[NETLINK]: Limit NLMSG_GOODSIZE to 8K.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 2a20f488ac1b..a9d3ad5bc80f 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -171,9 +171,16 @@ int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
 
 /*
  *      skb should fit one page. This choice is good for headerless malloc.
+ *      But we should limit to 8K so that userspace does not have to
+ *      use enormous buffer sizes on recvmsg() calls just to avoid
+ *      MSG_TRUNC when PAGE_SIZE is very large.
  */
-#define NLMSG_GOODORDER 0
-#define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
+#if PAGE_SIZE < 8192UL
+#define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(PAGE_SIZE)
+#else
+#define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(8192UL)
+#endif
+
 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)