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e93cbd7efd
[ Upstream commit1689f25924
] Overflow use refcount checks are not complete. Add helper function to deal with object reference counter tracking. Report -EMFILE in case UINT_MAX is reached. nft_use_dec() splats in case that reference counter underflows, which should not ever happen. Add nft_use_inc_restore() and nft_use_dec_restore() which are used to restore reference counter from error and abort paths. Use u32 in nft_flowtable and nft_object since helper functions cannot work on bitfields. Remove the few early incomplete checks now that the helper functions are in place and used to check for refcount overflow. Fixes:96518518cc
("netfilter: add nftables") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
244 lines
6.1 KiB
C
244 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/skbuff.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_core.h>
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#define nft_objref_priv(expr) *((struct nft_object **)nft_expr_priv(expr))
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void nft_objref_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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struct nft_object *obj = nft_objref_priv(expr);
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obj->ops->eval(obj, regs, pkt);
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}
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static int nft_objref_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_object *obj = nft_objref_priv(expr);
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u8 genmask = nft_genmask_next(ctx->net);
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u32 objtype;
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if (!tb[NFTA_OBJREF_IMM_NAME] ||
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!tb[NFTA_OBJREF_IMM_TYPE])
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return -EINVAL;
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objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
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obj = nft_obj_lookup(ctx->net, ctx->table,
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tb[NFTA_OBJREF_IMM_NAME], objtype,
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genmask);
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if (IS_ERR(obj))
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return -ENOENT;
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if (!nft_use_inc(&obj->use))
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return -EMFILE;
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nft_objref_priv(expr) = obj;
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return 0;
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}
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static int nft_objref_dump(struct sk_buff *skb,
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const struct nft_expr *expr, bool reset)
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{
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const struct nft_object *obj = nft_objref_priv(expr);
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if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->key.name) ||
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nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE,
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htonl(obj->ops->type->type)))
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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 void nft_objref_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_object *obj = nft_objref_priv(expr);
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if (phase == NFT_TRANS_COMMIT)
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return;
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nft_use_dec(&obj->use);
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}
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static void nft_objref_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_object *obj = nft_objref_priv(expr);
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nft_use_inc_restore(&obj->use);
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}
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static const struct nft_expr_ops nft_objref_ops = {
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.type = &nft_objref_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_object *)),
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.eval = nft_objref_eval,
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.init = nft_objref_init,
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.activate = nft_objref_activate,
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.deactivate = nft_objref_deactivate,
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.dump = nft_objref_dump,
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.reduce = NFT_REDUCE_READONLY,
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};
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struct nft_objref_map {
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struct nft_set *set;
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u8 sreg;
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struct nft_set_binding binding;
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};
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void nft_objref_map_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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struct nft_objref_map *priv = nft_expr_priv(expr);
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const struct nft_set *set = priv->set;
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struct net *net = nft_net(pkt);
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const struct nft_set_ext *ext;
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struct nft_object *obj;
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bool found;
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found = nft_set_do_lookup(net, set, ®s->data[priv->sreg], &ext);
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if (!found) {
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ext = nft_set_catchall_lookup(net, set);
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if (!ext) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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}
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obj = *nft_set_ext_obj(ext);
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obj->ops->eval(obj, regs, pkt);
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}
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static int nft_objref_map_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_objref_map *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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int err;
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set = nft_set_lookup_global(ctx->net, ctx->table,
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tb[NFTA_OBJREF_SET_NAME],
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tb[NFTA_OBJREF_SET_ID], genmask);
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if (IS_ERR(set))
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return PTR_ERR(set);
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if (!(set->flags & NFT_SET_OBJECT))
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return -EINVAL;
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err = nft_parse_register_load(tb[NFTA_OBJREF_SET_SREG], &priv->sreg,
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set->klen);
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if (err < 0)
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return err;
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priv->binding.flags = set->flags & NFT_SET_OBJECT;
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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 int nft_objref_map_dump(struct sk_buff *skb,
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const struct nft_expr *expr, bool reset)
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{
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const struct nft_objref_map *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) ||
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nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name))
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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 void nft_objref_map_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_objref_map *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_objref_map_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_objref_map *priv = nft_expr_priv(expr);
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nf_tables_activate_set(ctx, priv->set);
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}
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static void nft_objref_map_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_objref_map *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 const struct nft_expr_ops nft_objref_map_ops = {
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.type = &nft_objref_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
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.eval = nft_objref_map_eval,
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.init = nft_objref_map_init,
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.activate = nft_objref_map_activate,
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.deactivate = nft_objref_map_deactivate,
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.destroy = nft_objref_map_destroy,
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.dump = nft_objref_map_dump,
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.reduce = NFT_REDUCE_READONLY,
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};
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static const struct nft_expr_ops *
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nft_objref_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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if (tb[NFTA_OBJREF_SET_SREG] &&
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(tb[NFTA_OBJREF_SET_NAME] ||
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tb[NFTA_OBJREF_SET_ID]))
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return &nft_objref_map_ops;
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else if (tb[NFTA_OBJREF_IMM_NAME] &&
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tb[NFTA_OBJREF_IMM_TYPE])
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return &nft_objref_ops;
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return ERR_PTR(-EOPNOTSUPP);
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}
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static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
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[NFTA_OBJREF_IMM_NAME] = { .type = NLA_STRING,
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.len = NFT_OBJ_MAXNAMELEN - 1 },
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[NFTA_OBJREF_IMM_TYPE] = { .type = NLA_U32 },
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[NFTA_OBJREF_SET_SREG] = { .type = NLA_U32 },
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[NFTA_OBJREF_SET_NAME] = { .type = NLA_STRING,
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.len = NFT_SET_MAXNAMELEN - 1 },
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[NFTA_OBJREF_SET_ID] = { .type = NLA_U32 },
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};
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struct nft_expr_type nft_objref_type __read_mostly = {
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.name = "objref",
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.select_ops = nft_objref_select_ops,
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.policy = nft_objref_policy,
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.maxattr = NFTA_OBJREF_MAX,
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.owner = THIS_MODULE,
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};
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