linux-kernel - [PATCH 3.2 079/153] netlink: avoid a double skb free in genlmsg

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Date:   Wed, 30 May 2018 11:52:41 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Ben Hutchings" <ben.hutchings@...ethink.co.uk>,
        "David S. Miller" <davem@...emloft.net>,
        "Nicolas Dichtel" <nicolas.dichtel@...nd.com>
Subject: [PATCH 3.2 079/153] netlink: avoid a double skb free in
 genlmsg_mcast()

3.2.102-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nicolas Dichtel <nicolas.dichtel@...nd.com>

commit 02a2385f37a7c6594c9d89b64c4a1451276f08eb upstream.

nlmsg_multicast() consumes always the skb, thus the original skb must be
freed only when this function is called with a clone.

Fixes: cb9f7a9a5c96 ("netlink: ensure to loop over all netns in genlmsg_multicast_allns()")
Reported-by: Ben Hutchings <ben.hutchings@...ethink.co.uk>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 net/netlink/genetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -942,7 +942,7 @@ static int genlmsg_mcast(struct sk_buff
 	if (!err)
 		delivered = true;
 	else if (err != -ESRCH)
-		goto error;
+		return err;
 	return delivered ? 0 : -ESRCH;
  error:
 	kfree_skb(skb);