Re: [PATCH v2 2/3] netfilter: log: protect nf_log_register against double registering

[Marcelo Ricardo Leitner <mleitner@redhat.com>]

On 27-10-2014 20:09, Pablo Neira Ayuso wrote:
> Hi Marcelo,
>
> I just noticed another minor issue that I didn't notice in my previous
> review.
>
> On Fri, Oct 24, 2014 at 10:59:50AM -0200, Marcelo Ricardo Leitner wrote:
>> diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
>> index f1409d95f810c689ec70755eb8a85125d291ad47..e7c7439f48db590eba8f7f2eac61fafd9e571389 100644
>> --- a/net/netfilter/nf_log.c
>> +++ b/net/netfilter/nf_log.c
>> @@ -82,10 +82,19 @@ int nf_log_register(u_int8_t pf, struct nf_logger *logger)
>>   	mutex_lock(&nf_log_mutex);
>>
>>   	if (pf == NFPROTO_UNSPEC) {
>> +		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
>> +			if (nft_log_dereference(loggers[i][logger->type])) {
>
> Given that we're not dereferencing, I think you can use
> rcu_access_pointer() instead here.

Right! I'll update it (this and the below one) and send in a few, thanks.

Marcelo

>> +				mutex_unlock(&nf_log_mutex);
>> +				return -EEXIST;
>> +			}
>> +		}
>>   		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
>>   			rcu_assign_pointer(loggers[i][logger->type], logger);
>>   	} else {
>> -		/* register at end of list to honor first register win */
>> +		if (nft_log_dereference(loggers[pf][logger->type])) {
>
> Same thing here.
>