![Pablo Neira Ayuso](/assets/img/avatar_default.png)
Initialize set lookup matching element to NULL. Otherwise, the NFT_LOOKUP_F_INV flag reverses the matching logic and it leads to deference an uninitialized pointer to the matching element. Make sure element data area and stateful expression are accessed if there is a matching set element. This patch undoes24791b9aa1
("netfilter: nft_set_bitmap: initialize set element extension in lookups") which is not required anymore. Fixes:339706bc21
("netfilter: nft_lookup: update element stateful expression") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
240 lines
5.9 KiB
C
240 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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struct nft_lookup {
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struct nft_set *set;
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enum nft_registers sreg:8;
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enum nft_registers dreg:8;
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bool invert;
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struct nft_set_binding binding;
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};
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void nft_lookup_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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const struct nft_set *set = priv->set;
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const struct nft_set_ext *ext = NULL;
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bool found;
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found = set->ops->lookup(nft_net(pkt), set, ®s->data[priv->sreg],
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&ext) ^ priv->invert;
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if (!found) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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if (ext) {
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(®s->data[priv->dreg],
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nft_set_ext_data(ext), set->dlen);
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nft_set_elem_update_expr(ext, regs, pkt);
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}
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}
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static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
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[NFTA_LOOKUP_SET] = { .type = NLA_STRING,
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.len = NFT_SET_MAXNAMELEN - 1 },
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[NFTA_LOOKUP_SET_ID] = { .type = NLA_U32 },
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[NFTA_LOOKUP_SREG] = { .type = NLA_U32 },
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[NFTA_LOOKUP_DREG] = { .type = NLA_U32 },
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[NFTA_LOOKUP_FLAGS] = { .type = NLA_U32 },
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};
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static int nft_lookup_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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u8 genmask = nft_genmask_next(ctx->net);
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struct nft_set *set;
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u32 flags;
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int err;
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if (tb[NFTA_LOOKUP_SET] == NULL ||
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tb[NFTA_LOOKUP_SREG] == NULL)
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return -EINVAL;
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set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
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tb[NFTA_LOOKUP_SET_ID], genmask);
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if (IS_ERR(set))
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return PTR_ERR(set);
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priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
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err = nft_validate_register_load(priv->sreg, set->klen);
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if (err < 0)
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return err;
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if (tb[NFTA_LOOKUP_FLAGS]) {
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flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
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if (flags & ~NFT_LOOKUP_F_INV)
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return -EINVAL;
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if (flags & NFT_LOOKUP_F_INV) {
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if (set->flags & NFT_SET_MAP)
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return -EINVAL;
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priv->invert = true;
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}
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}
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if (tb[NFTA_LOOKUP_DREG] != NULL) {
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if (priv->invert)
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return -EINVAL;
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if (!(set->flags & NFT_SET_MAP))
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return -EINVAL;
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priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
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err = nft_validate_register_store(ctx, priv->dreg, NULL,
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set->dtype, set->dlen);
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if (err < 0)
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return err;
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} else if (set->flags & NFT_SET_MAP)
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return -EINVAL;
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priv->binding.flags = set->flags & NFT_SET_MAP;
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err = nf_tables_bind_set(ctx, set, &priv->binding);
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if (err < 0)
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return err;
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priv->set = set;
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return 0;
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}
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static void nft_lookup_deactivate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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enum nft_trans_phase phase)
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
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}
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static void nft_lookup_activate(const struct nft_ctx *ctx,
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const struct nft_expr *expr)
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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priv->set->use++;
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}
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static void nft_lookup_destroy(const struct nft_ctx *ctx,
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const struct nft_expr *expr)
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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nf_tables_destroy_set(ctx, priv->set);
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}
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static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
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if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
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goto nla_put_failure;
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if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
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goto nla_put_failure;
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if (priv->set->flags & NFT_SET_MAP)
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if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
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struct nft_set *set,
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const struct nft_set_iter *iter,
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struct nft_set_elem *elem)
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{
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const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
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struct nft_ctx *pctx = (struct nft_ctx *)ctx;
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const struct nft_data *data;
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int err;
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if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
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*nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
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return 0;
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data = nft_set_ext_data(ext);
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switch (data->verdict.code) {
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case NFT_JUMP:
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case NFT_GOTO:
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pctx->level++;
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err = nft_chain_validate(ctx, data->verdict.chain);
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if (err < 0)
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return err;
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pctx->level--;
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break;
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default:
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break;
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}
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return 0;
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}
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static int nft_lookup_validate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nft_data **d)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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struct nft_set_iter iter;
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if (!(priv->set->flags & NFT_SET_MAP) ||
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priv->set->dtype != NFT_DATA_VERDICT)
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return 0;
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iter.genmask = nft_genmask_next(ctx->net);
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iter.skip = 0;
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iter.count = 0;
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iter.err = 0;
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iter.fn = nft_lookup_validate_setelem;
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priv->set->ops->walk(ctx, priv->set, &iter);
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if (iter.err < 0)
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return iter.err;
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return 0;
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}
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static const struct nft_expr_ops nft_lookup_ops = {
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.type = &nft_lookup_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
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.eval = nft_lookup_eval,
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.init = nft_lookup_init,
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.activate = nft_lookup_activate,
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.deactivate = nft_lookup_deactivate,
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.destroy = nft_lookup_destroy,
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.dump = nft_lookup_dump,
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.validate = nft_lookup_validate,
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};
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struct nft_expr_type nft_lookup_type __read_mostly = {
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.name = "lookup",
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.ops = &nft_lookup_ops,
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.policy = nft_lookup_policy,
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.maxattr = NFTA_LOOKUP_MAX,
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.owner = THIS_MODULE,
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};
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