linux-kernel - [PATCH net] netlink: avoid a double skb free in genlmsg

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Message-Id: <20180314201023.12407-1-nicolas.dichtel@6wind.com>
Date:   Wed, 14 Mar 2018 21:10:23 +0100
From:   Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:     ben.hutchings@...ethink.co.uk
Cc:     davem@...emloft.net, netdev@...r.kernel.org,
        stable@...r.kernel.org, johannes.berg@...el.com,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        Nicolas Dichtel <nicolas.dichtel@...nd.com>
Subject: [PATCH net] netlink: avoid a double skb free in genlmsg_mcast()

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>
---
 net/netlink/genetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 6f02499ef007..b9ce82c9440f 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1106,7 +1106,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 	if (!err)
 		delivered = true;
 	else if (err != -ESRCH)
-		goto error;
+		return err;
 	return delivered ? 0 : -ESRCH;
  error:
 	kfree_skb(skb);
-- 
2.15.1