net: introduce nla_policy for IFLA_NEW_IFINDEX

In this case, we don't need to check that new_ifindex is positive in
validate_linkmsg.

Fixes: eeb85a14ee34 ("net: Allow to specify ifindex when device is moved to another namespace")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d51252afde0a2376a97124bf477c438e44d5a66b..9108a7e6c0c0ca0a850f7ec106730bbb8ecc1d17 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1877,6 +1877,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
                                    .len = ALTIFNAMSIZ - 1 },
        [IFLA_PERM_ADDRESS]     = { .type = NLA_REJECT },
        [IFLA_PROTO_DOWN_REASON] = { .type = NLA_NESTED },
+       [IFLA_NEW_IFINDEX]      = NLA_POLICY_MIN(NLA_S32, 1),
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2266,9 +2267,6 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[])
                        return -EINVAL;
        }
 
-       if (tb[IFLA_NEW_IFINDEX] && nla_get_s32(tb[IFLA_NEW_IFINDEX]) <= 0)
-               return -EINVAL;
-
        if (tb[IFLA_AF_SPEC]) {
                struct nlattr *af;
                int rem, err;