vhost: reject zero size iova range

BugLink: https://bugs.launchpad.net/bugs/1838349
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 7cbc18bdaf672f4b5b9c48c9f8f04fe0220eaf8a..6f86dd6cc4b33479f43ae5c156d88cf083e9ecdf 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -918,8 +918,12 @@ 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;