On Wed, Jan 31, 2018 at 5:44 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> On Wed, 2018-01-31 at 16:26 -0800, Cong Wang wrote:
>> rateest_hash is supposed to be protected by xt_rateest_mutex.
>>
>> Reported-by: <syzbot+5cb189720978275e4c75@xxxxxxxxxxxxxxxxxxxxxxxxx>
>> Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target")
>> Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
>> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
>> ---
>> net/netfilter/xt_RATEEST.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c
>> index 498b54fd04d7..83ec3a282755 100644
>> --- a/net/netfilter/xt_RATEEST.c
>> +++ b/net/netfilter/xt_RATEEST.c
>> @@ -36,7 +36,9 @@ static void xt_rateest_hash_insert(struct xt_rateest *est)
>> unsigned int h;
>>
>> h = xt_rateest_hash(est->name);
>> + mutex_lock(&xt_rateest_mutex);
>> hlist_add_head(&est->list, &rateest_hash[h]);
>> + mutex_unlock(&xt_rateest_mutex);
>> }
>
> We probably should make this module netns aware, otherwise bad things
> will happen.
Right, both the lock and the hashtable. I can do it for net-next,
if you don't.
>
> (It seems multiple threads could run, so getting the mutex twice
> (xt_rateest_lookup then xt_rateest_hash_insert() is racy)
Yeah, need to merge these two critical sections.
Thanks.
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