Re: nftables: Dynamically updating sets gives syntax error

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Sat, Jul 02, 2016 at 04:12:56PM +0200, Anders K. Pedersen wrote:
> Hello,
> 
> On lør, 2016-06-25 at 15:30 +0200, Anders K. Pedersen wrote:
> > With nftables 0.6 I'm getting a syntax error, when I try to use the
> > feature that was introduced
> > by http://git.netfilter.org/nftables/commit
> > /?id=a9467e55973b10c2e8fe37525514c961580f8506 . For example:
> > 
> > # nft filter input set add tcp dport @myset
> > <cmdline>:1:26-30: Error: syntax error, unexpected dport
> > filter input set add tcp dport @myset
> >                          ^^^^^
> > # nft filter input set add ip saddr timeout 10s @myset
> > <cmdline>:1:25-29: Error: syntax error, unexpected saddr
> > filter input set add ip saddr timeout 10s @myset
> >                         ^^^^^
> > # nft filter input set update ip saddr timeout 10s @myset
> > <cmdline>:1:28-32: Error: syntax error, unexpected saddr
> > filter input set update ip saddr timeout 10s @myset
> >                            ^^^^^
> 
> I did a git bisect on this and found that it was broken by
> 
> commit a3e60492a684be09374d0649735da42bdadc6b48
> Author: Pablo Neira Ayuso <pablo@netfilter.org>
> Date:   Sun Dec 27 22:15:17 2015 +0100
> 
>     parser: restrict relational rhs expression recursion
> 
> After studying it a bit I reverted a part of it with the following
> change, which made the commands above work again:
> 
> --- a/src/parser_bison.y
> +++ b/src/parser_bison.y
> @@ -2054,7 +2054,7 @@ set_elem_option		:	TIMEOUT			time_spec
>  			}
>  			;
>  
> -set_lhs_expr		:	concat_rhs_expr
> +set_lhs_expr		:	concat_expr
>  			|	multiton_rhs_expr
>  			;
>  
> The commit message indicated that it intended to handle rhs
> expressions, but this is a lhs expression, so maybe this change was
> unintended?

Thanks for reporting. This results however in shift/reduce conflicts
in the grammar, just sent patches to address this:

http://patchwork.ozlabs.org/patch/647448/
http://patchwork.ozlabs.org/patch/647447/

Please, test and let me know if this works for you. Thanks.