vhost: fix potential use-after-free for memory region

Reclaim outstanding zmbufs first before freeing memory regions,
otherwise there could be use-after-free.

Fixes: b0a985d1f340 ("vhost: add dequeue zero copy")
Cc: stable@dpdk.org
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 044651b..f008ec4 100644 (file)
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -769,4 +769,10 @@ mbuf_is_consumed(struct rte_mbuf *m)
        return true;
 }
 
+static __rte_always_inline void
+put_zmbuf(struct zcopy_mbuf *zmbuf)
+{
+       zmbuf->in_use = 0;
+}
+
 #endif /* _VHOST_NET_CDEV_H_ */

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 6d82535..36c0c67 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -93,15 +93,47 @@ get_blk_size(int fd)
        return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
 }
 
+/*
+ * Reclaim all the outstanding zmbufs for a virtqueue.
+ */
+static void
+drain_zmbuf_list(struct vhost_virtqueue *vq)
+{
+       struct zcopy_mbuf *zmbuf, *next;
+
+       for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
+            zmbuf != NULL; zmbuf = next) {
+               next = TAILQ_NEXT(zmbuf, next);
+
+               while (!mbuf_is_consumed(zmbuf->mbuf))
+                       usleep(1000);
+
+               TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
+               restore_mbuf(zmbuf->mbuf);
+               rte_pktmbuf_free(zmbuf->mbuf);
+               put_zmbuf(zmbuf);
+               vq->nr_zmbuf -= 1;
+       }
+}
+
 static void
 free_mem_region(struct virtio_net *dev)
 {
        uint32_t i;
        struct rte_vhost_mem_region *reg;
+       struct vhost_virtqueue *vq;
 
        if (!dev || !dev->mem)
                return;
 
+       if (dev->dequeue_zero_copy) {
+               for (i = 0; i < dev->nr_vring; i++) {
+                       vq = dev->virtqueue[i];
+                       if (vq)
+                               drain_zmbuf_list(vq);
+               }
+       }
+
        for (i = 0; i < dev->mem->nregions; i++) {
                reg = &dev->mem->regions[i];
                if (reg->host_user_addr) {
@@ -1212,19 +1244,7 @@ vhost_user_set_vring_kick(struct virtio_net **pdev, struct VhostUserMsg *msg,
 static void
 free_zmbufs(struct vhost_virtqueue *vq)
 {
-       struct zcopy_mbuf *zmbuf, *next;
-
-       for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
-            zmbuf != NULL; zmbuf = next) {
-               next = TAILQ_NEXT(zmbuf, next);
-
-               while (!mbuf_is_consumed(zmbuf->mbuf))
-                       usleep(1000);
-
-               restore_mbuf(zmbuf->mbuf);
-               rte_pktmbuf_free(zmbuf->mbuf);
-               TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
-       }
+       drain_zmbuf_list(vq);
 
        rte_free(vq->zmbufs);
 }

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 40a2923..a6a33a1 100644 (file)
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1063,12 +1063,6 @@ vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
        }
 }
 
-static __rte_always_inline void
-put_zmbuf(struct zcopy_mbuf *zmbuf)
-{
-       zmbuf->in_use = 0;
-}
-
 static __rte_always_inline int
 copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
                  struct buf_vector *buf_vec, uint16_t nr_vec,