| Message ID | 20230511021553.44318-1-zhangfei.gao@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | uacce: use filep->f_mapping to replace inode->i_mapping | expand |
On Thu, May 11, 2023 at 10:15:53AM +0800, Zhangfei Gao wrote: > The inode can be different in a container, for example, a docker and host > both open the same uacce parent device, which uses the same uacce struct > but different inode, so uacce->inode is not enough. > > What's worse, when docker stops, the inode will be destroyed as well, > causing use-after-free in uacce_remove. > > So use q->filep->f_mapping to replace uacce->inode->i_mapping. > > Signed-off-by: Weili Qian <qianweili@huawei.com> > Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org> > --- > drivers/misc/uacce/uacce.c | 16 +++++++++------- > include/linux/uacce.h | 4 ++-- > 2 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c > index 346bd7cf2e94..740ace422baa 100644 > --- a/drivers/misc/uacce/uacce.c > +++ b/drivers/misc/uacce/uacce.c > @@ -166,8 +166,8 @@ static int uacce_fops_open(struct inode *inode, struct file *filep) > > init_waitqueue_head(&q->wait); > filep->private_data = q; > - uacce->inode = inode; > q->state = UACCE_Q_INIT; > + q->private_data = filep; > mutex_init(&q->mutex); > list_add(&q->list, &uacce->queues); > mutex_unlock(&uacce->mutex); > @@ -574,12 +574,6 @@ void uacce_remove(struct uacce_device *uacce) > > if (!uacce) > return; > - /* > - * unmap remaining mapping from user space, preventing user still > - * access the mmaped area while parent device is already removed > - */ > - if (uacce->inode) > - unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); > > /* > * uacce_fops_open() may be running concurrently, even after we remove > @@ -589,6 +583,8 @@ void uacce_remove(struct uacce_device *uacce) > mutex_lock(&uacce->mutex); > /* ensure no open queue remains */ > list_for_each_entry_safe(q, next_q, &uacce->queues, list) { > + struct file *filep = q->private_data; > + > /* > * Taking q->mutex ensures that fops do not use the defunct > * uacce->ops after the queue is disabled. > @@ -597,6 +593,12 @@ void uacce_remove(struct uacce_device *uacce) > uacce_put_queue(q); > mutex_unlock(&q->mutex); > uacce_unbind_queue(q); > + > + /* > + * unmap remaining mapping from user space, preventing user still > + * access the mmaped area while parent device is already removed > + */ > + unmap_mapping_range(filep->f_mapping, 0, 0, 1); > } > > /* disable sva now since no opened queues */ > diff --git a/include/linux/uacce.h b/include/linux/uacce.h > index 0a81c3dfd26c..64b800b74436 100644 > --- a/include/linux/uacce.h > +++ b/include/linux/uacce.h > @@ -86,6 +86,7 @@ enum uacce_q_state { > * @state: queue state machine > * @pasid: pasid associated to the mm > * @handle: iommu_sva handle returned by iommu_sva_bind_device() > + * @private_data: private data for saving filep > */ > struct uacce_queue { > struct uacce_device *uacce; > @@ -97,6 +98,7 @@ struct uacce_queue { > enum uacce_q_state state; > u32 pasid; > struct iommu_sva *handle; > + void *private_data; Make this a real pointer to the inode, no need to make this "void *", right? thanks, greg k-h
On Thu, May 11, 2023 at 10:15:53AM +0800, Zhangfei Gao wrote: > The inode can be different in a container, for example, a docker and host > both open the same uacce parent device, which uses the same uacce struct > but different inode, so uacce->inode is not enough. > > What's worse, when docker stops, the inode will be destroyed as well, > causing use-after-free in uacce_remove. > > So use q->filep->f_mapping to replace uacce->inode->i_mapping. > @@ -574,12 +574,6 @@ void uacce_remove(struct uacce_device *uacce) > > if (!uacce) > return; > - /* > - * unmap remaining mapping from user space, preventing user still > - * access the mmaped area while parent device is already removed > - */ > - if (uacce->inode) > - unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); > > /* > * uacce_fops_open() may be running concurrently, even after we remove > @@ -589,6 +583,8 @@ void uacce_remove(struct uacce_device *uacce) > mutex_lock(&uacce->mutex); > /* ensure no open queue remains */ > list_for_each_entry_safe(q, next_q, &uacce->queues, list) { > + struct file *filep = q->private_data; > + > /* > * Taking q->mutex ensures that fops do not use the defunct > * uacce->ops after the queue is disabled. > @@ -597,6 +593,12 @@ void uacce_remove(struct uacce_device *uacce) > uacce_put_queue(q); > mutex_unlock(&q->mutex); > uacce_unbind_queue(q); > + > + /* > + * unmap remaining mapping from user space, preventing user still > + * access the mmaped area while parent device is already removed > + */ > + unmap_mapping_range(filep->f_mapping, 0, 0, 1); IDGI. Going through uacce_queue instead of uacce_device is fine, but why bother with file *or* inode? Just store a reference to struct address_space in your uacce_queue and be done with that... Another problem in that driver is uacce_vma_close(); this if (vma->vm_pgoff < UACCE_MAX_REGION) qfr = q->qfrs[vma->vm_pgoff]; kfree(qfr); can't be right - you have q->qfrs left pointing to freed object. If nothing else, subsequent mmap() will fail with -EEXIST, won't it?
On Thu, 11 May 2023 at 12:05, Al Viro <viro@zeniv.linux.org.uk> wrote: > > On Thu, May 11, 2023 at 10:15:53AM +0800, Zhangfei Gao wrote: > > The inode can be different in a container, for example, a docker and host > > both open the same uacce parent device, which uses the same uacce struct > > but different inode, so uacce->inode is not enough. > > > > What's worse, when docker stops, the inode will be destroyed as well, > > causing use-after-free in uacce_remove. > > > > So use q->filep->f_mapping to replace uacce->inode->i_mapping. > > > @@ -574,12 +574,6 @@ void uacce_remove(struct uacce_device *uacce) > > > > if (!uacce) > > return; > > - /* > > - * unmap remaining mapping from user space, preventing user still > > - * access the mmaped area while parent device is already removed > > - */ > > - if (uacce->inode) > > - unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); > > > > /* > > * uacce_fops_open() may be running concurrently, even after we remove > > @@ -589,6 +583,8 @@ void uacce_remove(struct uacce_device *uacce) > > mutex_lock(&uacce->mutex); > > /* ensure no open queue remains */ > > list_for_each_entry_safe(q, next_q, &uacce->queues, list) { > > + struct file *filep = q->private_data; > > + > > /* > > * Taking q->mutex ensures that fops do not use the defunct > > * uacce->ops after the queue is disabled. > > @@ -597,6 +593,12 @@ void uacce_remove(struct uacce_device *uacce) > > uacce_put_queue(q); > > mutex_unlock(&q->mutex); > > uacce_unbind_queue(q); > > + > > + /* > > + * unmap remaining mapping from user space, preventing user still > > + * access the mmaped area while parent device is already removed > > + */ > > + unmap_mapping_range(filep->f_mapping, 0, 0, 1); > > IDGI. Going through uacce_queue instead of uacce_device is fine, but why > bother with file *or* inode? Just store a reference to struct address_space in > your uacce_queue and be done with that... Yes, a struct address_space is enough. > > Another problem in that driver is uacce_vma_close(); this > if (vma->vm_pgoff < UACCE_MAX_REGION) > qfr = q->qfrs[vma->vm_pgoff]; > > kfree(qfr); > can't be right - you have q->qfrs left pointing to freed object. If nothing > else, subsequent mmap() will fail with -EEXIST, won't it? Good catch, will fix it. Thanks
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c index 346bd7cf2e94..740ace422baa 100644 --- a/drivers/misc/uacce/uacce.c +++ b/drivers/misc/uacce/uacce.c @@ -166,8 +166,8 @@ static int uacce_fops_open(struct inode *inode, struct file *filep) init_waitqueue_head(&q->wait); filep->private_data = q; - uacce->inode = inode; q->state = UACCE_Q_INIT; + q->private_data = filep; mutex_init(&q->mutex); list_add(&q->list, &uacce->queues); mutex_unlock(&uacce->mutex); @@ -574,12 +574,6 @@ void uacce_remove(struct uacce_device *uacce) if (!uacce) return; - /* - * unmap remaining mapping from user space, preventing user still - * access the mmaped area while parent device is already removed - */ - if (uacce->inode) - unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); /* * uacce_fops_open() may be running concurrently, even after we remove @@ -589,6 +583,8 @@ void uacce_remove(struct uacce_device *uacce) mutex_lock(&uacce->mutex); /* ensure no open queue remains */ list_for_each_entry_safe(q, next_q, &uacce->queues, list) { + struct file *filep = q->private_data; + /* * Taking q->mutex ensures that fops do not use the defunct * uacce->ops after the queue is disabled. @@ -597,6 +593,12 @@ void uacce_remove(struct uacce_device *uacce) uacce_put_queue(q); mutex_unlock(&q->mutex); uacce_unbind_queue(q); + + /* + * unmap remaining mapping from user space, preventing user still + * access the mmaped area while parent device is already removed + */ + unmap_mapping_range(filep->f_mapping, 0, 0, 1); } /* disable sva now since no opened queues */ diff --git a/include/linux/uacce.h b/include/linux/uacce.h index 0a81c3dfd26c..64b800b74436 100644 --- a/include/linux/uacce.h +++ b/include/linux/uacce.h @@ -86,6 +86,7 @@ enum uacce_q_state { * @state: queue state machine * @pasid: pasid associated to the mm * @handle: iommu_sva handle returned by iommu_sva_bind_device() + * @private_data: private data for saving filep */ struct uacce_queue { struct uacce_device *uacce; @@ -97,6 +98,7 @@ struct uacce_queue { enum uacce_q_state state; u32 pasid; struct iommu_sva *handle; + void *private_data; }; /** @@ -114,7 +116,6 @@ struct uacce_queue { * @mutex: protects uacce operation * @priv: private pointer of the uacce * @queues: list of queues - * @inode: core vfs */ struct uacce_device { const char *algs; @@ -130,7 +131,6 @@ struct uacce_device { struct mutex mutex; void *priv; struct list_head queues; - struct inode *inode; }; #if IS_ENABLED(CONFIG_UACCE)