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![Taehee Yoo](/assets/img/avatar_default.png)
The level of struct nft_ctx is updated by nf_tables_check_loops(). That is used to validate jumpstack depth. But jumpstack validation routine doesn't update and validate recursively. So, in some cases, chain depth can be bigger than the NFT_JUMP_STACK_SIZE. After this patch, The jumpstack validation routine is located in the nft_chain_validate(). When new rules or new set elements are added, the nft_table_validate() is called by the nf_tables_newrule and the nf_tables_newsetelem. The nft_table_validate() calls the nft_chain_validate() that visit all their children chains recursively. So it can update depth of chain certainly. Reproducer: %cat ./test.sh #!/bin/bash nft add table ip filter nft add chain ip filter input { type filter hook input priority 0\; } for ((i=0;i<20;i++)); do nft add chain ip filter a$i done nft add rule ip filter input jump a1 for ((i=0;i<10;i++)); do nft add rule ip filter a$i jump a$((i+1)) done for ((i=11;i<19;i++)); do nft add rule ip filter a$i jump a$((i+1)) done nft add rule ip filter a10 jump a11 Result: [ 253.931782] WARNING: CPU: 1 PID: 0 at net/netfilter/nf_tables_core.c:186 nft_do_chain+0xacc/0xdf0 [nf_tables] [ 253.931915] Modules linked in: nf_tables nfnetlink ip_tables x_tables [ 253.932153] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.18.0-rc3+ #48 [ 253.932153] RIP: 0010:nft_do_chain+0xacc/0xdf0 [nf_tables] [ 253.932153] Code: 83 f8 fb 0f 84 c7 00 00 00 e9 d0 00 00 00 83 f8 fd 74 0e 83 f8 ff 0f 84 b4 00 00 00 e9 bd 00 00 00 83 bd 64 fd ff ff 0f 76 09 <0f> 0b 31 c0 e9 bc 02 00 00 44 8b ad 64 fd [ 253.933807] RSP: 0018:ffff88011b807570 EFLAGS: 00010212 [ 253.933807] RAX: 00000000fffffffd RBX: ffff88011b807660 RCX: 0000000000000000 [ 253.933807] RDX: 0000000000000010 RSI: ffff880112b39d78 RDI: ffff88011b807670 [ 253.933807] RBP: ffff88011b807850 R08: ffffed0023700ece R09: ffffed0023700ecd [ 253.933807] R10: ffff88011b80766f R11: ffffed0023700ece R12: ffff88011b807898 [ 253.933807] R13: ffff880112b39d80 R14: ffff880112b39d60 R15: dffffc0000000000 [ 253.933807] FS: 0000000000000000(0000) GS:ffff88011b800000(0000) knlGS:0000000000000000 [ 253.933807] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 253.933807] CR2: 00000000014f1008 CR3: 000000006b216000 CR4: 00000000001006e0 [ 253.933807] Call Trace: [ 253.933807] <IRQ> [ 253.933807] ? sched_clock_cpu+0x132/0x170 [ 253.933807] ? __nft_trace_packet+0x180/0x180 [nf_tables] [ 253.933807] ? sched_clock_cpu+0x132/0x170 [ 253.933807] ? debug_show_all_locks+0x290/0x290 [ 253.933807] ? __lock_acquire+0x4835/0x4af0 [ 253.933807] ? inet_ehash_locks_alloc+0x1a0/0x1a0 [ 253.933807] ? unwind_next_frame+0x159e/0x1840 [ 253.933807] ? __read_once_size_nocheck.constprop.4+0x5/0x10 [ 253.933807] ? nft_do_chain_ipv4+0x197/0x1e0 [nf_tables] [ 253.933807] ? nft_do_chain+0x5/0xdf0 [nf_tables] [ 253.933807] nft_do_chain_ipv4+0x197/0x1e0 [nf_tables] [ 253.933807] ? nft_do_chain_arp+0xb0/0xb0 [nf_tables] [ 253.933807] ? __lock_is_held+0x9d/0x130 [ 253.933807] nf_hook_slow+0xc4/0x150 [ 253.933807] ip_local_deliver+0x28b/0x380 [ 253.933807] ? ip_call_ra_chain+0x3e0/0x3e0 [ 253.933807] ? ip_rcv_finish+0x1610/0x1610 [ 253.933807] ip_rcv+0xbcc/0xcc0 [ 253.933807] ? debug_show_all_locks+0x290/0x290 [ 253.933807] ? ip_local_deliver+0x380/0x380 [ 253.933807] ? __lock_is_held+0x9d/0x130 [ 253.933807] ? ip_local_deliver+0x380/0x380 [ 253.933807] __netif_receive_skb_core+0x1c9c/0x2240 Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
223 lines
5.6 KiB
C
223 lines
5.6 KiB
C
/*
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* Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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static 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;
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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 (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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}
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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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if (set->flags & NFT_SET_EVAL)
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return -EOPNOTSUPP;
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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_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_unbind_set(ctx, priv->set, &priv->binding);
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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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.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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