Re: [PATCH nft 3/3] src: evaluate: return immediately if no op was requested

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

On Sun, Jul 21, 2019 at 02:14:07AM +0200, Florian Westphal wrote:
> This makes nft behave like 0.9.0 -- the ruleset
> 
> flush ruleset
> table inet filter {
> }
> table inet filter {
>       chain test {
>         counter
>     }
> }
> 
> loads again without generating an error message.
> I've added a test case for this, without this it will create an error,
> and with a checkout of the 'fixes' tag we get crash.
> 
> Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1351
> Fixes: e5382c0d08e3c ("src: Support intra-transaction rule references")

This one is causing the cache corruption, right?

> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  src/evaluate.c                                  |  3 +++
>  tests/shell/testcases/cache/0003_cache_update_0 | 12 ++++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/src/evaluate.c b/src/evaluate.c
> index b56932ccabcc..8c1c82abed4e 100644
> --- a/src/evaluate.c
> +++ b/src/evaluate.c
> @@ -3258,6 +3258,9 @@ static int rule_cache_update(struct eval_ctx *ctx, enum cmd_ops op)
>  	struct table *table;
>  	struct chain *chain;
>  
> +	if (op == CMD_INVALID)
> +		return 0;
> +
>  	table = table_lookup(&rule->handle, &ctx->nft->cache);
>  	if (!table)
>  		return table_not_found(ctx);
> diff --git a/tests/shell/testcases/cache/0003_cache_update_0 b/tests/shell/testcases/cache/0003_cache_update_0
> index 05edc9c7c33e..fb4b0e24c790 100755
> --- a/tests/shell/testcases/cache/0003_cache_update_0
> +++ b/tests/shell/testcases/cache/0003_cache_update_0
> @@ -48,3 +48,15 @@ $NFT -f - >/dev/null <<EOF
>  add rule ip t4 c meta l4proto igmp accept
>  add rule ip t4 c index 2 drop
>  EOF
> +
> +# Trigger a crash or rule restore error with nft 0.9.1
> +$NFT -f - >/dev/null <<EOF
> +flush ruleset
> +table inet testfilter {
> +}
> +table inet testfilter {
> +      chain test {
> +        counter
> +    }
> +}
> +EOF
> -- 
> 2.21.0
>