[PATCH net] vhost: reject zero size iova range

[Jason Wang]

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/vhost/vhost.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

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;
 
-- 
2.19.1