Commit 371ebcbb authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nf_tables: add destroy_clone expression 



Before this patch, cloned expressions are released via ->destroy. This
is a problem for the new connlimit expression since the ->destroy path
drop a reference on the conntrack modules and it unregisters hooks. The
new ->destroy_clone provides context that this expression is being
released from the packet path, so it is mirroring ->clone(), where
neither module reference is dropped nor hooks need to be unregistered -
because this done from the control plane path from the ->init() path.

Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 79b174ad

include/net/netfilter/nf_tables.h

+2 −0
Original line number Diff line number Diff line
@@ -745,6 +745,8 @@ struct nft_expr_ops { 
						      const struct nft_expr *expr);

	void				(*destroy)(const struct nft_ctx *ctx,

						   const struct nft_expr *expr);

	void				(*destroy_clone)(const struct nft_ctx *ctx,

							 const struct nft_expr *expr);

	int				(*dump)(struct sk_buff *skb,

						const struct nft_expr *expr);

	int				(*validate)(const struct nft_ctx *ctx,

net/netfilter/nf_tables_api.c

+10 −2
Original line number Diff line number Diff line
@@ -4046,8 +4046,16 @@ void nft_set_elem_destroy(const struct nft_set *set, void *elem, 
	nft_data_release(nft_set_ext_key(ext), NFT_DATA_VALUE);

	if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA))

		nft_data_release(nft_set_ext_data(ext), set->dtype);

	if (destroy_expr && nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))

		nf_tables_expr_destroy(&ctx, nft_set_ext_expr(ext));

	if (destroy_expr && nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) {

		struct nft_expr *expr = nft_set_ext_expr(ext);



		if (expr->ops->destroy_clone) {

			expr->ops->destroy_clone(&ctx, expr);

			module_put(expr->ops->type->owner);

		} else {

			nf_tables_expr_destroy(&ctx, expr);

		}

	}

	if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF))

		(*nft_set_ext_obj(ext))->use--;

	kfree(elem);

net/netfilter/nft_counter.c

+1 −0
Original line number Diff line number Diff line
@@ -258,6 +258,7 @@ static const struct nft_expr_ops nft_counter_ops = { 
	.eval		= nft_counter_eval,

	.init		= nft_counter_init,

	.destroy	= nft_counter_destroy,

	.destroy_clone	= nft_counter_destroy,

	.dump		= nft_counter_dump,

	.clone		= nft_counter_clone,

};

CRA Git | Maintained and supported by SUSTech CRA and CCSE