Re: [PATCH nft] cache: don't crash when filter is NULL

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

On Tue, Apr 01, 2025 at 04:29:14PM +0200, Florian Westphal wrote:
> a delete request will cause a crash in obj_cache_dump, move the deref
> into the filter block.
> 
> Fixes: dbff26bfba83 ("cache: consolidate reset command")
> Signed-off-by: Florian Westphal <fw@strlen.de>

Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>

Thanks.

> ---
>  src/cache.c                                                 | 6 ++++--
>  .../testcases/bogons/nft-f/delete_nonexistant_object_crash  | 1 +
>  2 files changed, 5 insertions(+), 2 deletions(-)
>  create mode 100644 tests/shell/testcases/bogons/nft-f/delete_nonexistant_object_crash
> 
> diff --git a/src/cache.c b/src/cache.c
> index b75a5bf3283c..c0d96bd14a80 100644
> --- a/src/cache.c
> +++ b/src/cache.c
> @@ -902,6 +902,7 @@ static struct nftnl_obj_list *obj_cache_dump(struct netlink_ctx *ctx,
>  	int family = NFPROTO_UNSPEC;
>  	const char *table = NULL;
>  	const char *obj = NULL;
> +	bool reset = false;
>  	bool dump = true;
>  
>  	if (filter) {
> @@ -914,9 +915,10 @@ static struct nftnl_obj_list *obj_cache_dump(struct netlink_ctx *ctx,
>  		}
>  		if (filter->list.obj_type)
>  			type = filter->list.obj_type;
> +
> +		reset = filter->reset.obj;
>  	}
> -	obj_list = mnl_nft_obj_dump(ctx, family, table, obj, type, dump,
> -				    filter->reset.obj);
> +	obj_list = mnl_nft_obj_dump(ctx, family, table, obj, type, dump, reset);
>  	if (!obj_list) {
>                  if (errno == EINTR)
>  			return NULL;
> diff --git a/tests/shell/testcases/bogons/nft-f/delete_nonexistant_object_crash b/tests/shell/testcases/bogons/nft-f/delete_nonexistant_object_crash
> new file mode 100644
> index 000000000000..c369dec8c07d
> --- /dev/null
> +++ b/tests/shell/testcases/bogons/nft-f/delete_nonexistant_object_crash
> @@ -0,0 +1 @@
> +delete quota a b
> -- 
> 2.49.0
> 
>