[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/ipv6/route.c b/net/ipv6/route.c
index 0ad07c9..a6472cb 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2006,6 +2006,20 @@
return ip6_route_add(&cfg);
}
+static inline size_t rt6_nlmsg_size(void)
+{
+ return NLMSG_ALIGN(sizeof(struct rtmsg))
+ + nla_total_size(16) /* RTA_SRC */
+ + nla_total_size(16) /* RTA_DST */
+ + nla_total_size(16) /* RTA_GATEWAY */
+ + nla_total_size(16) /* RTA_PREFSRC */
+ + nla_total_size(4) /* RTA_TABLE */
+ + nla_total_size(4) /* RTA_IIF */
+ + nla_total_size(4) /* RTA_OIF */
+ + nla_total_size(4) /* RTA_PRIORITY */
+ + nla_total_size(sizeof(struct rta_cacheinfo));
+}
+
static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
struct in6_addr *dst, struct in6_addr *src,
int iif, int type, u32 pid, u32 seq,
@@ -2200,7 +2214,6 @@
struct sk_buff *skb;
u32 pid = 0, seq = 0;
struct nlmsghdr *nlh = NULL;
- int payload = sizeof(struct rtmsg) + 256;
int err = -ENOBUFS;
if (info) {
@@ -2210,15 +2223,13 @@
seq = nlh->nlmsg_seq;
}
- skb = nlmsg_new(nlmsg_total_size(payload), gfp_any());
+ skb = nlmsg_new(rt6_nlmsg_size(), gfp_any());
if (skb == NULL)
goto errout;
err = rt6_fill_node(skb, rt, NULL, NULL, 0, event, pid, seq, 0, 0);
- if (err < 0) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in rt6_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, pid, RTNLGRP_IPV6_ROUTE, nlh, gfp_any());
errout: