On Mon, Apr 25, 2016 at 06:05:41PM +0100, Patrick McHardy wrote: > On 25.04, Florian Westphal wrote: > > Patrick McHardy <kaber@xxxxxxxxx> wrote: > > > > > The alternative to internally handling it would be to some propagating > > > validation to immediates / sets which invoke the actual user of the data. > > > So in the case of helpers, we could replace the name by references to > > > the helper structures and reverse this during dumping. > > > > > > Regarding connlabels this doesn't really apply though. We expect userspace > > > to create a reasonable ruleset and anything that does not cause critical > > > errors is validated in userspace. > > > > Yes. So we have three choices here (pseudo-code) > > > > memcpy(ct->labels, regs->data[priv->sreg], sizeof(reg)); > > vs. > > set_bit(priv->imm, ct->labels); > > > > The latter is what the iptables module does, I do not mind if we > > go for #1 (treat the label area just like an 128bit register and > > replace it completely with whatever is in the source register). > > > > My only problem is that Pablo suggested #2 whereas you recommend #1. > > > > I don't want to resubmit until there is consensus as to what the > > preferred solution is. > > > > We could go for a 3rd alternative, namely: > > > > u16 bit = regs->data[priv->sreg]; > > set_bit(bit, ct->labels); > > > > i.e. have userspace place the _bit_ that we want to set in the > > source register. > > > > If we go for sreg that would be my favored solution. > > > > The only drawback vs #1 is that get and set work differently > > (get places all labels into dreg, set expects bit to set). > > That seems like a problem. I agree that #3 would generally be fine, but > we should also really have "ct labels set ct labels" not change the labels, > that would be highly counterintuitive. 'ct labels set' is actually operating a bitwise level. I suggested to introduce something like: 'ct labels bitset' so the user becomes aware of this operation. And we can just disallow "ct labels set ct labels" since it doesn't make sense for what Florian needs AFAIK. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
