1247..de102ca 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2899,10 +2899,10 @@  static int kvm_ioctl_create_device(struct kvm *kvm,
 
 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
 	if (ret < 0) {
-		ops->destroy(dev);
 		mutex_lock(&kvm->lock);
 		list_del(&dev->vm_node);
 		mutex_unlock(&kvm->lock);
+		ops->destroy(dev);
 		return ret;
 	}