vhost: reject zero size iova range

We used to accept zero size iova range which will lead a infinite loop
in translate_desc(). Fixing this by failing the request in this case.

Reported-by: syzbot+d21e6e297322a900c128@syzkaller.appspotmail.com
Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5ace833de746..351af88231ad 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -911,8 +911,12 @@ static int vhost_new_umem_range(struct vhost_umem *umem,
                                 u64 start, u64 size, u64 end,
                                 u64 userspace_addr, int perm)
 {
-        struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
+        struct vhost_umem_node *tmp, *node;
 
+        if (!size)
+                return -EFAULT;
+
+        node = kmalloc(sizeof(*node), GFP_ATOMIC);
         if (!node)
                 return -ENOMEM;