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Subject: Re: [PATCH] netfilter: initialize 'ret' variable
To:     Pablo Neira Ayuso <pablo@netfilter.org>
Cc:     Jozsef Kadlecsik <kadlec@netfilter.org>,
        Florian Westphal <fw@strlen.de>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org,
        kernel-janitors@vger.kernel.org, coreteam@netfilter.org,
        Yu Zhe <yuzhe@nfschina.com>
References: <20221202070331.10865-1-liqiong@nfschina.com>
 <Y43/iCzGY7qJckCe@salvia>
From:   liqiong <liqiong@nfschina.com>
Message-ID: <287de53c-78f1-94b5-6399-772e347057b5@nfschina.com>
Date:   Tue, 6 Dec 2022 08:29:09 +0800
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在 2022年12月05日 22:26, Pablo Neira Ayuso 写道:
> On Fri, Dec 02, 2022 at 03:03:31PM +0800, Li Qiong wrote:
>> The 'ret' should need to be initialized to 0, in case
>> return a uninitialized value.
>>
>> Signed-off-by: Li Qiong <liqiong@nfschina.com>
>> ---
>>  net/netfilter/nf_flow_table_ip.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
>> index b350fe9d00b0..225ff865d609 100644
>> --- a/net/netfilter/nf_flow_table_ip.c
>> +++ b/net/netfilter/nf_flow_table_ip.c
>> @@ -351,7 +351,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
>>  	struct rtable *rt;
>>  	struct iphdr *iph;
>>  	__be32 nexthop;
>> -	int ret;
>> +	int ret = 0;
>>  
>>  	if (skb->protocol != htons(ETH_P_IP) &&
>>  	    !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IP), &offset))
>> @@ -613,7 +613,7 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
>>  	u32 hdrsize, offset = 0;
>>  	struct ipv6hdr *ip6h;
>>  	struct rt6_info *rt;
>> -	int ret;
>> +	int ret = 0;
>>  
>>  	if (skb->protocol != htons(ETH_P_IPV6) &&
>>  	    !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IPV6), &offset))
> This can only happen with tuplehash->tuple.xmit_type:
>
> - FLOW_OFFLOAD_XMIT_UNSPEC
> - FLOW_OFFLOAD_XMIT_TC
>
> but this should not ever happen in that path.
>
> Instead, I'd suggest to add a 'default' case to the switch, set ret to
> NF_DROP and WARN_ON_ONCE(1).
Thanks,  I will send a v2 patch.