[1/1,SRU,C] vhost: fix OOB in get_rx_bufs()

Message ID 1549311752-18370-2-git-send-email-tyhicks@canonical.com
State New
Headers show
Series
  • CVE-2018-16880 - vhost_net out-of-bounds write
Related show

Commit Message

Tyler Hicks Feb. 4, 2019, 8:22 p.m.
From: Jason Wang <jasowang@redhat.com>

After batched used ring updating was introduced in commit e2b3b35eb989
("vhost_net: batch used ring update in rx"). We tend to batch heads in
vq->heads for more than one packet. But the quota passed to
get_rx_bufs() was not correctly limited, which can result a OOB write
in vq->heads.

        headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
                    vhost_len, &in, vq_log, &log,
                    likely(mergeable) ? UIO_MAXIOV : 1);

UIO_MAXIOV was still used which is wrong since we could have batched
used in vq->heads, this will cause OOB if the next buffer needs more
than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
batched 64 (VHOST_NET_BATCH) heads:
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

Comments

Kleber Souza Feb. 5, 2019, 9:08 a.m. | #1
On 2/4/19 9:22 PM, Tyler Hicks wrote:
> From: Jason Wang <jasowang@redhat.com>
>
> After batched used ring updating was introduced in commit e2b3b35eb989
> ("vhost_net: batch used ring update in rx"). We tend to batch heads in
> vq->heads for more than one packet. But the quota passed to
> get_rx_bufs() was not correctly limited, which can result a OOB write
> in vq->heads.
>
>         headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
>                     vhost_len, &in, vq_log, &log,
>                     likely(mergeable) ? UIO_MAXIOV : 1);
>
> UIO_MAXIOV was still used which is wrong since we could have batched
> used in vq->heads, this will cause OOB if the next buffer needs more
> than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
> batched 64 (VHOST_NET_BATCH) heads:
> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
>
> =============================================================================
> BUG kmalloc-8k (Tainted: G    B            ): Redzone overwritten
> -----------------------------------------------------------------------------
>
> INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
> INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
>     kmem_cache_alloc_trace+0xbb/0x140
>     alloc_pd+0x22/0x60
>     gen8_ppgtt_create+0x11d/0x5f0
>     i915_ppgtt_create+0x16/0x80
>     i915_gem_create_context+0x248/0x390
>     i915_gem_context_create_ioctl+0x4b/0xe0
>     drm_ioctl_kernel+0xa5/0xf0
>     drm_ioctl+0x2ed/0x3a0
>     do_vfs_ioctl+0x9f/0x620
>     ksys_ioctl+0x6b/0x80
>     __x64_sys_ioctl+0x11/0x20
>     do_syscall_64+0x43/0xf0
>     entry_SYSCALL_64_after_hwframe+0x44/0xa9
> INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x          (null) flags=0x200000000010201
> INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b
>
> Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
> vhost-net. This is done through set the limitation through
> vhost_dev_init(), then set_owner can allocate the number of iov in a
> per device manner.
>
> This fixes CVE-2018-16880.
>
> Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
> CVE-2018-16880
>
> (backported from commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd)
> [tyhicks: VHOST_NET_BATCH is VHOST_RX_BATCH in Cosmic]
> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>


Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>


> ---
>  drivers/vhost/net.c   | 3 ++-
>  drivers/vhost/scsi.c  | 2 +-
>  drivers/vhost/vhost.c | 7 ++++---
>  drivers/vhost/vhost.h | 4 +++-
>  drivers/vhost/vsock.c | 2 +-
>  5 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 6b86ca8772fb..b72bfeda82a5 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -984,7 +984,8 @@ static int vhost_net_open(struct inode *inode, struct file *f)
>  		n->vqs[i].rx_ring = NULL;
>  		vhost_net_buf_init(&n->vqs[i].rxq);
>  	}
> -	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
> +	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
> +		       UIO_MAXIOV + VHOST_RX_BATCH);
>  
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index fe7914dffd8f..0c3e413fe89f 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1398,7 +1398,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
>  		vqs[i] = &vs->vqs[i].vq;
>  		vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
>  	}
> -	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ);
> +	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
>  
>  	vhost_scsi_init_inflight(vs, NULL);
>  
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index c4424cbd9943..cd9ff58d6470 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -389,9 +389,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
>  		vq->indirect = kmalloc_array(UIO_MAXIOV,
>  					     sizeof(*vq->indirect),
>  					     GFP_KERNEL);
> -		vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
> +		vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
>  					GFP_KERNEL);
> -		vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
> +		vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
>  					  GFP_KERNEL);
>  		if (!vq->indirect || !vq->log || !vq->heads)
>  			goto err_nomem;
> @@ -413,7 +413,7 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
>  }
>  
>  void vhost_dev_init(struct vhost_dev *dev,
> -		    struct vhost_virtqueue **vqs, int nvqs)
> +		    struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
>  {
>  	struct vhost_virtqueue *vq;
>  	int i;
> @@ -426,6 +426,7 @@ void vhost_dev_init(struct vhost_dev *dev,
>  	dev->iotlb = NULL;
>  	dev->mm = NULL;
>  	dev->worker = NULL;
> +	dev->iov_limit = iov_limit;
>  	init_llist_head(&dev->work_list);
>  	init_waitqueue_head(&dev->wait);
>  	INIT_LIST_HEAD(&dev->read_list);
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 6c844b90a168..63f88f8e8184 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -166,9 +166,11 @@ struct vhost_dev {
>  	struct list_head read_list;
>  	struct list_head pending_list;
>  	wait_queue_head_t wait;
> +	int iov_limit;
>  };
>  
> -void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> +void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
> +		    int nvqs, int iov_limit);
>  long vhost_dev_set_owner(struct vhost_dev *dev);
>  bool vhost_dev_has_owner(struct vhost_dev *dev);
>  long vhost_dev_check_owner(struct vhost_dev *);
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index d27d7e9b2a9e..379d6571ed4c 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -531,7 +531,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
>  	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
>  	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
>  
> -	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
> +	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
>  
>  	file->private_data = vsock;
>  	spin_lock_init(&vsock->send_pkt_list_lock);
Stefan Bader Feb. 5, 2019, 10:12 a.m. | #2
On 04.02.19 21:22, Tyler Hicks wrote:
> From: Jason Wang <jasowang@redhat.com>
> 
> After batched used ring updating was introduced in commit e2b3b35eb989
> ("vhost_net: batch used ring update in rx"). We tend to batch heads in
> vq->heads for more than one packet. But the quota passed to
> get_rx_bufs() was not correctly limited, which can result a OOB write
> in vq->heads.
> 
>         headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
>                     vhost_len, &in, vq_log, &log,
>                     likely(mergeable) ? UIO_MAXIOV : 1);
> 
> UIO_MAXIOV was still used which is wrong since we could have batched
> used in vq->heads, this will cause OOB if the next buffer needs more
> than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
> batched 64 (VHOST_NET_BATCH) heads:
> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
> 
> =============================================================================
> BUG kmalloc-8k (Tainted: G    B            ): Redzone overwritten
> -----------------------------------------------------------------------------
> 
> INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
> INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
>     kmem_cache_alloc_trace+0xbb/0x140
>     alloc_pd+0x22/0x60
>     gen8_ppgtt_create+0x11d/0x5f0
>     i915_ppgtt_create+0x16/0x80
>     i915_gem_create_context+0x248/0x390
>     i915_gem_context_create_ioctl+0x4b/0xe0
>     drm_ioctl_kernel+0xa5/0xf0
>     drm_ioctl+0x2ed/0x3a0
>     do_vfs_ioctl+0x9f/0x620
>     ksys_ioctl+0x6b/0x80
>     __x64_sys_ioctl+0x11/0x20
>     do_syscall_64+0x43/0xf0
>     entry_SYSCALL_64_after_hwframe+0x44/0xa9
> INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x          (null) flags=0x200000000010201
> INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b
> 
> Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
> vhost-net. This is done through set the limitation through
> vhost_dev_init(), then set_owner can allocate the number of iov in a
> per device manner.
> 
> This fixes CVE-2018-16880.
> 
> Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> 
> CVE-2018-16880
> 
> (backported from commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd)
> [tyhicks: VHOST_NET_BATCH is VHOST_RX_BATCH in Cosmic]
> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
> ---
>  drivers/vhost/net.c   | 3 ++-
>  drivers/vhost/scsi.c  | 2 +-
>  drivers/vhost/vhost.c | 7 ++++---
>  drivers/vhost/vhost.h | 4 +++-
>  drivers/vhost/vsock.c | 2 +-
>  5 files changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 6b86ca8772fb..b72bfeda82a5 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -984,7 +984,8 @@ static int vhost_net_open(struct inode *inode, struct file *f)
>  		n->vqs[i].rx_ring = NULL;
>  		vhost_net_buf_init(&n->vqs[i].rxq);
>  	}
> -	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
> +	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
> +		       UIO_MAXIOV + VHOST_RX_BATCH);
>  
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index fe7914dffd8f..0c3e413fe89f 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1398,7 +1398,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
>  		vqs[i] = &vs->vqs[i].vq;
>  		vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
>  	}
> -	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ);
> +	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
>  
>  	vhost_scsi_init_inflight(vs, NULL);
>  
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index c4424cbd9943..cd9ff58d6470 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -389,9 +389,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
>  		vq->indirect = kmalloc_array(UIO_MAXIOV,
>  					     sizeof(*vq->indirect),
>  					     GFP_KERNEL);
> -		vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
> +		vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
>  					GFP_KERNEL);
> -		vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
> +		vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
>  					  GFP_KERNEL);
>  		if (!vq->indirect || !vq->log || !vq->heads)
>  			goto err_nomem;
> @@ -413,7 +413,7 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
>  }
>  
>  void vhost_dev_init(struct vhost_dev *dev,
> -		    struct vhost_virtqueue **vqs, int nvqs)
> +		    struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
>  {
>  	struct vhost_virtqueue *vq;
>  	int i;
> @@ -426,6 +426,7 @@ void vhost_dev_init(struct vhost_dev *dev,
>  	dev->iotlb = NULL;
>  	dev->mm = NULL;
>  	dev->worker = NULL;
> +	dev->iov_limit = iov_limit;
>  	init_llist_head(&dev->work_list);
>  	init_waitqueue_head(&dev->wait);
>  	INIT_LIST_HEAD(&dev->read_list);
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 6c844b90a168..63f88f8e8184 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -166,9 +166,11 @@ struct vhost_dev {
>  	struct list_head read_list;
>  	struct list_head pending_list;
>  	wait_queue_head_t wait;
> +	int iov_limit;
>  };
>  
> -void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> +void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
> +		    int nvqs, int iov_limit);
>  long vhost_dev_set_owner(struct vhost_dev *dev);
>  bool vhost_dev_has_owner(struct vhost_dev *dev);
>  long vhost_dev_check_owner(struct vhost_dev *);
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index d27d7e9b2a9e..379d6571ed4c 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -531,7 +531,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
>  	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
>  	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
>  
> -	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
> +	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
>  
>  	file->private_data = vsock;
>  	spin_lock_init(&vsock->send_pkt_list_lock);
>
Kleber Souza Feb. 5, 2019, 10:26 a.m. | #3
On 2/4/19 9:22 PM, Tyler Hicks wrote:
> From: Jason Wang <jasowang@redhat.com>
>
> After batched used ring updating was introduced in commit e2b3b35eb989
> ("vhost_net: batch used ring update in rx"). We tend to batch heads in
> vq->heads for more than one packet. But the quota passed to
> get_rx_bufs() was not correctly limited, which can result a OOB write
> in vq->heads.
>
>         headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
>                     vhost_len, &in, vq_log, &log,
>                     likely(mergeable) ? UIO_MAXIOV : 1);
>
> UIO_MAXIOV was still used which is wrong since we could have batched
> used in vq->heads, this will cause OOB if the next buffer needs more
> than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
> batched 64 (VHOST_NET_BATCH) heads:
> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
>
> =============================================================================
> BUG kmalloc-8k (Tainted: G    B            ): Redzone overwritten
> -----------------------------------------------------------------------------
>
> INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
> INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
>     kmem_cache_alloc_trace+0xbb/0x140
>     alloc_pd+0x22/0x60
>     gen8_ppgtt_create+0x11d/0x5f0
>     i915_ppgtt_create+0x16/0x80
>     i915_gem_create_context+0x248/0x390
>     i915_gem_context_create_ioctl+0x4b/0xe0
>     drm_ioctl_kernel+0xa5/0xf0
>     drm_ioctl+0x2ed/0x3a0
>     do_vfs_ioctl+0x9f/0x620
>     ksys_ioctl+0x6b/0x80
>     __x64_sys_ioctl+0x11/0x20
>     do_syscall_64+0x43/0xf0
>     entry_SYSCALL_64_after_hwframe+0x44/0xa9
> INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x          (null) flags=0x200000000010201
> INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b
>
> Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
> vhost-net. This is done through set the limitation through
> vhost_dev_init(), then set_owner can allocate the number of iov in a
> per device manner.
>
> This fixes CVE-2018-16880.
>
> Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
> CVE-2018-16880
>
> (backported from commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd)
> [tyhicks: VHOST_NET_BATCH is VHOST_RX_BATCH in Cosmic]
> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
> ---
>  drivers/vhost/net.c   | 3 ++-
>  drivers/vhost/scsi.c  | 2 +-
>  drivers/vhost/vhost.c | 7 ++++---
>  drivers/vhost/vhost.h | 4 +++-
>  drivers/vhost/vsock.c | 2 +-
>  5 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 6b86ca8772fb..b72bfeda82a5 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -984,7 +984,8 @@ static int vhost_net_open(struct inode *inode, struct file *f)
>  		n->vqs[i].rx_ring = NULL;
>  		vhost_net_buf_init(&n->vqs[i].rxq);
>  	}
> -	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
> +	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
> +		       UIO_MAXIOV + VHOST_RX_BATCH);
>  
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
>  	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index fe7914dffd8f..0c3e413fe89f 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1398,7 +1398,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
>  		vqs[i] = &vs->vqs[i].vq;
>  		vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
>  	}
> -	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ);
> +	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
>  
>  	vhost_scsi_init_inflight(vs, NULL);
>  
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index c4424cbd9943..cd9ff58d6470 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -389,9 +389,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
>  		vq->indirect = kmalloc_array(UIO_MAXIOV,
>  					     sizeof(*vq->indirect),
>  					     GFP_KERNEL);
> -		vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
> +		vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
>  					GFP_KERNEL);
> -		vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
> +		vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
>  					  GFP_KERNEL);
>  		if (!vq->indirect || !vq->log || !vq->heads)
>  			goto err_nomem;
> @@ -413,7 +413,7 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
>  }
>  
>  void vhost_dev_init(struct vhost_dev *dev,
> -		    struct vhost_virtqueue **vqs, int nvqs)
> +		    struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
>  {
>  	struct vhost_virtqueue *vq;
>  	int i;
> @@ -426,6 +426,7 @@ void vhost_dev_init(struct vhost_dev *dev,
>  	dev->iotlb = NULL;
>  	dev->mm = NULL;
>  	dev->worker = NULL;
> +	dev->iov_limit = iov_limit;
>  	init_llist_head(&dev->work_list);
>  	init_waitqueue_head(&dev->wait);
>  	INIT_LIST_HEAD(&dev->read_list);
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 6c844b90a168..63f88f8e8184 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -166,9 +166,11 @@ struct vhost_dev {
>  	struct list_head read_list;
>  	struct list_head pending_list;
>  	wait_queue_head_t wait;
> +	int iov_limit;
>  };
>  
> -void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> +void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
> +		    int nvqs, int iov_limit);
>  long vhost_dev_set_owner(struct vhost_dev *dev);
>  bool vhost_dev_has_owner(struct vhost_dev *dev);
>  long vhost_dev_check_owner(struct vhost_dev *);
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index d27d7e9b2a9e..379d6571ed4c 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -531,7 +531,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
>  	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
>  	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
>  
> -	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
> +	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
>  
>  	file->private_data = vsock;
>  	spin_lock_init(&vsock->send_pkt_list_lock);

Applied to cosmic/master-next branch.

Thanks,
Kleber

Patch

=============================================================================
BUG kmalloc-8k (Tainted: G    B            ): Redzone overwritten
-----------------------------------------------------------------------------

INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
    kmem_cache_alloc_trace+0xbb/0x140
    alloc_pd+0x22/0x60
    gen8_ppgtt_create+0x11d/0x5f0
    i915_ppgtt_create+0x16/0x80
    i915_gem_create_context+0x248/0x390
    i915_gem_context_create_ioctl+0x4b/0xe0
    drm_ioctl_kernel+0xa5/0xf0
    drm_ioctl+0x2ed/0x3a0
    do_vfs_ioctl+0x9f/0x620
    ksys_ioctl+0x6b/0x80
    __x64_sys_ioctl+0x11/0x20
    do_syscall_64+0x43/0xf0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x          (null) flags=0x200000000010201
INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b

Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
vhost-net. This is done through set the limitation through
vhost_dev_init(), then set_owner can allocate the number of iov in a
per device manner.

This fixes CVE-2018-16880.

Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

CVE-2018-16880

(backported from commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd)
[tyhicks: VHOST_NET_BATCH is VHOST_RX_BATCH in Cosmic]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
---
 drivers/vhost/net.c   | 3 ++-
 drivers/vhost/scsi.c  | 2 +-
 drivers/vhost/vhost.c | 7 ++++---
 drivers/vhost/vhost.h | 4 +++-
 drivers/vhost/vsock.c | 2 +-
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 6b86ca8772fb..b72bfeda82a5 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -984,7 +984,8 @@  static int vhost_net_open(struct inode *inode, struct file *f)
 		n->vqs[i].rx_ring = NULL;
 		vhost_net_buf_init(&n->vqs[i].rxq);
 	}
-	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
+	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
+		       UIO_MAXIOV + VHOST_RX_BATCH);
 
 	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
 	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index fe7914dffd8f..0c3e413fe89f 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1398,7 +1398,7 @@  static int vhost_scsi_open(struct inode *inode, struct file *f)
 		vqs[i] = &vs->vqs[i].vq;
 		vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
 	}
-	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ);
+	vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
 
 	vhost_scsi_init_inflight(vs, NULL);
 
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c4424cbd9943..cd9ff58d6470 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -389,9 +389,9 @@  static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
 		vq->indirect = kmalloc_array(UIO_MAXIOV,
 					     sizeof(*vq->indirect),
 					     GFP_KERNEL);
-		vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
+		vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
 					GFP_KERNEL);
-		vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
+		vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
 					  GFP_KERNEL);
 		if (!vq->indirect || !vq->log || !vq->heads)
 			goto err_nomem;
@@ -413,7 +413,7 @@  static void vhost_dev_free_iovecs(struct vhost_dev *dev)
 }
 
 void vhost_dev_init(struct vhost_dev *dev,
-		    struct vhost_virtqueue **vqs, int nvqs)
+		    struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
 {
 	struct vhost_virtqueue *vq;
 	int i;
@@ -426,6 +426,7 @@  void vhost_dev_init(struct vhost_dev *dev,
 	dev->iotlb = NULL;
 	dev->mm = NULL;
 	dev->worker = NULL;
+	dev->iov_limit = iov_limit;
 	init_llist_head(&dev->work_list);
 	init_waitqueue_head(&dev->wait);
 	INIT_LIST_HEAD(&dev->read_list);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 6c844b90a168..63f88f8e8184 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -166,9 +166,11 @@  struct vhost_dev {
 	struct list_head read_list;
 	struct list_head pending_list;
 	wait_queue_head_t wait;
+	int iov_limit;
 };
 
-void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
+void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
+		    int nvqs, int iov_limit);
 long vhost_dev_set_owner(struct vhost_dev *dev);
 bool vhost_dev_has_owner(struct vhost_dev *dev);
 long vhost_dev_check_owner(struct vhost_dev *);
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index d27d7e9b2a9e..379d6571ed4c 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -531,7 +531,7 @@  static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
 	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
 	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
 
-	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
+	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
 
 	file->private_data = vsock;
 	spin_lock_init(&vsock->send_pkt_list_lock);