Read-only fields in libnetfilter_conntrack ct_conntrack structure

[Daniel Collins <solemnwarning@solemnwarning.net>]

Hi

I've found a bug in libnetfilter_conntrack - the nfct_set_attr() function silently doesn't populate certain fields (this behavior is documented), but it still calls set_bit(), so it actually "sets" the field without initialising it. nfct_attr_unset() also works on these fields.

But before thinking about fixing that bug: Why not make all the fields writable? If the intent is to be a general-purpose structure representing a conntrack table entry, I should be able to set all the fields, as little use as that may appear to have, if the intent is just to allow changing useful/meaningful ones in the kernel... should the list of writable ones not be shorter?

Background as to why I want to set the fields: I'm writing Perl bindings for libnetfilter_conntrack and some other stuff using them, I want to be able to serialise an entire nf_conntrack structure in one (privileged) process and then pass it to other unprivileged ones where it will be deserialized and stuff done with it.

Happy to write a patch to make them all writable if noone objects to it.

Thanks