Re: nftables: Dynamically updating sets gives syntax error

["Anders K. Pedersen" <akp@akp.dk>]

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?

Regards,
Anders K. Pedersen