connector: bump skb->users before callback invocation

Orabug: 23330543

[ Upstream commit 55285bf09427c5abf43ee1d54e892f352092b1f1 ]

Dmitry reports memleak with syskaller program.
Problem is that connector bumps skb usecount but might not invoke callback.

So move skb_get to where we invoke the callback.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit f45f0213b831305572436cdd2f7f0709fcbe2887)

Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 30f522848c7353166af0d9605215205101c0b013..c19e7fc717c306a8b3f5bcea2b13fbe0f6066b79 100644 (file)
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -178,26 +178,21 @@ static int cn_call_callback(struct sk_buff *skb)
  *
  * It checks skb, netlink header and msg sizes, and calls callback helper.
  */
-static void cn_rx_skb(struct sk_buff *__skb)
+static void cn_rx_skb(struct sk_buff *skb)
 {
        struct nlmsghdr *nlh;
-       struct sk_buff *skb;
        int len, err;
 
-       skb = skb_get(__skb);
-
        if (skb->len >= NLMSG_HDRLEN) {
                nlh = nlmsg_hdr(skb);
                len = nlmsg_len(nlh);
 
                if (len < (int)sizeof(struct cn_msg) ||
                    skb->len < nlh->nlmsg_len ||
-                   len > CONNECTOR_MAX_MSG_SIZE) {
-                       kfree_skb(skb);
+                   len > CONNECTOR_MAX_MSG_SIZE)
                        return;
-               }
 
-               err = cn_call_callback(skb);
+               err = cn_call_callback(skb_get(skb));
                if (err < 0)
                        kfree_skb(skb);
        }