1 files changed, 19 insertions, 5 deletions

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 4148e274a204..1df6cd4568d3 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -306,6 +306,22 @@ errout:
         return err;
 }
 
+static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
+                                         struct fib_rule *rule)
+{
+        size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
+                         + nla_total_size(IFNAMSIZ) /* FRA_IFNAME */
+                         + nla_total_size(4) /* FRA_PRIORITY */
+                         + nla_total_size(4) /* FRA_TABLE */
+                         + nla_total_size(4) /* FRA_FWMARK */
+                         + nla_total_size(4); /* FRA_FWMASK */
+
+        if (ops->nlmsg_payload)
+                payload += ops->nlmsg_payload(rule);
+
+        return payload;
+}
+
 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
                             u32 pid, u32 seq, int type, int flags,
                             struct fib_rules_ops *ops)
@@ -384,15 +400,13 @@ static void notify_rule_change(int event, struct fib_rule *rule,
         struct sk_buff *skb;
         int err = -ENOBUFS;
 
-        skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
         if (skb == NULL)
                 goto errout;
 
         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
-        if (err < 0) {
-                kfree_skb(skb);
-                goto errout;
-        }
+        /* failure implies BUG in fib_rule_nlmsg_size() */
+        BUG_ON(err < 0);
 
         err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL);
 errout: