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

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Date:   Fri, 16 Mar 2018 12:36:29 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     nicolas.dichtel@...nd.com
Cc:     ben.hutchings@...ethink.co.uk, netdev@...r.kernel.org,
        stable@...r.kernel.org, johannes.berg@...el.com,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] netlink: avoid a double skb free in genlmsg_mcast()

From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
Date: Wed, 14 Mar 2018 21:10:23 +0100

> 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>

Yeah these "clone until final send" loops can be tricky to manage.

Good catch, applied and queued up for -stable, thanks.