[PATCH 0/4][SRU][D] CVE-2019-3900: vhost DoS

classic Classic list List threaded Threaded
8 messages Options
Reply | Threaded
Open this post in threaded view
|

[PATCH 0/4][SRU][D] CVE-2019-3900: vhost DoS

Tyler Hicks-2
https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-3900.html

 An infinite loop issue was found in the vhost_net kernel module in
 Linux Kernel up to and including v5.1-rc6, while handling incoming
 packets in handle_rx(). It could occur if one end sends packets faster
 than the other end can process them. A guest user, maybe remote one,
 could use this flaw to stall the vhost_net kernel thread, resulting in
 a DoS scenario.

All clean cherry picks. Build logs are clean. I tested with netperf's
TCP_RR test, initiated from both the host and the guest, to ensure that
the vhost-net connection was stable and that performance was similar
before and after the patches were applied.

Tyler

Jason Wang (4):
  vhost: introduce vhost_exceeds_weight()
  vhost_net: fix possible infinite loop
  vhost: vsock: add weight support
  vhost: scsi: add weight support

 drivers/vhost/net.c   | 41 ++++++++++++++---------------------------
 drivers/vhost/scsi.c  | 21 ++++++++++++++-------
 drivers/vhost/vhost.c | 20 +++++++++++++++++++-
 drivers/vhost/vhost.h |  5 ++++-
 drivers/vhost/vsock.c | 28 +++++++++++++++++++++-------
 5 files changed, 72 insertions(+), 43 deletions(-)

--
2.7.4


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

[PATCH 1/4] vhost: introduce vhost_exceeds_weight()

Tyler Hicks-2
From: Jason Wang <[hidden email]>

We used to have vhost_exceeds_weight() for vhost-net to:

- prevent vhost kthread from hogging the cpu
- balance the time spent between TX and RX

This function could be useful for vsock and scsi as well. So move it
to vhost.c. Device must specify a weight which counts the number of
requests, or it can also specific a byte_weight which counts the
number of bytes that has been processed.

Signed-off-by: Jason Wang <[hidden email]>
Reviewed-by: Stefan Hajnoczi <[hidden email]>
Signed-off-by: Michael S. Tsirkin <[hidden email]>

CVE-2019-3900

(cherry picked from commit e82b9b0727ff6d665fff2d326162b460dded554d)
Signed-off-by: Tyler Hicks <[hidden email]>
---
 drivers/vhost/net.c   | 22 ++++++----------------
 drivers/vhost/scsi.c  |  9 ++++++++-
 drivers/vhost/vhost.c | 20 +++++++++++++++++++-
 drivers/vhost/vhost.h |  5 ++++-
 drivers/vhost/vsock.c | 12 +++++++++++-
 5 files changed, 48 insertions(+), 20 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index df51a35cf537..061a06dc12a3 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -604,12 +604,6 @@ static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
  return iov_iter_count(iter);
 }
 
-static bool vhost_exceeds_weight(int pkts, int total_len)
-{
- return total_len >= VHOST_NET_WEIGHT ||
-       pkts >= VHOST_NET_PKT_WEIGHT;
-}
-
 static int get_tx_bufs(struct vhost_net *net,
        struct vhost_net_virtqueue *nvq,
        struct msghdr *msg,
@@ -845,10 +839,8 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
  vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
  vq->heads[nvq->done_idx].len = 0;
  ++nvq->done_idx;
- if (vhost_exceeds_weight(++sent_pkts, total_len)) {
- vhost_poll_queue(&vq->poll);
+ if (vhost_exceeds_weight(vq, ++sent_pkts, total_len))
  break;
- }
  }
 
  vhost_tx_batch(net, nvq, sock, &msg);
@@ -951,10 +943,9 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
  else
  vhost_zerocopy_signal_used(net, vq);
  vhost_net_tx_packet(net);
- if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) {
- vhost_poll_queue(&vq->poll);
+ if (unlikely(vhost_exceeds_weight(vq, ++sent_pkts,
+  total_len)))
  break;
- }
  }
 }
 
@@ -1239,10 +1230,8 @@ static void handle_rx(struct vhost_net *net)
  vhost_log_write(vq, vq_log, log, vhost_len,
  vq->iov, in);
  total_len += vhost_len;
- if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) {
- vhost_poll_queue(&vq->poll);
+ if (unlikely(vhost_exceeds_weight(vq, ++recv_pkts, total_len)))
  goto out;
- }
  }
  if (unlikely(busyloop_intr))
  vhost_poll_queue(&vq->poll);
@@ -1338,7 +1327,8 @@ static int vhost_net_open(struct inode *inode, struct file *f)
  vhost_net_buf_init(&n->vqs[i].rxq);
  }
  vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
-       UIO_MAXIOV + VHOST_NET_BATCH);
+       UIO_MAXIOV + VHOST_NET_BATCH,
+       VHOST_NET_WEIGHT, VHOST_NET_PKT_WEIGHT);
 
  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 23593cb23dd0..2f6154469f32 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -57,6 +57,12 @@
 #define VHOST_SCSI_PREALLOC_UPAGES 2048
 #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
 
+/* Max number of requests before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others with
+ * request.
+ */
+#define VHOST_SCSI_WEIGHT 256
+
 struct vhost_scsi_inflight {
  /* Wait for the flush operation to finish */
  struct completion comp;
@@ -1627,7 +1633,8 @@ 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, UIO_MAXIOV);
+ vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV,
+       VHOST_SCSI_WEIGHT, 0);
 
  vhost_scsi_init_inflight(vs, NULL);
 
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 674cfc5a4084..b8a5236ec163 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -413,8 +413,24 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
  vhost_vq_free_iovecs(dev->vqs[i]);
 }
 
+bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
+  int pkts, int total_len)
+{
+ struct vhost_dev *dev = vq->dev;
+
+ if ((dev->byte_weight && total_len >= dev->byte_weight) ||
+    pkts >= dev->weight) {
+ vhost_poll_queue(&vq->poll);
+ return true;
+ }
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
+
 void vhost_dev_init(struct vhost_dev *dev,
-    struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
+    struct vhost_virtqueue **vqs, int nvqs,
+    int iov_limit, int weight, int byte_weight)
 {
  struct vhost_virtqueue *vq;
  int i;
@@ -428,6 +444,8 @@ void vhost_dev_init(struct vhost_dev *dev,
  dev->mm = NULL;
  dev->worker = NULL;
  dev->iov_limit = iov_limit;
+ dev->weight = weight;
+ dev->byte_weight = byte_weight;
  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 9490e7ddb340..27a78a9b8cc7 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -171,10 +171,13 @@ struct vhost_dev {
  struct list_head pending_list;
  wait_queue_head_t wait;
  int iov_limit;
+ int weight;
+ int byte_weight;
 };
 
+bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
-    int nvqs, int iov_limit);
+    int nvqs, int iov_limit, int weight, int byte_weight);
 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 bb5fc0e9fbc2..47c6d4d43c70 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -21,6 +21,14 @@
 #include "vhost.h"
 
 #define VHOST_VSOCK_DEFAULT_HOST_CID 2
+/* Max number of bytes transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others. */
+#define VHOST_VSOCK_WEIGHT 0x80000
+/* Max number of packets transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others with
+ * small pkts.
+ */
+#define VHOST_VSOCK_PKT_WEIGHT 256
 
 enum {
  VHOST_VSOCK_FEATURES = VHOST_FEATURES,
@@ -531,7 +539,9 @@ 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), UIO_MAXIOV);
+ vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
+       UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
+       VHOST_VSOCK_WEIGHT);
 
  file->private_data = vsock;
  spin_lock_init(&vsock->send_pkt_list_lock);
--
2.7.4


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

[PATCH 2/4] vhost_net: fix possible infinite loop

Tyler Hicks-2
In reply to this post by Tyler Hicks-2
From: Jason Wang <[hidden email]>

When the rx buffer is too small for a packet, we will discard the vq
descriptor and retry it for the next packet:

while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
                                              &busyloop_intr))) {
...
        /* On overrun, truncate and discard */
        if (unlikely(headcount > UIO_MAXIOV)) {
                iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
                err = sock->ops->recvmsg(sock, &msg,
                                         1, MSG_DONTWAIT | MSG_TRUNC);
                pr_debug("Discarded rx packet: len %zd\n", sock_len);
                continue;
        }
...
}

This makes it possible to trigger a infinite while..continue loop
through the co-opreation of two VMs like:

1) Malicious VM1 allocate 1 byte rx buffer and try to slow down the
   vhost process as much as possible e.g using indirect descriptors or
   other.
2) Malicious VM2 generate packets to VM1 as fast as possible

Fixing this by checking against weight at the end of RX and TX
loop. This also eliminate other similar cases when:

- userspace is consuming the packets in the meanwhile
- theoretical TOCTOU attack if guest moving avail index back and forth
  to hit the continue after vhost find guest just add new buffers

This addresses CVE-2019-3900.

Fixes: d8316f3991d20 ("vhost: fix total length when packets are too short")
Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
Signed-off-by: Jason Wang <[hidden email]>
Reviewed-by: Stefan Hajnoczi <[hidden email]>
Signed-off-by: Michael S. Tsirkin <[hidden email]>

CVE-2019-3900

(cherry picked from commit e2412c07f8f3040593dfb88207865a3cd58680c0)
Signed-off-by: Tyler Hicks <[hidden email]>
---
 drivers/vhost/net.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 061a06dc12a3..2d9df786a9d3 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -773,7 +773,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
  int sent_pkts = 0;
  bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
 
- for (;;) {
+ do {
  bool busyloop_intr = false;
 
  if (nvq->done_idx == VHOST_NET_BATCH)
@@ -839,9 +839,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
  vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
  vq->heads[nvq->done_idx].len = 0;
  ++nvq->done_idx;
- if (vhost_exceeds_weight(vq, ++sent_pkts, total_len))
- break;
- }
+ } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
 
  vhost_tx_batch(net, nvq, sock, &msg);
 }
@@ -866,7 +864,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
  bool zcopy_used;
  int sent_pkts = 0;
 
- for (;;) {
+ do {
  bool busyloop_intr;
 
  /* Release DMAs done buffers first */
@@ -943,10 +941,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
  else
  vhost_zerocopy_signal_used(net, vq);
  vhost_net_tx_packet(net);
- if (unlikely(vhost_exceeds_weight(vq, ++sent_pkts,
-  total_len)))
- break;
- }
+ } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
 }
 
 /* Expects to be always run from workqueue - which acts as
@@ -1144,8 +1139,11 @@ static void handle_rx(struct vhost_net *net)
  vq->log : NULL;
  mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
 
- while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
-      &busyloop_intr))) {
+ do {
+ sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
+      &busyloop_intr);
+ if (!sock_len)
+ break;
  sock_len += sock_hlen;
  vhost_len = sock_len + vhost_hlen;
  headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
@@ -1230,12 +1228,11 @@ static void handle_rx(struct vhost_net *net)
  vhost_log_write(vq, vq_log, log, vhost_len,
  vq->iov, in);
  total_len += vhost_len;
- if (unlikely(vhost_exceeds_weight(vq, ++recv_pkts, total_len)))
- goto out;
- }
+ } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len)));
+
  if (unlikely(busyloop_intr))
  vhost_poll_queue(&vq->poll);
- else
+ else if (!sock_len)
  vhost_net_enable_vq(net, vq);
 out:
  vhost_net_signal_used(nvq);
@@ -1328,7 +1325,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
  }
  vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
        UIO_MAXIOV + VHOST_NET_BATCH,
-       VHOST_NET_WEIGHT, VHOST_NET_PKT_WEIGHT);
+       VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT);
 
  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);
--
2.7.4


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

[PATCH 3/4] vhost: vsock: add weight support

Tyler Hicks-2
In reply to this post by Tyler Hicks-2
From: Jason Wang <[hidden email]>

This patch will check the weight and exit the loop if we exceeds the
weight. This is useful for preventing vsock kthread from hogging cpu
which is guest triggerable. The weight can help to avoid starving the
request from on direction while another direction is being processed.

The value of weight is picked from vhost-net.

This addresses CVE-2019-3900.

Cc: Stefan Hajnoczi <[hidden email]>
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
Signed-off-by: Jason Wang <[hidden email]>
Reviewed-by: Stefan Hajnoczi <[hidden email]>
Signed-off-by: Michael S. Tsirkin <[hidden email]>

CVE-2019-3900

(cherry picked from commit e79b431fb901ba1106670bcc80b9b617b25def7d)
Signed-off-by: Tyler Hicks <[hidden email]>
---
 drivers/vhost/vsock.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 47c6d4d43c70..814bed72d793 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -86,6 +86,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
     struct vhost_virtqueue *vq)
 {
  struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+ int pkts = 0, total_len = 0;
  bool added = false;
  bool restart_tx = false;
 
@@ -97,7 +98,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
  /* Avoid further vmexits, we're already processing the virtqueue */
  vhost_disable_notify(&vsock->dev, vq);
 
- for (;;) {
+ do {
  struct virtio_vsock_pkt *pkt;
  struct iov_iter iov_iter;
  unsigned out, in;
@@ -182,8 +183,9 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
  */
  virtio_transport_deliver_tap_pkt(pkt);
 
+ total_len += pkt->len;
  virtio_transport_free_pkt(pkt);
- }
+ } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
  if (added)
  vhost_signal(&vsock->dev, vq);
 
@@ -358,7 +360,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
  struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
  dev);
  struct virtio_vsock_pkt *pkt;
- int head;
+ int head, pkts = 0, total_len = 0;
  unsigned int out, in;
  bool added = false;
 
@@ -368,7 +370,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
  goto out;
 
  vhost_disable_notify(&vsock->dev, vq);
- for (;;) {
+ do {
  u32 len;
 
  if (!vhost_vsock_more_replies(vsock)) {
@@ -409,9 +411,11 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
  else
  virtio_transport_free_pkt(pkt);
 
- vhost_add_used(vq, head, sizeof(pkt->hdr) + len);
+ len += sizeof(pkt->hdr);
+ vhost_add_used(vq, head, len);
+ total_len += len;
  added = true;
- }
+ } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
 
 no_more_replies:
  if (added)
--
2.7.4


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

[PATCH 4/4] vhost: scsi: add weight support

Tyler Hicks-2
In reply to this post by Tyler Hicks-2
From: Jason Wang <[hidden email]>

This patch will check the weight and exit the loop if we exceeds the
weight. This is useful for preventing scsi kthread from hogging cpu
which is guest triggerable.

This addresses CVE-2019-3900.

Cc: Paolo Bonzini <[hidden email]>
Cc: Stefan Hajnoczi <[hidden email]>
Fixes: 057cbf49a1f0 ("tcm_vhost: Initial merge for vhost level target fabric driver")
Signed-off-by: Jason Wang <[hidden email]>
Reviewed-by: Stefan Hajnoczi <[hidden email]>
Signed-off-by: Michael S. Tsirkin <[hidden email]>
Reviewed-by: Stefan Hajnoczi <[hidden email]>

CVE-2019-3900

(cherry picked from commit c1ea02f15ab5efb3e93fc3144d895410bf79fcf2)
Signed-off-by: Tyler Hicks <[hidden email]>
---
 drivers/vhost/scsi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 2f6154469f32..8bbe575ea568 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -923,7 +923,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
  struct iov_iter in_iter, prot_iter, data_iter;
  u64 tag;
  u32 exp_data_len, data_direction;
- int ret, prot_bytes;
+ int ret, prot_bytes, c = 0;
  u16 lun;
  u8 task_attr;
  bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
@@ -943,7 +943,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 
  vhost_disable_notify(&vs->dev, vq);
 
- for (;;) {
+ do {
  ret = vhost_scsi_get_desc(vs, vq, &vc);
  if (ret)
  goto err;
@@ -1123,7 +1123,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
  break;
  else if (ret == -EIO)
  vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
- }
+ } while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
 out:
  mutex_unlock(&vq->mutex);
 }
@@ -1182,7 +1182,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
  } v_req;
  struct vhost_scsi_ctx vc;
  size_t typ_size;
- int ret;
+ int ret, c = 0;
 
  mutex_lock(&vq->mutex);
  /*
@@ -1196,7 +1196,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 
  vhost_disable_notify(&vs->dev, vq);
 
- for (;;) {
+ do {
  ret = vhost_scsi_get_desc(vs, vq, &vc);
  if (ret)
  goto err;
@@ -1275,7 +1275,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
  break;
  else if (ret == -EIO)
  vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
- }
+ } while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
 out:
  mutex_unlock(&vq->mutex);
 }
--
2.7.4


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

ACK: [PATCH 0/4][SRU][D] CVE-2019-3900: vhost DoS

Connor Kuehl
In reply to this post by Tyler Hicks-2
On 8/7/19 9:43 PM, Tyler Hicks wrote:

> https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-3900.html
>
>  An infinite loop issue was found in the vhost_net kernel module in
>  Linux Kernel up to and including v5.1-rc6, while handling incoming
>  packets in handle_rx(). It could occur if one end sends packets faster
>  than the other end can process them. A guest user, maybe remote one,
>  could use this flaw to stall the vhost_net kernel thread, resulting in
>  a DoS scenario.
>
> All clean cherry picks. Build logs are clean. I tested with netperf's
> TCP_RR test, initiated from both the host and the guest, to ensure that
> the vhost-net connection was stable and that performance was similar
> before and after the patches were applied.
>
> Tyler
>
> Jason Wang (4):
>   vhost: introduce vhost_exceeds_weight()
>   vhost_net: fix possible infinite loop
>   vhost: vsock: add weight support
>   vhost: scsi: add weight support
>
>  drivers/vhost/net.c   | 41 ++++++++++++++---------------------------
>  drivers/vhost/scsi.c  | 21 ++++++++++++++-------
>  drivers/vhost/vhost.c | 20 +++++++++++++++++++-
>  drivers/vhost/vhost.h |  5 ++++-
>  drivers/vhost/vsock.c | 28 +++++++++++++++++++++-------
>  5 files changed, 72 insertions(+), 43 deletions(-)
>

Acked-by: Connor Kuehl <[hidden email]>


--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

ACK: [PATCH 0/4][SRU][D] CVE-2019-3900: vhost DoS

Kleber Sacilotto de Souza
In reply to this post by Tyler Hicks-2
On 8/8/19 6:43 AM, Tyler Hicks wrote:

> https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-3900.html
>
>  An infinite loop issue was found in the vhost_net kernel module in
>  Linux Kernel up to and including v5.1-rc6, while handling incoming
>  packets in handle_rx(). It could occur if one end sends packets faster
>  than the other end can process them. A guest user, maybe remote one,
>  could use this flaw to stall the vhost_net kernel thread, resulting in
>  a DoS scenario.
>
> All clean cherry picks. Build logs are clean. I tested with netperf's
> TCP_RR test, initiated from both the host and the guest, to ensure that
> the vhost-net connection was stable and that performance was similar
> before and after the patches were applied.
>
> Tyler
>
> Jason Wang (4):
>   vhost: introduce vhost_exceeds_weight()
>   vhost_net: fix possible infinite loop
>   vhost: vsock: add weight support
>   vhost: scsi: add weight support
>
>  drivers/vhost/net.c   | 41 ++++++++++++++---------------------------
>  drivers/vhost/scsi.c  | 21 ++++++++++++++-------
>  drivers/vhost/vhost.c | 20 +++++++++++++++++++-
>  drivers/vhost/vhost.h |  5 ++++-
>  drivers/vhost/vsock.c | 28 +++++++++++++++++++++-------
>  5 files changed, 72 insertions(+), 43 deletions(-)
>

Clean cherry-picks, good test results.

Acked-by: Kleber Sacilotto de Souza <[hidden email]>

--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team
Reply | Threaded
Open this post in threaded view
|

APPLIED: [PATCH 0/4][SRU][D] CVE-2019-3900: vhost DoS

Khaled Elmously
In reply to this post by Tyler Hicks-2
On 2019-08-08 04:43:31 , Tyler Hicks wrote:

> https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-3900.html
>
>  An infinite loop issue was found in the vhost_net kernel module in
>  Linux Kernel up to and including v5.1-rc6, while handling incoming
>  packets in handle_rx(). It could occur if one end sends packets faster
>  than the other end can process them. A guest user, maybe remote one,
>  could use this flaw to stall the vhost_net kernel thread, resulting in
>  a DoS scenario.
>
> All clean cherry picks. Build logs are clean. I tested with netperf's
> TCP_RR test, initiated from both the host and the guest, to ensure that
> the vhost-net connection was stable and that performance was similar
> before and after the patches were applied.
>
> Tyler
>
> Jason Wang (4):
>   vhost: introduce vhost_exceeds_weight()
>   vhost_net: fix possible infinite loop
>   vhost: vsock: add weight support
>   vhost: scsi: add weight support
>
>  drivers/vhost/net.c   | 41 ++++++++++++++---------------------------
>  drivers/vhost/scsi.c  | 21 ++++++++++++++-------
>  drivers/vhost/vhost.c | 20 +++++++++++++++++++-
>  drivers/vhost/vhost.h |  5 ++++-
>  drivers/vhost/vsock.c | 28 +++++++++++++++++++++-------
>  5 files changed, 72 insertions(+), 43 deletions(-)
>
> --
> 2.7.4
>
>
> --
> kernel-team mailing list
> [hidden email]
> https://lists.ubuntu.com/mailman/listinfo/kernel-team

--
kernel-team mailing list
[hidden email]
https://lists.ubuntu.com/mailman/listinfo/kernel-team