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>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index cfac26d674ede45d76fb199ce154297c7cf59609..2dd832592a310fdf981f6c929034d12ca9075b7e 100644 (file)
--- 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
         */