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Subject: Re: [PATCH] ipset: fix a missing check of nla_parse
To:     Kangjie Lu <kjlu@umn.edu>
Cc:     pakki001@umn.edu, Pablo Neira Ayuso <pablo@netfilter.org>,
        Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
        Florian Westphal <fw@strlen.de>,
        "David S. Miller" <davem@davemloft.net>,
        Stefano Brivio <sbrivio@redhat.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20181226035002.73614-1-kjlu@umn.edu>
From:   Kirill Tkhai <ktkhai@virtuozzo.com>
Message-ID: <c462e7f4-6c41-78e8-26e9-8ce16ca26a5c@virtuozzo.com>
Date:   Wed, 26 Dec 2018 12:16:25 +0300
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On 26.12.2018 06:50, Kangjie Lu wrote:
> When nla_parse fails, we should not use the results (the first
> argument). The fix checks if it fails, and if so, returns its error code
> upstream.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  net/netfilter/ipset/ip_set_core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
> index 1577f2f76060..4dc8057cff02 100644
> --- a/net/netfilter/ipset/ip_set_core.c
> +++ b/net/netfilter/ipset/ip_set_core.c
> @@ -1531,8 +1531,10 @@ call_ad(struct sock *ctnl, struct sk_buff *skb, struct ip_set *set,
>  		memcpy(&errmsg->msg, nlh, nlh->nlmsg_len);
>  		cmdattr = (void *)&errmsg->msg + min_len;
>  
> -		nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr,
> +		ret = nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr,
>  			  nlh->nlmsg_len - min_len, ip_set_adt_policy, NULL);
> +		if (ret)
> +			return ret;

In this function above nlmsg_new() allocates skb2, but I don't see, where you free it here.

>  
>  		errline = nla_data(cda[IPSET_ATTR_LINENO]);
>  
>