connector: bump skb->users before callback invocation

[ 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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index ea6efe8..8982912 100644 (file)
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -154,26 +154,21 @@ static int cn_call_callback(struct sk_buff *skb)
  *
  * It checks skb, netlink header and msg sizes, and calls callback helper.
  */
  *
  * 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 nlmsghdr *nlh;

-       struct sk_buff *skb;

        int len, err;
 
        int len, err;
 

-       skb = skb_get(__skb);
-

        if (skb->len >= NLMSG_SPACE(0)) {
                nlh = nlmsg_hdr(skb);
                len = nlmsg_len(nlh);
 
                if (len < (int)sizeof(struct cn_msg) ||
                    skb->len < nlh->nlmsg_len ||
        if (skb->len >= NLMSG_SPACE(0)) {
                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;
                        return;

-               }

 
 

-               err = cn_call_callback(skb);
+               err = cn_call_callback(skb_get(skb));

                if (err < 0)
                        kfree_skb(skb);
        }
                if (err < 0)
                        kfree_skb(skb);
        }