[PATCH 4.19 11/96] vhost: reject zero size iova range

Greg Kroah-Hartman
2019-04-24T17:50:45Z

From: Jason Wang <jasowang@redhat.com>

[ Upstream commit 813dbeb656d6c90266f251d8bd2b02d445afa63f ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/vhost/vhost.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -911,8 +911,12 @@ static int vhost_new_umem_range(struct v
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;