ipv6: Check return of dev_set_allmulti

allmulti might overflow.
Commit: "netdevice: Fix promiscuity and allmulti overflow" in net-next makes
dev_set_promiscuity/allmulti return error number if overflow happened.

Here, we check the positive increment for allmulti to get error return.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Acked-by: Patrick McHardy <kaber@trash.net> 
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index cfac26d674ed..2dd832592a31 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -595,6 +595,7 @@ static int mif6_add(struct mif6ctl *vifc, int mrtsock)
         int vifi = vifc->mif6c_mifi;
         struct mif_device *v = &vif6_table[vifi];
         struct net_device *dev;
+        int err;
 
         /* Is vif busy ? */
         if (MIF_EXISTS(vifi))
@@ -612,6 +613,11 @@ static int mif6_add(struct mif6ctl *vifc, int mrtsock)
                 dev = ip6mr_reg_vif();
                 if (!dev)
                         return -ENOBUFS;
+                err = dev_set_allmulti(dev, 1);
+                if (err) {
+                        unregister_netdevice(dev);
+                        return err;
+                }
                 break;
 #endif
         case 0:
@@ -619,13 +625,14 @@ static int mif6_add(struct mif6ctl *vifc, int mrtsock)
                 if (!dev)
                         return -EADDRNOTAVAIL;
                 dev_put(dev);
+                err = dev_set_allmulti(dev, 1);
+                if (err)
+                        return err;
                 break;
         default:
                 return -EINVAL;
         }
 
-        dev_set_allmulti(dev, 1);
-
         /*
          *      Fill in the VIF structures
          */