neigh: disallow un-init_net to change thresh of neigh

thresh and interval are global resources,
only init net can change them.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 86f9b165bbba..2569ab2cafbe 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2049,6 +2049,12 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
                 }
         }
 
+        err = -ENOENT;
+        if ((tb[NDTA_THRESH1] || tb[NDTA_THRESH2] ||
+             tb[NDTA_THRESH3] || tb[NDTA_GC_INTERVAL]) &&
+            !net_eq(net, &init_net))
+                goto errout_tbl_lock;
+
         if (tb[NDTA_THRESH1])
                 tbl->gc_thresh1 = nla_get_u32(tb[NDTA_THRESH1]);