Re: [PATCH net-next 1/1] netfilter: flowtable: Make sure dst_cache is valid before using it

[Roi Dayan <roid@nvidia.com>]

On 2021-04-11 1:58 PM, Pablo Neira Ayuso wrote:
> Hi Roi,
> 
> On Sun, Apr 11, 2021 at 11:13:34AM +0300, Roi Dayan wrote:
>> It could be dst_cache was not set so check it's not null before using
>> it.
> 
> Could you give a try to this fix?
> 
> net/sched/act_ct.c leaves the xmit_type as FLOW_OFFLOAD_XMIT_UNSPEC
> since it does not cache a route.
> 
> Thanks.
> 

what do you mean? FLOW_OFFLOAD_XMIT_UNSPEC doesn't exists so default 0
is set.

do you suggest adding that enum option as 0?

this is the current xmit_type enum

enum flow_offload_xmit_type {
        FLOW_OFFLOAD_XMIT_NEIGH         = 0,
        FLOW_OFFLOAD_XMIT_XFRM,
        FLOW_OFFLOAD_XMIT_DIRECT,
};



>> Fixes: 8b9229d15877 ("netfilter: flowtable: dst_check() from garbage collector path")
>> Signed-off-by: Roi Dayan <roid@nvidia.com>
>> ---
>>   net/netfilter/nf_flow_table_core.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
>> index 76573bae6664..e426077aaed1 100644
>> --- a/net/netfilter/nf_flow_table_core.c
>> +++ b/net/netfilter/nf_flow_table_core.c
>> @@ -410,6 +410,8 @@ static bool flow_offload_stale_dst(struct flow_offload_tuple *tuple)
>>   	if (tuple->xmit_type == FLOW_OFFLOAD_XMIT_NEIGH ||
>>   	    tuple->xmit_type == FLOW_OFFLOAD_XMIT_XFRM) {
>>   		dst = tuple->dst_cache;
>> +		if (!dst)
>> +			return false;
>>   		if (!dst_check(dst, tuple->dst_cookie))
>>   			return true;
>>   	}
>> -- 
>> 2.26.2
>>