netdev - Re: [PATCH 2/3] netfilter: Create revision 2 of xt

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Message-ID: <577C3735.2060207@akamai.com>
Date:	Tue, 5 Jul 2016 18:39:49 -0400
From:	Vishwanath Pai <vpai@...mai.com>
To:	Pablo Neira Ayuso <pablo@...filter.org>
Cc:	kaber@...sh.net, kadlec@...ckhole.kfki.hu,
	netfilter-devel@...r.kernel.org, coreteam@...filter.org,
	johunt@...mai.com, netdev@...r.kernel.org, pai.vishwain@...il.com
Subject: Re: [PATCH 2/3] netfilter: Create revision 2 of xt_hashlimit to
 support higher pps rates

On 06/23/2016 07:16 AM, Pablo Neira Ayuso wrote:
> On Wed, Jun 01, 2016 at 08:11:38PM -0400, Vishwanath Pai wrote:
>> +static void
>> +cfg_copy(struct hashlimit_cfg2 *to, void *from, int revision)
>> +{
>> +	if (revision == 1) {
>> +		struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from;
>> +
>> +		to->mode = cfg->mode;
>> +		to->avg = cfg->avg;
>> +		to->burst = cfg->burst;
>> +		to->size = cfg->size;
>> +		to->max = cfg->max;
>> +		to->gc_interval = cfg->gc_interval;
>> +		to->expire = cfg->expire;
>> +		to->srcmask = cfg->srcmask;
>> +		to->dstmask = cfg->dstmask;
>> +	} else if (revision == 2) {
>> +		memcpy(to, from, sizeof(struct hashlimit_cfg2));
>> +	} else {
>> +		BUG();
> 
> BUG here is probably too much, this halts the system. I can see we
> only use this somewhere else in this code. Instead, I'd suggest you
> propagate an error back to userspace if this ever happen.
> 
> I would like to see if this spots any problem with our test
> infrastructure under iptables/.
> 
> Thanks.
> 

copy_cfg is only used internally by the kernel module and the value for
revision is passed to the function by the module itself and not from
userspace. I will remove BUG() and propagate the error back to the
caller, will send a v2.