[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/ipv4/devinet.c b/net/ipv4/devinet.c
index 7602c79..f38cbba 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1120,6 +1120,16 @@
.notifier_call =inetdev_event,
};
+static inline size_t inet_nlmsg_size(void)
+{
+ return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
+ + nla_total_size(4) /* IFA_ADDRESS */
+ + nla_total_size(4) /* IFA_LOCAL */
+ + nla_total_size(4) /* IFA_BROADCAST */
+ + nla_total_size(4) /* IFA_ANYCAST */
+ + nla_total_size(IFNAMSIZ); /* IFA_LABEL */
+}
+
static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
u32 pid, u32 seq, int event, unsigned int flags)
{
@@ -1208,15 +1218,13 @@
u32 seq = nlh ? nlh->nlmsg_seq : 0;
int err = -ENOBUFS;
- skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ skb = nlmsg_new(inet_nlmsg_size(), GFP_KERNEL);
if (skb == NULL)
goto errout;
err = inet_fill_ifaddr(skb, ifa, pid, seq, event, 0);
- if (err < 0) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in inet_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, pid, RTNLGRP_IPV4_IFADDR, nlh, GFP_KERNEL);
errout: