Re: [PATCH nft] evaluate: bogus error when refering to existing non-base chain

From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org, charles@ccxtechnologies.com,
	Fernando Fernandez Mancera <ffmancera@riseup.net>
Subject: Re: [PATCH nft] evaluate: bogus error when refering to existing non-base chain
Date: Tue, 16 Jul 2019 18:47:11 +0200	[thread overview]
Message-ID: <20190716164711.GF1628@orbyte.nwl.cc> (raw)
In-Reply-To: <20190716115120.21710-1-pablo@netfilter.org>

Hi Pablo,

On Tue, Jul 16, 2019 at 01:51:20PM +0200, Pablo Neira Ayuso wrote:
[...]
> diff --git a/src/evaluate.c b/src/evaluate.c
> index f95f42e1067a..cd566e856a11 100644
> --- a/src/evaluate.c
> +++ b/src/evaluate.c
> @@ -1984,17 +1984,9 @@ static int stmt_evaluate_verdict(struct eval_ctx *ctx, struct stmt *stmt)
>  	case EXPR_VERDICT:
>  		if (stmt->expr->verdict != NFT_CONTINUE)
>  			stmt->flags |= STMT_F_TERMINAL;
> -		if (stmt->expr->chain != NULL) {
> -			if (expr_evaluate(ctx, &stmt->expr->chain) < 0)
> -				return -1;
> -			if ((stmt->expr->chain->etype != EXPR_SYMBOL &&
> -			    stmt->expr->chain->etype != EXPR_VALUE) ||
> -			    stmt->expr->chain->symtype != SYMBOL_VALUE) {
> -				return stmt_error(ctx, stmt,
> -						  "invalid verdict chain expression %s\n",
> -						  expr_name(stmt->expr->chain));
> -			}
> -		}

According to my logs, this bit was added by Fernando to cover for
invalid variable values[1]. So I fear we can't just drop this check.

Cheers, Phil

[1] I didn't check with current sources, but back then the following
    variable contents were problematic:

    * define foo = @set1 (a set named 'set1' must exist)
    * define foo = { 1024 }
    * define foo = *