The access of vsock is not protected by vhost_vsock_lock. This may
lead use after free since vhost_vsock_dev_release() may free the
pointer at the same time.
Fix this by holding the lock during the acess.
Reported-by: syzbot+e3e074963495f92a89ed at syzkaller.appspotmail.com
Fixes: 16320f363ae1 ("vhost-vsock: add pkt cancel capability")
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
Cc: Stefan Hajnoczi <stefanha at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
- The patch is needed for -stable.
---
drivers/vhost/vsock.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 34bc3ab40c6d..7d0b292867fd 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -210,21 +210,27 @@ vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
struct vhost_vsock *vsock;
int len = pkt->len;
+ spin_lock_bh(&vhost_vsock_lock);
+
/* Find the vhost_vsock according to guest context id */
- vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
+ vsock = __vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
if (!vsock) {
virtio_transport_free_pkt(pkt);
+ spin_unlock_bh(&vhost_vsock_lock);
return -ENODEV;
}
if (pkt->reply)
atomic_inc(&vsock->queued_replies);
- spin_lock_bh(&vsock->send_pkt_list_lock);
+ spin_lock(&vsock->send_pkt_list_lock);
list_add_tail(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_unlock(&vsock->send_pkt_list_lock);
vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+
+ spin_unlock_bh(&vhost_vsock_lock);
+
return len;
}
@@ -236,18 +242,22 @@ vhost_transport_cancel_pkt(struct vsock_sock *vsk)
int cnt = 0;
LIST_HEAD(freeme);
+ spin_lock_bh(&vhost_vsock_lock);
+
/* Find the vhost_vsock according to guest context id */
- vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
- if (!vsock)
+ vsock = __vhost_vsock_get(vsk->remote_addr.svm_cid);
+ if (!vsock) {
+ spin_unlock_bh(&vhost_vsock_lock);
return -ENODEV;
+ }
- spin_lock_bh(&vsock->send_pkt_list_lock);
+ spin_lock(&vsock->send_pkt_list_lock);
list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
if (pkt->vsk != vsk)
continue;
list_move(&pkt->list, &freeme);
}
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_unlock(&vsock->send_pkt_list_lock);
list_for_each_entry_safe(pkt, n, &freeme, list) {
if (pkt->reply)
@@ -265,6 +275,8 @@ vhost_transport_cancel_pkt(struct vsock_sock *vsk)
vhost_poll_queue(&tx_vq->poll);
}
+ spin_unlock_bh(&vhost_vsock_lock);
+
return 0;
}
--
2.17.1