[NETLINK]: Do precise netlink message allocations where possible
Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.
Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index b4b4783..0e097ba 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2410,20 +2410,27 @@
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_ARPD
+static inline size_t neigh_nlmsg_size(void)
+{
+ return NLMSG_ALIGN(sizeof(struct ndmsg))
+ + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
+ + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
+ + nla_total_size(sizeof(struct nda_cacheinfo))
+ + nla_total_size(4); /* NDA_PROBES */
+}
+
static void __neigh_notify(struct neighbour *n, int type, int flags)
{
struct sk_buff *skb;
int err = -ENOBUFS;
- skb = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+ skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC);
if (skb == NULL)
goto errout;
err = neigh_fill_info(skb, n, 0, 0, type, flags);
- if (err < 0) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in neigh_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
errout: