[NETLINK]: Ignore !NLM_F_REQUEST messages directly in netlink_run_queue()

netlink_rcv_skb() is changed to skip messages which don't have the
NLM_F_REQUEST bit to avoid every netlink family having to perform this
check on their own.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 8488c15f2643..7b455980e9bf 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1470,10 +1470,15 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 
         while (skb->len >= nlmsg_total_size(0)) {
                 nlh = nlmsg_hdr(skb);
+                err = 0;
 
                 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
                         return 0;
 
+                /* Only requests are handled by the kernel */
+                if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
+                        goto skip;
+
                 if (cb(skb, nlh, &err) < 0) {
                         /* Not an error, but we have to interrupt processing
                          * here. Note: that in this case we do not pull
@@ -1481,9 +1486,10 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
                          */
                         if (err == 0)
                                 return -1;
+                }
+skip:
+                if (nlh->nlmsg_flags & NLM_F_ACK || err)
                         netlink_ack(skb, nlh, err);
-                } else if (nlh->nlmsg_flags & NLM_F_ACK)
-                        netlink_ack(skb, nlh, 0);
 
                 netlink_queue_skip(nlh, skb);
         }